Section : Engine

Engine, cooling system, fuel system, exhaust system.

MKIV 1300 exhuast manifold/downpipe joint

Posted By : Alan Madin, 17-Jul-2007, 12:23pm

Driving home last night engine got a little noisy/rough then a metallic clunk on bulkhead followed by bang under car as a nut holding downpipe /manifold together came off a stud and parted company down the A1.

I had only checked these recently.
It seems I have a costant problem with the nuts loosening and the gasket blowing.
Proper studs, nuts and gaskets used - although have tried a Holts gasket out off a tube to see if that helps...gasket - yes, nuts staying on - no.
Overtighten and threads strip, under and they fall off ....but in use they don't stay tight anyway!!
What is the problem and cure!
Bemused
AL M

Followups :

MKIV 1300 exhuast manifold/downpipe joint

Posted By : Mark Hammond, 17-Jul-2007, 12:55pm

Are you using split washers to prevent the nuts coming loose?

Mark
- MKIV 1300 exhuast manifold/downpipe joint
  
  Posted By : Stuart Evans, 17-Jul-2007, 02:36pm
  
  You could always fit an extractor manifold and sports exhaust system
  
  Will solve your problem, look good and sound great.
  
  Stuart
  - MKIV 1300 exhuast manifold/downpipe joint
    
    Posted By : Clive Senior, 17-Jul-2007, 05:33pm
    
    Are the studs new (ish) or old. If old the threads are often poor leading to problems. New studs and brass (stainless even better) nuts should do the trick. Shouldn't be any need for sealants, just a proper gasket.
    Stud removal usually needs a lot of heat to be successful so I am told!
    - MKIV 1300 exhuast manifold/downpipe joint
      
      Posted By : Alan Madin, 17-Jul-2007, 09:08pm
      
      Hi Clive,
      Newish (as of Jan when engine was changed) studs - brass nuts but have just stuck last one of them on so next will be steel if I can find suitable size in box...
      
      Am going to check bolt fixing exhaust under car cos think that may be allowing play and vibration working them loose.....otherwise I think this is just a 'characteristic' of this car!!!
      Ah well, at least the petrol consumption continues to impove!!!
      Al M
      - MKIV 1300 exhuast manifold/downpipe joint
        
        Posted By : Ed Weller, 17-Jul-2007, 09:12pm
        
        You could try using two nuts per stud to lock them - providing the studs are long enough of course.
        
        MKIV 1300 exhuast manifold/downpipe joint
        
        Posted By : Clive Senior, 17-Jul-2007, 09:54pm
        
        thats a very good idea! That would help stop corrosion on the stud too. Using brass nuts can be tricky as they strip pretty easily, hence the stainless ones if you can get them. 5/16unf I do believe on a spit.
        
        MKIV 1300 exhuast manifold/downpipe joint
        
        Posted By : Chris Taylor, 18-Jul-2007, 11:51pm
        
        Try Namrick for stainless nuts. They will sell them individually. I'd be tempted to use a plain washer immediately next to the pipe flange as well as a lock washer under the nut, so that the lock washer is sitting square and bites evenly into the nut.
        Although it won't help the nuts coming loose, have you checked whether the pipe flange is flat, and any possible welding spatter left in place which would tend to start a gasket leak, or require excessive force on the nuts to seal in the first place.
MKIV 1300 exhuast manifold/downpipe joint

Posted By : Ian Young, 20-Jul-2007, 09:06pm

I had the same problem on my 1500. I've cured it now, I removed the manifold and old studs, drilled and tapped the manifold to take modern metric studs. These were studs from an Nissan X-trail exhaust manifold (I work at Nissan so they were free!). The nuts to go with these have a big flange, so hold the down pipe very tight. I know it seems a long way round of doing things but it saves having to replace the nuts every 6 months. If you want any studs and nuts I can send you some F.O.C. Just let me know. Cheers Ian