I have a 2000 S Series Jag, 80,000+ miles. I am having problems with the fan. It comes on after only a few minutes of driving, is very loud, but shuts off when the motor is off. I don't have good luck with the Jag dealers or foreign auto shops, I think because I'm a 74 year old woman. I would like to know what could be causing the problem before I take it in to be fixed to possibly prevent being charged an arm and a leg.

The thermostat was replaced a few months ago, the lines bled but the fan persists. In 2014 the previous owner, my sister, had a new compressor installed. About 6 months later the AC would only work when driving on open roads, would not work in town - no cool air, the blower works. I had 3 estimates - 2 places wanted to just replace the compressor even though the compressor works on the open road, the foreign auto place who replaced the compressor said I needed an Expansion valve. I kept asking them to explain things to me, but would not get any answers just that these things needed to be replaced. I'm retired and on social security, so didn't spend the large amounts of money they wanted and since I only drive to the store and back most of the time, I elected not to have anything done.

Then the car started to heat without the radiator overflowing. At that time the fan motor started running, loudly, after only a few minutes drive. A mechanic friend who works out of his van, finally explained everything to me. He said that in order for the dealers to offer a warranty on a compressor, the company who sells it to the dealer insists that the compressor, expansion valve and all the hoses have to be replaced else they won't warranty it. So evidently the foreign car mechanic who replaced the compressor only replaced the compressor, which he guaranteed, but did not replace the hoses or the expansion valve. Evidently trash is in the hoses or the expansion valve and that's why it only cools on the open road. (He will only install a new expansion valve because the compressor works. He still wants to charge an arm and a leg.) At least I know now what is wrong with the AC, I have an explanation.

So because my car was heating up, my friend replaced the thermostat (which had been replaced in 2014 as well). That took care of the overheating problem, but the fan still is kicking in and runs loud. I've seen some guesses on the internet that say I need a new motor mount, costs being around $500.

Before I blindly take my car into a mechanic, I would like to know what could be going wrong and approximate cost. On the other hand, what will happen if I keep driving my car the way it i? I have some out of town trips planned and would not like to have my car break down.

Thanks for any help.

 

I'm no a/c expert - so hang on for others to chime in - but I suspect it's not the hoses etc. I can't see how it would cool when on the move if it were.

Cooling on the move means the airflow through the radiator is working.

Beyond that... don't panic but do see what others say.

 

The cooling at speed sounds like the valve mod might be the answer.
See the attached PDF the system needs to be evacuated and recharged.
Not sure about the fan.

 

Wow, sounds like you've been getting advice from all over the map. Glad you found your way here, hopefully we can help.

My long-winded HVAC troubleshooting guide is here:

https://www.jaguarforums.com/forum/s...ol-how-185002/


Specifically, please see post #4. Near the end of that post, I talk about the AC pressure sensor. If that was bad, it could cause two things that match your symptoms exactly:

1) It shuts off the AC compressor.

2) It commands the radiator cooling fan to run at high speed.


Don't just skip straight to changing that, but I think it's worth a gamble after you run through the rest of post #4 to rule out some other possibilities. For example, with the car at idle, watch the face of the compressor to see if the clutch is engaged or not. This should help determine if the compressor is being commanded to run or not.

Also, please do the test of the DCCV as described in post #2. I don't think that your problem, but it's quick and easy to rule out, too.

 

One more thought to help isolate the AC pressure sensor:

Drive slowly with the AC running to make the fan kick on at high speed. On the AC control panel, select OFF. If the AC pressure sensor was at fault, the fan should stop or at least slow way down.

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Welcome to the forum!

When the cooling fan kicks on and is loud....does the a/c start to get cold?

 

Lots of information and a bit overwhelming for me. I need to have someone else look at the info and then get back to you.

Answer to last post - no, the fan does not effect nor is it effected by the coolness or noncoolness of the AC. Once the fan turns on it stays the same until the motor is turned off.

Thanks to all of you again,

I'll be back.
Billie