not a "what should I do" oil pressure question

I just want to know if it's normal for it to fluctuate as much as it does. Running a 258 I6. Even when warm it fluctuates a lot.

 

How much is it fluctuating? What are the readings? Is this a difference from idle to cruise speeds?

 

Starts off low, then when it warms up it at cruising speeds it fluctuates from about 55 to 70 psi. Idling is around 50-60 psi, sometimes a little lower.

 

Those numbers are great, plenty high. It's not uncommon for the numbers to be lower when your at idle because the pump is turning slower.

 

My 258 has 30-35 psi at hot idle, which I consider to be excellent. You'd expect the hot idle (not cold idle!) pressure to be 20-30 psi lower than on the highway.

Is this the OEM gauge? If so, I'd suspect the sender and gauge rather than the engine.

 

I think it's the original guage. I was actually worried about it being to high, but it hasn't pegged out. It just fluctuates hot between 50-70. I guess I shouldn't worry about it.

 

No, you should. The pressure should hold steady. Test the gauge per the FSM, check the connections at the gauge and esp. at the sender, and then replace the sender. Or else get a high-quality aftermarket gauge - I prefer a mechanical, full-sweep Stewart-Warner.

 

Is that 20psi fluctuation at a steady speed? If so I was confused and I agree with Tim. If that's the difference between idle and cruise then I think your fine.

 

:iagree: Hook up another gauge for a temporary comparison.

 

I've been having trouble with mine as well....

Does anybody out there have a valid part number to replace the sending unit - 1975 258 I6 - Screw terminal - not button on the sending unit.

I've purchased one (BWD S4057) from a local parts store but when I install it, the gauge shows 0 pressure.....

Thanks

 

Mine oil pres. gauge fluctuates like what your saying, but its due to a poor connection at the engine block where the oil pres. tube hooks up. Atually picked some copper sensor tubing today to replace it.

 

No it jumps around some as I'm cruising. I found my tester and I'll test next week. I need to test my fuel/temp guages too.