'98 intermittent overheating,
#1
'98 intermittent overheating,
So i have a '98 F150, i have ad it for about 7 months now, and since i got it i have had coolant flushed twice, (cleared out a lot of crap) and did a lot of non-coolant based work, overall truck has had about $3000 worth put into it...
since the start i have had a issue with overheating at intermittent intervals. my mechanic friends keep saying it is a head gasket issue, but all the pressure tests, and exhaust tests and the like come back negative for a head gasket issue.
when i notice it overheating, i turn off the truck, give it a few moments to chill out, start it again and the issue is resolved, leading me to believe a blockage is in the system. when it was flushed on monday, by a shop they flushed it for a solid hour to ensure it was clear (the guys were bored) pressurized and it was fine. i drove it for 15 min, it overheated and puked about a liter of coolant onto the pavement of the grocery store. i removed the reservoir cap, pressure escaped, let the truck sit for 5 min, attached cap, started it, she ran fine almost home, started to overheat according to dash indicators then dropped to cold and was not producing any heat.
i ran the truck with the reservoir pressure cap off, no bubbling up, but the reservoir did go down after she ran for about 7 min with no problems, even produced heat inside.
this morning she ran fine dropping off the wife for work (5 min drive produced heat to melt the snow and frost) but after dropping wife off, the heat in cab dissappeared, which normally indicated that the truck will read as overheating soon, but did not overheat on the temp gauge, it actually went down to cool... when i got to work, no coolant leaking, no throwup.
so i let it cool to outdoor temp (-20C) went out took off the reservoir pressure cap, released pressure, turned on truck, truck ran fine, coolant in res dropped to a normal range, heat was in the cab.
things of note
- Two full system flushes, first one indicated person before never took care of truck, second one cleaned out more crap, plans for third flush after another 1000km
- after first flush, new thermostat got blown, plunger was busted out, possible defective (shop say this is likely), possible pushed and broke from pressure build up...
- no white exhaust, oil dipstick shows no sign of coolant, exhaust tests show no sign of coolant, Rad does not bubble when cap off, res does not bubble when cap off
- "overheating" issue dissapears when truck is turned off for 20-30 seconds and restarted
- when it "overheats" all indications are that coolant is not flowing, but all other indications are that water pump working fine as issue dissappears after a truck restart
- there does appear to be a slight air hissing sound from the left side of engine bay
- on hard acceleration a loud whine happens, lasts about 3 seconds
- occasional stalls after a cold start and no "warm up"
- about 20% of the time truck has a hard time "kicking up" when transmission does
- Fuel Economy is **** (might just be me though as i drive a 2009 corolla as my main car)
what i am looking for is some tips and tricks from guys that know more than me on how to fix this sucker up... its a nice truck, i enjoy it, this problem seems to all be related though. everyone is telling me it is a head gasket, but the signs are not there to me, even a cracked head...
personally i have two theories, but i dont even know where to start to test them out...
1: a blockage in the coolant system, somewhere it occasionally gets sucked up and blocks flow, then when i turn off the truck and limit flow it releases and falls to rest. probably between the reservoir and the thermostat as the coolant overflows from the res and temp reads low.
2: a intake manifold gasket leak - honestly i dont know much about this stuff, but it seems like the fuel economy might be shot cause too much air flow, and that air is getting pushed into the coolant line, causing a pressure backup and overheating, that stopping and restarting may fix... this one would explain the "air hiss" (unless there is supposed to be a very low air hiss type sound) and the ****ty fuel economy.... unless it is just a truck...
sorry for the long post... any help would be greatly appreciated... and any way to eliminate the two things i have listed there would be great as well...
EDIT: i am about to take it out for another drive, and will report if anything fishy happens
since the start i have had a issue with overheating at intermittent intervals. my mechanic friends keep saying it is a head gasket issue, but all the pressure tests, and exhaust tests and the like come back negative for a head gasket issue.
when i notice it overheating, i turn off the truck, give it a few moments to chill out, start it again and the issue is resolved, leading me to believe a blockage is in the system. when it was flushed on monday, by a shop they flushed it for a solid hour to ensure it was clear (the guys were bored) pressurized and it was fine. i drove it for 15 min, it overheated and puked about a liter of coolant onto the pavement of the grocery store. i removed the reservoir cap, pressure escaped, let the truck sit for 5 min, attached cap, started it, she ran fine almost home, started to overheat according to dash indicators then dropped to cold and was not producing any heat.
i ran the truck with the reservoir pressure cap off, no bubbling up, but the reservoir did go down after she ran for about 7 min with no problems, even produced heat inside.
this morning she ran fine dropping off the wife for work (5 min drive produced heat to melt the snow and frost) but after dropping wife off, the heat in cab dissappeared, which normally indicated that the truck will read as overheating soon, but did not overheat on the temp gauge, it actually went down to cool... when i got to work, no coolant leaking, no throwup.
so i let it cool to outdoor temp (-20C) went out took off the reservoir pressure cap, released pressure, turned on truck, truck ran fine, coolant in res dropped to a normal range, heat was in the cab.
things of note
- Two full system flushes, first one indicated person before never took care of truck, second one cleaned out more crap, plans for third flush after another 1000km
- after first flush, new thermostat got blown, plunger was busted out, possible defective (shop say this is likely), possible pushed and broke from pressure build up...
