A week ago the radiator on my 98 XK8 blew up. Popped at the seam. I replaced the radiator and the car still was overheating in about one mile. I checked for coolant flow and the water is moving. I thought maybe the thermostat was faulty (I just replaced it last year). I removed the thermostat and the car ran cool, but when I turned the motor off you could hear it "gurgling". I bled that air out of the system and ran the heater and it seemed good to go. I was driving today and after about 15 miles the "crummy" gauge started going up. I was about 2 blocks from home so I made a sprint for the garage. About a block away I feel/hear an explosion from under the left side of the motor compartment. Got home and checked the fluid level in the reservoir and guess what? I could see the cam cover. Any ideas as to why this is such an intermittent issue and what it could be? Any help appreciated!

 

The more experienced will chime in soon, but I would check that the thermostat is working even if it is newish.

Also look at the water pump. The early models have a tendency to eat the plastic fan blades inside it.

Lastly, NEVER, EVER drive these cars if they are overheating. The hassle of being stuck 2 blocks from the house is small compared to a new engine.

 

Do you mean the reservoir also burst?

 

It sounds like you have two problems:
1. The radiator cap is not relieving pressure, hence the radiator and what sounds like a reservoir blowing up.
2. The cooling system was not properly bled after the first repair.
Replace the cap, and bleed the system properly.
Good luck,
White Bear.

 

Bypassed the thermostat to make sure that was not the problem. It was after that when the reservoir blew. I bled the system by removing the bleed cap on the thermostat housing and filled the reservoir, while the motor was running, untill there was no longer any bubbles coming out. Cycled the heater during this also. What is the pressure rating for the reservoir cap? Have you heard of these caps going bad and not releasing pressure?

 

Yes, pressure caps can go bad.

Also, on the XK8, you do not get proper coolant flow with the thermostat removed, because the thermostat also acts as a fluid deflector, so removing it is not a valid test.

I suggest you replace the thermostat (sometimes they do go bad quickly), the pressure cap and of course the reservoir and make sure you have a 50-50 mix of the correct coolant. The thermostat and cap are cheap.

If you still have problems, inspect the water pump for broken or worn vanes.

 

You may as well replace the WP. bet it is orig. EASY EASY job.

 

Thanks for all the help. I will tackle this again next weekend. I am missing my car!