Radiator fan

Author
Discussion

OctaneBooster

Original Poster:

326 posts

243 months

Monday 25th April 2005
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I have a '99 S Type 4.0, and recently I've noticed that the radiator fan is operating nearly all the time. As soon as the temp guage reaches the halfway mark, it comes on and seems to stay on until about two minutes after the engine is switched off, regardless of the type of journey. The temp guage reaches the halfway point quickly, but never moves from that point until the engine is switched off. Can anyone tell me if there's something wrong here, and if so what needs to be done.

Thanks in advance

triple7

4,015 posts

244 months

Monday 25th April 2005
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Hope dave_3d doesn't read this or you're not gonna like it!

As with anything, could be a thermostat problem, wa erpump problem, so get it checked out .

I alwayss find phoning your local Dealer and having a chat with amechanic is a good way of narrowing down items you can get done yourself. All else fails check her in.

If she is under warranty, go straight there and get it sorted, you don't want to shorten the life of compnents by running a too hot engine.

G

Pettsie

354 posts

264 months

Monday 25th April 2005
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That's how my problem started. Keep an eye on the temp guage. Mine 99 (3.2 XJ8) was ok for a few days then it started to creep up. Its in now being looked at. I suspect the water pump has given up over a few days. Its under warranty so.... See my post on overheating.

John Millar

93 posts

243 months

Pettsie

354 posts

264 months

Wednesday 27th April 2005
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Any news on what caused the problem?

OctaneBooster

Original Poster:

326 posts

243 months

Tuesday 3rd May 2005
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Checked into local main agent this morning. They could find nothing wrong at all. Suggested replacement of the fan switch, at a cost of £4 but 1.2hrs labour to fit!

IOLAIRE

1,293 posts

245 months

Tuesday 3rd May 2005
quotequote all
OctaneBooster said:
Checked into local main agent this morning. They could find nothing wrong at all. Suggested replacement of the fan switch, at a cost of £4 but 1.2hrs labour to fit!


I don't think it's that simple I'm afraid.
On some of these cars the fan speeds are also programmed into the ECU and are designed to react to very finite temperature variances by using the signals from the temperature time switches on the fuel injection system.
Some of them have a three terminal switch for the fan usually in the radiator.
I have to say however that I find the price you've been quoted so low that it has to be a mistake unless it is a simple on/off switch and the speed variance is controlled by the ECU.
If this is the case, you could be in for a nasty shock if there is an ECU fault.
Marquis Rex is your man for this; he works for Jaguar and writes the programmes.

OctaneBooster

Original Poster:

326 posts

243 months

Tuesday 10th May 2005
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Car went back to main agent this morning for a new fan switch. After fitting it they decided that this was not the problem and that I had in fact been operating the climate control at too low a temperature (21) and that if I turned the heater up the fan would not operate so much! My first thought was b******t but gave them the benefit of the doubt and tried it. Made absolutely no difference at all except the temp guage read slightly higher. I think it's pointless going back to them, but my limited knowledge suggests a fault with the water pump or thermostat, and that the fan is working harder to compensate and keep the required engine temperature. Any thoughts?

John Millar

93 posts

243 months

Tuesday 10th May 2005
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Think you're right

OctaneBooster

Original Poster:

326 posts

243 months

Monday 27th June 2005
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Fixed it! It was the thermostat in the end.