Hey guys,

My oil pressure is 40 when running freeway but then goes down to 20 when at idle. The manual doesn't specify what constitutes low pressure, what is considered low pressure?

Thanks in advance!

 

I had the same question on my 08. From what I've read, that is "normal" but it just doesn't sit right with me.

Replying to the thread to get more replies.

 

Temp will change pressure. Rule of thumb 10psi per 1k rpm. Just make sure to keep that oil/filter clean and only use a quality 5w30 full synthetic.

 

20 psi is not bad but its not good either.
Make sure you have a good oil filter. I ran into a batch of junk ones a while back that had defective bypass valves inside.
There is also a small metal filter on some LQ4's beneath the oil pressure sending unit that can get clogged. Its a bear to get to without removing the intake manifold. Toss it and buy a new GM sending unit. All of this is much easier with manifold off, then you can also replace knock sensors.

Tim

 

When I purchased my last 06 H2 SUT the oil pressures you mentioned are close to what I remember. On top of that the pressure sensor at the rear of the intake manifold was also leaking oil. I have read this is a common problem that usually occurs before the sensor fails completely and then provides either no oil pressure or pegs the gauge.

Its a pain in the *** to replace because you need to sit on top of the radiator support and lean over the engine and mostly replace it by feel. After I replaced the unit I notice my oil pressures reading both at idle and running where about 25% higher then with the old unit.

Not that this is your problem but its a consideration.

 

I have an 05 and an 08. My 05 the psi sits at around 40 which is normal for the 6.0 engine. the 08 with 6.2 they have variable timing and the oil pressure is at 40-60 when cold, when hot its 40 but when hot and idling, it will go down to 20 which is very normal for this engine. All the guys I know who have the 08-09 all say the same thing. fluctuates between 20-40 or so when hot.

 

The 08 is the first year they moved away from the LQ4 and used the L92 6.2 instead. 20-40 seems about right. Mine forever has done 18-20 idle(just below the 2nd mark) and usually only goes up to 30 when cruising and 35-45 on the highway. This seems normal to me. On cold starts mine reaches about 50.