Thread: Oil Pressure ALARM

And this morning zero oil showing on the dip stick, so I guess the oil isn't draining back into the sump. Changing oil filter and new oil see, what happens.

Hmmm.
Not good.

Pressure releif valve is in the bottom of the timing housing cannot remember if it is sump on or off to check.

Pop the filler cap, youll see if it is not draining back.

Check timing belt housing and rear main housing drain plugs.

Check intercooler pipes for excess oil.

Check exhaust to see if it is burning oil.

Cut the old filer open and look for anything sinister.

That'll keep you busy till the more advanced guys arrive

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Changed filter and topped it up....didnt take a lot of oil to get it back to full. Warmed it up, operates okay, sounds normal but the oil pressure is fluctuating a lot and erratically, electrical connection is sound. Generally about 1 Bar higher than usual.

At driving engine speeds it fluctuates from about 3.5 Bar to 4.2 Bar and drops down to about 1.7Bar at idle. Previously normal temp/speed 3 Bar steady and 1 bar idle. Im thinking the pressure relief valve is sticking.

Sump comes off for that.,,,and then from what I've read it can be a bugger to get out.

Does anyone know exactly how it works? If it sticks open does that cause High or Low pressure?

I'd be trying another pressure sender first, or temporarily run a mechanical gauge to double check.

Originally Posted by bee utey

I'd be trying another pressure sender first, or temporarily run a mechanical gauge to double check.

Thats a good point. I dont have a mechanical gauge. The unit came with the MadMan which I have only had a few moths, but it could be faulty, quite possible.

Thanks for the idea...I'll see what other senders I have.

It seems to have improved, now mostly between 3-4 Bar, rarely over 4 Bar. Sometimes erratic, sometimes stable. The alarm was set at 8 Bar....and it stated the max it reached was 10 Bar...which is the upper max of the readout. I have now set the alarm to 4.6 Bar as under that it should be right until I can sort it out.

An electric glitch could cause the gauge to spike for no good reason, mine did that a few times over the years. But a spike & erratic readings & loss of oil, I dont like the sound of.

I think the relief valve stuck open will cause low pressure, but cant be sure right now.

Between this and your other thread you have a good list checks to start narrowing it down.

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Ditto what Simon and Bee Utey say.

Some easy checks:
check earthing of your sender
check your cyclone breather is clean
check your drain hose from the cyclone breather for blockages
check the engine breather hose for blockages

Oil pressure relief valve requires the sump to come off. I've read a few threads where the spring for the relief valve loses its springyness. Check the length of the spring to a new one. (not sure how long a new is though).

How much oil do you think you put in get it back to normal level?

I'm tracing similar problem on '97 300tdi auto and mine is intermittent but I don't have a pressure gauge connected yet. (long story)

Let us know how you get on.

Originally Posted by mike123

Ditto what Simon and Bee Utey say.


How much oil do you think you put in get it back to normal level?

I'm tracing similar problem on '97 300tdi auto and mine is intermittent but I don't have a pressure gauge connected yet. (long story)

Let us know how you get on.

Only a litre or so....it has some extra leaks by the looks so the oil level issue is unrelated, its been longer than I thought since checking....the darn thing has a few drips that add up. No sign of any leaking from the oil filter, no pressure in the rocker cover.

Ill check earth, try a different sender etc and see how it goes. I have to drive it back home 160km, if I keep it at around 90ks it stay around 4 Bar which isnt too bad, it should be able to deal with that.