Scirocco Register

My 1985 1.8 GTL (carburettor) appears to be overheating, or at least warming up way faster than normal.

Have looked at Haynes and searched the forum, my symptoms seem a little inconsistent so would like some opinions before I start replacing stuff willy-nilly:

• Temperature gauge goes to 75% within 2-3 minutes, normally sits just past 50%, and takes 5-10 minutes to get there depending on ambient temperature
• Fan is working but doesn't kick in until much later, in fact around the time I would expect it to, normally starts when the gauge is about 50%
• Idle speed normally drops from 2k to 1k about the time the gauge goes to 50% but is still high with the gauge at 75%, drops about the time I would expect it to
• Top and bottom radiator hoses are hot, engine bay feels hot, intuitively the engine appears to be getting to temperature sooner than normal
• Slight leak from water pump, at the bottom it appears, though that may just be gravity, seemed to be a bit of bubbling of the drop dangling from the bottom but that could just be boiling rather than air from a crack or pinhole in the casting
• No evident coolant loss, the expansion tank is full to the mark and I haven't topped it up recently
• Heater works as normal
• Have noticed a brief screeching on startup in recent weeks which I had assumed to be a slipping fanbelt but it passes within 30 seconds or less
• There seems to be a bit of mis-alignment between the crankshaft pulley and the water pump pulley, and the alternator pulley and water pump pulley, whereby the pump pulley seems to be pulling the belt slightly off running perfectly centrally around the alternator and crankshaft pulleys, but we're talking a couple of mm, it's not grossly out of alignment and this could be a red herring

I would be inclined to believe it's just a faulty gauge were it not for my feeling that the engine is warming up faster than normal.

All input gratefully received.

Could be just a dodgy sender, you can pick them up easy enough from GSF and Euro.

marcus wrote: [*]There seems to be a bit of mis-alignment between the crankshaft pulley and the water pump pulley, and the alternator pulley and water pump pulley, whereby the pump pulley seems to be pulling the belt slightly off running perfectly centrally around the alternator and crankshaft pulleys, but we're talking a couple of mm, it's not grossly out of alignment and this could be a red herring[/list]

That's quite normal. You can space out the water pump pulley with some washers if it bothers you. (Which I have done).

Thanks Brunty.

Assuming it is just a faulty sender, is there any 'easy' way of measuring the actual water temperature to confirm? What should the temperature be anyway? Haynes says the thermostat is supposed to open at 82C but what does that translate to?

I have a digital thermometer with a probe on a 50cm wire, could I just stick that in the expansion tank or would that give a false reading, given that it's not really in the main circulation path?

I also have an infra-red thermometer (ie the kind with the laser dot that you point at things to get a temperature reading), if I point that at the top hose would that give any reliable indication, or is the insulating effect of the rubber too great?

The fan switch on both my Sciroccos has 93 degrees stamped on it, that's when the fan kicks in.

I seem to have four sensors on my EX engine, not including the fan sensor on the rad, intake manifold preheater on top of the top rad hose connection on the spark plug side, automatic choke on the bottom of same, temperature gauge sender on top of the heater hose connection at the end of the cylinder head (red/yellow wire as per checking the temperature gauge), and another one going straight into the end of the cylinder head below and slightly in front of the gauge sensor, with a black wire, any ideas what this latter is for?

marcus wrote:Thanks Brunty.

Assuming it is just a faulty sender, is there any 'easy' way of measuring the actual water temperature to confirm? What should the temperature be anyway? Haynes says the thermostat is supposed to open at 82C but what does that translate to?

I have a digital thermometer with a probe on a 50cm wire, could I just stick that in the expansion tank or would that give a false reading, given that it's not really in the main circulation path?

I also have an infra-red thermometer (ie the kind with the laser dot that you point at things to get a temperature reading), if I point that at the top hose would that give any reliable indication, or is the insulating effect of the rubber too great?

Point your laser thermometer at the engine block. They're great, used them a bit for tyre temperatures :) And also for finding out how cold the workshop was..