I couldn't find this addressed, but I sure it has been:

My '04 XJ8 VDP has over heated again.

My mechanic is stumped and has already replaced the thermostat housing.
I picked up the car last night and drove it for about 50 miles of city stop-and-go driving without incident.
I drove it to work at 65mph and it ran beautifully for 10 minutes.
I turned the climate control on and it blew cold air even though its set on 85degress (it worked intermittently so I thought I'd check)
The car overheated within 5 minutes, I turned the climate control off and pulled of the exit, the gauge went back to normal.
I park the car, it was dumping fluid underneath.
The car has 106K miles.

This wouldn't hurt so much if the car didn't perform so damn well when its fixed. I'm sure one of you seasoned Jag Veterans has encountered this before, any suggestion would be greatly appreciated.

Thanks!

 

Not sure why it would be blowing the cold air at this time of the year. If this was some 1960's vehicle, I might suspect a stuck butterfly valve in the exhaust. In any event, I wouldn't drive the car unless the overheating problem was solved. It sounds like nobody came up with a solution yet so probably your best bet would be to take it in to the dealer.

By the way, what's the coolant mix rated at right now?

 

It is possible that you have an air lock in the cooling system.

try parking the car on a slope facing upwards and bleed the system.

Do not run engine with cap off head tank (JTIS).

Are you saying that the cooling system is fine while the climate control is switched off?

If that is the case it's difficult to explain since there are no valves on the water side, ie there is allways flow through

the heater core.

 

Thanks for response Rickkk, I have the coolant in at a 50-50 ratio.

I haven't seen a thread that had a similar problem addressed but I'm poking around until I get a better sense of what I'm dealing with. In the mean time I will prepare myself for the dreaded dealer visit...

 

Thanks for the suggestions Meirion1. Last night I didnt run the climate control because I really didnt need it. This morning I turned it on while driving to work and it was then that the car began overheating.
I honestly don't know if it began overheating because I had been driving it for 10 minutes at highway speed or because I turned the climate control on.

I'm total stumped and so is my mechanic, this was his 3rd try :-(

 

My guess is you have air in the system most likely in the heater circuit

* raise the car up on ramps so the header tank is at the highest point
* open the radiator cap and fill to the high mark
* turn on the ignition but do not start the engine
* tun on the heater and set to max
* check the overflow for signs of coolant flow, check the heater pipes for pressure and the intercooler pipes on the s/c engines fr pressure.
* let this run for 5 mins (the aux heater pump and s/c pumps will be on)
* top up coolant as needed before replacing the cap
* run the engine up to temp and let ilde for 5 mins after getting to temp
* take the car off the ramps and allow it to cool
* check the coolant and top up as needed


While you are waiting for it to idle up to temp you may also want to check the radiator fan is working by removing the plug behind the fog light

See my post here https://www.jaguarforums.com/forum/x...4/#post1059380

Cheers
34by151

 

Hi Randy,

We're all assuming that the fluid that was dumping underneath engine coolant, and this only happens when the engine overheats and otherwise no coolant leaks anywhere from the system.

On our '04 XJR There is a bleed screw on the expansion tank that must be opened while slowly filling the system, then running the engine to hot, allowing the engine to cool, then opening the bleed screw again and refilling the expansion tank to the MAX mark. I followed the procedure in the Workshop Manual for draining, refilling and bleeding the system and had no problems. I didn't need to jack up the front of the car because on the X350 the bleed screw is already at the highest point in the system.

You can download the manual in six sections at the links below. The coolant draining and refilling procedure begins on pdf page 1160 of the Powertrain section:

http://www.mediafire.com/download/md...f+contents.pdf
http://www.mediafire.com/download/aa...nformation.pdf
http://www.mediafire.com/download/n3...2.+Chassis.pdf
http://www.mediafire.com/download/9b...Powertrain.pdf
http://www.mediafire.com/download/0i...Electrical.pdf
http://www.mediafire.com/download/4j...+and+Paint.pdf


One other thought is that it could be possible that your mechanic installed the new thermostat incorrectly. If following the coolant refill/bleed procedure doesn't resolve the issue, I'd ask the mechanic to open the thermostat housing while you watch and confirm the 'stat is installed in the correct orientation and with the wiggle pin on top.

