Oil pressure gauge fluctuating
I put an AZ manual gauge on it rather than mess with putting a new sending unit.
There's quite a few things that will cause this to occur:
-oil pump
-air is being sucked into the upper insertion point of the oil pump's screen tube.
-airating due to crank splashing in the oil thus whipping air into the oil due to oil level is too high
-open / intermittent ground at the sending unit thus the drop to zero and back
-pressure transducer is intermittently working
-restrictions in the oil passage ways
-wrong or incorrect oil filter
-oil fiter collapses. Filter medium collapses thus blocking the flow thus switching over to bypass mode
-wrong or incorrect type of motor oil / viscosity and TYPE SAE or standard rated.
-electrical problem in that CKTs or shared CKTs / ground or supply.
-worn engine parts
Those are the ones that I am aware of. There may be more than that. Now, about that plenum leak and, about it affecting the oil pressure: when my plenum gasket blew, the psi never fluctuated beyond a slight drop in psi when hot, at idle. It was rock solid.
CM
-oil pump
-air is being sucked into the upper insertion point of the oil pump's screen tube.
-airating due to crank splashing in the oil thus whipping air into the oil due to oil level is too high
-open / intermittent ground at the sending unit thus the drop to zero and back
-pressure transducer is intermittently working
-restrictions in the oil passage ways
-wrong or incorrect oil filter
-oil fiter collapses. Filter medium collapses thus blocking the flow thus switching over to bypass mode
-wrong or incorrect type of motor oil / viscosity and TYPE SAE or standard rated.
-electrical problem in that CKTs or shared CKTs / ground or supply.
-worn engine parts
Those are the ones that I am aware of. There may be more than that. Now, about that plenum leak and, about it affecting the oil pressure: when my plenum gasket blew, the psi never fluctuated beyond a slight drop in psi when hot, at idle. It was rock solid.
CM
Last edited by cmckenna; Aug 5, 2010 at 06:26 PM.
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Didn't mean to infer that the plenum and gauge are related, IMO they are two entirely different issues. Was just letting the readers know that I did have the Hughes plenum and that that shouldn't be their issue. FWIW, installing the Hughes plenum did take care of my oil usage issues. I went from using a quart every 200-300 miles to using none,
Last edited by JC NC; Aug 6, 2010 at 07:20 AM.
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From: Wendell, NC
I was towing a boat to the coast 2 summers ago when, sitting a stoplight, I noticed the oil pressure gauge was just barely above zero. Turned off all the sources of noise and the engine sounded fine. Went about 1/2 a mile till I could pull off before I shut it down. Gave it a few minutes, checked the oil, and started it back up. Let it run for about 15 minutes - no overheating, no sound, just no pressure on the gauge. Decided to just go for it and towed it another 60 miles without a problem. Went to the local dealer the next morning and they had me on my way with a new pressure sensor in less than an hour. That was at about 75,000 miles - at 185, 000 now and it's still working.
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I have a simular problem with my 99 Ram 1500 with the 5.2. Loses pressure at idle enough to cause the rockers to rattle then pressure comes back up. Next time might go 2 weeks and be fine then act up again. New oil pump was installed, pickup is clear, pulled mains looked great, same problem. Could it be the plenum gasket causing the problem ? Any help is appreciated.
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Had the same exact thing happen to Betty. Turned out to be a bad plenum gasket.
If this is your problem, symptons may include, but are not limited too: oil pressure dropping to zero and returning to normal, burning or using oil (not leaking), squealing or various noises.
To check: Pull off the filter housing, climb on top of the engine, then look down into your throttle body to see if you have any pooling of oil in the intake manifold. Sometimes there will be oil in there, but you can't see it. If your truck has a good amount of miles and the plenum hasn't been fixed, you have very good chances of this being the root cause of the problem.
The good news is that a new Hughes plenum plate kit is only $200 at their website, and a DIY will take around 5-8 hrs depending on you mech. skills.
Hope this helps, keep us updated....
If this is your problem, symptons may include, but are not limited too: oil pressure dropping to zero and returning to normal, burning or using oil (not leaking), squealing or various noises.
To check: Pull off the filter housing, climb on top of the engine, then look down into your throttle body to see if you have any pooling of oil in the intake manifold. Sometimes there will be oil in there, but you can't see it. If your truck has a good amount of miles and the plenum hasn't been fixed, you have very good chances of this being the root cause of the problem.
The good news is that a new Hughes plenum plate kit is only $200 at their website, and a DIY will take around 5-8 hrs depending on you mech. skills.
Hope this helps, keep us updated....
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From: Clayton MI
There is usually a seller on ebay for them as well. (he is a member here.) Get the plate, and bolts, for less than what hughes sells them for. Still need the gaskets though. (source locally)