Well, let me start from the beginning. I have a 2004 xj8, and over the past few months I've had a slow leak somewhere the cooling system. I would have to top off the coolant about once ever two or three weeks. So one morning while my wife was driving home from work, she called and said it ran hot and immediately pulled over. So after investigating I noticed the nipple from the reservoir tank had broken off.

So at this point I thought the slow leak might have been coming from the reservoir tank. So I soon replaced it, and decided to take it for a spin to test it out. About 3-5 miles down the road the temp needle began to rise. Then I started to smell antifreeze. Oh no, I thought, then it rose to the point the red light came on, and the coolant light also came on. Right when I was about to pull over, the temp needle went back down. And it fluctuated until I got back home. When I got home, the fans where running wide open, and ran several minutes after I turned the engine off.

I took off the engine cover and saw that it was leaking out of the top of of a seam in the thermostat housing, and coolant was sprayed all over the engine. So I concluded that both the thermostat was bad, and I needed to replace the housing as well(double whammy!). So later I realize I didn't bleed the system when I replaced the reservoir, so after doing that, I decided to take it for another spin when I noticed the fans didn't kick on.

So after returning home, the fans still didn't run after turning the car off, wasn't running loud when the car was one, and there wasn't coolant all over the engine compartment. So I took it for another spin, this time driving for about 4 miles, the same thing when I got home. The coolant light never turned on again. There was still a little coolant seeping out of the housing, but to a much lesser extent.

So now I have a few question. I'm not 100% sure if my thermostat still isn't bad or not. if it isn't, could not bleeding it cause it not to open up? And also, since it's a very slow seepage out of the housing, could I get by with just putting some type of sealant over the seam, or do I still at the very least replace the housing.

Sorry for the very long post, I'm just a little baffled at this point.

 

I would replace the thermostat and the housing, not worth a failure there when far from home. I also suggest looking closely at the water pump and hoses as well, this car is getting old and this stuff wears out with age. I never mess around with coolant leaks, I fix them with new parts, never band aids. Don't forget to bleed the system every time its opened for any reason.

 

Thanks for the advice. That's the route I'm probably going to take. Is there a guide somewhere on how to replace the thermostat and housing? I can't seem to find on throug a google search.

 

I'd replace the thermostat. Its usually the cause of coolant issues.

As you said you refilled the system, you may also have air in the system. Did you follow the refill procedure.

Cheers
34by151

 

Not the first time, and it resulted with air getting into the system. The seconded time I air bleed the system. I did this by letting the car run at 2000rpm with the heat on, then bled by turning the knob on the reservoir tank. Is this the proper way to bleed?

 

Check out some pics here on my thermo replacement
https://www.jaguarforums.com/forum/x...no-more-87243/

Enjoy
-mag

 

Thanks, those pics are very helpful.