Club 80-90 Forums

Hi All

I have recently picked up a 1986 1.9 waterboxed T25 DG engine (according to VWHeritage).

So first thing the Oil pressure Valve, was stuck, so after much head scratching and talking to a tractor shop to get a valve puller success. and replaced.

Brilliant, the buzzer and light are gone...

1 day later.. the light start to act up erratically and the buzzer start up again but not in relation to revs.
next day, the buzzer stops but the light flashes from the moment the engine starts.

Due to the erratic nature I contacted VWHeritage and order an Oil Pressure switch, according to their lists I needed a White to replace my High Pressure switch.

Now according to this forum and Haynes I should have a Low pressure switch on the left of the engine and a High pressure one at the rear.

Well I found the left one, which turned out to be a white one??? should it be?? does not seem right.
but absolutely no sign of the rear, High pressure switch.

I pulled the lead off the low pressure, White, left, and started the engine to see what happens to the light and buzzer.
Brilliant the light does NOT light up nor does the buzzer sound, so maybe it was a defective switch and replaced it with the new one just to see.
No change. Start the engine and the light flashes!

So if I only have 1 switch is this a pre '86 engine, but in that case where has the buzzer come from?
If I have a true '86 engine where is the high pressure switch and what colour should the low pressure switch be?

I think I might have "the Buzzer of What the blithering heck".

Any suggestions welcome.

MrBeard

The high pressure oil switch (if fitted) is between the oil pump and the oil filter, there will be a brown wire that drops down next to the water pump to it.

The B.O.D. should only sound above 2,000 revs, once switched on though it stays on until either the pressure raises above the switch pressure or the ignition is switched off.

What oil are you using ?

Ian

There should be a sender between the push rod tubes..

Hi guys
Thanks for your help

I also contacted VWheritage to check the low pressure switch colour.
They also sent me an image that when combined with your descriptions enabled me to find the high pressure switch next to the oil filter behind the belt and pumps.
I couldn't find the wire previously as it had been attached to another part and seemed to come from there instead of the high pressure switch.

After destroying my hands getting in there (Not enough space for a spanner). I finally pulled out a RED switch and put in my white one.
The buzzer and light stopped, but after about a couple of minutes it sounded for a minute then stopped and all is well.
I haven;t tested it fully yet, just a small trip around the block. will test it properly tomorrow.

Thanks for you help

MrBeard

this is the correct switch for the oil light and low pressure (0.3)

blue switch the blue wire to it changes to brown at the two pin conector

And this is the correct switch for the high pressure at the rear of the engine (0.9)

grey switch the yellow wire to it changes to brown at the two pin connector

I contacted VWHeritage and order an Oil Pressure switch, according to their lists I needed a White to replace my High Pressure switch.

oh dear...

I finally pulled out a RED switch and put in my white one.

oh dear, oh dear

Well we took it out for a spin earlier and it coped fine no buzzer. the light came on occasionally (but I think we might actually have low oil - again)

One thing that did worry me was the little bit of oil that came out when I took out the low pressure (left).
And the very very slow drip from where the oil pressure release valve screw is.

Well it drives okay.
only the occasional drop in power if you suddenly try to increase revs and put your foot down hard on the accelerator.

MrBeard

It worries me that you think the light is just for low oil.

it is for low oil pressure.. below 0.3 bar aswell as low oil

MrBeard wrote: only the occasional drop in power if you suddenly try to increase revs and put your foot down hard on the accelerator.

MrBeard

transfer jet.... but that's a new thread

kevtherev wrote:It worries me that you think the light is for low oil.

it is for low oil pressure.. below 0.3 bar in fact.

I repeat my question .... What oil are you using ?

Ian Hulley wrote:

kevtherev wrote:It worries me that you think the light is for low oil.

it is for low oil pressure.. below 0.3 bar in fact.

I repeat my question .... What oil are you using ?

Sorry Ian I though I had answered (I intended too)
I am using Custom Classic oil. Our local retailer of all thing vehicle parts related recommends it.
It has however had some various grades in the past and the previous owner mentioned that he had stuffed uop a few seals in the past with an incorrect oil, but said he had fixed all that.

I had run for a while without a working Oil Pressure Valve!

kevtherev wrote:It worries me that you think the light is for low oil.

it is for low oil pressure.. below 0.3 bar in fact.

I was thinking that if the oil was low then it is easier for the pressure to become low shortly after starting.
This is my first Vehicle that I am doing any real work on, so my understanding and logic may well be flawed at times.

kevtherev wrote:transfer jet.... but that's a new thread

Thanks, I'll start a separate thread about that. I mentioned it in case the oil pressure issues may have caused it.

Cheers everyone for your comments and help

MrBeard

MrBeard wrote:
Sorry Ian I though I had answered (I intended too)
I am using Custom Classic oil. Our local retailer of all thing vehicle parts related recommends it.
It has however had some various grades in the past and the previous owner mentioned that he had stuffed uop a few seals in the past with an incorrect oil, but said he had fixed all that.

so what was this classic oils viscosity 20w 50, 15w 40? [all mineral]

I was thinking that if the oil was low then it is easier for the pressure to become low shortly after starting.
This is my first Vehicle that I am doing any real work on, so my understanding and logic may well be flawed at times

.
the oil light is low pressure, either way you never drive anywhere with it on... so when it did come on ..did you ignore it, and did you check the level?[/quote]

Hi Guys

kevtherev wrote:so what was this classic oils viscosity 20w 50, 15w 40? [all mineral]

I am pretty sure it was 15/40. I checked it with the manual and haynes while in the shop with the guy behind counter and friend who knows some stuff about campers.
I can't find the can, but it was supposed to be the best option available

kevtherev wrote:the oil light is low pressure, either way you never drive anywhere with it on... so when it did come on ..did you ignore it, and did you check the level?

When I purchased the T25 it came with the high revs low pressure buzzer issue.
So yes we drove it for a bit then - to get it home and for testing.
Once the valve was replaced. I drove it round the block to test etc.
atm it seems to be ok,
I believe that the may be a low oil leak as when my friend filled it with the custom classic oil he only filled to half ( no idea why) and now it down to min. which is why I made the comment about during the latest drive the light came on occasionally.
Today I intend to get some more oil and do a double check.
tomorrow we need to get the van to Nottingham (1hr away) so we can have the roof changed to a high top.

Thanks
MrBeard

It is actually 20/50 oil for '60-'80's classic vehicles!

If it is still hesitating there is still an air leak from somewhere


it is indeed.. and mineral not synthetic would be best.
So the oils OK.
therefore the oil level could well have been the reason for the flashing light
as the light takes it's information from a pressure sender, you have to eliminate other reasons as well. (electrical, oil viscosity, oil pump, pressure relief valve)

I was wrong to say "it worries me that you think the light is low oil"

you have my apologies for that

Drove it 1.25hours today to nottingham, and it ran nicely.
No problems with the oil light and pressures today.

It's now in Notts where it is having a new High top roof added. until next weekend (21st ish)

Cheers
MrBeard