Hi everyone, The plastic cap I'm speaking of is the one on the top front of the engine above the water pump. The original one was leaking due to what appeared to be a tiny crack. I went to the Jag dealer and go a new cap but this one wont stop leaking either, and yes the rubber gasket on it is good. Has anyone had this problem before? Also ever since this coolant leak I've been having misfire issues but I cant tell for sure if it's due to the coolant since it's a very small leak. Thanks for your advice.

 

The solution is the replacement aluminum thermostat tower. The leak may be in the old plastic unit.

 

Sounds like your problem is not your cap, but maybe your coolant is boiling over... The cap is supposed to let out the coolant when pressure exceeds a certain point.

 

I think you are referring to the reservoir cap not the indicated thermostat tower cap.

 

Only good solution is to buy ALUMINIUM thermostat housing kit with aluminum cap and seals. These plastic parts tend to warp with heat and never seal properly again.
New aluminum set with gaskets and "o" rings can be found on-line for as low as $48 plus shipping & tax. Don't waste any more time on these plastic parts.
I have 2 jags of this series..both had same problem. I was unable to solve same issue after trying several different ways in a professional manner. Until I did what I am suggesting you to do.

 

Thanks guys. I asked the manager at this Jag dealer and he said they don't know about a metal one.

 

Hi
I have been pricing a replacement thermostat housing for our 2001 xj8.

I think the best deal is from Welsh Enterprises website. They have a thermostat kit that includes a aluminum thermostat housing and its related parts (also made out of aluminum) plus the thermostat for $65.95 plus about $8 shipping.

These prices for the metal ones are less money than the plastic ones they are replacing.

Most of the other online auto parts websites charge at least $100 for the aluminum thermostat tower parts and they do not include the thermostat (around $27 at most of the sites - Jaguar charges about $65 retail and $47 discounted).

Jim Lombardi

 

Jim -- If you order the kit taking a picture of the parts would be helpful - I would be interested in seeing the thermostat they supply.

The price is almost too good ! They should know what they are doing so it would be interesting to see what they supply.

 

Hi Yeldogt
Welch Enterprise price now is $75.95, it was $65.95 April 2011.
Here is a screenshot of the Thermostat Kit that manufactured by Welch:



We replaced ours 11 months ago and have had no problems since.

Look at this other thread on the thermostat housing kit:

https://www.jaguarforums.com/forum/x...65-95-a-52760/

Many of the forum members have used this welch kit and have recommended Welch.

Jim Lombardi

 

That is a great investment. I did mine too.

 

Jim - Now that you link to it I now remember your discussion.

The AL part is surprisingly cheap and is a must do upgrade for cars w/o SC - this is a no brainer.

........... would be interested in knowing where the thermostat comes from and where Jaguar is getting them from at this point.


My group of collectors have and unwritten rule regarding thermoses.