Coolant Sensor & Alternator Problems

[dmw9255 0]

Hi all, just new to the forum and VW Corrados.

 

I bought an 1.8 16v corrado a couple of months back, had a few issues with it, which seem to be resolved now, well it drives, and I can change gear now, but I can deal with the bigger issues later.

 

I have two nigly problems which are winding me up.......

 

1. Engine coolant temperature never rises above 70 degrees C. The temperature rises from its stop and then sits at around 70 for all my journeys, I have seen this rise above once when sitting in a traffic jam, it rose to about 110 degrees C, then once on the move settled back down to 70. I do not beleive it is possible for the water temperature to remain this low. I am unable to locate the suspect sensor, can anyone tell me where this is located?

 

2. The headlights and interior lights seem very dim, and seem to flicker. I beleive this is probably down to the bridge rectifier unit on the alternator? again has anyone any experience of this? Or is more likely to be the alternator.

 

For note the car is a late 1989 in Blue with full leather interior. Will be a nice car once I get it all sorted, bit off a dog to drive at the moment.

 

Cheers.

 

Dean.

[boost monkey 0]

1. Engine coolant temperature never rises above 70 degrees C. The temperature rises from its stop and then sits at around 70 for all my journeys, I have seen this rise above once when sitting in a traffic jam, it rose to about 110 degrees C, then once on the move settled back down to 70. I do not beleive it is possible for the water temperature to remain this low. I am unable to locate the suspect sensor, can anyone tell me where this is located?

 

Why can't you believe this? Maybe you have a really good cooling system with lots of parts in that work as they should! If you mean the sensor for the dash guage, it is one of the 1-pin sensors on the flywheel end of the engine, underneath the distributor.

 

2. The headlights and interior lights seem very dim, and seem to flicker. I beleive this is probably down to the bridge rectifier unit on the alternator? again has anyone any experience of this? Or is more likely to be the alternator.

 

Mine flicker like a MOFO. I'm thinking it could be alternator related too, what kind of voltage are you getting coming out of the alternator whilst the engine is running?

 

 

For note the car is a late 1989 in Blue with full leather interior. Will be a nice car once I get it all sorted, bit off a dog to drive at the moment.

 

Awesome! probably one of the rare early ones... is it on an F plate?

[dmw9255 0]

Why can't you believe this? Maybe you have a really good cooling system with lots of parts in that work as they should! If you mean the sensor for the dash guage, it is one of the 1-pin sensors on the flywheel end of the engine, underneath the distributor.

 

Never had a VW that ran with such a low temperature, I have 2 single pin sensors under the distributor, but disconnecting either made no difference, again I will have a look tomorrow, does anyone know what type of resistance I should be getting for normal running temps?

 

Mine flicker like a MOFO. I'm thinking it could be alternator related too, what kind of voltage are you getting coming out of the alternator whilst the engine is running?

 

Not checked yet, will let you know tomorrow

 

Awesome! probably one of the rare early ones... is it on an F plate?

 

On a G plate, it has had a re-spray, but seems to be of original colour, needs a lot of TLC. Bought it as a project, think my next job will be to get a manual for it.

 

Regards.

 

Dean

[boost monkey 0]

Hi dean,

 

that's cool. The sensor I pointed tou to literally just covers the dash readout, plus you should have three there in total, 2 above the water pipe and one below and left of it.

 

let us know how you get on with the alternator.

[dmw9255 0]

Hi dean,

 

that's cool. The sensor I pointed tou to literally just covers the dash readout, plus you should have three there in total, 2 above the water pipe and one below and left of it.

 

let us know how you get on with the alternator.

 

Replaced one of the sensors today for the coolant temperature gauge, and the temperature indication when running is still around 70 degrees C, doesn't make sense to me (maybe the thermostat is running fully open all the time?). Anyway leaving this one until the summer now.

 

Measured the voltage from the alternator as well today, the voltage was 13.9 to 14.3 volts, fluctuating, I then replaced the bridge rectifier unit on the alternator and the voltage stablised at 13.8 volts, not sure if the lights are flickering (due to day light), but found another probem. The voltage at the headlights is 9 volts, a little too low for my liking, looks like I have a big job on my hands with this cars electrics. May have to make the change listed in the knowledge base.

 

Regards.

 

Dean.

[boost monkey 0]

Yeah the headlights always need uprating, there's a massive amount of detail on those here, and uprated wiring loms are readily available on ebay too. it's because the wiring goes from the battery > fusebox > back to headlights so there's a massive voltage drop.

 

my coolant gauge hasn't worked since I had my car too, not sure if it's the sensor or the 'stat. Just adding it to the list tbh!

 

where is the rectifier unit on an alternator? sounds like something I could do with checking as my alternator out and all lights fluctuate slightly.

 

Cheers,

 

jon.

[dmw9255 0]

where is the rectifier unit on an alternator? sounds like something I could do with checking as my alternator out and all lights fluctuate slightly.

 

Its located on the back of the alternator, two screws to remove to replace it, takes about 2 minutes to do, done it previously with my old Golf. Cost me about £20 from a VW "specialist"

 

Regards.

 

Dean.