Hi Guys,

My S Type overheated today.

First, it was hot (around 94 degrees) I had the AC on and that was the first thing I noticed the air became warm. Then I glanced at the temp gauge while I was at a red light and it was approaching the red zone and the "engine temp" message flashed. I thought the worst... bye bye 4.0...

I parked her immediately and shut off. I opened up the expansion tank cap and noticed fluid on the ground (but didn't come out of the cap filler)

I let things cool down for about 20 minutes and turned on - I noticed no fan running. Checked 80A fuse - good..

I shut off and spun the fan blades a bit (best I could) and they turned freely. As the flat bed pulled up I turned on the car and the fan came on. I drove the car about 3 miles to my house and checked things out from top to bottom - no leaks and fan was running and temp normal.

I drove about 30 more miles (with heater on) and all was normal. No engine noises, smooth driving. Fluid level in expansion tank was steady... (minus the bit lost when opening up cap)

I noticed about a week or so ago a weird almost bearing like sound coming from the fan after shutting the engine off. but didn't think anything of it.

Two trains of thought...

Fan motor on the way out.

Fan relay module issues. (I did swap some relays in the engine fuse box) but I did realize there are no relays in the engine fuse box that control the fan relay module... or are they?

Any feedback would be appreciated.

Thanks

 

Workshop manual JTIS is free download and has electrical guide as PDF.

Have you changed to the metal-bodied chain tensioners (& related parts)? Your engine is on borrowed time if not.

 

This is significant. The AC should remain cold irrespective of coolant temp. I wonder if the entire car had a voltage melt down that resulted in no signal to the coolant fan to turn on and no signal to the AC compressor clutch to engage (?)

 

Sounds like a one off maybe?


I know you are very good at maintaining your car and the fan could be getting a bit lazy in it's old age. After all you have more miles on a gen I Jaguar than anyone I know! That's a LOT of hours on that fan motor!
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Has the issue with JTIS not loading on windows 8.1 and 10 been resolved?

 

No idea but it's FREE. I suggest you put some effort in if you want it e.g. grab a cheap PC with the right windows. Or pay for the PDF version on ebay.

There's always the non-free way...

 

JagV8 - yes, tensioners and everything else all done by me. Pushing 244K miles on the 4.0 engine.. I do have JTIS and WDS - I wanted to get input from my fellow members on my situation..

 

Thanks Mikey and Tbird6 - going to do a good evaluation of the car on Saturday including electrical.. (traveling currently - not w/ Jag) I'm leaning towards the lazy fan motor. Seems like it has seen better days...

Thanks again guys for your input, it's greatly appreciated.

 

If you can get hold of an appropriate tool (such as a 'scope - oscilloscope) you could look at what it's being told to do. Ii's via PWM so you're expecting a fairly square wave (well, it'll be non-square and anyway more rectangular than square) whose DC (duty cycle) changes. You may have to look when it should not have the fan running (er, cold engine, a/c off) so you'll grasp whether it changes when you're sure it should be running.

I suspect a normal DVOM (multi-meter) won't be much help though I've not tried looking at the signal(s) on our cars using one.

You wouldn't need a high speed 'scope - anything at all would do.

BTW, the fuel pump modules are also via PWM.

 

Mikey
Without airflow through the condenser (via the rad fan or driving above about 40 MPH) the A/C pressure would build until the pressure switch disabled the compressor clutch. This is a safety system designed into the car.

If you never slow down you don't need a radiator fan.

bob gauff

 

That makes sense and substantiates the thought of cooling fan failure.

 

I bought the 5000 page manual off ebay. It is presented in sections, not page numbers. Takes a while to find things sometime.

 

I expect so but you could always get a suitable PC if it bothers you.

 

Keep us posted on what your investigation tells you. As previously stated, you have a record amount of miles on your car and any original component could now be suspect....

I sure hope the fix turns out to be relatively easy and relatively inexpensive for you....

 

I'm currently running both JTIS and JEPC on Windows 8.1 and have run them on Windows 10 as a test:



They are installed directly and not in a Virtual Machine.

Graham

 

Good to know!

I have my free copy of Win10 but just can't leave my Win7 as it does everything I need and so far has been the best operating system I have used.

I do run JTIS in virtual XP Pro machine mode but JEPC is just an icon click on the desktop.
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Would it be possible to start a thread showing us compooter dummies how to get JTIS to run on Windows 10?

 

Update... Pulled out fan assembly. Connections to fan control relay clean and tight. No overheating. Once operating temp reached let engine run at idle.

Pressure tested cooling system - good and no leaks, including the expansion tank..

Listening to the fan motor initially engage at low speed I hear what sounds to me like bearing noises then dissapears as the fan motor speed increases..

Cooling fan motor is original to the car...So im going to order a replacement cooling fan motor from a Lincoln LS..

 

Just a heads up on the LS part. This was one area that Ford strayed from the Jaguar side a bit.

The early LS (2000-2002) at least the V-8 models used a hydraulically driven engine cooling fan. Current explanation was the LS had a smaller alternator than the S Type and could not handle the added load of the electric fan.

This has been troublesome and for the 2003 and up LS's Ford swapped to the more normal electric fan assembly. And I guess upgraded the alternator at the same time.

You can tell because the engine compartment has what looks like 2 P/S fluid reservoirs.

Don't know if the 2003-2006 LS fan would work or not but I bet it will.
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Same exact thing happened to my X350 last month. Replaced fan assembly and all is well.