AJK

'79 5 Speed

Just completed head gasket replacement and valve stem oil seal replacement plus head resurfacing.

I don't remember what the oil pressure at idle at operating temp was before the work, but now it is at 1 bar. At idle cold and above 2500 RPM warm, the pressure is at 5 bar.

Do I have a problem?

AO

Let me make sure I understand what you are saying:
Engine Warm @ idle = 1 bar
Engine Cold @ idle = 5 bar
Engine Warm @ 2500 rpm and higher = 5 bar

On the surface, it sounds okay. Perhaps a bit low on the warm idle. However it's very dependent on the oil you use. What weight (i.e. 10W-30) do you have in there? I think most people are running a 10W-30 or 10W-40. John Veniger suggested a synthetic 15W-50 during his fluids tech session at the Frenzy IIRC.

heinrich

1bar == too low if correct.

IcemanG17

What weight oil....@ 1 bar warm I would guess 10-30 or so....try a synthetic 15-50 or 20-50 & it will bring up the pressure! 1 bar does sound a bit too low, however I have heard that 1.5 bar is about right for warm lighter weight oil. Typically I get no lower than 2 bar (usually 2.5) at idle with Mobil 1 15-50.

Jim_H

What Iceman said. I would guess you are using a 10-30 also, hopefully, otherwise there may be cause for concern. You will get some people touting 3 bar at warm idle, but that's isn't necessarily that important.

John Veninger

AJK,

What weight and type oil are you using?
I wouldn't start putting on a 20W-50 with winter approaching if this is a daily driver.
The other thing to check is the connectors to the OP sender and the pod.
A check with a mechanical gauge should be done if you are using a 5w-40 or 15w-50 and still get a 1 bar warm.
A very hot 928 will drop to 1-1.5 bar (on the track), but normal street use should show around 1.5 when pretty hot.
I've seen just under 2 when pretty hot on my GT

Your 2500rpm, 5 bar is just fine.

AJK

Thanks all. Andrew has it exactly right with respect to the conditions I am seeing.

I am using 10W-30 and idle is at about 900RPM.

I had previously been using 10W-50 oil.

Guess I'm OK.

Thanks again.

Fastest928

Either your bearing and lifter interfaces are worn, or your oil is very hot or wrong oil weight or your gauge is wrong .... there is a procedure for checking oil temp and pressure in the workshop manuals and it is very important to know what is going on..

1 bar at hot idle is very low ... best check it out and make sure.

AO

Yep. 10W-30 is too thin. Switch up to a 10W-40 minimum and all should be okay.

FlyingDog

5W40 Synthetic like Delvac 1, Mobil 1 Truck & SUV, or Shell Rotella T would be good for winter.

Jim_H

It's what I use, Doug Hillary recommends it which is good enough for me. Now if only I could find the 5qt jugs somewhere besides Walmart for $20. That place scares me.