Ok so I finally get the Jag inspected and tagged, and took it for a quick spin. Here in Houston it was 90 degrees outside, and the temp gauge settled just to the right of the 'N' on the gauge. I let it idle for a while, and it didn't rise any further, but the engine idle seemed to deteriorate.
It looks to have had a new radiator, the hoses all look good, and the electric fan is kicking on. If it were a V12 alarm bells would be ringing, but is this also the case with the AJ16 ? If indeed it is a cause for concern, what would be the next step, thermostat replacement ?, and if so anything special about the thermostat, or its positioning in this motor ?
Thanks in advance

 

I think my next step would be to take an infrared thermometer and check the temps on the top hose and the radiator. If the temp is in the 190 range, it's fine - the gauge or the sending unit could be off a bit.

 

AJ16's can have a thermostat issue, as in they JAM. Mine did, and temp gauge did all sorts of wierd stuff. NOT expensive, and waaaay easier to change than the V12.

That plastic screw on radiator tank pressure cap should also be replaced, and make sure you DO NOT fill that header tank too full. I forget now on the XJ-S, but the X300 (1995 on) has a low and full mark down inside the tank, which is visible thru the cap opening. Too full and coolant gums up the valve in the cap.

 

Glad to see another AJ16 XJS in Houston!!!!


The facelift gauge is notoriously flaky. Having gone thru this and having spend lots and lots of money trying to make it read right, I suggest the first thing you do is go to Autozone or O'Reilly's and get a OBD2 scanner, the kind you can plug into the car and see values as you are driving, and see what temperature your CTS (coolant temp sensor for the ECU) is getting.

As you are able to, I would suggest you get a new fan clutch, rod the radiator , and make sure all the foam around the radiator is in good shape, and that you have the correct thermostat.

Let me know if you need any help

 

Thanks to all that replied, I have an OBDII scanner so I'll try that, and also have an infra red thermometer on the way. If it is actually running hot, and it's not just the gauge, I will replace the thermostat with a 180 one. Noticed today that when the lights and A/C are both on, the battery voltage drops to the mark between the 9 and 13 on the gauge, is this also normal, or am I in for a new alternator as well ?
Glad to see another XJS AJ16 in Houston, that I can come to for help, as there is lots I need to do .........starting with the drivers seat recover, the door mirrors, and removing the SRS panel on the dash ...........wish me luck ...

 

Alternators on these cars are pretty sturdy. The voltage drop is most likely related to the ignition switch connector under the steering wheel or less likely your harmonic balancer. Thinking I was being proactive, I replaced the OEM alternator with a 400 dollar Bosch replacement, and not only did the Bosch replacement fail within a year, but the voltage problem never went away until I found out about the ignition switch connector. Solution to that is to eliminate the switch and weld the cables together, you also want to check all the main power connections at the firewall ( battery unplugged for both things)

Before I buying a lower temperature thermostat, I would make sure the radiator is clear, the mechanical fan clutch is new and the radiator is sealed all around+ your flaps on the shroud are all there. All this can be done for little money.....oh yes and you want to make sure your aux fan is working!!!

I, too am in the process of recovering the seats. I bought some new skins I am waiting to install, but other things have taken precedence.

 

Again, thanks for the reply. The radiator looks to be new, as the fins are still black, and very clear for a 17 year old car. The flaps on the surround are all in place, and the aux fan is working. Can you elaborate on the ignition switch connector for me ?
Where did you purchase your seat skins from ? as I have seen covers that vary from $700 to $1350 for the front seats.
Again, thanks for the help !

 

Magredvet,

Please make sure to document the process to remove the SRS wood panel.

This issue has come up several times.

You can do a search on these forums. I believe you will read that using the lower temperature thermostat will be a waste of money.

The gauge on my dashboard reads halfway between the N and H on hot days. I've gotten readings on my OBDII reader as high as 216. 190 is normal.

 

If..if the radiator is new, is the electric fan is working, and if all your flaps are there, you are way ahead than a lot of us when we got our cars. I hope that is the case.

The hottest my car got was last summer when we where at 100 degrees: I placed the car on "D" put my foot on the brake, the A/C on high, and sat there for 15 minutes. I got up to 215. That is consistent with what Vee and other AJ16 owners (X300 and XJS) have reported from their engines.

I would still get a new mechanical fan clutch if you are running on the original and make sure you have foam all round the radiator

The poor idle you mentioned earlier might be unrelated to the temp. For some AJ16 owners it can be a challange to get perfectly smooth idle. You might have a coil on the way out, spark plugs, an injector...nothing too difficult. Good thing, it is nice and easy to work on the Aj16 straight 6 engines. Not like the nightmare V6's or V8's

Download the free electrical diagram for our cars from:

Jaguar electrical reference

They are kind enough to have them for free. I am looking at mine to try to figure out why your mirrors are not working.

Finally I got my 2 front seat skins from Autoberry. I am ver satisfied. Usually when you order leather seats, they do only the panels that you sit in in leather and the sides are synthetic. I paid them extra to have every single panel made in leather. Also my car is CREAM (NDR) interior, And I bought the new skins in coffee/barley (SDC), and since all I bought is the two front seats, everything else that is cream like the door panels and the rear seats will be dyed to match the new skins.

 

Again thanks for the info, do you intend fitting the covers yourself, or having some one do it, I've heard 'stitches' on SH6 does a good job, and is an Autoberry recommended shop.
Lastly if you could give me any more info about the ignition switch wires, mentioned in your previous post, I would be grateful.
I tried searching, but may have been using the wrong terms..............

 

Hi Magred,

The covers will be fitted professionally. What I do not know yet is if I will redye the rest of the interior to match or if I will have that done too.

This is the switch under the steering wheel.

AJ16 XJS IGNITION SWITCH CONNECTION - YouTube

 

Thanks again for the info, so do you just cut the connector out, and splice and solder the wires together ?

 

Yes but you must disconnect the battery and know how to solder VERY well. This is a main power connection. And remember, your connections in the engine bay must also be in good shape.

 

Ok Thanks again ! I take it just cleaning the connections won't work ?
Went out this morning and the battery is totally dead, obviously more to this than meets the eye

 

Sounds like you have a drain. I just had a problem with the interior lights staying on which turned out to be a simple cable touching ground. A common source of drain on the facelift is the power antenna motor failure

 

Updates !
Sat with the OBDII tool connected yesterday morning, and had the car idling with the AC and lights on. The temp gauge got as high as in the middle of the N and the H, but didn't get any higher, but the temp from the scanner showed a high of 204F, then when the AC was switched off, it dropped to 199F, so by reading what others have reported, I take it this is OK ?
The voltmeter is a different matter. Cleaned the terminals at the bulkhead, put a fully charged battery on, and the gauge is showing above 13 ..........great I thought, then i turn the lights on ...gauge flickers , but back up to 13 .....so far so good ........then I turn the AC on with the lights, gauge starts to drop, rev the motor...........no difference, but heres the strange thing, turn the AC and lights back off, but the gauge still does not come back to 13, even when reving the motor ?
So does this still point to the ignition connector, or could the alternator be shot. It had a new alternator, about 40K miles ago ...........

 

Temp sounds OK..specially considering we got up to 97 this weekend. I would still get a new mechanical clutch, thermostat, and change the coolant..

My gauge was doing the same thing. Still sounds like the switch to me. Could be wrong

 

Thanks again ! ......any tips for changing the coolant?, are there any special procedures, eg does it have a bleed screw like the V12's