1995 xjs 6 cylinder running hot

It’s due to the ac condenser being warm and “pre heating” the air before it even gets to the rad. The incoming air cools the condenser first the the rad.

And frequently airflow at idle or in traffic is not enough to make the condenser work well, so additional airflow help is needed. Hence the fan.

check to make sure that the rubber “gates” on the side of the radiator are intact and not brittle. If these are brittle or broken, the fan cannot draw air across the radiator when it is at idle or low RPM, the air just recirculates around the radiator. they are fairly simple to fabricate and replace with silicon rubber (or even intertube material). On my 94, they were in bad shape.

Don’t know about straight sixes, but on the V12s, when AC is activated, the extra air valve opens a vacuum line to intake manifold for some extra rpm to help with the extra turning of the compressor. If the L6 has this too, I’d make sure its working.

I think the problem may be my thermostatic switch. Really basic question here, how do I get these black plastic connectors apart so I can take it out and test it.

“gates” = flaps, for some of us :smiley_cat: Also, be sure that your front spoiler (I guess that’s what it is called ? :confused:) is intact, as it is important in directing air flow through the engine compartment as well, esp. while the car is in motion.

See the three stripes? From memory you squeeze that point and pull. It will be stiff to remove.

This is false.

The auxiliary fan is controlled by a thermostat, or temp sensor switch.

There is a mod that can be done, as I have, to activate the aux fan anytime the AC is turned on.

Instead of bothering with troubleshooting why the aux fan doesn’t come on, just buy a relay with a socket and some wire taps and your problems will be solved. Worked for me.

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Vee,

thanks for that info! I will test it again by allowing the temperature to rise. I read over this thread you refer to and like the idea of doing the mod, but my concern is that if there is something wrong with the aux fan temperature switch then I will lose out on extra cooling when the temperature rises but the AC is off, so I do want to resolve the issue it’s having.

Well, let’s weigh in on a second opinion then (anyone?). :thinking: I think PhoenixBob was alluding to this feature in his response. I have seen it mentioned on here many times before on the 4.0s (don’t know about the 6.0s, VK) that the aux. fan comes on whenever the a.c. is on (as well as at other times when the engine temp gets too hot, of course, via the mentioned thermostatic switch, which is RARE with the 4.0s, absent a malfunction in the cooling system). In fact, I have also seen many post on here that theirs (even here in the SW :sun_with_face: ) has never needed to come on while they have owned their 4.0s. Except for the a.c., it’s apparently almost like a redundant feature (fortunately for those of us with bad fan motors :relieved: ).

If I’m reading the original post correctly, it seems with the suggested mod you would have to turn the a.c. on whenever you wanted the aux fan manually on (if the added relay is getting power from the compressor circuit), but as I pointed out earlier (and VK disagrees) that happens anyway whenever the 4.0 a.c. is activated, so that mod would not seem to change anything. The original poster, btw, also has a 6.0, so I’m suspecting there are differences in the circuits between the two models in that regard. :thinking:

My personal philosophy: best not to tamper with “Mother Jaguar” (i.e. the factory set up) … so I agree there, Rubin :grimacing:

Well, a four pin relay s quite simple. Two ins for the load circit and two for the control circuit. One side of each is hot. One constant. wire probaly brown. One pin hot only when it is comanded to do so. here the AC or a temp sesor??

Tme for the VOm r test lamp. test for power.

I don’t know electronics well, but if the relay is only 4pin then doesn’t it makes sense that only the themostatic switch is controlling the aux fan? Wouldn’t you need a fifth pin to add the AC compressor as well?

Not really. teh relay could be energized by either or both sourses,

Paul,

No need for opinions. Go out to your car. Turn the car on. Check that the aux fan is off. (Car should still be trying to get to temperature)

Now turn the AC on.

Does your auxiliary fan come on? Engine should still be cold, so the that thermostatic switch should not turn that fan on.

If you check your wiring diagrams on www.jagrepair.com you can confirm it. As a matter of fact, I believe the wiring diagram used as the base of the mod shows you all you need to see.

As for the need of that thermostatic switch, I think I concluded the following:

  1. If it’s not hot enough to require AC, it won’t be hot enough to require the use of the aux fan
  2. If your coolant temp is rising on a cool day, and you think you need your aux fan, then something is wrong with your cooling system and the aux fan will, at best, only slow down the inevitable. If that’s the case, you can manually turn that fan on and get somewhere where you can address the issue.
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To revert back to an earlier post, this indicates to me that the bearings are dry, when I had my ‘40 my aux fan was stuck, I managed to drill a small hole in the motor casing and injected an amount of oil into the back bearing and this freed up the fan.

Good point, VK, and I could try that, except my a.c. (compressor) doesn’t turn on. When I had my belt(s) replaced at NTB some time back, apparently the tech took off the a.c. belt and never replaced that one … (kept it for someone else, maybe? :angry: ). I guess I had made the mistake of telling him that my a.c. system is broke anyway (leaking compressor, is my guess) so maybe alternatively he thought he was doing me a favor by leaving the belt off for a few additional HP. :thinking: Still, though, he should have told me he was doing that and given me the belt out of the 3-pack in case later on I did get the a.c. repaired. :angry:

However, back when the belt was in place, as mentioned, whenever I would try to turn the a.c. on the engine temperature would, after just a few minutes of running both, rise into the lower part of the red zone on the gauge. :open_mouth: My aux fan (the motor being broke) never did come on, though … If the engine was not fully warmed up at that point and the fan not come on automatically (i.e. b/c the a.c. was on), then what caused the sudden and dangerous rise in engine temp.??? :confused: I have otherwise never had my temp gauge rise above normal range (except one time when my thermostat went bad) and things have stayed at the temps they should even in the hottest weather here (and boy have we had that of late! :sun_with_face: :slightly_frowning_face: )

I disconnected the thermostatic switch and shorted the two wires together that go to it. The aux fan turned on no problem, so I guess the issue is indeed this switch. I know a parts car so going to try that before spending the money for a replacement.

I might give that a try then, Robin. :smiley_cat: It does make me kind of nervous though about “oiling” any kind of electric motor, as sometimes the oil can make its ways into the windings, stators, etc. and cause issues. :grimacing: I’m particularly reminded of that conspicuous warning printed on our alternators “DO NOT OIL” :no_entry_sign: :oil_drum: .

Good going, Rubin. :+1: I’m going to try that to see whether my aux. fan even makes any “effort”. If it does and blows (yet another) fuse, then I’m going to try what Robin suggested. :thinking:

This has been a miserable day! I went to the pick a part in Ontario California because they have a 1995 Jaguar there and I was hoping to score a themostatic switch as well as some other parts I need like the abs control module. The car they had was pretty well stripped, the radiator was gone completely so no luck on that and the other parts I wanted were missing as well. Although it did have a temperature control knob which I need. While out there it started pouring rain. I was trying to use the internet to find if there was another car that has an aux fan switch 22mm thread 35mm bolt but the internet wasn’t working for shit and the rain was getting heavier while trying to use it. So I trucked back to the checkout line and waited in it while we got rained on. So effing miserable…I don’t know why I go to places like this in order to save a few bucks!? Well the one exchange that brightened my day is I finally get my turn at the register and the check out lady with bright blue piercing eyes see my petty little plastic part and my dollars in hand ready to pay and says, '‘happy birthday… Just take it’. That was lovely of her, but still I wish I hadn’t spent all that time getting rained on with a heavy backpack of tools.