Join Date: Feb 2003
Location: Wokingham, Berkshire
Local Time: 06:44 PM
Mentioned: 0 Post(s)
Quoted: 24 Post(s)
I've certainly had problems with leaking rad caps on my MCS JCW's. I replaced the first one as soon as I bought the car as it continued to leak despite tightening it so hard that I had to use a pair of 'grips' to undo it.
I noticed that the expansion tank had a very slight seam/moulding mark right on the surface of the header tank where the cap seal should be making a perfect seal.
I then replaced the cap again, but it still leaked despite tightening it down beyond the point where you can undo it easily by hand.
So recently I replaced the plastic header tank with an alloy one.
It isn't a FORGE tank as these may be excellent but far too expensive for my budget. I found a similar alloy tank on ebay for £88 plus shipping.....about half the price of a Forge. It was great quality when I unpacked it and it certainly looks good installed.
It was very easy to fit, (I syringed the coolant out of the old tank before undoing the bottom hose connection and you don't end up losing any coolant from the enigine, or need to bleed the system afterwards), and the only problem I had was that the return pipe inlet is slightly set at the wrong angle so that it comes very close to the power steering cap when installed into the original mounting bracket. Not a huge problem, and the return hose doesn't actually rub against the power steering cap in use, but it's close!
Since then with another new expansion tank cap I have not had any further leaks.