High Oil Pressure

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muttleypup
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High Oil Pressure

Post by muttleypup »

Oil pressure has suddenly risen and will (indicated on gauge) peak at 100psi+ cold / 80psi hot under load/high revs. Idle pressure when hot is approx 20psi which is what it always has been on the gauge (TIM gauge and sender). Previously, peak pressure hot was around 60psi
I have already replaced sender and gauge with new TIM items, along with a new signal wire and re-done both live (picked up from a switched live at the brake warning lamp on dash) and earth, same readings as before. Also done oil and filter change to rule out blocked filter.
I suspect the oil pressure relief valve in the pump has stuck but before I drop the sump (I figure I may as well replace the pump at that point rather than try cleaning the valve since the time is much the same) any other ideas on what the cause may be?
1987 single cab pickup 1.9 1Y

davidoft1
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Re: High Oil Pressure

Post by davidoft1 »

Check it’s not the valve in the filter first

Ps what engine?

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muttleypup
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Re: High Oil Pressure

Post by muttleypup »

It’s a new (mann) filter...is there a valve in the filter mount/housing?. It’s a 1y
1987 single cab pickup 1.9 1Y

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937carrera
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Re: High Oil Pressure

Post by 937carrera »

New parts can be faulty, and I have seen occasion when even a Mann filter was defective, though that would normally give low pressure
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

davidoft1
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Re: High Oil Pressure

Post by davidoft1 »

muttleypup wrote:It’s a new (mann) filter...is there a valve in the filter mount/housing?. It’s a 1y


Was it doing it before the filter change ?

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muttleypup
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Re: High Oil Pressure

Post by muttleypup »

The symptoms were there prior to oil and filter change, oil had only been changed about two months ago but re-did it to rule out filter
1987 single cab pickup 1.9 1Y

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937carrera
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Re: High Oil Pressure

Post by 937carrera »

In which case I would suspect PRV too.

:ok
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

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muttleypup
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Re: High Oil Pressure

Post by muttleypup »

Thanks, just wondered if I'd missed something, looks like i need to change the pump though
1987 single cab pickup 1.9 1Y

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muttleypup
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Re: High Oil Pressure

Post by muttleypup »

Before I go ahead and drop the sump, do I NEED the gasket with the baffle plate or will a standard gasket be OK? Brickwerks listing both

E D I T after more poking around online, I'll be getting the one with baffle plate
1987 single cab pickup 1.9 1Y

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muttleypup
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Re: High Oil Pressure

Post by muttleypup »

pump changed today, not by me, farmed it out to mechanic i use for jobs i don't fancy. has made no difference to pressure readings. sump was clean, no sludge build up or debris. Engine runs absolutely fine and is quiet, for a diesel anyway. does anyone have any other thoughts on possible cause?
I have tried to find what the official/VW readings should be for a 1Y but no luck, if anyone knows I'd be grateful.
1987 single cab pickup 1.9 1Y

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muttleypup
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Re: High Oil Pressure

Post by muttleypup »

managed to find the oil pressure specs - '@2000rpm, hot engine minimum is 2 bar, at higher revs it should not exceed 7 bar.  mine is running in line with these figures when hot, although higher readings than i've had for the last five years or so since fitting a gauge in the cab. 
prior to the sudden change in readings, pressure would drop off fairly quickly as engine warmed although never worryingly low, hot idle was about 1 bar and it'd max at around 4.5 bar. hot idle is now around 1.5 bar it'll max at around 6 if pushed hard.
Since neither I or my friendly mechanic can find anything wrong, engine runs fine, no leaks, no smoke, no nasty noises and sump was very clean when removed/new pump was fitted the assumption is that relief valve in the old pump had been stuck partially open and just freed off suddenly.
It's only a best guess really but I've been using it every day and if anything was blocked causing the high pressure it'd likely have either seized something or be knocking like hell by now.......worst case scenario and it does let go I have another known/good engine sitting on a pallet
1987 single cab pickup 1.9 1Y

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