My 93 XJS 4.0L auxilliary fan works via the temperature switch when the A/C is on or off but does not come on when I turn the A/C on. It is supposed to work continuously when the A/C is on. Any suggestions?

Submitted by SE21-33540J on Wed, 06/08/2011 - 20:17

Sandy,

I did not see your post until today. I hope you resolved the issues with Faster Jags. I had no problem with my order, but it was just the thermal switch.

Submitted by SE21-33540J on Wed, 06/08/2011 - 20:14

Al,

If you could send me an e-mail at: jagunut1ataol.com and tell me how difficult it is to remove the radiator, and if you don't mind, what was the cost to have it rodded and cleaned. With these hot days here in the Carolinas I am above N and more so with the A/C on.

Jerry Cohen

Submitted by aljaszcar@emba… on Wed, 06/08/2011 - 09:20

Finally bit the bullet and pulled the radiator and had it rodded and cleaned. Temperature settles below "N" now with both ac on and off. Radiator shop owner said radiator was 80% clogged.

Submitted by browder@nuventrs.com on Sat, 05/07/2011 - 14:51

Jerry: I see that you have dealt with FasterJags....I worked with Brian Welker last week to put together a pretty nice order for him but since I sent the funds I cannot get an email or voice mail response....obviously it has me a little concerned. Any thoughts on this?

Submitted by stevejag@sbcgl… on Wed, 05/04/2011 - 22:53

Before you go yanking the radiator, let's try something else first so we cover all the bases. Do this on a morning COLD START. Open the bonnet so you can hear what's going on, reach in and start the engine, then lean over the wing and grab the throttle. Raise the engine speed a little, to about 1200 RPM and hold it there. While you are doing that, listen to the sound of the engine fan. At first it should be quite noticeable. After 20 or 25 seconds the fan should slow down so you can barely hear it.
Try that and let us know the result.

Cheers,

Submitted by aljaszcar@emba… on Wed, 05/04/2011 - 21:44

Although my Jag has over 100K miles the previous owner took excellent care of it. Took the valve cover off to put new gasket and engine valve train was pristine, like new. Radiator has been out once and looks fairly new. Engine compartment looks new also so I can't assume anything at this point and bottom radiator hose is right at Thermostat temperature of 180 degrees..

Submitted by browder@nuventrs.com on Wed, 05/04/2011 - 21:23

CatCooler and Dual Hi Flow Electric Fan system going in my old cat along with new hoses, new thermostats, new switch. Hope that I never see the north side of "N"..... ;-) My "assumption" is that in a 20 year old car with 100,000 miles the existing radiator MUST need cleaning to start with....just natural, why not?

Sandy Browder
Winston-Salem, NC

1990 XJS Convertible

Submitted by aljaszcar@emba… on Wed, 05/04/2011 - 21:15

The only thing that keeps me from yanking the radiator out for cleaning is that it takes at least 45 minute to an hour of driving for it to register 3/4 on th temp gauge on a hot day or with the A/C on. I would think that if the radiator was gummed up it would heat up much faster than that. And then on cool days its stays below N.

Comments

Submitted by dougdwyer1@com… on Mon, 05/02/2011 - 21:31

Ok, good....

The good news, IMHO, is that your temp gauge seems accurate and you're not running hot enough to hurt anything.

It's a reasonable assumption that the "N"....middle of the gauge....would represent about 190??F. Typically "N" on the dial face is thermostat rating temp....in your case 88??C or 190??F.
Using your "top of radiator readings" (which is what would use, FWIW) we can see that the gauge reading and the infra reading are close enough for government work.

The 210??F on the inra-red when the gauge is at 3/4 seems to follow along as well.

Now that, IMHO, we've determined the guage isn't taking us the garden path ....an extra step that needed to be done....you're still faced with the issue of running too warm for the given conditions.

I think it's time to clean the *inside* of the radiator.

Cheers
DD

Submitted by aljaszcar@emba… on Mon, 05/02/2011 - 19:37

Received infrared temp. sensor yesterday. Here are the readings:

Temperature reading Normal:
Top radiator hose = 170
Bottom radiator hose = 152
Top of Radiator = 184
Engine block = 170

Temperature reading almost 3/4 on gauge
Top radiator hose = 202
Bottom radiator hose = 180
Top of Radiator = 210
Bottom of radiator = 168
Engine block = 206

Held sensor about a foot from all points of measurement.

Comments?

Submitted by SE98-32482CJ on Wed, 04/27/2011 - 06:46

I agree with Doug-and no Doug we have yet begun to get hot. In the weather we have now I would expect a reading lower on a correct gauge. My V12 right now after a long run and then into traffic hits N.

Submitted by dougdwyer1@com… on Tue, 04/26/2011 - 23:39

Good work, Allen, but........

I hate to say this but I'm not sure you're out of the woods yet. Unless it's already 100??F in South Carolina and/or you're stuck in a gridlock traffic jam, you really shouldn't be above the "N" at all.

If the temps are still moderate in SC right now, what's gonna happen in August?

Do you have one of those infra-red thermometers? if so, check the temps at the upper and lower radiator hoes and at the thermostat. Let's see what the engine temp really is.

Cheers
DD

Submitted by stevejag@sbcgl… on Tue, 04/26/2011 - 22:14

Good job, Allen. Actually I think you did wire it as my diagram. The "thermal switch" is the temp switch on the radiator. Your A/C should work much better this summer.

Keep on JagIN!

Submitted by aljaszcar@emba… on Tue, 04/26/2011 - 21:34

Wired up relay, cleaned outside of radiator, added second fan. All is fine now. With a/c on or off temperature only goes about 1/4 inch past N on temperature gauge. Thanks Steven. I did wire the relay a little differently. I took the 12 volts from the compressor of course but wire the contacts on the relay across the temperature switch on the radiator. Works fine.

Submitted by stevejag@sbcgl… on Wed, 04/06/2011 - 16:49

You could try the lower temperature switch, but my preference would be to make the fan run any time the compressor is engaged. My feeling is that by doing that, you actually get a jump on the temperature before it rises to the point that would trip the temp switch to turn the fan on. The hookup below will accomplish it and still leave the loop intact so the fan will run if the temp is high when the key is turned off.

Just my preference.

Good luck!

Submitted by stevejag@sbcgl… on Mon, 04/04/2011 - 09:51

Edited on 2011-04-04 9:52:57

No, unfortunately Jaguar didn't make the fan operate continuously with the A/C on. I wish they would have. The fan can run after the key is turned off, however, until the temp goes low enough to open the temp switch. Somewhere along the line I think someone told us they did that for MPG. Engineers, ya gotta love 'em! The added alternator load of running the fan hurt MPG.
I have in some cases had to make some circuit changes to a car here and there to make the fan come on any time the compressor was engaged. Usually they were cars that spent a lot of time in traffic.

Because of this, I always recommend keeping an eye on the fan clutch to make sure it operates correctly.

Cheers,