Quick question for the group. It's summer in Texas which means hot and humid and my radiator fans are running on high almost all the time unless I'm traveling down the highway at speed. They are also consistently (but not continuously) running on shutdown which also doesn't seem normal for the car.

​​​​​​My code reader is inop at the moment so no real readings to share, but every time I've checked in the recent past all has been normal.

Can other hot - climate folks chime in? Does yours behave similarly? It could be I just have a short memory and it's always done this. You know how it is when you become aware of something and can't stop fixating on it. Lol

 

Yep Super hot here too.

My fans run on after shutting off, for a while (few minutes) after a long drive in the car. During summer, after I park up in my garage, I normally open the hood (Trick I got from Rothwell) to let things cool off. Noticed the fans shut off quicker then. Plus maybe I give a little more lifetime to the plastic bits... maybe....

 

Similar behavior here in NC in the summer. High fan on a great deal in town, on for a few minutes after removing the key. Realgauge and OBDII engine temp still within normal range.

 

Thanks. Sounds like normal behavior then.

 

mhminnich,

Most of the time, after shutting down the Engine, the Fans will run for about 20 seconds and shut down....I would be concerned if they ran any longer than that...

Billy Clyde in Houston

 

It’s also quite hot here but my fans don’t do that. The one time they did that was when my thermostat was failing. I have Realgauge and my engine temperatures hover between 190 ish and 212°F (90 - 100°C).

I would suspect either your thermostats or water pumps are failing. You monitor your engine temps just to be sure. It could be nothing, but I suspect something may be wrong.

 

My CAN temperatures/realgauge temperatures on all of mine are similar to yours, yet the high fan runs after ignition shutoff for some period of time when it's hot.

Perhaps it's something having to do with better thermosiphoning in the XKR? Perhaps it's the unit of time that is the perceived difference. Mine can run from me getting out of the car, going to the back of the car to open the boot/trunk and putting the charger on, walking inside and over to my chair in the living room, logging on to the computer and starting work. I can hear the garage from my chair across the house. I leave the door open to make it cooler when I want to go to the garage, much to my wife's dismay.

So, I'm sure I can't do that in 20 seconds with my level of dexterity unless I was on fire. As noted before, seemed like up to a few minutes.

 

On mine, the fans are off as soon as I take the key out of the ignition. I would expect the XKR to produce more heat because of the supercharger. I don't know if it should have better thermosiphoning but maybe those vents in the bonnet do actually make a difference. On an XKR, you do feel heat radiating out of the bonnet vents.

 

Remember, the cooling fan system was updated for the 4.2l engines. Before, the system is the conventional high/low speed. The later system is "continuously variable" PWM, based on a fan controller providing air flow as needed. Direct comparison of these 2 systems could be misleading.

 

These Jag's run hot, I have removed the 2 engine covers so the heat dossent get trapped in there. If you want your fans run longer after you parked it turn the engine off and right away turn the ignition key back on ,don't start the motor the fans will run as long you turn the ignition off. After I get home I also open the hood to let heat escape.

 

I comfort myself with the knowledge that Durham's (NC) record high temperature ever (105F/40C) was David Yau's temperature today.

Edit: Entertainingly, Durham UK's highest temperature ever (92F/33.6C) was somewhat below our temperature today (97F/36C).

 

normal operation for UP TO 5 minutes after shutdown. To reduce heat soak and drop ac system head pressure. remember that the fans operate for not only engine cooling but AC performance too.

 

Data point:

Out driving, temperature was about 97F/36C. Had the top down, A/C on LO with full fan, in town driving mostly for about 30 minutes. Let it sit in my driveway idling in the sun for a 5-10 minutes with everything on at the end of the drive.

CAN coolant temperature was 103C/217F at the end of this (still within normal range here, was around 96C for most of the drive). The AC compressor appeared to still be on, so the car was not yet alarmed at the temperature. I timed the fan on time after I switched of at 3:35. I expect all of this is normal behavior.

 

Revisiting this, I got a fresh reader in and my temps are running 222-228. That's higher than normal which usually peaked around 208-212 in traffic on the hottest days, and otherwise ran pretty comfortably in the 195 range. Something is afoot.

 

Perhaps, especially since it is a change in behavior, more investigation or a flush is in order.

When I went looking around a while back for what's normal (and normal for the 4.0 XK8 and XKR of this era may be different as already noted in the fan behavior), seemed like the top temperature with the needle in the middle of the original gauge (i.e. 'normal') peaked out at about 230F/110C. See post #1
https://www.jaguarforums.com/forum/x.../#&gid=1&pid=9

 

+1 to Dale's suggestion.

As with all thing X100, engine overheating is definitely #1 thing to look out for. Well spotted mhminnich! Check coolant level and condition. Turkey baster in the expansion tank works for me to extract the fluid.

I recently did a Coolant Flush (along with the front engine Coolant Renewal of hoses, cross over etc). My coolant had lots of sludge in it, so I went for a DIY chemical flush. No big deal and well documented for home DIY here. As with all things on this car, the first time you do a job it takes ages, but I think I can confidently do this now in less than 1 hour, including the hose flush, & chemical flush too, but excluding the time for engine "run in" and letting the coolant cool before topping up. I even learned that you can reach the radiator coolant drain plug from above so no need to go crawling under the car.

 

Thanks guys. I'll go the flush and fill route and see if that improves things.

 

'Cool' thing is that it's summer. One could let it stay in there a few days while driving a bit in lieu of the 3-6 hours driving in a session (according to BlueDevil customer support).

 

My general hot running became too hot today while I was parked and idling. I shut her down well before the danger zone. There was a casualty in the cool down though, as the coolant reservoir split at the seam.

New parts here Wednesday , then a thorough servicing.

 

Fascinating and troublesome. I would like to think that the coolant reservoir would not operate so 'close to the edge' in terms of material thermal behavior. OEM or URO (or other?) on the reservoir?

Good luck with it.