1984 F150 running cold?
04-03-2013, 08:05 PM
#1
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1984 F150 running cold?
I have a 1984 F150, straight 6, carb, 2wd.
My engine temp gauge is showing it is running just above the C when at operating temp. Obviously this could be two things: electrical issue with the sending unit to the gauge or thermostat.
The other issue is the oil has some milky white goo. Yes the first reaction is head gasket but coolant levels are stable and no smoke. Oil cap is also "leaking" and soon to be replaced and PCV valve needs replacing too.
So, I'm thinking thermostat shot and moisture getting into oil?
Ideas?
My engine temp gauge is showing it is running just above the C when at operating temp. Obviously this could be two things: electrical issue with the sending unit to the gauge or thermostat.
The other issue is the oil has some milky white goo. Yes the first reaction is head gasket but coolant levels are stable and no smoke. Oil cap is also "leaking" and soon to be replaced and PCV valve needs replacing too.
So, I'm thinking thermostat shot and moisture getting into oil?
Ideas?
04-06-2013, 02:02 AM
#2
Senior Member
How long have you had the truck? If a long time how long has it ran cold?
My guess is tstat is not "shot" but either not in it or a lower temp than called for. If it gives acceptable heat there is nothing really wrong with it running low except the engine probably isnt as efficient as it could be.
The oil issue
Im gonna guess its an automatic. If so it may have a modulator valve. If the valve goes bad it can let tranny fluid into the oil. Just a possibility.
My guess is tstat is not "shot" but either not in it or a lower temp than called for. If it gives acceptable heat there is nothing really wrong with it running low except the engine probably isnt as efficient as it could be.
The oil issue
Im gonna guess its an automatic. If so it may have a modulator valve. If the valve goes bad it can let tranny fluid into the oil. Just a possibility.
04-08-2013, 12:42 AM
#3
Nuclearseal, my 89 had the same problem with the thermostat. the guage would not move, if it did it would not reach the N on NORMAL. I knew it was either the thermostat or the sending unit.
The thermostat is a cheap part, very easy to replace on a 4.9l. I would say go ahead and put a new thermostat in that is the recommended temperature. That way it the guage still shows cold, you know thats the problem since you put a new thermostat in.
The white goo could be many things. basically its moisture of some sort mixing with oil. We had white goo on our 85. Everything checked out, but it would only come about when the weather was a certain way (cant remember what those ways were).
Sorry for the long post, but hope this helps.
The thermostat is a cheap part, very easy to replace on a 4.9l. I would say go ahead and put a new thermostat in that is the recommended temperature. That way it the guage still shows cold, you know thats the problem since you put a new thermostat in.
The white goo could be many things. basically its moisture of some sort mixing with oil. We had white goo on our 85. Everything checked out, but it would only come about when the weather was a certain way (cant remember what those ways were).
Sorry for the long post, but hope this helps.
04-11-2013, 07:27 PM
#5
Project Whiskey Tango
My 86 does the same thing. I put a new thermostat, gasket and a sending unit in and ended with the same results. I'm goint to put in a set of AutoMeter gauges in it now and see what happens..
04-12-2013, 02:15 PM
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Yeah I'm not sure what's going on either.
I have the two sensors; the one right by the thermostat and then the sending unit under the exhaust manifold (probably the worst possible spot to put pretty much anything). I could test the sending unit but I figure the time I contort myself and get at it I might as well put a new one in, less the $10 so what the heck.
If that doesn't work then I would have to say it's either a wiring issue or the gauge itself.
I'll keep you posted.
I have the two sensors; the one right by the thermostat and then the sending unit under the exhaust manifold (probably the worst possible spot to put pretty much anything). I could test the sending unit but I figure the time I contort myself and get at it I might as well put a new one in, less the $10 so what the heck.
If that doesn't work then I would have to say it's either a wiring issue or the gauge itself.
I'll keep you posted.
12-20-2013, 09:17 AM
#7
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1986 300 same issue.
I have the same thing. The t-stat looked corroded and not working. The coolant sensor looked dry! I found that the bypass hose had leaks in it and if the cooling system was functioning correctly it would have leaked.
Also as I was trying to replace t-stat last night the housing cracked. Both of them will be replace tonight when I get home.
My water pump is shot, which is why I started this in the first place. But my gauge only once went over the lower normal line once. With low coolant and and a leak.
The old water outlet has a gooseneck with the sender in it, two wire. The new water outlet looks to have a threaded boss now. Does a new temp sender go in the water outlet now?
Pictures would be great if you guy have them.
Thanks
Dave
Also as I was trying to replace t-stat last night the housing cracked. Both of them will be replace tonight when I get home.
My water pump is shot, which is why I started this in the first place. But my gauge only once went over the lower normal line once. With low coolant and and a leak.
The old water outlet has a gooseneck with the sender in it, two wire. The new water outlet looks to have a threaded boss now. Does a new temp sender go in the water outlet now?
Pictures would be great if you guy have them.
Thanks
Dave