Cheers,

Don

 

Your in Las Vegas? Who is your mechanic? Just replaced my thermostat and I burped the car and it seems like my cooling hoses have too much pressure, the ribs are now showing.... car runs great but I am concerned.

 

Could the water pump be a contributing factor here?

 

Good question, Lagonia.

I had briefly considered it but ruled it out because "mechanical water pumps rarely stop working, they just begin to leak." But prompted by your question, it dawned on me that a lot of modern water pumps have plastic impellers that can disintegrate, so you could very well be correct that a failed water pump impeller could be the cause of Randy's grief.

Does anyone know if the OE impeller is plastic or metal? The answer is probably already in a thread in the forum somewhere.

Don

 

The first order of business is to locate and repair the cause of the fluid dumping underneath. If it still overheats, then move to the next thing, a pressure test. If your thermostat housing was replaced, the thermostat is built in to those housings, so location of jiggler pins and such is not an issue.

 

oldmots,

Thanks for clarifying this. On our '04 XJR the thermostat is a separately-replaceable part. I had forgotten that it's a combined replacement housing/thermostat on the N/A cars.

Cheers,

Don

 

When the Jaguar V8s came out, there was a spate of water pump problems with impeller blades breaking off, so coolant didn't get pumped around. However this problem was fixed during the production of the 4 litre engine. The later 4.2 litre engines obviously have the later pump, but clearly if everything seems OK with coolant level and thermostat, one has to carry on looking.

So if the bleeding doesn't work, maybe look at the pump, which is unfortunately a bit of a PITA to remove. Only other thing would be a clagged up radiator, either externally or internally. Maybe check the air flow side of the radiator first to make sure it is clear, then the pump.

Edit
Has it got the correct coolant in ? If somebody put in the old type, (non-OAT type), then there is a possibility of sludge forming, because the two don't mix, and that will clog up the system

 

I wondered about the water pump as well as I was reading down through the thread. I replaced thermostat/tower and water pump and not soon after had an overheating problem. I replaced the new thermostat thinking it was defective, but the overheating problem didn't go away. I didn't consider that the water pump was bad because I had just put a new one in. As a last resort I removed the water pump and found that the plastic impellor was broken. Put in another water pump (with a metal impellor this time), and problem solved.

It was also challenging diagnosing because the car didn't overheat every time. It was hard to figure out why it did some times and not others.

Your situation sounds a little similar. Just saying...

 

I went to 808 Motors on Sunset Kellyfontes. I took it there because the dealer I bought the car from had them do the recondition after they got it from the auction, so I figured they would have some history on it. They are nice guys, this is just stumping them at the moment

 

"Does anyone know if the OE impeller is plastic or metal? The answer is probably already in a thread in the forum somewhere.

It looks like the answer is that it can be plastic or metal."

 

Where exactly is the coolant leaking from?

 

Hello Team!
I went out on lunch and restarted the car after adding a gallon of antifreeze. It idled at normal temp for 20 minutes.
I started to drive the car home and it started running hot after about 10 minutes of stop and go driving. I stopped and let it sit. Some fluid was spilling.
After 90 minutes I drove the car home without incident in stop and go driving, normal temperature. More fluid when I stopped at home, the fan was running.
This afternoon I open the hood and checked the antifreeze. I added a gallon to bring it back to Max level.
I left the cap off and opened the bleed screw and started the engine.
After about 5 minutes the screw started percolating and blowing air bubbles. After another 5 minutes the bubbles had stopped and the engine had heated up to normal temperature.
After another 3 minutes I shut the car off, closed the screw and added another half gallon of antifreeze to bring it back to Max level.
The car is cooling off. Am I ready for a test drive? Can the fix be this simple after stumping my mechanic?
Thanks again to all of you for all of you help, I appreciate it greatly!

 

I don't see a leak anywhere at the moment. I only found residue around the top of the reservoir.

 

Wow, you added gallons of coolant? where did it all go in the first place?

Checked your oil?