Buzzer of Doom - Good course of action

[willpom]

Hi

Been reading other posts and wiki on the Buzzer of Doom. Just would like someone in the know to say I'm on the right course so I'm not wasting my time.

4spd DG 1.9l '85 watercooled, recent oil & filter change, well serviced by previous owner. BoD comes on occasionally, usually during a fast drive when I have to slow and revs drop to around 2000-2500rpm. Can cancel it out by shifting down a gear to keep revs higher. After a few miles driving at a slower pace when not holding high revs for as long then no more BoD even under similar circumstances/revs.

Do I start by changing the high pressure switch (which I have) and check the wiring. I've had a look and it looks bloody awkward to get to but also the wiring around the switch is a little grubby. Then see what happens after that, or do I take it to a garage and get them to do a proper pressure test and spend the bucks?

Am I right in thinking I don't need to worry with the low pressure switch? Every thing seems to be working fine here, light on at ignition, off after cranking.

Thanks

[Hacksawbob]

I think the basic test is while the engine is running, disconnect the wire from the switch and earth it, this is recreating an oil low pressure situation. if it is the high revs switch then the oil warning should come on at higher revs (ie boot the engine to 2500 RPM to test it.) check condition of the wire, look for damage where it might be earthing somehwere. If all this checks out then swap the oil pressure switch. If it is still going off then it's time to get the oil pressure checked at a garage.

[KINGPRAWN]

That was my exact scenario .... So I fitted a pressure gauge which showed I had low oil pressure ... 4 years on still have but changed oil to Mobil 10/60 which is a little thicker when hot and that has helped a lot ( still low though) also I earthed out the sender so the buzzer won't sound !!

[Hacksawbob]

la la la can't hear you

[marlinowner]

I had these exact symptoms, engine lasted another 10,000 miles before failing in a major way.

[Mocki]

Change the oil pump

[what2do]

How long have you been running with that engine oil?

[KINGPRAWN]

Change the oil pump

I changed the pump.... Made no difference !!
But Mobil 10/60 has made a big difference ... Still low but better than it was !!

[willpom]

I think the basic test is while the engine is running, disconnect the wire from the switch and earth it, this is recreating an oil low pressure situation. if it is the high revs switch then the oil warning should come on at higher revs (ie boot the engine to 2500 RPM to test it.) check condition of the wire, look for damage where it might be earthing somehwere. If all this checks out then swap the oil pressure switch. If it is still going off then it's time to get the oil pressure checked at a garage.

Thanks, will give it a go when I get a mo.

I had these exact symptoms, engine lasted another 10,000 miles before failing in a major way.

Please elaborate, why did it fail?

How long have you been running with that engine oil?

500 miles, it was regularly serviced by previous owner

[marlinowner]

Can't say exactly how my engine failed as I had made the possibly sacrilegious decision that I wasn't going to spend much on the van other than running costs as it would make more sense to spend money on a different van. Engine was tired at 180,000 miles, using oil and water, bodywork was dented and rusty, interior was nothing special, etc. The "high" oil pressure warning gradually got more frequent over around 10,000 or so miles, from coming on when slowing from a long high speed run which wa s "fixed" for a while by using 20w-50, to coming on as soon as the engine was hot and the rpm cutoff was reached. Engine finally failed by loosing power/misfiring/nasty noises/copious amounts of smoke/steam from exhaust/water pouring out. I didn't investigate further though so might not even have been oil pressure related.

[tommin]

Well those symptoms are nothing new? These are the trait of these old girls, i do believe this why so many of us here on the forum like em so much, not unlike her in doors some would say just some tender tlc now and then, a regular oil change, and washdown periodically, yep just like her indoors

[pfield69]

I had the buzz of death too. My engine only has high pressure gauge (no low pressure gauge).
I removed the little clapper from the relay - no more buzz.
The oil light has been flashing at idle for 3 years 20,000miles.

[willpom]

Thanks guys. I'll have a go at changing the higher low pressure switch and checking its wiring. Then if needs be a pressure check. And may be next oil change a different grade.

[Ads1987]

How did you get on with this in the end willpom?

I'm having the same issues unfortunately!

[willpom]

Hmmm, on going, haven't had the time to do it yet. I'm either working, looking after my boy or away in the van!

Hope it is just a faulty pressure switch or wiring. I've noticed I can avoid it by anticipating when it is going to happen and therefore change gear or brake bringing the engine speed down through 2000rpm, it doesn't happen when braking