1993 80 1.9tdi coolant light, charging light/battery not charging - related issue?

[jacollins]

Hi I recently acquired an 80 1.9tdi from a friend (been say on his drive since August, took it as part payment for fixing his boiler - scrap value was same as boiler part £120!).

Got the car on the road been using it as a run-around (every time I fill it up it saves me £50 because I'm not using my Hilux!).

Don't know if they are related, the coolant light started flashing, then a bit of work to unsuccessfully resolve that and I notice that the charging light is coming on, even with the key turned without the engine running. Trying to work out if they are separate issues or related, i.e. if the alternator is on the way out it start putting other warning lights on.

Full story:
Day after 180 mile round trip, go to see a mate 11 miles away. On 1 mile from his the coolant and (!) light are flashing. At his house I pop the bonnet the water has dropped about 1cm below the minimum. I top it up - no difference.

Me and my mate have a proper look around, and find that although the top hose to the rad if hot, the bottom hose is clap cold. Although the temp gauge moves it barely gets off the bottom, so thinking that maybe the rad might be blocked we disconnect the hoses and flush it through with the garden hose. Having refilled the lights come on after a few seconds. We then clean the contacts on the temp sensor, if that's what it is, in the rad - makes no difference.

A trawl through the forum suggest the reservoir. We take it of clean it out, shake it to make sure the float isn't stuck, clean the contacts, no difference. Disconnect the plug to the float switch, no difference. Bridge the terminals in the plug - no difference.

Then we cleaned the contacts on the blue 3 pin plug at the back of the cylinder head - no difference.

We give up!

On the way home I notice that the charging light is on dimly.

A few day later having kept driving the car I decide, in view of the bottom hose being cold, to change the thermostat. Once changed let the engine idle for 15-20 minutes (coolant lights still on). The gauge didn't move much, the fan didn't come on and the bottom hose was still clap cold. So I took it for a drive. After about 3 miles notice that the fuel gauge is dropping rapidly the engine starts getting rough and the charging light gets a bit brighter. I manage to get the car home, knock the engine of and try to fire it up again - nothing the battery is dead.

After giving the battery a good charge I check the battery with a multimeter - 12.5v. I start the engine, no warning lights on the dash. Multimeter across battery shows 14.7v. Go to switch of engine, see coolant light and charging light are on. Check battery again - 12.3v. Knock engine off and fire it up again, coolant light and charging light are on, battery still showing 12.3v. Continuity test from alternator to battery is positive. This to me suggests the alternator, but why doesn't the charging light come on with the key turned but engine not running and the battery is freshly charged?

If the alternator has had it, is it the likely cause of the coolant warning light? Or could it be the other way about, and issue with the electrics causing the coolant light to come on and screw up the charging circuit?

Given how much the car is worth, not a lot, I don't want to put an alternator on it for it not to be an issue with the alternator, and/or for the real issue to ruin the replacement alternator if that's going on.

The other issue is, I cannot work out how to release the tensioner on the alternator drive belt.

Has anyone come across this before?

Thanks in advance for any help

Jonathan

[zollaf]

welcome to the forum.
the alternator tensioner is best released from below using a tool to move the pulley, or a lever. not the best design ever. the po of mine made one from a piece of flat bar.
does the heater get hot ?
the temp should get to 90 and stay there, but they don't need much cooling so top hose hot and bottom cold is usual.
i wonder if you have some dodgy contacts in the dash panel. easy enough to remove, strip and resolder.

[jacollins]

Thanks Zollaf, I have seen the threads re the temperature gauge and the dodgy contacts. The heater does get hot, quite quickly. If I can resolve the charging issue I might get round to looking at the contacts in the dash, at the same time I might as well see about sorting out the odometer seeing as it appears to have been stuck at 182,172 miles for the this and the previous MOTs!

I'll see how far I get levering the pulley.

[scotty33]

I think the overtemp alarm can also be triggered by a grey temp sensor/thermal switch. Not sure where it is on the TDi sorry.

[merton1973]

when i have started my engine without the alternator belt on both the charge light and coolant overtemp/level warning always come on. 14.7volts sounds a bit high , maybe the alterator voltage regulator is playing up, they are only about a tenner, maybe you could test if the voltage changes with the engine revs as i guess the volts should stay the same at all revs if all is well. or maybe sounds like the alternator is on its way out. the tensioner has a 17mm nut in the middle, maybe covered, if you turn that clockwise it will release the tension so you can remove the belt.