Oil pressure problem??
Senior User
Joined: Jan 2004
Posts: 342
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From: British Columbia
Originally Posted by fordberg
Back to the oil pressure problem. You said there were some pieces of gasket in the oil strainer. I'm guessing you would have done like me and replaced the oil pump and put the original strainer on the new oil pump. Well, what if there is some junk in the strainer? That would starve the oil pump of oil and you would lose pressure. Not sure why the temp would change the starving.
A friend did a complete rebuid on a 401 and everything was great until he had to pull the intake for something. When he was puting it back together a small blob of gasket goop fell under the intake and made it's way down to the oil pump screen and then got inside in some way. His pressure was good until he stepped on the gas and the pressure dropped to 0 for 1/2 second and then shot up. If he wouldn't have had an electronic oil pressure gauge on it he wouldn't have seen it because the mechanical gauge wasn't fast enough. Tore the engine down twice to find the problem.
A friend did a complete rebuid on a 401 and everything was great until he had to pull the intake for something. When he was puting it back together a small blob of gasket goop fell under the intake and made it's way down to the oil pump screen and then got inside in some way. His pressure was good until he stepped on the gas and the pressure dropped to 0 for 1/2 second and then shot up. If he wouldn't have had an electronic oil pressure gauge on it he wouldn't have seen it because the mechanical gauge wasn't fast enough. Tore the engine down twice to find the problem.
Laughing Gas
Joined: Mar 2003
Posts: 877
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From: Colorado, U.S.A!
Originally Posted by fordberg
I'll try and remember what a mechanic told me. I think they posed a question.
What weight of oil is 10-40 after it is used or starts to breakdown? Who knows.
Same question for 30 wt. Answer 30 wt.
That was one opinion. Good mechanic. Might make some since for higher mile engines.
What weight of oil is 10-40 after it is used or starts to breakdown? Who knows.
Same question for 30 wt. Answer 30 wt.
That was one opinion. Good mechanic. Might make some since for higher mile engines.
I change my 10W-40 at about 3K miles and use a mechanical pressure gauge. The pressure does not change between oil changes. I take that to mean that the oil is retaining it's viscosity over at least that many miles.
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Freshman User
Joined: Apr 2004
Posts: 32
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From: Alexandria, VA
The oil pressure dropped off when I got the truck back from the mechanic that did the water pump and timing chain cover (because of the gasket material clogging up the screen), it did not fluctuate after that. 20 psi cold, 0 psi hot.
So far the new pump woks better, but its seems consistent - 70 psi cold 6 psi hot at idle.
I'm pretty sure the pick-up tube was clear of any debris. I poured carb cleaner through the pump side of the tube and it flowed freely out of the screen end.
I'll try the 30 weight oil, but I guess the engine is on its last leg.
I just need it to give me about 8 more months, until I can get a nice used '04 f150 for a reasonable price. Those new trucks are sweet.
So far the new pump woks better, but its seems consistent - 70 psi cold 6 psi hot at idle.
I'm pretty sure the pick-up tube was clear of any debris. I poured carb cleaner through the pump side of the tube and it flowed freely out of the screen end.
I'll try the 30 weight oil, but I guess the engine is on its last leg.
I just need it to give me about 8 more months, until I can get a nice used '04 f150 for a reasonable price. Those new trucks are sweet.
Elder User
Joined: Jun 2002
Posts: 519
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From: CT
I have a 5.0l thats been running 30wt for quite a few years now -- don't know if its prolonged its life or not since everything else is rotting around it and its used sparingly now.
Check cylinder compresson and vacuum on intake manifold to get an idea of engine health -- possibilty you have a oil restriction if everything checks out?
Check cylinder compresson and vacuum on intake manifold to get an idea of engine health -- possibilty you have a oil restriction if everything checks out?
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Freshman User
Joined: Apr 2004
Posts: 32
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From: Alexandria, VA
O.K., I just took the truck to get an emissions inspection. On the way over my "check engine" light came on. I turned off the ignition then started it back up and the light went off, but I noticed the truck ran kind of sluggish. At this point I'm thinking the engine's gone.
While the guy was dong the emissions test I noticed a lot of blue smoke coming out of the exhaust and the guy is shaking his head. Now I'm thinking about how I'm going to get home.
The test showed my truck was running nine times richer than it should. The smoke was from gas not oil. I told him about the oil pressure problem and he said the truck was running so rich that gas could be getting into the crankcase and thinning out the oil.
Needless to say it didn't pass the test, and it surged and bogged halfway home, after it cooled down a bit it wasn't so bad but still sluggish.
I told the guy I'd bring it back to him next week if I can't figure out the problem.
Any ideas?? What could be making it run so rich?
the oxy sensor, catalytic conv, and idle control valve were recently replaced but I don't know if that makes any difference.
Thanks
While the guy was dong the emissions test I noticed a lot of blue smoke coming out of the exhaust and the guy is shaking his head. Now I'm thinking about how I'm going to get home.
The test showed my truck was running nine times richer than it should. The smoke was from gas not oil. I told him about the oil pressure problem and he said the truck was running so rich that gas could be getting into the crankcase and thinning out the oil.
Needless to say it didn't pass the test, and it surged and bogged halfway home, after it cooled down a bit it wasn't so bad but still sluggish.
I told the guy I'd bring it back to him next week if I can't figure out the problem.
Any ideas?? What could be making it run so rich?
the oxy sensor, catalytic conv, and idle control valve were recently replaced but I don't know if that makes any difference.
Thanks
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