Low oil pressure question

[Todd D]

My wife's 07 yukon denali has very low oil pressure from time to time. It gets down to around 10 which is just above the red line. Any ideas on what could be wrong? Oil pump?

 

[07burb]

Any common events that cause it to happen?

 

[Todd D]

Not really except that it seems to get low after it is warmed up.

 

[07burb]

Does it seem to go away for a while after an fresh oil change? How many miles do you have?

 

[Vista Cruiser 69]

Hi,
oilpressure is influenced by "actual" viscosity of oil, its SAE class(second number behind W), oil temperature, revs and condition of oil pump.

"Actual" means that Oil looses viscosity over time by mechanical shear and by absorbing some resident fuel. So the further in your change interval, the thinner it got. BTW a reson why oils consumtion tends to go up at end of interval. Suppose you drive an oil with viscosity class 5W-30 as recommended. 5W tells something how liquid it is in low temps only (5W goes well down to -25°C and still flows after cold start). The second number tells about viscosity at 100°C. The higher the number the thicker the stuff. So if your 5W-30 was not enough anymore you either change to a fresh 5W-30 or use 5W-40 instead which provides more pressure when hot. Rule should be: as thin as possible - as thick as necessary. Oils with lower numbersd (hot and cold) provide good Fuel Economy, but if too thin then the engine wears out. Modern Chriysler engines use 5W-20, Honda uses 0W-20 but these engines are built to cope with that thin stuff by using higher volume oil pumps. Funny enough these big oil pumps eat up a share of the fuel economy that the thin stuff could provide by burning internal energy.

 

[07burb]

Thanks for the post, Vista. The reason I was asking the questions I was posting was because I've had a problem very similar and I was trying to see if it was the same as I've resolved my issue. It's highly doubtful the OP's issue had anything to do with viscosity :waytogo:

 

[Todd D]

It does have 130,000 miles on it and I believe the GM dealer is putting 5W-30 but I will double check. It does not vary from fresh oil change that I have noticed but I will watch closer. I don't know but I am thinking I have a pump issue. I appreciate your input.

 

[07burb]

Next oil change try these steps detailed in this link and see if it resolves your problem before spending the money on replacing your oil pump. It's rare for the oil pump to go bad on these engines. It could also be the oil pressure sensor which I'd also replace before changing your oil pump.

Here's the link:http://www.tahoeyukonforum.com/forum/showthread.php?t=62826

 

[Todd D]

Its worth a shot! Thanks bro!!!

 

[07burb]

No problem man

 

[Vista Cruiser 69]

Hm, checked the things in the thread you suggested but I won't recommend these things. If the engine had bad oil pressure because black sludge and ablocked oil pump basket then not at low revs but on high when it can't suck in enough volume. If you reguarly made oil changes then no need fot any funny chemistry or additives, which no OEM lkes or approves. Go for an oil with next higher viscosity class and you will be fine, sounds like 5W-40. I have a very high mileage (>350Kmls) 455 Rocket -still going strong- but tends to show me red light when idling after fast driving (= high oil temp). 5W-40 helped for some time but now on a fully synthetic 10W-60 hes doing smoother than ever. No chemisty no antiwuddayacallit additive...

 

[07burb]

Lol

 

[MO Viet Vet]

Oil pressure sender? Likely not. Best if you get to where you just can't figure it out easily with other threads is to do an actual pressure reading with a gauge from a cold start to a full warm engine condition.

 

[whiteyukon]

low oil pressure/shut engine off light.

I just bouht an 07 yukon. Drove it about 3 miles from dealership and it said it had no oil pressure and to shut down the engine. The light does no come on at cold start up. The neeedle goes to zero after about 5-10 minutes. It it starts dinging and resds low oil pressure has.....shut engine off. Any ideas what it mat be. It does have fresh oil change. Oil looked good and it was at proper level. Any ideas of a possible problem?

 

[Vista Cruiser 69]

Sounds to me as if this was something your dealer should find out instead of you? I mean 3 mls from his yard...? Does needle go to 0 when driving, say revs over 1200? Or idling with 600? If there was no difference, and if the oil pressure sensor played no tricks on you - than it was severe. This could be a totally black sludged engine, oil intake basket in the sump blocked, no volume to come through anymore, no pressure. Maintainance history OK or a couple of oil chAnges left out? Try to get as deep as possible into the engine through filler cap. Any brown cream or black sludge up there is an indication of a catastrophy down there, which is oil sump. If so than it needs dismatlinbg, mechanicall scrubbing off the böack stuff, chemical cleaning and fingers cross keeping.... or return to sender!

 

[whiteyukon]

Thanks vista. The dealer is gonna fix it. I just wanted to have a lil head's up when they give me a diagnosis. Not sure of rpms. I was going about 55mph when it dropped. Never came back up until it sat for a bit. The dealer has it as we speak. They said that the lift kit is what caused it. Im ass...uming that the wires are to short (due to the lift) for the sensor. They are supposed to be getting a different harness tomorrow. Judging from what ive been researching, thats not gonna fix my problem. Ill just wait and see. Dealer says they will have it fixed by lunch tomorrow. Guess I'll have to wait and see bout that as well. I will post an update when i talk to them tomorrow.

 

[07burb]

LOL at the lift kit causing the issue :lol: That's the thing I hate about dealerships. If they see anything not OEM about your ride they are VERY quick to point the blame at that regardless of how asinine the logic....keep us posted on what they find IF they find anything. When this issue was happening to me the oil pressure would come back up upon stopping and restarting the engine. Made it very hard to track down the issue.

 

[whiteyukon]

It is now Thursday. They say they have fixed the oil pressure problem, but discovered a problem with the ABS wanting to engage during turns. They've been dealing with that since yesterday before lunch. It is now 2 o'clock Thursday. The lift is getting the blame for that one as well. Im not % 100 sure what the fix was for the oil pressure. Ill find out more this evening and give you guys a detailed report. Maybe you guys can can help me out.

 

[Vista Cruiser 69]

Hi white yukon,

curious about what came out on the oil, pressure and ABS issue you mentioned. Any news?

 

[whiteyukon]

Hi white yukon,

curious about what came out on the oil, pressure and ABS issue you mentioned. Any news?

They replaced the oil pressure switch, which resolved the low pressure issue. Also got the ABS system to quit kicking in. They did manage to get it to stop kicking in but now it has thrown the traction control light and service tire monitoring system light. They shut the lights of with a scan tool, but within 100 miles they came back on. Gonna take it back to them next week. Someone told me that i could get tire replacement/aftermarket pressure monitoring sensors for the wheels. I haven't looked into it yet though.