Mk3 Tdi oil alarm keeps bleeping

[sparkie]

Hi fellas and fellettes, just wondering if someone can help. I have a 1996 Mk3 Tdi, and the oil alarm and oil light keep coming on after driving up hills, and more recently even on the flats. The oil sender was replaced and it has sort of done it since. The oil is at the correct level and the engine temperature gauge seems to stay at 90 degrees or in the middle. So why is the bleeping thing going off?before the oil sender was replaced I never had this problem and I drive some pretty steep long hills around the Sunny Coast Hinterland with air-con on, etc.

[Jarred]

I believe that the oil buzzer is actually a low pressure warning, rather than level. I'd be very cautious!

(it used to happen in one of my cars, but that's cause it was actually low on oil, and the pick up must have starved. Needless to say, I rectified the situation pronto!)

[Idle]

Could be engine wear, oil pump problem, sensor/wiring fault etc.

For peace of mind, get your hot engine oil pressure checked.

[gldgti]

what rpms?

if you have got the engine very hot and then the low pressure warning goes off at idle, thats not unheard of, and you might 'fix' the problem by using a better quality oil.

if the buzzer is going off at higher than idle rpms then you might need to investigate your oil pump for wear, or your big end bearings or intermediate shaft bearings. could be pretty serious.

What oil do you use? I would be using a 5-40 synthetic or semi synth.

[sparkie]

if the buzzer is going off at higher than idle rpms then you might need to investigate your oil pump for wear, or your big end bearings or intermediate shaft bearings. could be pretty serious.

What oil do you use? I would be using a 5-40 synthetic or semi synth.

Thanks for the advice, It seems to go off after a fair amount of climbing up hill, so the engine is hot. It does it whether I am in high rpm or low, though if I ease of the acceleration when it goes off and drive more sedately it seems to calm down a bit - though not always. I do the same school run every day, and if it is a cool morning and raining I can be pretty confident the alarm won't go off

Not sure what oil I use, whatever the mechanic puts in there! It is due a service in March so I'll get him to use what you recommend, and ask him to check the oil pump assuming that's an easy job?

[h100vw]

Probably worth dropping the sump off to check the oil pump pick up for debris.

Gavin

[gldgti]

Thanks for the advice, It seems to go off after a fair amount of climbing up hill, so the engine is hot. It does it whether I am in high rpm or low, though if I ease of the acceleration when it goes off and drive more sedately it seems to calm down a bit - though not always. I do the same school run every day, and if it is a cool morning and raining I can be pretty confident the alarm won't go off

Not sure what oil I use, whatever the mechanic puts in there! It is due a service in March so I'll get him to use what you recommend, and ask him to check the oil pump assuming that's an easy job?

Not and easy job exactly... and takes some specific knowledge. Make sure you are getting good quality oil in it, makes a big difference.

I have read 10psi hot pressure difference (at idle) between mineral oil and fully synthetic. If your oil is breaking down it will be causing wear issues - you should try to rectify it asap

[sparkie]

OK thanks for the heads up on getting something done asap. My mechanic suggests that we put an oil pressure guage on the engine and run it hot to see what is happening, in case the new switch is faulty. So does anyone know what pressure the oil should be when the alarm switch triggers the audible alarm and light on the dash? BTW the oil I use is Fuchs 10-40 synthetic

[Jmac]

Yep oil pressure test is what you need to do, so the recommendation is correct there. Also depending in the colour of the switch depends on its function and what pressure it reads, you have blkue, brown, white and black all different.
I still have a listing of pressures in my "black book" if you need to know what switch is doing what ping me a pm
cheers
Jmac

[gldgti]

I think the mk3 diesel have a blue switch and the alarm is normally set to go off at below 8psi

Hot idle pressure you really dont want much less than that worst case, and it should go up to ~30psi hot at 3000rpm (roughly speaking 10psi per 1000rpm is about right.)