1997 f-150 oil pressure gauge bouncing
06-19-2008, 03:47 PM
#11
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Hello All,
I have a 1997 F-150 standard trans., V6 with 95000 miles. I just had my oil changed last week (put in the 5W 30 SAE) and have been experiencing the "oil pressure gauge bounce" ever since. If I take off and go highway speeds, it stays at a consistent medium reading. However, as I get through stop and go traffic in town, it plummets to low, or even nothing - flatlined. Is it the summer heat? I drive 30 miles to work in morning and return in the evening.
Curious to know if I should consider this some impending doom for the engine...
I have a 1997 F-150 standard trans., V6 with 95000 miles. I just had my oil changed last week (put in the 5W 30 SAE) and have been experiencing the "oil pressure gauge bounce" ever since. If I take off and go highway speeds, it stays at a consistent medium reading. However, as I get through stop and go traffic in town, it plummets to low, or even nothing - flatlined. Is it the summer heat? I drive 30 miles to work in morning and return in the evening.
Curious to know if I should consider this some impending doom for the engine...
06-19-2008, 05:02 PM
#12
Senior Member
Hello and welcome. You've put a winter low viscosity oil into your engine. Replace it with ... i think 15W40 or 20W50 will do fine.
http://www.valvoline.com/carcare/art...1ov§ion=hm
http://www.valvoline.com/carcare/art...1ov§ion=hm
08-14-2009, 04:06 PM
#13
Little Red 98
Been There, Done That!
I had the same problem, eventually it did not have any oil pressure, and the lifters pumped down and chattered in protest. Basically the top end is not getting oil. Forget the oil pressure sending unit, the tappets tell the story. Oil is not getting to the lifter galley and into the lifters, so how? Hard sludge is most likely your enemy.
I keep my engine clean, inside and out and full of good synthetic oil, but over the years the carbon blow-by will settle in areas that are not oiled with pressure, like the lifter galley.
Oil leaves the oil pump and is forced through the crank oil holes to oil the mains and connecting rods, then it is directed up to the top of the heads to oil the valve train, then runs down into the lifter galley, here it is pooled to keep the lifters full and then drips down past the cam and into the pan. The oil pump sucks the oil through the screen and pick up tube, then through the oil filter then past the oil pressure sending unit and into the crank holes again. These small crank holes create back pressure which the oil sending unit registers as oil pressure to the gauge.
This may sound like auto shop 101, but you need to understand this perfectly to diagnose an oil pressure problem.
First drain the oil into a clean metal tray, pour it off and look at the bottom. If you see fine metal glimmers, it is most likely the babbit surface of the mains and cam bearings. This means the oil is not leaving the pump, hence the valve train is starved and so the lifters which tick when they pump down, or run out of oil. If there is no presence of this fine metal, then the oil is most likely getting through the crank and up to the valve train and into the liter galley. This is a great place for carbon to separate from the oil and build up into a hard sludge. Eventually it can close off holes and block oil from filling the lifters, hence the lifters start tapping, usually one or two at first.
So the oil pump is almost bullet proof, so it is usually not the problem, but to make sure you can pull it in 20 minutes and use a feeler gauge to check its tolerances. The specs are in any Chilton or Hayes manual. If there is no scoring of the internal aluminum casting from the pump gears, your oil pump is fine, mine was fine. This is a positive displacement pump, so it can't pump if the intake (oil pick up tube and screen) or any passages after the pump are clogged. The cam drives the pump with a gear and shaft, if this is broken you would know it, plus lots of big metal pieces in the oil.
So to check the pick up tube and screen, reach in through the drain hole with a coat hanger bent so you can feel around. If the tube is loose, you can feel it. Next with the pump off, spray degreaser through the intake port in the timing chain cover (this is in the aluminum casting the oil pump bolts to). If the degreaser runs freely out the oil drain hole, the screen is not plugged, if it is plugged this will clean it without pulling the pan, which means pulling the engine on our trucks.
