Club 80-90 Forums

Took the van off the road to change the front gearbox mount. Put it back together again and cleaned/checked the earth strap. Continuity is good.

Started it up and oil pressure light stays on. After a short while it starts to flicker more and more an nearly goes out. Not driven it though.

Never had issues with oil pressure before. Recent oil change and new good quality Mann filter on it.

Any suggestions of where to start? JX TD by the way.

madjak wrote:Any suggestions of where to start?

Check the wiring. Then replace the sender. But - given what you've just been doing - my money's on the wiring.

Wiring on the sensor is good just need to check the rest out.

Just read the DOP guide on the wiki and have a question.

My oil light is coming on at low speed - well tick over, however the guide states that the buzzer should sound at low speed.

No buzzer, so does this mean the Dynamic Oil Pressure (High Speed) sensor (the one in the filter housing is triggering) or is this impossible until the engine gets over 2250 RPM?

If this is impossible then it must be the cylinder head one, yes?

Or am I way off track with all of this....

Oh and I do not have access to a pressure tester.

i would replace the low pressure switch[on the front of the head]...have you got any oil leaks?

dave friday wrote:i would replace the low pressure switch[on the front of the head]...have you got any oil leaks?

I've just fixed a load of leaks from oil filter housing, diesel injectors oil filler tube and rocker cover, why?

Because any leaks[on the pressure system] will affect the oil pressure,leaks from the cam cover,oil filler wont .
Check for oil leaks on the oil feed pipe that goes from the oil filter flange to the turbo.
Is the gasket under the oil filter flange in good condition?

OK have already done the gasket under the oil filter flange, There was a lot of oil coming from the top of the engine and a lot of oil all over the turbo but I decided to fix the ones at the top first and then see where else the oil was coming from. Thought it may have been coming down off the rocker cover onto the turbo.

Will clean and check the turbo feed pipe as well. Has not done enough miles yet to really see where else it may be coming from.

Have not noticed any really big leaks coming from anywhere.

Had a look at the wiring again last night (rather cold!), cannot see any obvious problems. Removed the Gearbox earth, cleaned again and replaced, no change.

From the cylinder head oil pressure switch checked to ensure that the sensor was closed with the engine off, was still closed with engine running...

Today a slight change in behaviour; engine off flashing as you'd expect, with the engine running, the pressure light stays on but is dull and no flashing also no buzzer of doom? With the engine running I put the meter in line with the sensor and got 12.83v slightly odd behavior, with that voltage why didn't it just flash? Resistance across the sensor was pretty much 0. Pressure light goes out when disconnected, pressure light flashed continually when the sensor wire is put directly to earth via the cylinder head, what I'd expect from a sensor who's default state is closed.

So it looks like s failed low rpm sensor or an actual pressure problem. Only this is if it is a pressure problem why does the light not just flash and the buzzer sound?

So I'll change the sensor to start with. But the sensor is black, according to the Wiki they'd either be brown or blue. According to Brickwerks the black one is normally open and for use on the DOP side on the filter housing flange. So any ideas what sensor I should replace it with?

The blue sensor [.25psi...normaly closed] all the other sensors on the "Brickwerks site are normaly open sensors.

Cool new blue sensor ordered, also no oil leaks that are going to cause oil pressure problems.

Blue sensor fitted to the cylinder head. Problem solved, thanks for your help all.

Still confused as to why there was no buzzer though.

the buzzer only sounds when the oil pressure is below .9bar and the rpm is above 2000rpm!

dave friday wrote:the buzzer only sounds when the oil pressure is below .9bar and the rpm is above 2000rpm!

Ok good info, thanks

Look up "Oldiebut goodie" in "any other matters " for the "bently manual" [you'll have to become a 80-90 member first]