Hi all, I've recently changed the head gasket as car was overheating, and after all round maintenance including oil + filter change, the buzzer and light came around (wasn't there before). I've tried both 10w30 and 20w50 but still the issue persists, maybe a bit better with 20w50. There is also a whining/squealing noise coming from the back end of the engine, especially when engine reaches running temperature. I also confirmed that its Not any other component (such as alternator bearing etc..) by the wooden stick to ear method. 

 

Also disconnecting the yellow high pressure wire and shorting it to ground, with engine running, turns off the buzzing and flashing light. Also tried swapping wires around both sensors, and made the issue worse (buzzing right off from idle). Leading me to think that electrics are working fine, as issue was never there beforehand. 

 

Could it be a faulty oil pump? A dirty oil pick up? Its just strange having also tried different viscosities of oil. Would appreciate any help.  

i would buy a cheap oil pressure gauge and see what it says ...theyre not expensive

 

this will confirm if its really a low pressure fault or elec gremlin 

did you inspect the gasket carefully to make sure its correct and not blocking an oilway?

Comparing the Head gaskets, the marked holes were missing within the new head gasket, however I assumed that these do not pass oil through as they are past the red gasket material + the shop I bought it from confirmed that it is for the HZ engine model. Could it be these two holes? 

is that a mech tappet engine ?

 

id agree i think its outside the area that matters 

According to Haynes no, its a hydraulic bucket tappet type.

 

Went for a quick drive and its over heating as well, however what caught my eye is when I blink the full beam lights, the temperature led starts to flash and goes out after a while. Beginning to suspect the dash now, however quite strange that the dash is malfunctioning after the work done on it. 

 

Will be manually testing oil pressures as well as lost all hope on the electrics.  

any earth straps left off during the job?

 

is it really overheating or maybe just a gauge fault?

Not that I recall of no earth straps needed to be removed, apart from the carby brown negative lead which goes on one of the intake bolts. 

 

Well it never goes over the limit of the temperature gauge as the fan kicks in. Judging by no dip in power or previous head gasket failure, it may not be actually overheating and it has always been 'overheating' since the day I got it. 

 

Good little write up here about the VW dynamic oil pressure system, in case you need to check it again.

 

https://vincewaldon.com/2009/03/08/howto-diagnose-the-dynamic-oil-pressure-warning-system/
 

Buzzer should only come on with flashing oil light if engine is above 2k revs and the oil  has not reached a certain pressure, which I think is 1.4bar on an HZ engine. 

 

If your buzzer and light went off when you shorted it to earth that would seem to prove that the dynamic oil pressure wiring and electronics  are ok.

 

The only things left are the high pressure sensor that could be faulty or you have a genuine oil pressure problem.

Edited 7 December, 20214 yr by mk2tastic

Yep great write up, got around to it today, opened oil pump and everything seems to be within tolerances, will be changing oil pressure sensor next. Could it be that 20w/50 is to thick for it? but that would create more oil pressure, more so 10w30 carried the same issue...

 

Correct it is 1.4bar. does the buzzer come on when this pressure is exceeded or reached? (When over 2k rpm) 

we run 10/40 with the uk climate ...imagine 20w is a little hard on cold starts unless its very warm there?

 

i really would just test the pressure before throwing parts at it , many replacement parts cant be trusted now a days

Buzzer comes on when revs over 2000 and pressure below high pressure sensor threshold.

 

I ended up cutting the tacho feed wire inside the dash clocks to the J114 circuit board, as a pressure gauge showed all was 

totally normal. This seemingly drastic act keeps the low pressure warning system used by every other car maker on the planet.

Engine's still running fine 13 years later.

 

 

7 hours ago, Drew99 said:

Yep great write up, got around to it today, opened oil pump and everything seems to be within tolerances, will be changing oil pressure sensor next. Could it be that 20w/50 is to thick for it? but that would create more oil pressure, more so 10w30 carried the same issue...

 

Correct it is 1.4bar. does the buzzer come on when this pressure is exceeded or reached? (When over 2k rpm) 

The buzzer comes on if the 1.4bar sensor hasn’t been seen to operate by the time the engine gets to 2000rpm.Or to put it another way, the Buzzer won’t come on if the 1.4bar pressure figure has been reached/exceeded.