So if it's not plugged the blockage must be on the other side of the pump. This is a little more difficult to diagnose. Pull a valve cover and look at the valve train. If there is lots of gunk build up, then you can imagine what the lifter galley looks like. This is what my problem was. So then put it back together and fill it with very thin engine oil (15 wt. diesel oil is good) along with a quart of engine flush. I suggest letting the engine idle for a long time, rather than driving it and putting heavy loads on the engine. If you are lucky the gauge will show pressure all the time this is running and the lifters should pump up and stop ticking. Don't get too excited yet, if the engine has ever gotten hot or you missed allot of oil changes, or it's just old like mine with 150,000 miles, the passage ways may not clean easy, if at all. Drain the oil and look at it, if it's dirty, do it again and as many times as it takes to start getting clean oil. The option is to pull the engine and pull the pan and intake manifolds, manually clean the lifter galley and lifters, check the main bearings etc., etc. Yuck!
It is always best to replace the stock oil sending unit with a mechanical one and gauge, at this point you don't need to install it in the dash, just set it where you can watch it throughout these tests. The fitting just replaces the electric sending unit (which is just a lousy switch that closes and provides a circuit to the gauge at about 15 psi, it's not proportional and will not vary with small pressure changes, basically it's just an idiot light) with a metal tube coming out of it to the gauge; a real oil pressure gauge!
I have been working with engines for 40 years and have never seen one that collects gunk like this one, it's a design flaw, basically it's a big sh*t sandwich and we are all going to have to take a bite!!
I pulled my engine, cleaned it, replaced all the bearings and put it together... runs great with lots of good smooth oil pressure and she'll go another 200,000 if I change the oil every 3,000 and don't let it sit for long periods with dirty oil in it, it gives the carbon time to separate.
Good luck!
Mark
I keep my engine clean, inside and out and full of good synthetic oil, but over the years the carbon blow-by will settle in areas that are not oiled with pressure, like the lifter galley.
Oil leaves the oil pump and is forced through the crank oil holes to oil the mains and connecting rods, then it is directed up to the top of the heads to oil the valve train, then runs down into the lifter galley, here it is pooled to keep the lifters full and then drips down past the cam and into the pan. The oil pump sucks the oil through the screen and pick up tube, then through the oil filter then past the oil pressure sending unit and into the crank holes again. These small crank holes create back pressure which the oil sending unit registers as oil pressure to the gauge.
This may sound like auto shop 101, but you need to understand this perfectly to diagnose an oil pressure problem.
First drain the oil into a clean metal tray, pour it off and look at the bottom. If you see fine metal glimmers, it is most likely the babbit surface of the mains and cam bearings. This means the oil is not leaving the pump, hence the valve train is starved and so the lifters which tick when they pump down, or run out of oil. If there is no presence of this fine metal, then the oil is most likely getting through the crank and up to the valve train and into the liter galley. This is a great place for carbon to separate from the oil and build up into a hard sludge. Eventually it can close off holes and block oil from filling the lifters, hence the lifters start tapping, usually one or two at first.
So the oil pump is almost bullet proof, so it is usually not the problem, but to make sure you can pull it in 20 minutes and use a feeler gauge to check its tolerances. The specs are in any Chilton or Hayes manual. If there is no scoring of the internal aluminum casting from the pump gears, your oil pump is fine, mine was fine. This is a positive displacement pump, so it can't pump if the intake (oil pick up tube and screen) or any passages after the pump are clogged. The cam drives the pump with a gear and shaft, if this is broken you would know it, plus lots of big metal pieces in the oil.
So to check the pick up tube and screen, reach in through the drain hole with a coat hanger bent so you can feel around. If the tube is loose, you can feel it. Next with the pump off, spray degreaser through the intake port in the timing chain cover (this is in the aluminum casting the oil pump bolts to). If the degreaser runs freely out the oil drain hole, the screen is not plugged, if it is plugged this will clean it without pulling the pan, which means pulling the engine on our trucks.
So if it's not plugged the blockage must be on the other side of the pump. This is a little more difficult to diagnose. Pull a valve cover and look at the valve train. If there is lots of gunk build up, then you can imagine what the lifter galley looks like. This is what my problem was. So then put it back together and fill it with very thin engine oil (15 wt. diesel oil is good) along with a quart of engine flush. I suggest letting the engine idle for a long time, rather than driving it and putting heavy loads on the engine. If you are lucky the gauge will show pressure all the time this is running and the lifters should pump up and stop ticking. Don't get too excited yet, if the engine has ever gotten hot or you missed allot of oil changes, or it's just old like mine with 150,000 miles, the passage ways may not clean easy, if at all. Drain the oil and look at it, if it's dirty, do it again and as many times as it takes to start getting clean oil. The option is to pull the engine and pull the pan and intake manifolds, manually clean the lifter galley and lifters, check the main bearings etc., etc. Yuck!
