Squealing manifold gasket. Doing any harm?

Benny the Ball · Post by **Benny the Ball** » Mon Nov 05, 2007 8:16 pm

Dear All,

The Bongo doctor recently informed me that I would be needing a new manifold gasket, as it had a small blow coming from it. (Sounded like a fan belt slipping to me). It only makes the noise for a minute or two til the engine heats up (and I presume the gasket expands to block the hole). Am I hurting my Bongo If I don't get it sorted straightaway? Will it affect mpg badly? Not getting any fumes inside the cab, and Bongo Dr said 'see how much it annoys you' in response to my question, 'should i get it sorted straightaway'?

Not in a desperate rush as I've spent £500 on it this month already- 2 new exhaust bits, aircon pump, new tyres etc.....

Cheers,

Benny.

haydn callow · Post by **haydn callow** » Mon Nov 05, 2007 8:45 pm

Are you sure it's not the No 1 manifold stud sheared off. Very common and easy to fix. Can be done without removing anything much.
You can see the stud (the only one you can) above and to the right of the alternator under the passenger seat. You will start "burning" the manifold and clylinder head if you drive it for long in that condition. I would get it fixed asap

Post by **Simon Jones** » Mon Nov 05, 2007 9:54 pm

We ran round for several months with a broken no. 1 stud with no ill effects. When we had it booked into Bellhill Garage for an MOT, I asked them to replace all 8 studs & the gasket. Didn't want to risk just replacing one, only to find another one go at a later date.

Benny the Ball · Post by **Benny the Ball** » Mon Nov 05, 2007 11:12 pm

Sound advice, as ever. I'll have a look at the stud in the morning when its light, but mechanic did mention the gasket as opposed to the studs. Was hoping that after engine warmed exhaust (stops squealing after a minute) it would 'seal' the crack in the gasket, thus not letting any more heat/emissions out than normal. It needs sorting anyway, sooner rather than later by the sounds

Cheers.

haydn callow · Post by **haydn callow** » Mon Nov 05, 2007 11:17 pm

the garage could have missed a broken stud and even if it is sheared the gases can come past the gasket but not harm it. once a new stud is fitted and pinches it all tight it may fix the problem.

Post by **Bob** » Mon Nov 05, 2007 11:46 pm

Any blow from the manifold/gasket leads to a reduction in back pressure, which can caust the exhaust valves to burn = compression loss.

kawasaki kid · Post by **kawasaki kid** » Tue Nov 06, 2007 1:29 am

And to fix that is a cylinder head off job.

smartmonkey · Post by **smartmonkey** » Tue Nov 06, 2007 1:56 pm

I dont think you will do any significant damage in a month or two but I would be very nervous with an exhaust leak under the seats. Even if you cant smell or taste exhaust you could easily be getting fumes in the cab, I just dont see its worth the risk.

Craig · Post by **Craig** » Tue Nov 06, 2007 5:34 pm

I had a stud go on a trip to Ireland, Ended up doing a thousand miles squealing like a banshee! No immediate danger , but watch for fumes!
Get the whole gasket n all the studs replaced.

RobnKathryn · Post by **RobnKathryn** » Wed Nov 07, 2007 11:05 am

The stud has probably broken as a result of the differing behaviour of the iron exhaust manifold and the aluminium cylinder head when exposed to heat/pressure. All the time that you run with a broken manifold stud, the exhaust manifold will progressively get more twisted and warped, thus increasing the chance of a repitition of the condition. This can be avoided by dealing with the stud immediately, and by having the exhaust manifold face skimmed when the stud is replaced.