- no white exhaust, oil dipstick shows no sign of coolant, exhaust tests show no sign of coolant, Rad does not bubble when cap off, res does not bubble when cap off
- "overheating" issue dissapears when truck is turned off for 20-30 seconds and restarted
- when it "overheats" all indications are that coolant is not flowing, but all other indications are that water pump working fine as issue dissappears after a truck restart
- there does appear to be a slight air hissing sound from the left side of engine bay
- on hard acceleration a loud whine happens, lasts about 3 seconds
- occasional stalls after a cold start and no "warm up"
- about 20% of the time truck has a hard time "kicking up" when transmission does
- Fuel Economy is **** (might just be me though as i drive a 2009 corolla as my main car)
what i am looking for is some tips and tricks from guys that know more than me on how to fix this sucker up... its a nice truck, i enjoy it, this problem seems to all be related though. everyone is telling me it is a head gasket, but the signs are not there to me, even a cracked head...
personally i have two theories, but i dont even know where to start to test them out...
1: a blockage in the coolant system, somewhere it occasionally gets sucked up and blocks flow, then when i turn off the truck and limit flow it releases and falls to rest. probably between the reservoir and the thermostat as the coolant overflows from the res and temp reads low.
2: a intake manifold gasket leak - honestly i dont know much about this stuff, but it seems like the fuel economy might be shot cause too much air flow, and that air is getting pushed into the coolant line, causing a pressure backup and overheating, that stopping and restarting may fix... this one would explain the "air hiss" (unless there is supposed to be a very low air hiss type sound) and the ****ty fuel economy.... unless it is just a truck...
sorry for the long post... any help would be greatly appreciated... and any way to eliminate the two things i have listed there would be great as well...
EDIT: i am about to take it out for another drive, and will report if anything fishy happens
Last edited by pyro5050; 03-15-2013 at 12:35 PM. Reason: new info
#2
So i took it out for a drive, 12 km one way, then a short 3km, then 12 back to the shop.
it overheated after about 7 min, produced heat for first 5 then stopped flow of coolant and over heat, no coolant spill. after a few min i had it working fine. the 3 km trip nothing bad happened. the 12 back to the shop was punctuated after about 5 of overheating issues again, after they were solved, the heat the truck produced from the vents was intense....
shop is doing another pressure test to make sure, if it passes again, i am starting with the lowest cost fixes, a new cap for the rad...
EDIT: 2 hours after this post, shop let the wife know (she works at a dealer) that it passed with flying colours, she gave them the go ahead to throw a new cap on, top off fluids if needed, and let me know.... i will be taking her for a spin tonight and hopefully it is something just as stupid and minor as a busted Rad cap....
it overheated after about 7 min, produced heat for first 5 then stopped flow of coolant and over heat, no coolant spill. after a few min i had it working fine. the 3 km trip nothing bad happened. the 12 back to the shop was punctuated after about 5 of overheating issues again, after they were solved, the heat the truck produced from the vents was intense....
shop is doing another pressure test to make sure, if it passes again, i am starting with the lowest cost fixes, a new cap for the rad...
EDIT: 2 hours after this post, shop let the wife know (she works at a dealer) that it passed with flying colours, she gave them the go ahead to throw a new cap on, top off fluids if needed, and let me know.... i will be taking her for a spin tonight and hopefully it is something just as stupid and minor as a busted Rad cap....
Last edited by pyro5050; 03-15-2013 at 05:14 PM. Reason: New info!
#3
As it stands right now, the rad cap looks like it is the correct fix... she ran, after 7km temp started to drop, heat in truck went from warm to cold air, i was worried. but she never went to overheat and after 2km the heat in truck started working again.... so it appears to be good, gonna take it for a spin again tonight after it cools down so i can see if it will repeat the success, be better, or revert to "oh god why!?!"
#4
Ford Owner
Have you tested or replaced the water pump? The impellers tend to disintegrate in a poorly maintained vehicle and do not pump the coolant through your system like it should. To test, pinch the upper radiator hose with engine running. Release the hose and it should quickly go back to normal and you should hear a definite "Swish" . The other possibility is you have an air bubble in your system because low fluid is the most common cause of no heat.
#5
Senior Member
It sounds like you might have a hose collapsing, your post was kind of long but i see no mention of hose replacement. Also if you don't have the heater on while you are filling the system (thermostat need to be opened) that cavity of the cooling system does not fill and you end up with low/no heater and quite possible overheating. Good luck.