I've got a 90 Spec 8V GTi (PB engine code) and it's getting hot in traffic. It's not the stat, and it's not the rad, as both have been changed. The coolant isn't sludge. What could be causing the car to overheat? Timing too advanced or fuel mixture? The other option I can see would be the fan, but it's coming on before the engine gets silly hot and so the only problem with it could be that it's not shifting enough air.
Even if the coolant's not sludge it could still be the head gasket. Get the coolant sniffed and a compression check done.
John
Did you test the new stat before you put it in?
It's not uncommon for brand new stats not to work. I always make a point of dunking them in some boiling water to check them before fitting.
Also, is it just a single speed fan? Perhaps it's a double speed fan, and the second stage isn't cutting in.
Next step after that would be to give it a good flush, and see how it goes.
Another clue in that would be that oil goes a milky colour....
Chris
If you cant keep it cool in this weather you dont stand a chance during the summer, something is seriously wrong!
Are you sure the rad isnt sludged?
My car stood still at op.temp in this weather needs at least 20mins before even the fan cuts in.
Tim..
"Tim (remove obvious)" wrote in message news:doup6r$jad$ snipped-for-privacy@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com...
Have to agree. I have the same motor with same suspect headgasket. Fitted a new genuine rad as the old one burst. It still takes 20min to get oil upto temp, even then the fan only kicks in slowly. Now H2O is weeping from the senders on the side of the block - the next weakest link. Time for a lump change to my spare sub 100k PB methinks!
The only other area I'd look at after the rad would be the waterpump and/or it's belt. Is the belt slack? Do the pulleys have a 'polished' look to them - if they do then they're quiet when the belt slips (which they can do when the belts damp).
Chris
Take the plugs out. Their colour will give you an idea of fuel mixture (look at the haynes manual). If they look very clean (steam cleaned!) suspect the head gasket. The only other possibility I can think of it a water pump that the impellor has fallen off, but that's a bit of a long shot.
Start it from cold, and open the coolant reservoir - is it definitely being pumped round - if you've got the same reservoir as mine you should be able to see water coming out of the return pipe when the engine is running.
(Obviously don't open it if you've just been driving it, or you will get very hot water at pressure pour all over you)
Regards Chris
Are you really sure you ARE overheating? The temp guage could be faulty or reading high. Does it ever actually overheat? Once the fan cuts in, does it blow for a while and then shut down? If so I suspect it is actually fine!
Headgasket was sorted relatively recently, so should be fine. It's not dropping any coolant and showing no HG symptoms. Still, could check it out.
I didn't, but water's getting to the rad, so it's working. It's a lower temp than standard stat too, so no problems there (needs to go back to standard to warm up quick enough IMO).
I'll have a shufti at the manuals.
Can be done when I put the stat back, *but* it's a brand new rad, and it's had the coolant out after the HG, so I'd be surprised if it's gunged it up.
Which res have you got? The square one or the round MK3 style?
Good point. Fan cuts in and keeps running. It's yet to blow it's HG but it does get stinking hot (too hot to put my hand on the rad), which suggests the sensors are reading right - the expansion tank was changed at the same time as the HG so should be giving correct readings (sensor is integral to the tank). The gauge could be dead. I'll check oil temps in comparision to water temps next time it starts going off.
The temp sensor isn't integral with the expn tank, this will be a coolant level sensor.
It is possible that if previously overheated that the coolant sensor has subsequently failed. If it has been replaced seperatley, make sure it is the correct one for your engine as there appears to be a selection for this era of VW.
Doki wrote:
Could be an airlock.
take the thermostat out altogether & see if it still does it. & flush the engine & the radiator. Is the fan blowing in the right direction?
The big square one - not the flying saucer one....
Regards Chris
Had a look today - when it was actually hot in traffic. The fan seems to be on it's last legs - failing some of the time but not all of the time. Flick it with your finger and it'll start, exactly the same as a knackered pc cooling fan...
'cept that a PC fan is unlikely to damage your finger.
Aye. I made a point of getting my hand out of the way sharpish.
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