My 1998 XJ8 is boiling out anti freeze from the overflow tank after driving for an hour or so (city stop and go type driving). The car isn't overheating at all, but I'm losing fluid from the overflow tank after I stop. Any ideas, anyone?
Could it be the thermostat sticking?
Any help or ideas would be greatly appreciated as I am supposed to take a long trip Sunday and don't think I can trust the car.

 

Be aware the factory temp. gauges are not precise, usually when it indicates overheating, it's too late.

Also check the lines going to your coolant reservoir they should be crossed, a lot of people install backwards. Below is the correct install.

 

If the pipes are crossed the next things to check are the thermostat and water pump. Be advised that the thermostat housing and crossover pipe both become brittle and it would be a good idea to replace the housing with an aluminum one and also replace the crossover pipe and short hose.

The main radiator hoses should be checked for swelling under pressure, or just replace them also.

Replacing the water pump is also a good idea.

 

Wow, my pipes are NOT crossed. I repaired the coolant reservoir several months ago, and I guess when I reinstalled it, I did not put the two hoses in the right place!
I have also had ALL hoses replaced and water pump as well in the last 6 months so my new question is...
Could it be that the weather has become hot and the misplaced hoses are just now causing my problem?
Many, many thanks to all....

 

Ambient temp.,driving duration & intensity are all contributing factors. Switch your lines, top off w/ coolant, then go for some spirited driving & see.

Godspeed !

 

I certainly will! Thank you KC!!

 

Okay, switched the hose connections to correct placement (crossed), and now my self-repaired resivoir tank is dripping from the bottom. At least now I know I have the correct pressure, as I can now see the "flow" of the coolant when the cap is removed! Now looking for replacement tank, or I may repair mine again, as these are some new materials I have found that may make the repair more permanent.
In any case, thank you again for your expertise, it solved a mystery I would have never figured out!!

 

Hopefully no bubbles in reservoir?

 

No bubbles! Just a Leakey resivoir tank, which I will repair and should be good to go!
Thank you much