My 2004 XJ8 is still having the low coolant light go on. It has had passed two compression checks and had the cracked temperature housing replaced. What else could be wrong?

 

I would check the coolant level probe under the expansion tank, if you do have coolant in expansion tank and still getting the warning.

 

You will have to give us some history. It sometimes takes awhile to get all the air out. Did you do a pressure check on the cooling system?

 

I have had two compression checks already. Is that what you mean by pressure check?

History. 2004 XJ8

1. coolant light warning was on. I took it in and they did a compression check and coolant flush. About three days later the light came on again. I ignored it.

2. About two weeks later my engine overheated and coolant sprayed out all over the place. Towed it to the mechanic.

3. The mechanic did compression check and replaced cracked temperature housing.

4. A few days later the warning light came back on. I brought it in again and he added more coolant.

4. A week later the coolant light is on again. The car is back with the mechanic.

 

did you replace the whole water inlet pipe or just the thermostat housing?

If you have the part# of the part replaced would be helpful.

 

A common fault with these cars is a leaking coolant tank at the bleeder connector. Replacing the tank is the normal fix. I have replaced mine at 60K, I have heard of many others.

 

I had a low coolant light come on in my 05 XJR at age 4.5years and sent the car in for checking. The first thing found was a cracked and leaking coolant tank. This was replaced but didn't solve the problem. The radiator was also found to be cracked and leaking, at a hose connector junction. The radiator was replaced. At that time, some water hoses were found to be soft and had surface cracks (but not yet leaking), so an order went in for a new set of hoses, but before the whole set arrived, I had a hose leak. All hoses within easy reach were subsequently changed when I received them, except for the one that ran below the supercharger....

Of course, that would then be the next one to blow. So I had the supercharger removed to replace the hose..... and then the car no longer had a leak, but had very high coolant temperatures....

It turned out that the problem was that the electric fan was dying (but not totally dead) so it still spun, but not at it's proper performance so no one realised it was a fan problem. Once the fan was changed, all the cooling problems were resolved.....

except that within a year+ I noticed transmission fluid blobs in my radiator water... The transmission cooler (of the new radiator) was leaking into the water cooling side of the radiator.... another new radiator was put in.... I hope this one lasts a bit longer than the last.... sigh....

Don't even start me on the air suspension issues..... my wife laughs at me and is very happy with her 350CLS.... but it's not a supercharged jag...

 

The mechanic did another pressure check and found a leak. The bill said he put on two EGR hoses. I hope I never see that coolant warning light again!
I love my Jag. :-)