It is always best to replace the stock oil sending unit with a mechanical one and gauge, at this point you don't need to install it in the dash, just set it where you can watch it throughout these tests. The fitting just replaces the electric sending unit (which is just a lousy switch that closes and provides a circuit to the gauge at about 15 psi, it's not proportional and will not vary with small pressure changes, basically it's just an idiot light) with a metal tube coming out of it to the gauge; a real oil pressure gauge!
I have been working with engines for 40 years and have never seen one that collects gunk like this one, it's a design flaw, basically it's a big sh*t sandwich and we are all going to have to take a bite!!
I pulled my engine, cleaned it, replaced all the bearings and put it together... runs great with lots of good smooth oil pressure and she'll go another 200,000 if I change the oil every 3,000 and don't let it sit for long periods with dirty oil in it, it gives the carbon time to separate.
Good luck!
Mark
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Kapis (04-24-2013)
08-14-2009, 04:26 PM
#14
Senior Member
Nice write up Mark, suggest you think about doing a similar write up in the How to section. We need good knowledgeable people around here to help us less informed around an engine. 
Last edited by Good old Bill; 08-14-2009 at 04:39 PM.
11-08-2009, 02:45 PM
#16
Little Red 98
No V6 Oiling Problems Known
As far as I know there are no oiling problems with any of the Ford truck engines.
The problem I found was carbon and filler separating from the oil while using an oil for high milage vehicles. These oils have a "filler" in them to increase compression and help stop minor oil leaks on old engines. However it can separate easily... I DO NOT recommend ever using this kind of oil! It adds to major sludge problems. Live and learn
Mark
The problem I found was carbon and filler separating from the oil while using an oil for high milage vehicles. These oils have a "filler" in them to increase compression and help stop minor oil leaks on old engines. However it can separate easily... I DO NOT recommend ever using this kind of oil! It adds to major sludge problems. Live and learn
Mark
02-21-2010, 12:43 PM
#17
I had the same problem, eventually it did not have any oil pressure, and the lifters pumped down and chattered in protest. Basically the top end is not getting oil. Forget the oil pressure sending unit, the tappets tell the story. Oil is not getting to the lifter galley and into the lifters, so how? Hard sludge is most likely your enemy.
I keep my engine clean, inside and out and full of good synthetic oil, but over the years the carbon blow-by will settle in areas that are not oiled with pressure, like the lifter galley.
Oil leaves the oil pump and is forced through the crank oil holes to oil the mains and connecting rods, then it is directed up to the top of the heads to oil the valve train, then runs down into the lifter galley, here it is pooled to keep the lifters full and then drips down past the cam and into the pan. The oil pump sucks the oil through the screen and pick up tube, then through the oil filter then past the oil pressure sending unit and into the crank holes again. These small crank holes create back pressure which the oil sending unit registers as oil pressure to the gauge.
This may sound like auto shop 101, but you need to understand this perfectly to diagnose an oil pressure problem.
First drain the oil into a clean metal tray, pour it off and look at the bottom. If you see fine metal glimmers, it is most likely the babbit surface of the mains and cam bearings. This means the oil is not leaving the pump, hence the valve train is starved and so the lifters which tick when they pump down, or run out of oil. If there is no presence of this fine metal, then the oil is most likely getting through the crank and up to the valve train and into the liter galley. This is a great place for carbon to separate from the oil and build up into a hard sludge. Eventually it can close off holes and block oil from filling the lifters, hence the lifters start tapping, usually one or two at first.
So the oil pump is almost bullet proof, so it is usually not the problem, but to make sure you can pull it in 20 minutes and use a feeler gauge to check its tolerances. The specs are in any Chilton or Hayes manual. If there is no scoring of the internal aluminum casting from the pump gears, your oil pump is fine, mine was fine. This is a positive displacement pump, so it can't pump if the intake (oil pick up tube and screen) or any passages after the pump are clogged. The cam drives the pump with a gear and shaft, if this is broken you would know it, plus lots of big metal pieces in the oil.
