De-cat/cat gasket woes

Post by **Pushki** » Wed Apr 17, 2013 3:40 pm

At my MOT I had an advisory that I had a minor exhaust leak in one of the de-cat gaskets.
I bought one off-the-shelf gasket for one end, and I made one for the odd shaped end out of gasket material.

After fitting them both this morning, they now leak worse than before.

I've tightened them up with all my strength but they still leak.

Any advice?

Old picture for reference. I avoided using any paste this time.

Post by **4thgenphil** » Wed Apr 17, 2013 3:41 pm

get stronger?

refit oem exhaust?

tried a bit of exhaut paste on either side of gasket

Post by **indigolemon** » Wed Apr 17, 2013 3:42 pm

4thgenphil wrote:tried a bit of exhaut paste on either side of gasket

This. Even the best gaskets can't fully accommodate for the slight variations, this is why paste was invented

Post by **Donald** » Wed Apr 17, 2013 3:45 pm

You have a decat?!

Post by **4thgenphil** » Wed Apr 17, 2013 3:46 pm

Donald wrote:You have a decat?!

seriously donald, WTF is wrong with you?

Post by **Donald** » Wed Apr 17, 2013 3:50 pm

How do you mean?

I'm just surprised that Pushki has such a mod going on!

Post by **Pushki** » Wed Apr 17, 2013 3:50 pm

indigolemon wrote:
4thgenphil wrote:tried a bit of exhaut paste on either side of gasket
This. Even the best gaskets can't fully accommodate for the slight variations, this is why paste was invented

The MOT guy frowned when I told him I used paste last time.
To be honest, I really can't be bothered to climb under there and go through it all again.

Lol at Donald.

106pete · Post by **106pete** » Wed Apr 17, 2013 4:07 pm

Some gaskets are too soft, so when you pull them up really tight they compress around the bolt and the flange just bends opening out the flange between bolt holes.

The reason they frown about exhaust paste is because you should never use it before the cat, and I guess they can't get that out of their heads.

Your solutions? Fit more paste or remake the decat with 10mm flange!

Mudgey · Post by **Mudgey** » Wed Apr 17, 2013 4:08 pm

How did you get through an MOT without a CAT in the first place?

Post by **Pushki** » Wed Apr 17, 2013 4:09 pm

Mudgey wrote:How did you get through an MOT without a CAT in the first place?

BB4!