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2005 GMC Yukon - Low oil pressure

I have low oil pressure at idle due to a slipping cam (crankshaft not cam shaft) shaft bearing. I verified this by dropping the oil pan and seeing the displaced bearing. It is over half way out of position and I can easily see the hole on the bottom of the bearing that allows the oil to pass through. The bearing does not appear scared or damaged otherwise. The car seems to run fine other than the fluctuating oil pressure. At idle it drops to zero and the alarms go off. I have several questions. How long can I drive before the car dies because of the bearing or other damage caused by the oil pressure? Can I alleviate the low oil pressure by increasing the idle or by installing a high volume oil pump?
Thanks for any help!

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I am not a mechanic. I would think you could not see the affect of on either the cam shaft or the internal portion of the bearing. If you plan to keep your vehicle have the bearing replaced correctly.

This is the first case of a slipped cam bearing on a small block Chevy I’ve heard of. I’m also not a mechanic, but I wonder if the engine is so worn it enabled the bearing to slip, but the low oil pressure is from all the bearing being worn out. How many miles? How much oil do you use (miles per quart)? How long have you owned it?

That’s a crankshaft bearing.

If you’re lucky, you might make it to the junkyard.

Tester

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Yeah, that sounds more likely, but I sure would like to see a photo of this - I’m having trouble imagining there’s enough clearance for any of the bearings to come out that far.

I too was wondering how he could see the camshaft bearing, but I have never looked up into an engine. My only experience was replacing a hydraulic lifter on a 361 Chrysler.

Even my Crystal Ball can’t answer that .

The lifter bores can be seen in that picture. If the camshaft were in that engine you would be able to see it and not the lifter bores.

I too have never heard of a cam bearing coming out, but I suppose it could happen. If that is the case, the only answer is to slide the bearing back in place, but I’m not sure it would stay there. I think this would call for removing the cam and installing all new bearings but inspect the block for cracks around the bearing that came out.

However, this engine does have a history with the pressure control spring, over pressure valve sticking in the open position and dropping oil pressure to zero. If you have the pan off, it’s an easy fix. There are Youtube videos on this.

Edit: You really ahve to know what you are doing to replace this oil pump, but fixing a stuck valve is fairly easy.

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Yes, it is the crank shaft bearing. My bad. The car has 160k. The oil is not leaking an the level on the stick is consistent so I do not think I am losing any. I have a good picture if I can attahch it.

If one crankshaft bearing is bad and you have low oil pressure your engine is on its last legs . Time to decide if you want to repair the engine , replace with a rebuilt or just replace the vehicle .

A picture will not change the fact that you have a major problem.

I added a picture anyway

That looks like the camshaft in the picture.

When a bearing spins in its journal and pops out, the engine is finished.

This is like asking what kind of glue to use so the deck chairs on the Titanic don’t slide.

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The picture @texases posted is an old small block Chevy, the picture @p.morrison_2018_173915 is an LS series engine, the one in his Yukon. The picture shows a failed camshaft bearing that is sliding out of its “home”. The technical term for this condition is “busticated”.

That engine is not far from catastrophic failure, though the OP may be lucky and get thousands more miles from it. Just remember, when the oil pressure drops low the rest of the engine is suffering as well.

The most economical repair would be to replace the engine with a good used unit.

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So will an increase in the idle or a HV pump help alleviate the low oil pressure?

I doubt if there is an answer to that question. Why try a fix that might not even help you get a few more miles out of the thing . If the vehicle it self is in good shape then find an engine used or rebuilt and do a proper fix. It stands to reason that you have engine damage because of the low oil pressure and it will not go away .

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Your engine is close to total failure, I don’t think band aids will help

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No way. I am as cheap as the day is long, and even I don’t see either of these “solutions” as being helpful. Increasing the idle speed will do nothing more than accelerate the wear to this already worn out engine, and perhaps increase the oil pressure by a few PSI, if that. A higher flow oil pump probably won’t help either, at least not with a displaced bearing insert. It is possible that a higher flow oil pump will compensate for loose tolerances provided that new bearing inserts are installed, and the mating surfaces aren’t too rough.

I agree that the best solution is a working used engine from a junkyard. Before buying a used engine, I would remove the oil pan and check the connecting rod bearings for gross wear–i.e. the “wiggle test”. Any gross wear, or evidence of oil sludging or coolant contamination? Don’t buy that engine. After buying a used engine, I would pull the head(s) and have it/them cleaned and reconditioned by a local machine shop, then reassemble the engine with all new seals and gaskets, new brass core plugs, and new timing belt/chain set since that is all ridiculously easy to do while the engine is sitting on the floor.

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Hi P.Morrison:
About 40 years ago I had the same thing happen on my old car. The oil light would shut off at a high idle.

I was young and foolish and thought I could keep driving (because the light was off while driving down the road).

I only got a few hundred miles before I spun a crank bearing. You might get lucky and go more miles than I did. But you won’t know where and when it decides to finally give up on you.

All the best.

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