Afm delete and still low oil pressure.

LSFAN · June 24, 2020

I had a dod delete done on 2008 sierra vortec max. Had low oil pressure before and still does. Had new Melling 10296 installed with delete. 20ish psi at hot idle. 40 psi at startup. I kept the VVT and installed l96 cam. Any thoughts on what could be the cause? Has 140k.

Thanks in advance.

CamGTP · June 24, 2020

Did you remove the oil pressure relief valve in the oil pan?

They install those to limit oil pressure for the AFM system. Removing that should up the pressure a bit. And 20-25psi at hot idle is more than enough oil pressure.

LSFAN · June 25, 2020

No. I did not remove the relief valve. I was told it needs to be the for the VVT. I'm used to seeing 35-40 psi l like on my 5.3 Silverado. I'm guessing it will be ok. Just wanted some other input. Thanks.

CamGTP · June 25, 2020

Gen 4 and Gen 5 engines will run at lower oil pressure than a Gen 3 engine.

dkjbama · September 24, 2020

What's the oil pressure at highway speeds? I suspect worn lifter bores bleeding off pressure from wear incurred due to extended oil change intervals (following the GM Oil Life Monitor) Been down this road with my fiance's 2013; 120,000 miles. Had lifters done due to lifter chirp and then 6 months later I stomped on it to pass on a two lane road and spun a rod bearing. After the lifter repair oil pressure was lucky to be 25 or 30 running down the interstate. If I had it do do over again, I'd have run Rotella T6 5w-40 or even a 20w-50 to keep the pressure up; It might have saved, or at least prolonged the life of the motor a little bit.

swathdiver · October 2, 2020

On 6/24/2020 at 11:54 AM, LSFAN said:

I had a dod delete done on 2008 sierra vortec max. Had low oil pressure before and still does. Had new Melling 10296 installed with delete. 20ish psi at hot idle. 40 psi at startup. I kept the VVT and installed l96 cam. Any thoughts on what could be the cause? Has 140k.

Thanks in advance.

You put in an iron block oil pump, not the M365 which is the one for aluminum block engines. You cut you're volume by over 1/3 per engine rpm. Try switching oil filters, the M1 EP oil filters dropped my pressure about 3 psi compared with ACDelco and K&N. If all else is ok, the cam bearings are usually the first to drop the pressure.