Hello all-

99 XJ8L/308

I've searched the forum extensively and saw that Scottish Chap was/is having a similar issue as I am with the cooling system, but I'm not sure I've seen an actual FIX as of yet.

Symptoms: After new water pump and thermostat, was having an overheating issue still, which I believe was air trapped in the cooling system. That I resolved, as I bled the system by elevating the (US) driver's side and running the car a while, heater/AC on/off. I attached a digital thermometer to the upper radiator hose as I saw suggested in a post and covered it w/ insulation. Hose gets to 183F, then slowly drops to around 165F once the t-stat opens so I'm comfortable saying the water pump and t-stat aren't at issue. Now for the issue...

As Scottish Chap eluded to, I'm getting "gushing" sound and then coolant comes out of the overflow bottle in the driver's side front bumper area. Temp gauge (although from the forum I know LIES) stays dead in the middle the entire trip. It only seems to be when I shut the car off that I then get this expulsion of coolant. (At the fill/upper resevoir, the small hoses at the front appear to be correct as they look "crossed".)

Any ideas now guys? Am I missing something or can I check something else? Kind of embarrasing to have a large puddle of coolant under the rig after shutting her down after driving each time. This does, I might add, only happn after a DRIVE. Idling and shutting down does not make this purge happen...

Thanks in advance for any tips or ideas!

Templar

 

Check that the expansion tank is connected to the overflow properly:

https://www.jaguarforums.com/forum/a...nsion-tank-jpg

 

I would bet on RJ's diagnosis.

 

YOu have the black hoses misconnected to the overflow bottle.

 

Hi all-

Thanks for the input, I appreciate it! As an update, I've double checked the small tubes going to the resevoir and they're hooked up correctly (as according to the link rj237 posted). On the way home yesterday it overheated so I'm back to the drawing board. Here's where it stands:

New water pump - check
New t-stat - check
Checked resevoir hoses - check (they cross as per diagram)
Fans are coming on when engine gets hot, lower first then upper (AC fan) once REALLY hot or when the A/C is on.)
System was bled of air (resevoir bottle side higher to help air escape to highest point)

So any other thoughts? Even after the engine is completely cooled, overnight, I check the resevoir level and coolant erupts out. I'm wondering if I've got a plugged radiator now. The car wasn't running when I got it so I have slowly been going though it. WAY too nice of a car to give up on it!

Thanks guys!

Templar

 

Could be the old orange and green coolant coagulation - or whatever it's called. They don't mix and your car is on the cusp of the change. I'm not sure which you should be using, but you probably need to try to flush it out first.

 

I do not believe it is the cause of your overheat,but your description of the fan operation is not normal. Both fans run low, then high. Perhaps you just observed something wrong. If they really run like you say, you have might have a bad fan motor or a bad relay in the fan circuit.

 

Ill check things again guys, thanks for the advice. Should probably flush the entire system since I'm sure the current coolant has now boiled. I'll get to the bottom of this and make sure I post what I find if it can possibly help others.


Templar

 

Do you get white smoke exhaust?

 

The fact that it is holding pressure overnight would seem to rule out incorrectly fitted pipes , or a failed header tank cap. It may be that you have a blown head gasket, pressurising the cooling system, the gas not purging until you release the cap. You can get materials to test for exhaust gas in the coolant; that would be my next step.

 

Do you really mean your fans operate like this?
"lower first then upper (AC fan) once REALLY hot or when the A/C is on."
Again, that is not right!

 

Hello all-


Here's the long time coming solution to my problem. I hope this never happens to any of you, but if it does, be prepared for some expense. Fredd was correct. It DID end up being a blown head gasket that was super pressurizing the system. Once the head gasket was replaced and coolant system bled correctly, the car runs very nicely and temperature gauge is right in the middle.


This was the major portion of my issue, then as things were "fixed" other issues popped up like sensors failing, then the throttle body motor failed and needed to be rebuilt, etc.... All in all, the total cost was several thousand US to get the Jag back on the road.


Best regards,




Templar

 

Glad to hear you finally got it sorted: but did it really take 18 months?

 

Hahaha.... Jhartz, yes but only because I opened a brewery and it distracted me from working on it. Ended up taking it to some mechanic friends and they worked on it in their "slow" times. Just realized I didn't update my original post.