update and help on coolant problem

update and help on coolant problem

Author
Discussion

pauli

Original Poster:

111 posts

272 months

Wednesday 15th December 2004
quotequote all
hi all,

with regard to the coolant problem i had with my 88 turbo, i have narrowed this down and replaced the cooling fan switch which has now let the fans kick in and do their job. And i also replaced the thermostat which has now solved the problem with the temperature gauge in the car, which is all reading fine now. But the problem i do have now is the tell tale light is still coming on but the temperature is fine and the fans are doing their job. Any help on this one please. Must say also that it has felt so good being able to drive the car after her being off the road for 3 years.

many thanks

Pauli

Dr.Hess

837 posts

255 months

Wednesday 15th December 2004
quotequote all
Does the tell tale come on with a low coolant level? And I assume your coolant level is up.

Dr.Hess

pauli

Original Poster:

111 posts

272 months

Thursday 16th December 2004
quotequote all
Hi Dr Hess,

no the coolant level is fine, if i undo the bleed screw in the radiator and let a small amount out the tell tale will be off, but then come on again after approx 1 or 2 minutes.

Pauli

pauli

Original Poster:

111 posts

272 months

Thursday 16th December 2004
quotequote all
Hi Dr Hess,

no the coolant level is fine, if i undo the bleed screw in the radiator and let a small amount out the tell tale will be off, but then come on again after approx 1 or 2 minutes.

Pauli

Dr.Hess

837 posts

255 months

Thursday 16th December 2004
quotequote all
Hey Pauli,
I am no expert on your (Bosch) car, but according to the schematic, there are two ways for the coolant idiot light to come on: Low Coolant Level Probe and Engine Overheat Otter Switch (Make on temp raise 120C). Now, assuming that there is plenty of coolant in the tank and the engine temp is below 120C, you have a problem in one or the other sensor or an intermittant ground in the wiring. Note that the light is wired: +12v -> light bulb -> 2 sensors (switches) in parallel -> ground. If either switch closes, the light comes on. So, what I would do if I were you is wait for the light to come on, then disconnect each switch in turn and see which one makes the light go out. You then found your problem. I would venture to guess that the switch at the header tank is bad, as I have heard of that happening to others. I don't know how it comes off, but it may respond to a thorough cleaning, I don't know. It is located on the header tank.

Dr.Hess