Hi Folks - Ah the delights of these lovely cars....it's like a gift that just keeps on giving!

I had an overheat problem in stop/start traffic in Manchester, UK last week...on a warm day - 18 degrees celcius (yes...in February!!). I noticed that the temp gauge had shot up to nearly the red section...so I pulled over safely and stopped the engine. In the previous week, I had covered over 600 miles without issue.

No coolant leaks...but also, I noticed...no cooling fans working. After a 2 hour wait the AA breakdown chap arrived (not bad for a busy Friday afternoon!). He checked the car over and suggested it wasn't a coolant leak, or a head gasket issue...but that the fans had not kicked in to keep the engine cool at low speeds. We investigated fuses, etc. but were both clueless. He gave me the option of being flat-bedded back to Inverness (500 miles) or just drive home along the motorways and switch off if stuck in traffic. I chose this option, and sure enough...arrived home safely 6 hours later with no rises in the temp gauge. Car drove like a rocket with no performance issues.

So, what have I learned since...
* The fans are controlled by a module on the fan assembly...not fuses and relays (I think??) It is a 2003 model which has a different setup to the pre 2002 models.
* They should come on at about 103 degrees C - or 215 degrees F - they do not - as I just plugged in my OBD11 with my laptop...no fans!
* They should come on when the A/C is switched on...at any engine temperature.....they do not!
* The dashboard temperature gauge should not be trusted as it doesn't move off "NORMAL" until the engine temp is way too high anyway...so if this happens... STOP IMMEDIATELY!!
* Ditto the above as regards the Oil Pressure gauge too....not related...but useful to learn!

So....please HELP!
Is there a fuse somewhere that needs checking?
Is there a water coolant temp sensor that needs replacing? If so...where is it located?
Is the Cooling Fan Module on the Fan Assembly the likely culprit? The fans are spinning freely when moved by hand (not with engine running of course!).
Or ALL of the above??

If there is anywhere else I should be checking, please let me know. I really don't want to take it to the Jaguar Dealer yet as they cost a bomb...but I will if necessary.

As usual, I will sincerely thank in advance, all Members who offer advice...as you never fail to go out of your way and devote your time to helping other Members and myself. A truly great Forum!

Warmest (but hopefully not over-heated) regards

Andrew

 

have a pressure test done of cooling system, pumped air into system to eliminate or spot small leaks, to see it it is a coolant related fault.
have electrical person check out fan , relays, wiring , etc to see if it is an electrical fault.

 

Cooling fans fuse. Engine compartment left side fuse #12 30 amps.

Relay: engine compartment left side below headlamp. Large relay.

John

 

Remember, you can use the cabin heater to shed some extra heat in these situations. Doing Face and "HI" seems to move a lot of air and get a lot of heat off the cooling system. Not saying it is comfortable if the outside temp is high...

 

Thanks John...but not on this model. There is no fuse 12 and I believe no relay as you describe as the later models have a cooling fan control module on the fan body. There is a fuse #16 which is a 5a fuse for the control module...and in my case...this fuse is good.

 

Hi Andy,
2003 JTIS shows an un-numbered 80A fuse in the 'Cooling Fans Fuse Box' It supplies the fans via the control module on the fan shroud. That's a pretty beefy fuse so it may be a cartridge type.

The box is somewhere around the top of the LHS strut under the bonnet. This post by chopr describes where:
https://www.jaguarforums.com/forum/x...97/#post694291

I haven't read the whole thread, but it may give you some clues.

 

Hi Michael - thank you for that...I will check the fuse and also clear out any debris from around the rad as mentioned in the article.

Also, after doing a few internet checks...I decided to buy a used fan assembly off Ebay which is marked as in working order...it comes complete with the control module and loom. If nothing else..I'll have something to swap out if all checks fail.

 

Hi Andrew,

Have you looked into doing the RealGauge modification? This will then have your temperature
and oil pressure gauges showing what is really happening.

 

Check F14 10A in the engine management fuse box, and the 50A in the cooling fan fuse box.

 

Checked and they were fine thank you. I suspect it may well be a faulty fan control module after all. I'll know more when I receive the one from ebay and swap it out.

 

I've learned about these in the past few days...I will certainly consider them...thank you

 

Most likely it is the fan control module if the fans are not coming on. I had to replace mine about 2 years ago with the same symptoms.

 

Hi All

I sorted the Fans Not Working issue. The replacement fan assembly and module did not work either. They never came on, even with the AirCon/Auto switches.

After reading advice on the internet, someone suggested fitting a new AirCon Pressure Switch/Sensor...on the aircon line running along the bottom of the radiator as this can fail, affecting the operation of the fans. Hey Presto! The fans now work! The sensor/switch was only £17.50 inc delivery from ebay and was a doddle to fit.

I now have a full fan assembly with module available which was not required after all.

Thank you for all the helpful suggestions.

Perhaps Admin could mark this thread as "Solved"? Thanks

All the best - Andrew

 

Andrew - glad to hear you were able to resolve the issue