So to check the pick up tube and screen, reach in through the drain hole with a coat hanger bent so you can feel around. If the tube is loose, you can feel it. Next with the pump off, spray degreaser through the intake port in the timing chain cover (this is in the aluminum casting the oil pump bolts to). If the degreaser runs freely out the oil drain hole, the screen is not plugged, if it is plugged this will clean it without pulling the pan, which means pulling the engine on our trucks.
So if it's not plugged the blockage must be on the other side of the pump. This is a little more difficult to diagnose. Pull a valve cover and look at the valve train. If there is lots of gunk build up, then you can imagine what the lifter galley looks like. This is what my problem was. So then put it back together and fill it with very thin engine oil (15 wt. diesel oil is good) along with a quart of engine flush. I suggest letting the engine idle for a long time, rather than driving it and putting heavy loads on the engine. If you are lucky the gauge will show pressure all the time this is running and the lifters should pump up and stop ticking. Don't get too excited yet, if the engine has ever gotten hot or you missed allot of oil changes, or it's just old like mine with 150,000 miles, the passage ways may not clean easy, if at all. Drain the oil and look at it, if it's dirty, do it again and as many times as it takes to start getting clean oil. The option is to pull the engine and pull the pan and intake manifolds, manually clean the lifter galley and lifters, check the main bearings etc., etc. Yuck!
It is always best to replace the stock oil sending unit with a mechanical one and gauge, at this point you don't need to install it in the dash, just set it where you can watch it throughout these tests. The fitting just replaces the electric sending unit (which is just a lousy switch that closes and provides a circuit to the gauge at about 15 psi, it's not proportional and will not vary with small pressure changes, basically it's just an idiot light) with a metal tube coming out of it to the gauge; a real oil pressure gauge!
I have been working with engines for 40 years and have never seen one that collects gunk like this one, it's a design flaw, basically it's a big sh*t sandwich and we are all going to have to take a bite!!
I pulled my engine, cleaned it, replaced all the bearings and put it together... runs great with lots of good smooth oil pressure and she'll go another 200,000 if I change the oil every 3,000 and don't let it sit for long periods with dirty oil in it, it gives the carbon time to separate.
Good luck!
Mark
I keep my engine clean, inside and out and full of good synthetic oil, but over the years the carbon blow-by will settle in areas that are not oiled with pressure, like the lifter galley.
Oil leaves the oil pump and is forced through the crank oil holes to oil the mains and connecting rods, then it is directed up to the top of the heads to oil the valve train, then runs down into the lifter galley, here it is pooled to keep the lifters full and then drips down past the cam and into the pan. The oil pump sucks the oil through the screen and pick up tube, then through the oil filter then past the oil pressure sending unit and into the crank holes again. These small crank holes create back pressure which the oil sending unit registers as oil pressure to the gauge.
This may sound like auto shop 101, but you need to understand this perfectly to diagnose an oil pressure problem.
First drain the oil into a clean metal tray, pour it off and look at the bottom. If you see fine metal glimmers, it is most likely the babbit surface of the mains and cam bearings. This means the oil is not leaving the pump, hence the valve train is starved and so the lifters which tick when they pump down, or run out of oil. If there is no presence of this fine metal, then the oil is most likely getting through the crank and up to the valve train and into the liter galley. This is a great place for carbon to separate from the oil and build up into a hard sludge. Eventually it can close off holes and block oil from filling the lifters, hence the lifters start tapping, usually one or two at first.
So the oil pump is almost bullet proof, so it is usually not the problem, but to make sure you can pull it in 20 minutes and use a feeler gauge to check its tolerances. The specs are in any Chilton or Hayes manual. If there is no scoring of the internal aluminum casting from the pump gears, your oil pump is fine, mine was fine. This is a positive displacement pump, so it can't pump if the intake (oil pick up tube and screen) or any passages after the pump are clogged. The cam drives the pump with a gear and shaft, if this is broken you would know it, plus lots of big metal pieces in the oil.
