: Low Oil Pressure after Head Gasket Repair



Netjive8
04-10-10, 09:39 AM
I picked up a 98' Deville as a project car, with blown head gaskets. I just got the car back yesterday after having Jake's stud kit installed. After test driving it for about 10 miles the low oil pressure light began to flicker and eventually became solid (chiming, and "stop engine" message) for a few seconds then went away. It has done this intermittently since. The shop that worked on it told me that it was normal for that to happen for a few weeks until the car has re-learned/calibrated the computer. They said that they had tested the pressure at the shop but could not get the light to go away. I don't know if this is helpful though since it is intermittent. There is also a misfire (p0300, Service Engine Light) but probably unrelated. So do you think that I just need to keep driving the car and see if it goes away? The "stop engine" message has me a little worried, but the engine sounds fine. Thanks.

KHE
04-10-10, 09:52 AM
The computer doesn't need to "relearn" anything. I would hook up an oil pressure gage to the port on the oil filter adapter and see what the actual oil pressure really is when the warnings display on the information center. If the oil pressure is at specification, the problem is probably a bad oil pressure sending unit. If that is the case, replace it with a new one from GM, not the local parts counter.

If the oil pressure is in fact low, it could be that the balancer pulley bolt was not properly tightened. There is a initial torque spec. plus 120 degrees.

There could also be dirt in the relief valve causing the pump to lose prime but that doesn't seem to be the issue in your case since the warning is intermittent.

Submariner409
04-10-10, 10:18 AM
37 ft/lb + 120 degrees. Engine has to be locked to get that much torque on the crank bolt.

The oil pump is driven by harmonic balancer friction (tightness) so, as KHE posted, that bolt MUST be properly torqued, and there's no "computer" relearn involved.

Make sure the spark plug wires are connected properly according to diagrams posted here, in Seville, Deville, and in the service manual. Make sure the ICM ground is clean and tight.

dub devil
04-23-10, 09:43 PM
i have a lil over 3k miles on my head gasket rebuild with jakes studs. today i had my low oil pressure light come on, then about 10 mins later it started ticking. found this post and went and checked my harmonic balancer bolt.. it was easily loosened with a wrench lol. cant believe that got overlooked like that. but i torqued it to the spec above and it instantly fixed all problems... if it wasn't for this site, i would still be sitting at home bummed out that i bought a pos . now i get to arrive in style. THANKS GUYS

coaster
04-24-10, 01:59 AM
what are friends for :):):):)