toofer

I`m a recent owner of a very nice 80 928S Euro. The oil pressure has been pegged on 5 or high at all RPMs. So I decided to get a new unit. I removed the oil filter and managed to get on the unit hex nut at the engine block. I can`t budge it. I have read about you guys changing them out and can`t recall anyone having trouble like this. Can anyone shed some light on this for me??? Toofer

largecar379

as far as I know, 928 oil pressure gauges stay at 5 bar and above when the engine is running as it should.....

if the gauge is functioning properly, why are you changing out the sending unit?

at this point, I would advise stop what you are doing......?

--Russ

worf928

Oil pressure should drop to 1.5 to 2.0 BAR once the oil is at operating temperature.

Have you checked continuity from the sender harness connection to the 14-pin connector at the jump post and then to the fuse panel?

Better access to the OP sender can be had by dropping the alternator. Otherwise it is very difficult to get leverage.

marton

but at relatively low revs, like 750rpm to 1500 rpm.

Marton

Tom. M

We were just in there on a car at our shop. There are two parts to the sender up there. One is the pressure sender and one is the "bypass" that has the spring in it to divert oil to the cooler when so equipped. The sender "nut" is a 26mm and you'll likely need a crows foot wrench to get at it. The bypass (silver aluminum part up against the block) is a 27. If you can separate the sender from the bypass then you can use a 27mm socket to get it out. If you are only replacing the sender then you can hopefully just pull that one and screw on the new one.

Worst case you can sacrifice the sender and just vice grip that sucker and twist it off. Otherwise get a crows foot wrench..will give you more torque to get it off.
Also, make sure you get a new aluminum crush ring up top (if you pull the bypass) and make sure it's snug against the block.

good luck
Tom

toofer

Thanks guys, Tom you hit my problem on the head. I was hoping there was a narrow wrench designed for this problem. I`m gonna need to head to a tool supplier and get some tools. I`ve got U.S. from 1/4 to 1" and metrics from 4mm to 17mm, they obviously are not going to handle working on it. I do enjoy workjng on my 928 but when you don`t have the right tools things turn south quick. Thanks for the input, it always helps. toofer

toofer

Thanks Dave, I was just thinking it looked like it may be easier if I dropped the Alt, I`ll start with that if I can`t find a wrench narrow enough to get the sender off. And yes I checked the wiring harness first, it was good. Thanks again for your help. toofer

bronto

I've wondered about this...

When the car is cold my oil pressure gauge reads pegged at 5 even when at idle, then after 2 or 3 miles it starts reading as you would expect - varying with rpm. So, this is normal??

bd0nalds0n

On Tony's writeup, he mentioned using an adjustable wrench because he couldn't get a regular wrench to fit (clearance). I ordered a set of adjustables from harbor freight for $7.99 today.

http://members.rennlist.com/v1uhoh/oilp.htm

Shark Attack

I forget how i got on mine, I do remember it was not easy... I think i desroyed the old sender on the removal.

Bill Ball

Yep.

An oil pressure reading that is pegged at idle after the oil warms up is a clear sign of no signal. It happened to my car, and turned out to be a bad sender.

The problem with getting the sender out is limited working space for a wrench. I went through most of my collection before I found one that would work.

largecar379

interesting.....my gauge does not drop down to 1.5 or 2 bars after warming up, but does drop to 4 bars on very hot day after use.

I don't advocate that these gauge readings are the gospel truth, it seems the gauges are unreliable--- so many folks say.

I also didn't see where toofer's gauge stayed pegged regardless of engine temp....?

is this the case?


perhaps installing a mechanical gauge would give you a more accurate reading.

--Russ

dr bob

Hopefully this will clarify--

On a COLD engine, the oil pressure will peg at 5+ bar at IDLE.

On a WARMED engine, the oil pressure will drop to 1.5-2.5 bar at IDLE, depending on which oil you are using. By the time the engine reaches 2000 RPM or so, oil pressure should be at 5+ bar again.


If you aren't used to seeing the opil pressure pegged, the 928 charactersitic will seem a bit odd. Once you get used to it, there's a lot of sense in the one-look gauge. If you are driving under any normal condition, the gauge should be at or near the top at all times. The only time it will be less is at hot idle.

IcemanG17

Like Tony says its easiest to remove the whole assembly.....while your at it also change the two springs...they tend to fatigue over time and will cause low oil pressure at low rpms when the oil is very hot....

You will need a stubby 27mm wrench to get the assemby off...once its off its easy to counter hold the 26mm to get the pressure sender off......

Tom. M

Pulling the oil filter will give you pretty good access up there. A lot easier than pulling the alternator..

have fun..

Cya,
Tom