So to check the pick up tube and screen, reach in through the drain hole with a coat hanger bent so you can feel around. If the tube is loose, you can feel it. Next with the pump off, spray degreaser through the intake port in the timing chain cover (this is in the aluminum casting the oil pump bolts to). If the degreaser runs freely out the oil drain hole, the screen is not plugged, if it is plugged this will clean it without pulling the pan, which means pulling the engine on our trucks.
So if it's not plugged the blockage must be on the other side of the pump. This is a little more difficult to diagnose. Pull a valve cover and look at the valve train. If there is lots of gunk build up, then you can imagine what the lifter galley looks like. This is what my problem was. So then put it back together and fill it with very thin engine oil (15 wt. diesel oil is good) along with a quart of engine flush. I suggest letting the engine idle for a long time, rather than driving it and putting heavy loads on the engine. If you are lucky the gauge will show pressure all the time this is running and the lifters should pump up and stop ticking. Don't get too excited yet, if the engine has ever gotten hot or you missed allot of oil changes, or it's just old like mine with 150,000 miles, the passage ways may not clean easy, if at all. Drain the oil and look at it, if it's dirty, do it again and as many times as it takes to start getting clean oil. The option is to pull the engine and pull the pan and intake manifolds, manually clean the lifter galley and lifters, check the main bearings etc., etc. Yuck!
It is always best to replace the stock oil sending unit with a mechanical one and gauge, at this point you don't need to install it in the dash, just set it where you can watch it throughout these tests. The fitting just replaces the electric sending unit (which is just a lousy switch that closes and provides a circuit to the gauge at about 15 psi, it's not proportional and will not vary with small pressure changes, basically it's just an idiot light) with a metal tube coming out of it to the gauge; a real oil pressure gauge!
I have been working with engines for 40 years and have never seen one that collects gunk like this one, it's a design flaw, basically it's a big sh*t sandwich and we are all going to have to take a bite!!
I pulled my engine, cleaned it, replaced all the bearings and put it together... runs great with lots of good smooth oil pressure and she'll go another 200,000 if I change the oil every 3,000 and don't let it sit for long periods with dirty oil in it, it gives the carbon time to separate.
Good luck!
Mark
The following users liked this post:
ReTread (06-12-2016)
02-22-2010, 03:51 PM
#18
Little Red 98
Bouncing (or no) oil pressure!
Hi fellow 4.2 owners with bouncing (or no) oil pressure!
There is another- more disturbing problem that can affect our oil problem, but it would be the last place I would look! This engine has a known problem with the lower intake manifold gasket coming loose and leaking coolant into the oil. Now I know all you pros out there say "just check the dip stick or drain the oil and look for coolant bubbles". That's what I did, and as most of you have found, there is nothing, but after I bumped into a long thread on this site about the intake manifold problems hundreds of people have experienced, it all came together.
The intake manifold gasket leaks just enough to pollute the oil, more of a seepage. You may have noticed that the coolant slowly disappears, but there are no leaks, this is the first sign of the problem. Coolant seeps into the oil which along with other things can coagulate the oil into sluge which will not drain out with an oil change and the first thing to clog is the oil pick-up screen; YEP! See the pic of the one I had.
It was so bad that I couldn't clean it enough, so I replaced it ($25). Of course I had to pull the engine to get the pan off, that's the catch! However in doing this I found that you can get the pan off and change the tube with the engine part way out. Use common sense and a good hoist. Pull only the things necessary to lift the engine high enough to get the pan by the cross member. Take pix of every plug and hose you have to remove to get the engine just raised enough to clear, but don't unbolt the tranny or you might damage the input shaft. I was surprised I was able to lift the engine that high without the upper intake manifold on, the tranny will just rotate as you lift... just don't force it!
Once that's replaced, you can now remove the lower intake manifold and install new gaskets. NOTE: while removing the bolts, you will probably notice some are loose- way below torque- BINGO! At this point consider yourself lucky as many people have had a big enough leak to suck coolant onto the cylinder and BANG!!... hydraulic lock, bent rods etc., etc.
