172 manifold prone to cracking?

[ben_r1]

I've had a quiet but very annoying exhaust blow on the 172 now for about a year and can't seem to source it's origin. With the window open it's definitely located nearer the engine, I've changed the mesh ring with a new genuine fitting kit and other end of the decat has a new gasket too. Lambda sensor is tight.

Now for anyone who's familiar with where the decat meets the manifold on the 172 you can understand how it's be difficult to check that for blows although from what I can see ( usually leaves carbon/black blow by marks ) it's not blowing.

So the only item left to check is the manifold. I've done a quick search and can't find anything on this subject but has anybody experienced a cracked 172 manifold or a blow between the head and manifold? I've gone over what I can see from the top of the engine but can't see any damage or cracks.

Cheers all.

 

[Budgie]

Need to make sure there's a gasket on between the head and the manifold.

I've never heard of an OE 172 manifold cracking.

 

[ben_r1]

Why wouldn't there be? As far as I'm aware it's never been off...

 

[levaz]

I've got a standard 172 mani up for grabs CHEAP if you need one!
£15 inc post?

 

[Djw John]

They just don't break but gaskets do sometimes give up. Usually mani to cat one rather than head to cat mind you.

 

[ben_r1]

I've changed the mani to cat ring and the old one didn't show any signs of blow by. Didn't seem to change the fault either. I have aqquired a mani gasket from Renault, anyone know if I disconnect the cat if the manifold can be pulled back far enough to swap gaskets over with the manifold in situe? ( I.e save dropping the subframe ).

 

[levaz]

should be able to, I took the inlet off mine and lifted the old mani up out the top when I fitted the 182 system

 

[Fred@BTM]

just make sure you have the right gasket from Renault, there are 2 listed (1 is for late 172/182 the other for early 172 with oval ports)

no need to disconnect the cat, just undo the 9 x 10mm nuts and you'll be able to move it enough

 

[ben_r1]

Cheers chaps I'll get a picture up of the gasket so you experts can confirm before going ahead! Much love.

 

[AlexW]

I'd try and feel for blows with it running, just dont touch the exhaust, as it'll be hot.

Checked for cracks on the decat?

 

[ben_r1]

Yes I have, whilst on a euro trip last year I had a rather violent bottom out on a dangerously large kerb in Amsterdam and presumed I'd damaged the decat however removed it for full inspection and was fine.

This is the correct gasket for the Ph1?

 

[Dan@SJM]

Yes that's correct.

 

[ben_r1]

Brilliant I'll try replacing that then thanks. Anyone got the part No. for a mani to cat fitting kit?

 

[Mr R.]

Brilliant I'll try replacing that then thanks. Anyone got the part No. for a mani to cat fitting kit?

Just message Adam.