Hi everyone. I have been a voyeur to this site for years, and I thank everyone for all the problems it helped me solve. This is a awesome site, but I now have a problem that I can't find the answer!

My wife's x-type starts to overheat when at an idle or up to 1.5k RPM. It moves (temp gauge) in small spurts past the normal until it overheats, but if I increase the RPM to around 2k, I can watch the gauge drop back down in small spurts until it is back to center gauge. I have replaced the water pump thinking that where wasn't enough flow, nope. I replaced the thermostat thinking it might be sticking until the pump pressure increased, nope. I replaced the coolant reservoir cap thinking it wasn't holding pressure and causing the problem (reaching here), nope. I burped and burped this cat thinking there might be an air bubble near sensor and the increased flow pushes it out of the way temporarily, but nothing changed (at least the kids stopped crying after I burp them!). I don't have any leaks, and the fans come on at idle (once at operating temp). If I don't let the car run until it starts to overheat the fans turn off with the car. If I run the car enough to overheat (not really overheat just above normal operating temp) the fans stay on after I turn the car off. Not sure if that makes a difference or not, but it seems very logical to me. Any help would be greatly appreciated, my wife has taken my car until I can resolve this

 

Hello
I'm sorry to hear of your problems, it might be a blockage somewhere in the heater matrix? I assume the fans are coming on at the correct temp? Are you using the right coolant? Should be red antifreeze, hope you get it sorted soon.

 

I had similar overheating problems and they were all caused from a bad fan control module which wouldn't turn the fans on full blast when they needed to be which lead me to overheat. It is a really easy swap and would rule one more thing out especially as these fan modules tend to die pretty quickly in these cars. If you want to get a module for cheap like I got mine ($45 shipped) then check out this link:

https://www.jaguarforums.com/forum/x...modules-73510/

 

Thanks for the feedback. I'll look into another fan control module, but in the mean time I went on a little drive today. The issue really seems to be RPM dependent. Car sitting still, idle, temp starts to go up. Car sitting still, 2k RPM, temp goes back down. Car going 40 mph, 1.4k RPM (overdrive), temp starts to go up. Car going 40 mph, 2k RPM (4th gear), temp goes back down. Couldn't get to overheat at highway speeds, RPM to high. (or wind??) I'm not sure, but wouldn't 40mph wind be stronger than the fans? And what would the RPMs have to do with fan control? Am I missing something? FYI I'm in Florida it was 88 degrees today, with a feels like of almost 100, and the A/C seemed to be doing the same thing. When the car coolant starts to get over norm temp the a/c is not cold, just cool (maybe even warm). But when the RPMs go back up and the coolant temp goes back down, the a/c temp get cold again. Not sure if there is a clue in the a/c function to the overheating problem, but you just never know.

 

Ok, if you turn off the a/c does it still overheat? To me, it seems like your fan control module and your a/c aren't communicating. This could be due to a bad fan control module. To test if this is your problem, sit with the car at idle without the a/c on and listen to the fans. Then turn on the a/c and listen to the fans. If the fans are not louder when the a/c is on, then your problem could be due to a bad fan control module.

 

My fans stay running 10 minutes after I turn car off. Car overheats reservoir is full. Not sure if its water pump or module....

 

stljag, if you are driving down the highway and the car gets too hot, then you can rule out the fan module. I would somewhat rule out the fan modules now, but I would recommend one simple check. Drive the car, park it with the fans running. Now, open the hood and lean over the radiator some. Is your face getting blasted with lots of hot air or are you feeling a nice gentle breeze of warm air? You should be getting a good blast of air. If you are getting the gentle breeze, then you may have a combination of things with one being a fan module on its way out.

If the car is overheating while going down the road, it can be either the water pump or the thermostat. I would say to replace both while you are in there. Both show the same sort of symptoms other than the water pump in a lot of cases will leak from its shaft seal (you don't mention any loss of coolant). But the shaft leakage does not always happen.

 

I would suspect the airflow through the radiator. Sounds strange, but are the fans blowing the correct way; are they both blowing the same way?
Is there a blockage in the radiator.
On the X-type, is there a panel underneath, between radiator and motor, to stop hot air recirculating, (is yours missing).
Does the motor use water?

 

I'm with Fredd on blockage. I once had a radiator on another vehicle (not the Jag) where the rad core exterior (fins) became almost completely clogged with dirt and debris. The water channels inside were clear and coolant was flowing. But no heat was being exchanged. That blockage also restricted airflow through the AC condenser and caused poor AC performance as well.

 

After a twelve hour road trip to Nevada from Washington my Jag overheats. It happen first when I pulled into Reno, took the car to Jiffy Lube for new coolant fluid and oil change. As I drove through Spokane on the return trip from Nevada, overheated again, after twelve hours of driving. Vehicle has only 16K....puzzled and I'm peeved. Fan is not running after I turn off engine, fan module the problem?

 

schoenleber, first off, welcome to The Forums. Lots of good info here But, we like to keep things friendly here and as part of that, we like to get to know one another. So, please stop by the New Member Section and tell us a little bit about yourself. This will also give you a chance to meet those that make this place what it is.

As for your problem, based on what you are describing, it is your engine coolant temp sensor that is having issues. I have been seeing a rash of these lately. The sensor is fairly cheap and easy to replace.

Not to ask a silly question, but after the long drive, are you finding the expansion tank low on fluid? If so, you may want to check the system for leaks. The most likely place is the nipple going into the back/top of the overflow bottle as this can be bumped easily and result in the plastic cracking and causing a slow leak. After that, explore the engine compartment for any standing coolant and idle the car and see if you can spot any coolant dropping to the ground. From there, we can give you more detailed possibilities.

