My 2004 tahoe with a 5.3 will lose oil pressure intermittently and I can hear the rattling of the engine. I can shut it off and restart immediately and noise stops and oil pressure comes back up to normal most times. What is causes this? It’s been going on for a year now with almost 300k on it.
Intermittent low oil pressure
- Thread starter Hotrod686
- Start date
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strutaeng
Full Access Member
Yikes! Well, rattling is never a good sign...
You need to hook up a mechanical guage to see what the real oil pressure is. You can remove the oil pressure sender (need a special socket) on the rear/top of the engine.
Have you taken a look at your oil when you've changed the oil? Any glitter in it?
You need to hook up a mechanical guage to see what the real oil pressure is. You can remove the oil pressure sender (need a special socket) on the rear/top of the engine.
Have you taken a look at your oil when you've changed the oil? Any glitter in it?
nonickatall
Full Access Member
Oil Pump O-Ring,
oil pressure relief valve
Oil pump problem or a
lot of dirt in the oil pan .
Did you remove the oil pan lately to check for dirt which clogges the oil tube filter?
oil pressure relief valve
Oil pump problem or a
lot of dirt in the oil pan .
Did you remove the oil pan lately to check for dirt which clogges the oil tube filter?
300k miles on it could be the answer as well as the suspects that have been listed. Attach an oil pressure gauge and tape to w/s and drive it and watch.
nonickatall
Full Access Member
For what you need an oil pressure gauge?
The rattel noise of the engine is evidence enough.
I would not drive one mile with this car, because a low oil pressure up to engine rattle, is a Guarantee for a massive engine failure soon.
I would remove the oil pan, check for dirt, swap the oil pressure relief valve and the o-ring and look what happenes.
If this not fixed the problem, I would change the oil pump.
Or what I would do, just because I'm so keen to disassemble and rebuild an LS engine, after all that fckn Audi/VW or BMW shit, which I rebuilt recently...
I would pull the engine and rebuild it with love.
But not everybody can do this himself, has the tools, knowledge, experience and capabilities or money to give the engine to trusted Garage.
But as far as I know rebuild engines are in the USA not very expensive, compared to an engine for an German car. For example a Mercedes AMG engine cost up to 60,000 euros and last mostly only 150,000 kilometers...
What a waste of money....
So every saved LS engine is good for environment and for the legacy of a time where people could build cars....
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He shuts off and restarts and noise is gone. I am a visual person. I want to see oil pressure when this scenario happens. He has some inspections to do. He did not mention adding oil or even checking oil level. Going on for a year now. I would much rather install a "sight" gauge than to drop a pan. it may still need to be dropped but at 300k miles, I would be leaning toward dropping money on the counter for another engine.
nonickatall
Full Access Member
Well depends on the condition of the engine and how the engine history is. Dropping the oil pan is something real easy, if you are not equipped with two left hands, like we say in Germany.
I would do that first. But i have a lift, tools, a second car to stay mobil and did it once at my truck.
But if he has money, love his truck and will invest in the future, it is not a bad idea to swap the engine...
I love measuring as well, but when the oil pressure drops at the gauge and a rattle start, you know that the problem is not the gauge.
It can be the wear out pressure relief valve, when it opens because of s lack of spring pressure, maybe combined with the o-ring which let air pass..
And when you switch of engine and started again, probably the valve close short and the condition is slightly different...
strutaeng
Full Access Member
Yeah, that's pretty high mileage. But seen engines go farther than that, based on maintenance.
The fact that OP hears rattling but has managed to drive it like that for one year is puzzling...
The fact that OP hears rattling but has managed to drive it like that for one year is puzzling...
300k is no big deal if the oil was changed even close to regularly. The pick up tube 1 bolt connection and associated o ring is very likely
I wonder if you have some debris floating around in the pan and it will get stuck on the pickup screen and starve the pump. When you shut down the engine, it falls off and gets back into the pan - then repeat. Just a thought.
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