Oil Pressure Problem

Tiny
RMOP
  • MEMBER
  • 2001 GMC SAFARI
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 60,000 MILES
A "Check Gauge" light is on in response to low oil pressure at idle speeds. I'm not sure when this developed, but think it was many months ago, and I suppose I wasn't paying much attention, as the light cleared immediately upon acceleration from idle and never appears otherwise. The engine runs beautifully and apart from this ominous warning, there are no active issues. However, the appearance of the "Check Gauge" light has recently become much more frequent at idle, and the gauge needle at such times is actually in the RED, which I don't recall seeing before, though I might have missed it if it were only briefly in that alarming range.

I've just recently had the pressure checked MECHANICALLY by two different garages. The first said things were OK in spite of the low gauge reading. The second mechanic said he used two different gauges to ensure reproducibility of the readings, which were taken at three different engine speeds. Reading from the second and more particular mechanic are as follows:

1000rpm--04psi (06psi expected)
2000rpm--14psi (18psi expected
4000rpm--22psi (24psi expected)

Signal from oil pressure sender to computer said OK. 2nd mechanic suggested flushing the engine in conjunction with an oil change in hope that it might dislodge suspected crud blocking the proper circulation of oil. It didn't help. He doesn't do major engine overhauls, and discouraged me from opening the engine just yet. I'm a bit nervous, but not enough to have stopped driving this van.
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Thursday, December 2nd, 2010 AT 2:58 AM

5 Replies

Tiny
RASMATAZ
  • MEMBER
If the oil pressure switch checks out could be a blockage on the oil pick-up tube screen, engine bearings and oil pump its time to go in and investigate
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Thursday, December 2nd, 2010 AT 3:07 AM
Tiny
RMOP
  • MEMBER
Sounds like the suggestion to flush first was in hope of cleaning the pick-up tube screen. What sort of labor and cost would each of the three scenarios entail to diagnose and fix? Thanks for the quick reply.
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Thursday, December 2nd, 2010 AT 3:30 AM
Tiny
RASMATAZ
  • MEMBER
Its gonna take about 2.5hrs of labor and labor/costs varies with location
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Thursday, December 2nd, 2010 AT 7:58 PM
Tiny
RMOP
  • MEMBER
Well, upon conferring with another local mechanic, he stated that he'd NEVER seen a pick-up tube clogged on a GMC Safari or similar engine. He said it was nearly certain that my main bearings were worn, and that the failure to generate oil pressure to spec was a result of this "play" in the guts of my engine. Given that this is one of the suggestions of the computer dx readout, I'm inclined to agree. What think you?

The engine has only 60K miles, has been well-maintained, but seems headed for trouble. Cost of a replacement engine was said to be around $6000 -- with no pressure from this mechanic to get one. Instead, he suggested a higher viscosity oil (15/40) and to wait and see and hope for the best. He said if the pressure goes up with the thicker oil, it would be practically diagnostic of worn bearings. The "treatment" is clearly temporizing, but is more attractive than a new engine.

What if anything can be predicted based on the above? Should I trade this car ASAP or drive it till it dies?

Thanks.
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Thursday, December 23rd, 2010 AT 1:46 AM
Tiny
HMAC300
  • EXPERT
Usually if your main bearings are worn you will hear a deep knock or rap on start up. Sometimes on idle. One thig to check that wouldtake to drop the pan is under the rear main bearing there is a ball that is pounded in to block another oil passage. These sometimes came loose and allow the pressure to drop. But the question here is wheteher you want to put the money into the vehicle and find that that is not the problem. However you could peek at the main bearings to see if that was the problem as well. Also sometimes oil filters cause a low pressure problem as well.
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Sunday, December 26th, 2010 AT 7:19 PM

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