I'm trying to decifer advantages and disadvantages to using higher weight oil. Everyone brags about having good oil pressure. But mine is always low. And it seems that most other'* oil pressure increses with RPM, but mine never does. It'* always stable, and when I first got the car running, it was at 45PSI, but right around when the head gasket blew, it was around 39PSI. Now, I realize the head gasket blowing could very well have played a role in the oil pressure drop, however the car has always had 40-45PSI oil pressure. And it never would increase with RPM. I use 5W-30 oil. But, I think I want to try 10W-40. I think maybe the extra weight with higher temps may help a little with engine protection. However, I live in Michigan, so I live in a cold climate, and I buy my oil by the case. So I would rather not switch between weights. I want one that can handle everything.

I also realize that oil filters have a bypass valve for when the pressure is too high and the filter cannot handle the flow, so when the weather is cold, I could still run 10W-40 taking advantage to that bypass valve? Or would it always be bypassing the filter until the engine is up to temp?


-justin

your oil pressure is just fine... leave it be. i'm running a constant 45 psi or so in mine, a wee bit more when cold. but since I moved to full synth, it'* pretty solid. stick with the 5-30 unless you actually have a problem with it...

I live in Michigan and I run 10w30 year round. Haven't had any problems with it yet...

What does your oil filler cap say on it that you should use? Mine says 10-30 but 45 pounds is fine. My 95 gets down around 20 at idle when it is warmed up. The 97 doesn't go below 30 when warmed up.

5W-30 everywhere [oil cap, owners manual, FSM].

I know it is in an acceptable range, but i'm not sure why it doesn't increase with RPM like a lot of other members. Could it possible be something up with my oiling system?


-justin

I'm running 10w-30, and my oil pressure never drops below 1/2 on the guage. It also goes nuts on WOT runs and increases with RPM'*. I always though there was something wrong with the guage, but I guess it'* a good thing. To my knowledge this engine has never had any major work done, just the tranny.

captain: when you say nuts, do you mean erratic, or increases significantly? If it is the latter, what is your WOT pressure?

Okay, 10w-30, not 10w-40..


-justin

It slowly climbs, then at about 4500RPM'* it goes right up, and then starts declining. Some times it bounces around really high as well.

Just a first gear run - http://members.shaw.ca/bonneville01/MVI_0007.avi

BTW, if anyone knows how to stop my turn signal indicator from coming on with the head lights, be my guest....

captain: that is sweet! I wish mine would do that! lol [and i'm talking about the oil pressure]. Hardcore **** man. That'* what I am going to aspire to. What kind of oil filter do you use?


-justin