So, the engine obviously like more air flow. This suggests that adding another aux cooling fan, as you mentioned, is worth considering






Let's add a bit of perspective.

With a 15 pound pressure cap, and at sea level, the system will boil over at about 265ºF. If we define overheating as boiling over then you're obviously well below that stage. Perhaps there's some comfort in that.

Of course, we'd all feel more comfortable if temps could be held at 190-200ºF. I doubt that the Jaguar cooling system is capable of doing that in the conditions you've described. On my older Jags 90ºF ambient seemed to be the tipping point for the cooling system.....coolant temp would start creeping up in city traffic. I can remember seeing 110ºC/230ºF a few times myself. Nothing horrible happened. Just slightly frayed nerves.

For me the worry stems the notion that aluminum engines can't tolerate these sort of temps like old cast iron engines can. This might be unfounded; in fact my *own experience* suggests that it IS unfounded. But, still, there's that nagging little worry

(Back in the day I remember hauling my ski-boats from Los Angeles to Lake Mead, Lake Havasu, etc. with cast iron V8 powered tow cars and pick-ups. We'd go hour after hour with the temp needle at 240ºF and never think twice about it. So long as it wasn't boiling over we were "good to go" )


I'm rambling.

My point is that your worry is totally understandable but perhaps totally unnecessary as well . If you've never seen higher than 228ºF, and the gauge has never actually gone into the red, well, that might just be as good as it gets.

If you're sure everything in the cooling system is already fault free then you can add an extra fan. It might make *you* more comfortable. Whether or not the *engine* needs any additional comforting is up for debate

Cheers
DD

 

The huge problem that all of us Facelift owners face is not the mechanical gauge. It's a mechanical gauge that passes N at only 200. 215 to 225 might be normal on stop and go traffic or 105 degree weather but NO ONE likes to see their needle past N. I sure don't.i have replaced every component of my cars cooling system. I have done the impossible and found 4 new OEM senders dac11079-no longer available for over 10 years- I have a new gauge sitting on my new parts box-all so I can get that needle below N. The only thing that had actually worked is a lower temp thermostat that makes te car run 15 degrees cooler than it should.

 

I know.

That's why Jaguar, BMW, and so many others have gone to the semi-fixed reading type temperature gauges such as on my X300





Do you want the engine to run cooler, or do you just want the gauge to read cooler?

If the latter, then you're torturing yourself just to get a gauge reading that makes you more comfortable !

If the former then maybe it's time to consider that extra cooling fan you mentioned. Or perhaps a custom-built higher capacity radiator?




Cheers
DD

 

Mark,

Have you noticed any change to your fuel economy when running that much lower? I would have thought it would make the engine run richer?

Allan

 

Well there is no need as far as I can tell-and I do have to electric aux fans in front of the condenser to help keep it cool-

As far as I can tell the X300 gets way higher that 215 and does not past the middle of its dummy gauge. The AJ16 XJS is quite close to the red area at that point. At least 95-96 owners have the OBD2 por to tell what is really going on..

The lower thermostat went in just before I dropped the car for her repaint. It's staying there thru the hot Texas summer since the car is going to get up to at least 185 and beyond anyway. It won't matter if I stick 120 thermostat in there. For the long term the solution will be the one I mentioned earlier on this thread, to put the correct thermostat back on and put a resistor between the sender and the gauge so that the N is actually 210 or 215.

 

No just as crudy as always. It's not a 160 thermostat it's 180, so it gets pretty close to what it should, just gives me the placebo effect with the needle. I have heard people predict the world will end if the carries not reach the magical number of 195, but I think the ECU considers a number as low as 160 as fully warmed, so it isn't staying on closed loop.

The fuel consumption was already bad before and did not change with the new thermostat

 

Thank you very much for your friendly answers, Doug

Now I'm going to keep the 190 stat, and I'll see how works all next weeks as Spanish summer is very hot too
Yes: for the V12 engine were available both stats, 180 or 190, but for my 3.6 straight-six I always see just only the 190 one
That's important: now I get an aftermarket thermostat, theoretically equivalent, interchangeable, with the original EBC3621. Mine is from Vernet manufacturer, there's a lot of another manufactures as I told you before, but always of 190 F.

But yes, some people say the original part from Jaguar is not exactly like another ones, so maybe it's better to fit only the original one. But another people say all they are and works the same, and the only difference is the price: original stat is (here in Spain) three times more expensive than others

I don't sure what's the manufacturer of the original Jaguar thermostat, maybe waxstat?
Yes, that's the question. Maybe is a psychological issue, but after checked everything, seeing the gauge so high still causes concern

 

On researching my catalogs and the JDHT site, I've reached the same conclusion




Having just looked at the illustrations of the EBC3621 I don't see anything particularly unique about it, unlike the thermostats used in the V12s.




I believe so, yes. I know that Waxstat supplied Jaguar with many thermostats. But "many" isn't the same as "all", so I'll leave some room for doubt.

Cheers
DD

 

Pressurizing the cooling system increases the boiling point of liquids As a result some autos run at over 250F. Much cooling of the motor is done by the motor oil. I had a '69 E-type in Denver, six cyl, that would overheat in traffic or when AC used. Overheating was common at 5280 feet altitude. Some members of the club went as far as installing four core radiators. I took a different route. I installed a racing oil cooler behind the radiator and AC condenser (number three in line for cool air) and never had another overheat problem. I did find out that the oil pump pumped about 30 gallons per minute. I now live in Houston and so far my '93 XJS has not overheated