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Cool running

S

swright

New member
My car always runs to cool. The temp gauge hardly ever goes over the quarter mark even after some sprited driving!! I had the car sat running for a while the other day to see if i could get the fans to cut in but no joy. It simply wouldnt get hot enough.

I did notice however that one of the rad fans runs at a slow speed at all times. Im not sure if it runs from cold start but it was certainly running after the car had been only been stood for 5 mins running from cold.

Has anyone got a clue as to whats going on? Faulty temp sender maybe?
 
I would say that your thermostat is almost certainly old and open all the time. The springs tends to weaken and open too early so a new one will keep closed until the engine reaches the correct operating temperature. I don't think the slow fan should be on all the time but have a good read of the coolant section of the Garage Shop Manual at www.clarks-garage.com
 
Don't the two fans cut in at different temperatures? I seem to recall reading this somewhere but can't remember where ... this could explain what you are seeing.

Temperature: Mine goes up to the first mark on the gauge pretty quickly (within 5 minutes), and only goes above on hot days, in traffic, or when thrashing it hard. It always drops back down fairly quickly once it goes above this mark as well. If yours is otherwise, a thermostat would be my first suspect as well.


Oli.
 
Yes the fans have stepped engagement, but the low one still only comes on when it's warm enough. I'd definitely replace the thermostat if it runs cool - or in fact if the temp fluctuates at all in anything but traffic. In my experience most cars benefit from a new one if it hasn't been done for a while.
 
how easy is the thermostat to change, and where is it (is there just one?). My fan seems to be on most of the time in this warm weather, which had me thinking that there was something wrong with it

I didn't know there were 2 fans.....
 
Bit of a fiddle, but possible.

I think a set of angled rat-nose pliers make the whole thing a LOAD easier.


Oli.
 
It does warm up quickly and gives out good heat. Il give it a flush and some new coolent along with a new thermo this weekend.

Cheers,
Stu
 
Well our temp gauges do read low - it is one of the many gauge quirks of our cars like the dicky voltmeter and fuel gauge. However a specialist explained to me that the two fans are stepped but work such that when the engine is on both fans will run together and when the engine is off only one fan will run to save the battery. I know this because my specialist replaced my thermostat he found that when my imobiliser was installed by one of the cars previous owners they cut the wire from the ignition to the second fan so that I only ever had one fan working wether the engine was on or off. Apparently at idle and stationary once the fan kicks in it should cool the engine such that the fan switches itself off again within 4 mins and is usually around 2 mins if both fans are running as they should. In my case with only one fan working it was taking up the full 4 mins. That's how he sussed out the second fan wasn't running.
 
I dont think that's quite right. As I recall one fan comes on at a given temp and stays on for a few minutes to bring the temp back down (basically between two graduations on the gauge). The other is employed only if required i.e. the single one isn't coping. I'm positive that no fan runs with air-con off (or not present) and the engine up to temperature, and I'm pretty sure the second one hardly ever runs - it's really noisy so you know if it kicks in whereas a single fan isn't all that noticeable.

There is also some linkage between air-con and 2 fans, my guess being that one runs all the time when the air-con is running to help cool the condenser.
 
Maybe. I must admit I didn't notice any real difference in the operation of the fans in terms of noise or speed of cooling.
 
Well the mystery deepens. I just got back from a run and no fans were running at all!! I couldn't even hear the electric turbo water pump running. and these should always run for a certain amount of time to help cool the turbo down.

Very annoying and a little worrying too. i don't want to melt the seals etc in the turbo[:eek:]
 
If you can see through your header tank you should see a little fountain of water when the turbo pump is running. If you think it has failed then just idle the car (or drive off boost) for a minute before you shut it off and the turbo will be fine. You should really do that anyway especially after a hard run.

If the car runs cool then it would be right that no fans are running at all so don't worry about that. I'd be surprised if a new 'stat doesn't make a surprising difference to both the position and stability of the gauge. It shouldn't move much at all unless the car is stationary.
 
Thanks Fen. I always do the 1 min idle before i turn it off anyway . Il check to see if i can see the fountain of water.

Cheers,
Stu
 
ORIGINAL: 944Turbo

One fan runs when the ac is on - could that be why it was running and has now stopped?
Tony
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Oh lordy, now you mention it, i think i did have the aircon button pressed!!! Il get me coat.....................

Im still worried why the fan wasnt running when i pulled up today though as it always has ran for a few mins before today. No matter what temp the engine is at.
 
All is well again(in fact it was never wrong in the first place) After a good long run today the gauge moved up a bit more than usual and the fans kicked in perfectly and brought the temp down nicely. I also heard the electric turbo water pump working its magic when i switched her off[:)]

Had a chap come up to me today whilst i was filling with petrol. I though eye eye, whats going on here then!! He simply wanted to talk about my car and was loving it[:D] As was i. The same thing happened when i want to have some tyres fitted. Ended up with three chaps stood round talking about it.

God i love this car[:)][8D]
 
ORIGINAL: Alpine

how easy is the thermostat to change, and where is it (is there just one?). My fan seems to be on most of the time in this warm weather, which had me thinking that there was something wrong with it

I didn't know there were 2 fans.....
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replacement of the thermostat is straight-forward enough but it can be an absolute bitch to bleed the coolant system on some cars. My indie had to bleed my Lux 3x times and ended up suspending a filler tank to get some pressure head to force the air out.

Your problem sounds more likely to be the temperature sensor switch in the rad.
Only turbo's and S2 cars with Air/con have 2x fans as standard as far as I am aware
 
ORIGINAL: Fen

I'd be surprised if a new 'stat doesn't make a surprising difference to both the position and stability of the gauge. It shouldn't move much at all unless the car is stationary.
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I had a stat change which left my temp gauge indicating mid gauge when cool which was a bit disconcerting at first after a head gasket replacement. It turned out that some stats have a different temperature point at which they open.
Might be worth asking the temperature setting of a new stat before supply
 
ORIGINAL: swright

All is well again(in fact it was never wrong in the first place) After a good long run today the gauge moved up a bit more than usual and the fans kicked in perfectly and brought the temp down nicely. I also heard the electric turbo water pump working its magic when i switched her off[:)]

Had a chap come up to me today whilst i was filling with petrol. I though eye eye, whats going on here then!! He simply wanted to talk about my car and was loving it[:D] As was i. The same thing happened when i want to have some tyres fitted. Ended up with three chaps stood round talking about it.

God i love this car[:)][8D]
Click to expand...

I still think you should change the thermostat.
 
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