Hello all, new here, found this place while trying to research what is going on with my 1996 Blazer. The past week my oil pressure went from its normal reading of 40 while driving to settling on 60 now. I have read various things about it possibly being a dirty oil filter, bad sending unit, etc.; I am not sure what to try first at this point. I've never had a problem with the oil pressure before. When I noticed it first rising, I thought I smelled oil burning, but I have not noticed anything since.

Any help is appreciated and I can provide whatever other info that might be needed. Thank you in advance for your time.

 

The factory dash gauge is mainly for looks, they're not known for their accuracy. Most auto parts stores sell, (or rent) oil pressure testers that are far more accurate. Remove the oil pressure sending unit, (next to the distributor) and screw in the adapter hose from the tester. Start the engine and note the pressure when cold and hot at ~1500 rpm. Post your results and we can analyze them.

 

first things first. change the oil! if its dirty and causing some type of clot it will raise the psi. when you drain the oil inspect it for any type of contaminates or possibly coolant.

also have you done the lower intake manifold gasket? it can leak coolant into the oil causing it to thin out and raise the psi, thats what happened to mine.

 

That sounds like a good start. I did check the oil at least and it did not look bad, to my eyes anyway. I just googled the intake manifold leak and I'll have to read more about that. Hopefully the oil change and filter change will help. If not I may have to try what you're saying next. Thanks for the replies. I may not get to change it today but I'll post what I find when I do.

 

If your max oil pressure was 40, and now it's 60, you are right to be concerned. You need to find out what happened.
However your truck is probably not on the road to destruction. If the sender and gauge are accurate, then 60 is where it should be at cruising rpm.
If everything is clean and operating properly, the oil pump will bypass at abut 57 psi. I dont know why 57.. but 'back in the day' that was what everyone with Stewart Warner 270 sweep ga saw with new oil pump

 

60 psi on cruise and 40 on idle is normal?

 

Well no... When warm your gauge will say more like 25-30 idle and 40-50 cruising.

 

So im running high.. What should I do to lower it down. Its been like this since I bought the truck a few years ago.

 

Actually it is normal - on my car. But I'm really frustrated because in many searches on what the normal factory oil pump bypass pressure is, I cannot find a figure given anywhere.

And on my and numerous friends' small block chevy's in the 60's, 60 psi was also the norm. The standard of measurement then being the Stewart-Warner 270 deg sweep gauge.

And the only oil sender specs on resistance @ psi I can find are on Wells/Airtex senders; a wide range given, and certainly suspect in itself.

If you do check it with a good mechanical gauge, PLEASE post the peak oil pressure. Without that, your reading at 'cruise' and idle dont mean so much.

But until I can find real data, this -in my opinion- is the important part: The oil pump bypass valve is more accurate than the gauge. Whatever you see on your gauge as the peak pressure with _w 30 warm is the system pressure, And I assume for now that is 60 psi.*

If your oil is fresh and bearings are in good shape, It should happen at about 1500 rpm or less.
And if that is so, idle oil pressure will likely be 20-25 psi less.

The higher the rpm at peak oil pressure, the lower the idle pressure will be.

* Smoky Yunick long ago did a lot of practical research on oiling systems, using small block chevy's. His conclusion was that engines need 10 psi additional per 1000 rpm. Redline normal on factory engines being about 6000 rpm would explain bypassing at 60.

 

Just start with oil and filter change. Jimmeny Cricket!!