Overheating

[darkangel1975]

I have a 1986 1.6 n/a diesel that seems to be overheating. Its hard to explain, if you idle the van the rad gets hot as its supposed to and all is well for a while, then the rad starts to cool down and the water in the header tank just starts to boil until it overheats. I've tried to bleed it all seems well, deosn't appear to be any air in it.Please help pulling my hair out
many thanks
John

[kit]

Try driving with the heater on I think if it gets hot it means your water pump is ok so that will eliminate that, have you tried replacing the Dalek head I believe these are prone to not working and that would restrict water going back to the expansion tank, worth a try?

[darkangel1975]

Thanks kit, heater works fine, water pump seems to be working, the temp gauge sits just to the right of the red light and moves towards three quaters as you drive. Does anybody know if there is a bleed valve on the engine anywhere? i've bled the rad, and that seems fine. Is this normal?
Thanks
john

[kit]

I remember Baxter saying you should not get air locks in them, try the Dalek head they are less than a tenner from memory and they do fail.

[Red Westie]

Based on how you have described the fault this is a probable head gasket failure.
BUT
Is the thermo switch bringing in the electric fan (first speed should come on when the needle goes just after half way.

As Kit has pointed out: the pressure caps (known as a Darlek Cap because it looks like a Darlek) do fail leaving the cooling system prone to boiling (cooling systems need to pressurize to function properly as they are there to increase the coolants boiling point)
Are the coolant pipes getting hard when the engine is up to temperature (best to drive the vehicle and check when hot) this will prove the Darlek cap is working correctly.
Martin

[darkangel1975]

Thanks all, forgot to mention that i changed the heater matrix over the winter, didn't seem to have any problems before that ( I don't think,) the van hasn't been mine for that long, and started work on her just after buying her.It is posible to have an air lock from this? and if so how do you bleed it.
Thanks
John

[floz70]

Im having the same problems, does anybody know where to get the expansion tank (its the metal, spring half turn one) and topping up tank caps as the RAC said the one isnt letting the pressure out properly and i have lost the one on the top up tank behind the no. plate. And i need a new level sensor and rubber. Thanks

[kingdalg]

i have the same engine in my bus, the temp gauge sits at 3/4 but doesnt go any higher. coolant doesnt boil up or pressurise and the fan NEVER kicks in. this is my first bus, is the normal or a sender fault? cheers

[gavnjax]

Strange I came on for help today with simular problem. 1.6 diesels need their own club.
I had a split hose due to pressure. found a replacement, new dalek cap, new stat, filled it up, bled it, only to find hoses buldge and rad stays cold. Had a machanic round today, pressure not high enough to be gasket, but cant understand why it wont flow. I may take the pump off but it looks like its working, may put the old stat on as that we know works. I'm leaning towards airlock as it takes 17 litres and could only fit 12 in, but not sure how many still in the system.
This is a comman problem with 1.6 d. Mine is an 1986 as well. I will watch this space and let you know if I find a cure.

[Red Westie]

I suppose it could be possible for the impeller (in the water pump) to come loose on the shaft. Later VW models use a plastic impeller which most definately does fail (having had a recent replacement on my 2litre petrol engined Beetle)

Martin

[T25Convert]

I suppose it could be possible for the impeller (in the water pump) to come loose on the shaft. Later VW models use a plastic impeller which most definately does fail (having had a recent replacement on my 2litre petrol engined Beetle)

Martin

I'd second that - I've had two golf water pumps and one skoda water pump (its basically the same!) where the metal impeller has become detached from the shaft. Its almost impossible to spot as you take the pump out, give everything a wiggle and it seems fine. Its only if you clamp the pully / shaft in a vice and turn the impeller you notice the two no longer turn as one.

Note though that these were all replacement pumps, not originals, so it may be possible that original pumps had woodruff keys or similar to stop this.

Cheers,

Alex

[gavnjax]

That was suggested by Rutland Campers. Gonna look into that.

[darkangel1975]

Hi all, Had a mechanic round yesterday and he bled my system properly, replaced the daleks head (take the daleks head off and blow through it, if it lets air through bin it) and touch wood i think he's cured it. My fault , i didn't bleed it properly when i fitted the heater. He did say that these are a nightmare to bleed, and any removal of a pipe will require bleeding.Hope this helps.
P.s if mine deosn't work then i'll be the one parked on the hard shoulder on my way to bus types.
Many thanks
John