16v 9A Overcooling

[yalan 0]

Now just to be different to all the overheatring problems, I thought I'd share my overcooling problem.

 

If started whilst standing, it'll warm up nicely and get to temperature and stay there until the fan comes on. It'll then happily stay at a good temperature (100? was it?)

 

But if i'm on the road, the wind rushing through will cool it down loads - to the point that on a dual carriageway it'll even dip back below the first graduation (70?)

 

OK - so that'd probably be a stuck thermostat but it probably shouldn't be cooling quite that much I wouldn't have thought....?

 

But even weirder is the fan. Arrive home after a 30min drive, gauge reading about 75 - 80 degrees and park up. And 5 minutes later the fan is running. And still running 5 minutes after that.

 

I'm guessing its possibly the thermostat and one or 2 temp sensors. Can anyone suggest locations of likely sensors and an order or priority with regard replacement?

 

Cheers,

[davidwort 0]

get a genuine VAG thermostat in there, it sounds exactly like a stuck open stat, unfortunately you've got to take the PAS stuff off to get at the flange though.

[yalan 0]

Will get the Stat sorted asap -

How about the overenthusiastic after-run fan? Possibly faulty temp sensors?

[davidwort 0]

when you remove the stat and drain the water, take the rad switch out and check it switches on and off with a multimeter accross the two paths separately, and a ciggy lighter flame to warm it up to temp, should click and make contact through the two paths at slightly diff temps for the high and low speed circuits

 

also check the small sensor on the top left front of the head, this will cause fan run on to keep the injector pipes cool, could be dodgy and shorting too easily when warm