 

For about a week and a half, the coolant was draining out of the overflow. Coolant had to be added on commute going and coming almost every day. Then started going 50/50 on coolant/water, and now it hardly ever needs any??? There seemed to be coolant towards the passenger side, but not a lot. The ground was not saturated. Has anyone had this problem? So far, it has not overheated at all.
REALLY CONFUSED!!

 

COnfused, if you look by the IMT valves, there is a coolant connection there that has an o-ring in it. This has been a problem for some in the past that it will start leaking and give the conditions that you are seeing. You will also note that the hose that runs to the top of the overflow bottle runs over there too. So, it may be possible you have a small pinhole leak in the hose too that would require you to replace the hose. A little bit of looking over on the passenger side of the engine should give you an idea of where the coolant is coming from.

 

I have read your very insightful answers and glad to get something specific to try for this problem. Will check out your suggestions ASAP!!!
Thanks, again!!

 

Similar problem here.
When i stay with the car in a spot with A/C or just fans, car is starting to overheat.
The guy before me used destilated water not antifreez.
Here in Dubai temperature can be over 45 degree and one minute in the spot temp start to raise.
When i drive the car it starts to cooldown, as soon as i slow the speed it starts to overheat, but i noticed that if i turn off the A/C it doesnt raise temp fast, even when i put just fans to work it starts again to overheat.
Water is not losing, but the mechanic guy told me that there is a leak somewhere. He will check i today and tell me.
When i turn off the car the fans are still working up to 10min somethimes.
I checked the fans and i felt a hot air blowing in direction to the engine.
As i saw it from previous posts here im hoping that somebody can give me insight of their solution to the problem.
Im hoping that it is some minor problem but im scare of long roads and middle of the day traffic jams, because if i stop and car starts to overheat both of us will be dead during this summer weather in Dubai.
Any help would be much appricciated.

 

big system flush out, sorted mine out and its OK now
got a lot of thick sludge out of system.
mine is nearly 15 years old now

 

So you say it's not a big problem?
The car is at mechanic at the moment, he told me he is gonna solve the problem.
Just im a little bit sceptic, i payed the first service to much and if he doesn't solve that overheating thing i would be in difficult situation. Thanx for reply. Cheers m8

 

Tihomir, part of the problem is that you are running straight water. Coolant actually can store more heat than the same amount of water. So, running straight water in the coolant system is not a good idea. Also, the coolant has corrosion inhibitors. So, running straight water will cause your radiator to rust faster, leading to its failure sooner.

As for the root of your problem, it is sounding like to me that you have a water pump that is starting to go. In short, at low engine RPMs, the pump is not able to move enough water to keep things cool. Get the engine RPMs up and the water pump can move sufficient amounts of water to remove the heat.

As for why running the A/C causes the car to overheat quicker, that is a simple answer. In front of the radiator is another "radiator". This is a heat exchanger for the A/C system. It takes hot A/C gases and runs them through this heat exchanger to cool them which is then run into the inside of the car to cool the air coming out of the dash. So, instead of having say 40C air entering the engine's radiator, you now have 45C air entering because the A/C radiator/heat exchanger is adding heat to the outside air, making it that much more difficult to remove the engine's heat.

One other check that I would tell you to try is to check the radiator fans. This you can do yourself. Open the hood/bonnet of your car. Now, start the engine and turn your A/C system on as high as it will go (select the lowest temperature you can, dash fan speed as high as it will go, MAX A/C selected). Now, keeping your hands away from the fans, lean in over the radiator like you are going to kiss the air box. Do you feel a gentle breeze of air coming by your head or are you feeling a rather strong blowing of air? You should be feeling a very strong blowing of air (if in doubt, find a friends car and try the same thing). This would confirm the failing water pump. If you are getting a nice gentle breeze, then your fan controller is starting to go and what is happening is your fans are now running slower than they should be which is resulting in not enough air being moved through the radiator when you are sitting still. At highway speeds, the car is pushing enough air through the radiator due to simply moving that the fans are not having any effect.

 

Ty Thermo, i have red all of your previous comments to other guys.
The problem is that it is my first time i am doing a car maintence by myself.
Now here in Dubai there is too much services that tryes to ripp you off, so as far i i know, i saw a water liking when i was buying a car and the guy told me it is normal thing because of A/C working. But i was stupid and now i see that the problem is in his poor maintance the car and probably all the things that you said ( water pump, no antifreez etc...)
I have checked the ventilators when i started the car and they were blowing nicely the air to the motor.
The serviser told me that i have a licking of water problem and he is going to solve it.
He also told me that my trothle body is dirty and i need to replace that. Now because there is no spare parts at the moment he is going to clean it for me.
After diagnostic he told me car had 14 errors and he reset it all.
Probably he is trying to make a story that the car is in bad shape so he could charge more money.
Im aweare of that just my bihgest concern is about that overheating, i will for sute invest the money to make a car neat and tidy for ridding. Just wanted to get the knowledge od what could be wrong and not to became a fool once more of paying high price for not knowing things.
Ty a lot for your insight, will keep updating once i get car back and test it after service that they done.
Probably i will have more questions, thanks for the patience and tour time to respond me in details. God bless you, have a nice day.

 

Had same problem.. Unfortunately I tried all the wrong and had to replace my engine myself.. Yah.. Fun.. But come to find out it was my radiator.. After I did water pump, hoses, no leaks (well at first then I had a broken head gasket) but started with the radiator.. Not sure why now but after I took everything apart I found broken parts.. So sorry and good luck. Just finished with rebuild but now can't get air out of brakes. Done everything from bleeding with partner to hose.. Any suggestions please.. Thanks