Strange oil pressure problem

[Roger Chatfield 0]

I've noticed a strange thing with my oil pressure.

 

Sometimes when I start the car from cold I've noticed that the oil pressure shoots up high, 8-9 bar, it'll stay like that until I slightly 'blip' the engine it then drops to normal cold idle level (about 4 bar)

 

Anyone have any idea whats going on??

 

Rog.

Edited June 26, 2014 by Roger Chatfield

[g0ldf1ng3r 14]

Hi Rog

 

I had an issue when my VR was having its head rebuild etc at stealth.

 

Vince sent me pics to show that when cold my oil pressure was about 9 bar & was way too high. IIRC vince also said that when he was testing if he gave it a fair amount of throttle when cold the engine cut out

 

he diagnosed it to be an issue with the sump oil pump not providing enough flow & a sign it was failing.

 

in my case this resulted in springing/forcing an oil leak through the brand new head gasket they fitted

 

a new sump oil pump (& new sump as mine was quite tatty) resolved the problem & it has not repeated again since the 2nd rebuild vince did

 

hope that helps

[Roger Chatfield 0]

Mmmmmmm, interesting, I can't see how a failing pump can cause high oil pressure.... Am I missing something here?

 

Rog.

[g0ldf1ng3r 14]

Mmmmmmm, interesting, I can't see how a failing pump can cause high oil pressure.... Am I missing something here?

 

Rog.

 

i thought similar too Rog. however, after much discussion with vince i figured that if the oil pump was not providing a high enough flow rate then the pressure has to build somewhere until it finds a weak point & then escapes through such.

 

in my case it resulted in forcing a leak past the brand new head gasket fitted on the 1st head rebuild

 

ive just checked the image vince sent me on my phone & the needle is right on 9 bar (its not on my work PC else i would post it)

[Roger Chatfield 0]

Just had a quick google and it appears that it could be the oil pressure relief valve that is at fault.

 

http://the-corrado.net/showthread.php?t=22528

 

Rog.

[Jim Bowen 1]

Got my oil pump in bits at the moment if pics would help

[seanl82 23]

It's a simple shaft driven vane pump Rog. Not heard many (if any) instances of them failing. Unless the mesh on the pickup has become blocked, I can't see it being the pump. Easy enough to check thougg by dropping the sump and removing the two hex bolts that secure it mate.

[Roger Chatfield 0]

I've had it off already Sean, (when I did the bottom end) and all seems fine, I'd rather not do it again as I have some rather expensive oil in the old girl atm.

 

TBH it doesn't really bother me, a quick blip and all is normal, it's just I rather know what the problem was if you know what I mean.

 

Rog.

[seanl82 23]

Yeah fair enough mate. I just had to order a second helping of the fuchs pro race too. The six litres I ordered previously only got about a third way up the dipstick level indicator, so I thought it was.pointless ordering a single litre. Got another 5 litres and a litre free again from opie. Hopefully should be enough to do the next change though as a little should remain.

[g0ldf1ng3r 14]

Just had a quick google and it appears that it could be the oil pressure relief valve that is at fault.

 

http://the-corrado.net/showthread.php?t=22528

 

Rog.

 

good find Rog!

 

seems the valve/pump are not repairable though according to the below post

 

'erm, sorree it's a bill. Not repairable as its a bore wear problem and I'm not aware of an oversize plunger to fit once bored out.'

[vag 10]

relief valve sticking and not allowing the pump to relief oil pressure,blipping the throttle most likely unsticks the relief valve.

 

If the relief valve is totally stuck closed and if you rev it hard the hydraulic tappets pump up to much and wont allow the valves to close causing the engine to stall, and upon restarting will sound like its got no compression until the tappets come back down to normal operating pressure.

[g0ldf1ng3r 14]

relief valve sticking and not allowing the pump to relief oil pressure,blipping the throttle most likely unsticks the relief valve.

 

If the relief valve is totally stuck closed and if you rev it hard the hydraulic tappets pump up to much and wont allow the valves to close causing the engine to stall, and upon restarting will sound like its got no compression until the tappets come back down to normal operating pressure.

 

those are the exact syptoms vince explained to me vag.

 

he also explained that as i historically never go above 3000 rpm until oil temp reaches over 70 i had more than likely never experienced it cutting out, which i hadnt

[vag 10]

yeah sounds about right, i first experienced it in my 16v mk2 it had crappy tappets that were always loosing pressure and tapping so replaced them with new vw ones, soon as i revved it kept doing the above. It baffled me for a while you couldn't drive it until it reached temp as it just cut out and would have to crank it for ages until the cylinders slowly come back on line. any way replaced the pump and all was well.

[g0ldf1ng3r 14]

yeah sounds about right, i first experienced it in my 16v mk2 it had crappy tappets that were always loosing pressure and tapping so replaced them with new vw ones, soon as i revved it kept doing the above. It baffled me for a while you couldn't drive it until it reached temp as it just cut out and would have to crank it for ages until the cylinders slowly come back on line. any way replaced the pump and all was well.

 

yup! nail...head there m8, especially the very last part :D