W124 300D Oil pressure stays at 3

[roadhog]

Hi all,
Small problem with my 300. I parked it up last week and left it for a few days due to having a new toy. When I eventually got back to it I noticed the oil pressure gauge sitting at 3 (bar?) even before I started the engine. Car runs fine with no noticeable problems or noises.
I did some research and found out that this relates to the over pressure valve in the oil pump being stuck. Is this correct?
What are my chances of unsticking the valve with a flush and oil change? Or is this a sump off and clean the valve job?
I've checked the gauge and it works, just that the oil pressure sits at 3 every time I switch the engine off rather than slowly dropping down as it used to.

Cheers
roadhog

 

[Xtractorfan]

By all means try flushing oil, if that dont work u could always try the old diesel and lube trick it gets to places other oils cant reach ..and works wonders one gall of diesel add 1 lt of cheap engine oil and run car for 3 or 4 mins..

 

[Bolide]

If you turn on the ignition on a cold engine and the pressure gauge snaps up to 3 then it's a gauge fault

There's a thread running about this on one of the forums. I've seen it on a couple of cars

Nick Froome
www.w124.co.uk

 

[stumpy]

Or the sender perhaps

 

[star]

the guage works on an earth return, so if there is a poor contact or broken wire to the sender unit it will stay at 3 bar, check connections to sender, then earth wire to sender and the guage should read 0, if that works change sender unit.

 

[roadhog]

I'm fairly certain the gauge and sender are OK.
When I got in the car after it had been stood for three days the gauge was reading 3. This before I'd even inserted the key.
I ran the engine, drove it for a short while and noticed nothing untoward, the gauge was still at the same position.
Once back home I removed the centre bolt from the oil filter as I'd read somewhere that the small bore can clog up and cause oil pressure problems. I got a bit of sludge out and refitted it. Got back in the car and the gauge was reading zero.
"Fixed it" I thought, started the engine and the gauge duly moved to 3. Nice smooth movement as usual (a short or any electrical cause would have made it move quite quick?). This was more like a gradual build up, just like it always was.
Turned the engine off and the gauge stayed at 3 again, doh!
All the above (and sorry for the longwinded post) leads me to think the the gauge and sender are doing what they're supposed to. Unless, of course, you know different. In which case don't hold back.
My German equivalent to the Haynes book mentioned the over pressure valve as a possible cause hence the original post.
This all happened last Thursday, I parked the car up and took the Saab to work. I haven't been able to investigate further as I'm not back until Monday.
At this stage I'm inclined to try a flush and change the oil and take it from there. Not much lost if it doesn't cure it. The next change is due in 1000 or so miles anyway.
On a similar (and possibly related) note, I'll be going back to Shell Helix again. I did my last oil change using some oil I bought from the local motor factor, can't remember the brand. I did notice that ever since then the oil pressure dropped lower than usual when the car was idling with a hot engine, i.e. just below 2 instead of over 2 with the Shell. Or perhaps I'm just clutching at straws now...
Anyway, that's enough for one post. Thanks for reading, your thoughts and advice as always much appreciated.

Cheers
roadhog

 

[roadhog]

Quick update..

Well, a good flush and some decent oil seem to have cured that particular problem. Unless I've just jinxed it....
Whilst I was under the car I changed the engine mounts for some very expensive new ones. Boy, what a difference! Soooo quiet! The old ones were well and truly shot!
This afternoon however I found a huge puddle of diesel under the car which turned out to be from the return off the fuel filter. Cut the end off and seems OK for now, need to get a new hose though as it's a bit on the short side now.

Also noticed on my way to Belgium yesterday that the front offside wheel bearing is on it's way out. Is this a big job? And why do these things only happen when I'm away?

 

[television]

front wheel bearing is dead simple to do, just ask when you are ready

 

[roadhog]

Thanks for that.
I just wondered how much of a job it is as I'm abroad with only a basic tool kit and also forgot my manual (typical really)
I'll see if I can get a spare part and I'll be back.