So the moral here is to watch the coolant level like a hawk! It should only use about a cup between oil changes, if it drops all the way to empty, it's time to fix NOW! Don't be too bummed, I found the engine in rather good shape, strong pistons, still honing marks in the cylinders, cam and lifters all good, along with the main and con-rod bearings, all good etc. At this point if you want to pull the engine and rebuild it, all you need is to replace (or have replaced) the cam bearings, main, conn-rod Bearings. Hone and new rings. You may need the heads rebuilt and clutch replaced, depending on wear. I had 155,000 miles, heads OK, replaced clutch. Follow the book, the conn-rod and head bolts cannot be reused. They are "Torque-to-spec". A full gasket kit and your done; about $500-800 in parts and machining. Just a bit of elbow grease and you save almost $2,000. Just to ease the pain; this engine comes out pretty easy, better than with older trucks.
Don't forget to put in a mechanical/electric progressive oil pressure gauge and sender kit! The original is just a fancy looking "idiot light", that's why it bounces!
If any one wants more info, just ask...
Good luck!
There is another- more disturbing problem that can affect our oil problem, but it would be the last place I would look! This engine has a known problem with the lower intake manifold gasket coming loose and leaking coolant into the oil. Now I know all you pros out there say "just check the dip stick or drain the oil and look for coolant bubbles". That's what I did, and as most of you have found, there is nothing, but after I bumped into a long thread on this site about the intake manifold problems hundreds of people have experienced, it all came together.
The intake manifold gasket leaks just enough to pollute the oil, more of a seepage. You may have noticed that the coolant slowly disappears, but there are no leaks, this is the first sign of the problem. Coolant seeps into the oil which along with other things can coagulate the oil into sluge which will not drain out with an oil change and the first thing to clog is the oil pick-up screen; YEP! See the pic of the one I had.
It was so bad that I couldn't clean it enough, so I replaced it ($25). Of course I had to pull the engine to get the pan off, that's the catch! However in doing this I found that you can get the pan off and change the tube with the engine part way out. Use common sense and a good hoist. Pull only the things necessary to lift the engine high enough to get the pan by the cross member. Take pix of every plug and hose you have to remove to get the engine just raised enough to clear, but don't unbolt the tranny or you might damage the input shaft. I was surprised I was able to lift the engine that high without the upper intake manifold on, the tranny will just rotate as you lift... just don't force it!
Once that's replaced, you can now remove the lower intake manifold and install new gaskets. NOTE: while removing the bolts, you will probably notice some are loose- way below torque- BINGO! At this point consider yourself lucky as many people have had a big enough leak to suck coolant onto the cylinder and BANG!!... hydraulic lock, bent rods etc., etc.
So the moral here is to watch the coolant level like a hawk! It should only use about a cup between oil changes, if it drops all the way to empty, it's time to fix NOW! Don't be too bummed, I found the engine in rather good shape, strong pistons, still honing marks in the cylinders, cam and lifters all good, along with the main and con-rod bearings, all good etc. At this point if you want to pull the engine and rebuild it, all you need is to replace (or have replaced) the cam bearings, main, conn-rod Bearings. Hone and new rings. You may need the heads rebuilt and clutch replaced, depending on wear. I had 155,000 miles, heads OK, replaced clutch. Follow the book, the conn-rod and head bolts cannot be reused. They are "Torque-to-spec". A full gasket kit and your done; about $500-800 in parts and machining. Just a bit of elbow grease and you save almost $2,000. Just to ease the pain; this engine comes out pretty easy, better than with older trucks.
Don't forget to put in a mechanical/electric progressive oil pressure gauge and sender kit! The original is just a fancy looking "idiot light", that's why it bounces!
If any one wants more info, just ask...
Good luck!
12-02-2012, 11:32 PM
#19
Junior Member
Join Date: Dec 2012
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sorry to bump a old thread, but I'm also having the same problem as stated by others. wondering if there is any other way to fix this other than removing the oil pan? it looks like a lot of work to just pull the pan.
03-05-2013, 10:40 PM
#20
Little Red 98
I have a 1997 F-150 I just purchased the oil pressure gauge goes up and down, when it idles the hand shows low, when I press on the gas it goes up to past middle and high. When the hand shows low the oil light comes on, it looks like maybe an oil temp light? Does anybody know what I should do?
