I'm running mobil 1 5w30 in my 92 305 tbi with 99,000 miles on her. I can't seem to get any more than 15 psi of oil pressure at idle once warmed up. What effect will putting a thicker oil such as 10w30 in my engine have on oil presure?

 

Should increase, but maybe not even enough to notice.

 

Yeah, what he said.....plus I don't think 15 PSI at idle is too bad. On a hot day-engine fully warmed up....sounds OK to me??

 

i'd change the sender or use a mechanical gauge, you may not really have a problem with preasure

 

Just changed it 3 days ago and still get the same readings.

 

15 at idle is fine. 10 psi per 1000 rpm is usually plenty. How much pressure at say 2500 rpm, engine hot?

 

at 2500 i prolly have about 35 psi

 

ive got between 35 and 40 psi at just 700 rpm is that good to hav ethat high of psi at idle. motor was rebuilt 30 grand ago

 

Maybe you have a high volume pump. My car does and it never falls below 60 psi. It really is unneeded though.

 

25thRSS,

Check your owners' manual. There is a temperature at which you should no longer use 5W30, about 40°F, IIRC. I would advise using the highest grade recommended at a given ambient temperature.

 

Sounds good then. I wouldn't worry about it at all. If someone has a chiltons or something it will list the oil pressure at a specific rpm--not idle. I would run 10w30, but that's just me and it's what I use. The difference in pressure will be small.