Oil pressure gauge dropping to 0 and then going back up
 

A couple months ago, while I was driving home, I heard a *ding* and looked down and saw a low oil pressure warning...I then looked at my gauge and saw it read 0. I immediately cut-off my engine and got off the road.

I checked the oil level which was fine and when I started it again, it read the normal idle pressure. I just figured it was a fluke and didn't think much of it. I went months with no issues.

Yesterday it happened to me again once, but I didn't notice it right away because I had music playing (a little loudly). It caught my eye and I saw it was at 0 and then it jumped back up before I could shut the motor off.

Today it has happened to me 2 or 3 times. It drops to either 0 or a very low pressure reading and then jumps back up.

Does this sound like a bad sending unit/oil pressure sensor or possible failure of the oil pump? The car is a base 2007 with ~48k miles.

Any help is appreciated!

EDIT:


Thanks everyone for the insight.

Yes, that's exactly what it sounds like.

:iagree:

If your oil pump was dying you would have consistently lower readings, not zero and back to normal. The oil pump is a gear driven pump and wouldn't display that kind of behavior if it failed.

Sounds like a bad sending unit. Search this forum for the trick method for replacing the sender without removing the intake manifold. If mine fails , I think I will try this method. [ cut through the cowl ] :thumbs:

Not so..... I had my pump replaced under warranty for the exact condition.

PIP4158C: Low Oil Pressure Due To Seized Oil Pressure Relief Valve - (Dec 29, 2009)


Subject: Low Oil Pump Pressure due to Seized Oil Pressure Relief Valve

Models: 2008-2009 Buick Lacrosse, Allure (Canada Only)
2007-2010 Cadillac CTS-V, Escalade
2007-2010 Chevrolet Avalanche, Corvette, Silverado, Suburban, Tahoe
2007-2008 Chevrolet Monte Carlo SS
2007-2009 Chevrolet Impala SS, Trail Blazer
2009-2010 Chevrolet Colorado
2010 Chevrolet Camaro
2007-2010 GMC Envoy, Sierra, Yukon
2009-2010 GMC Canyon
2008-2010 Hummer H2
2008-2010 H3 Alpha
2008 Pontiac Grand Prix GXP
2008-2010 Pontiac G8 GT
2007-2009 Saab 97x
with the Following Aluminum V8 Engine RPOs:
L76, L77, L92, L94, L99, L9H, LC9, LH6, LH8, LH9, LS2, LS3, LS4, LS7, LS9, LSA, LZ1

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

Some customers may complain of low oil pressure, no oil pressure, and/or engine noise, which may be the result of a sticking oil pump pressure relief valve. In some instances, this may occur intermittently if the valve frees up when the engine cools down.
Recommendation/Instructions:

If SI diagnosis isolates low mechanical oil pressure at the oil filter housing and oil pressure sensor, replace the oil pump, flush the oil cooler lines (if equipped), clean the inside of the oil pan, change the oil and filter, and re-evaluate the concern.

Notice: If an engine noise is noticed after replacing the oil pump, follow the SI diagnosis and repair the engine as necessary.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Subject: Low Oil Pump Pressure due to Seized Oil Pressure Relief Valve

Models: 2008-2009 Buick Lacrosse, Allure (Canada Only)
2007-2010 Cadillac CTS-V, Escalade
2007-2010 Chevrolet Avalanche, Corvette, Silverado, Suburban, Tahoe
2007-2008 Chevrolet Monte Carlo SS
2007-2009 Chevrolet Impala SS, Trail Blazer
2009-2010 Chevrolet Colorado

I stand corrected.

Should have added that the technician Thomas, at Vara Chevrolet in San Antonio did an excellent job. Have had no further issues since the pump was replaced a little over 6 months ago. My car was flatbedded to the dealership in the morning and I had my car back by COB next day. Car was washed and the paper floor mat protectors were still in the car when I picked it up.

this explains why all the LS7's are blowing up lol. i used to like dealers washing my car when it went in for service. now i'll let someone else have the swirl marks.

Thanks for the replies guys. It happened to me once today. It dropped to 0 then I gave it some gas and it shot right back up. The possible failure of the oil pump has me concerned. I'll take it in to a dealership to be safe.

If the oil pressure was really at 0 for a couple of seconds, wouldn't you expect the temperature of the engine to raise rapidly?

I might expect to see the oil temp rise (if the pressure came back and there was oil flow again). What I would NOT want to see is bearing material on the bottom of the oil pan or in the filter. If the oil pressure stayed at zero long enough kiss most of the rotating parts in the engine good bye. The amount of time it takes for that to happen isn't long enough to heat up the coolant.

Probably nothing more than the connection at the oil pressure sending unit. Mine would go XXX periodically and bounce right back up. I knew it wasn't the oil pump due to the fact it could happen for at least 20-30 seconds and no engine seize.

Yea, that's what I'm thinking or hoping at least. I know it was probably at 0 for 10-20 seconds before I noticed it one time.

I just wish I had some free time to take care of this right away. I might try to bounce from work tomorrow and get the dealership to look at it. Or I could wait until I get back from vacation and do it myself. Decisions decisions...

curious, did you ever get this taken care of? seems to be a problem around Austin :)

I didn't because the problem just went away after I changed my oil... until today (months and months later).

It seems as soon as the weather heated up, the problem came back. But now, it's just stuck at 0. No bouncing at all. I tried changing the oil today to see if that would make a difference and it didn't. I am taking the car to the dealership tomorrow to be safe. I will post what they find.

It was in fact the oil pressure sending unit that had malfunctioned. Got a new one put in at the dealership and everything is peachy!

I was hoping we would get away with the same thing as I had the same symptoms....changed out the pressure switch today, still at 0

Sorry to bring this back from the dead...I had this issue happen to me today. Oil pressure would drop down to seemingly zero, the pop right back up to normal. It did it twice in a few blocks. It did not seem to have any other strange symptoms (raise in temp, strange sounds, poor running, etc.). I will continue to monitor on the way home tonight.

Edit- no major dips like earlier in the day, it seemed to hold steady and good pressure. I checked the oil and everything seemed to be in order. I'll continue to keep a close eye on it.

It could also be the oil press sending unit. Mine went high for a while then zero for a while, but since there was no valve clatter, I knew that I had oil. Got new sensor on Amazon, 2 hours to replace...hard to get to, and all has been good for years since. With zero oil pressure, the valve train will start clattering soon and long before any engine damage...this is the easy way to tell.:thumbs:

Silver Raptor
 

:salute:Just the other night while driving home on a quiet street with my 2008 vette LS3 I was doing 40mph I decided to jump on the gas what a launch just for a few seconds. My oil pressure gauge went to 80 and stayed there then bounced around took it right home. Next day started right up no engine noise went for a ride for a half hour oil gauge went to zero, loaded with worry went home made some calls and did some research. Me on a pension and SS looking for the best mechanic and price,dealer said its sounds like sending unit I talked to a reliable machanic and he wants to put in a hp oil pump due to the issues corvette has with its original equip thats 1700.00 does that sound right?