I have an 89 GXL that I just bought and its in great condition but there's one thing I might be worried about. At idle my oil pressure reads in between the 30 and 60 mark so about 45. But when Im driving on the freeway or whatever at a steady speed or when I step on the gas the oil pressure gos up just below 110. Its at about 95-100 is my guess. I did quite a bit of searching but didnt find a solid answer for 89 GXL.

I also read that it should go down when your on the gas rather than going up in my case. Any help would be appreciated, I'll get un-noobish soon thanks for putting up with my questions. Peace!

 

30 at idle is good. 60 at 3000rpm+ is good.

stock engine should never go over 75.

I'm guessing your gauge is always reading high.

 

From what I've read in the Factory Service Manual (commonly referred to as the FSM and easily downloadable at www.fc3s.org) and from how my GXL is, oil pressure should be about 30psi at idle, and 60psi under load. The stock pressure relief valve should open up between 60 and 70psi.

 

Pressure relief valve = Thermo Bypass pellet/valve

Yes, no?

 

na,
pellet = thermostat
bypass thingy= oil pressure regulator

 

Oil pressure should always go UP as the rpms increase. Get a aftermarket mechanical gauge like a SunPro (cheap). Remove the rear oil hose banjo bolt. Drill a hole and tap it out to the thread size of the SunPro. Install the banjo bolt and install the SunPro in the new threaded hole. Read the real oil pressure vs the stock gauge oil pressure. It's as simple as that. Oil pressure goes up as rpms increase(with minor exceptions).

 

No...

Pressure relief valve (inside and above the oil pan, back of the motor) monitors oil pressure and dumps excess oil into the pan to maintain the proper pressure.

Thermo Bypass valve, is in the E-shaft, and prevents full oiling of the rotors and engine, until the oil temp is warm to shorten the time the engine takes to warm up.

 

Thanks.

Thermo Pellet I knew about, but I was unaware of the pressure relief valve.. Thought he was referring to the same thing..

 

well thanks for the help guys, should I be worried or is it a common thing for the stock guage to just be off?

 

Could be the gauge or the sender.

The gauges on the car aren't exactly reliable after so many years.

The connection at the pressure sender could be bad, as the sender itself could be..

(hopefully I didn't paraphrase someone else.. I didn't look back.. )