leak from exhaust manifold

[Fun_Bucket]

I got knocked back in a RWC the other day, and one of the reason was the the RHS exhaust manifold has a leak.I was told ages ago when getting the exhaust replaced from the cat back, that it had taken a knock at some point, and one of the headers had bent as a result.

Seems where ever the bend is, is causing it no to seal completely around the gaskets.


Can i find the leak and seal it up with something?

Or am i most likely looking at a replacemement part?

[somefool]

ive been told as i have a similar problem, that you cant get any sealant that can withstand the temperature of the headers. only welding. But yours is round the gaskets/joins.. so its a bit different, welding may be out of the question

if its bent, then its best to replace,
or if you can and have the right tools.... un-bend it

[Fun_Bucket]

Is it safe for me to operate a welder under the bonnet?

[somefool]

I personally wouldnt, as it could potentially fry electrics in the car, + the headers would be so so awkward to get at with a welder when they are installed.

I'd take out the piece to be welded and do it properly on a benchtop, that way no damage to the car could happen plus the weld would be a lot more accurate.

and if your headers are cast iron then there can be problems there, but if your good at welding you can do it with a little research + some special rod that is made for welding cast iron.

Crack in stock headers...

Theres the thread of my problem. Basically my info is recirculated from 88greenvn and greenfoam

[Fun_Bucket]

i just had a look, i can definately hear the leak.I checked the bolts, one was finger loose, so i tightened that up, along with another.How many bolts should be on there.From what i can see, there are 2 which can be acsesed with a spanner, and 1 at the front which looks like i'll need a socket to get to it.SHould there be another bolt at the back? i can see a hole, where i'm assuming a bolt should be.If there is a missing bolt, would that be the cause of the leak?

[savage1987]

HCVP

Buy some sensor safe sealant, I use some copper coloured stuff from super cheap auto that comes in a toothpaste tube. MUST BE SENSOR SAFE.

Buy a set of exhaust manifold gaskets. I got my last set from Veale auto parts for $15.50.

Buy some loctite. Realistically, any sort will be better than nothing. High temp resist stuff if you feel rich.

Remove your header on the problem side.

Remove old gasket leftovers with a scraper on both surfaces

Bead around each exhaust port on your new exhaust gasket with the sealant you newly acquired. Thick enough it'll make a good seal, but you don't need TOO much. (Do this for every other join you undid to get the header off also.)

Give it a couple of minutes to 'gum up' a bit

Install exhaust header, loctiting all bolts

??????

Profit.



Hope that helps
Sam

[purrVN]

mate any bolts loose or missing will definately cause the leak, the top of your exhaust manifold runs at surprising high pressure... i can't remember how many bolts there are exactly but i think its 5, one of them right down the back and kind of hidden until you have a close look. you don't necessarily need all the stuff mentioned above as long as you scrape the crap off both sides thoroughly especially locktite as it'll do sweet bugger all at the kind of temps the headers get to. if you're worried about bolts loosening off you can always chuck on a set of good spring washers and keep them nice and tight. one thing you should do is put a metal ruler or another very straight surface agaisnt the inside surface of the header to make sure its not warped

[savage1987]

mate any bolts loose or missing will definately cause the leak, the top of your exhaust manifold runs at surprising high pressure... i can't remember how many bolts there are exactly but i think its 5, one of them right down the back and kind of hidden until you have a close look. you don't necessarily need all the stuff mentioned above as long as you scrape the crap off both sides thoroughly especially locktite as it'll do sweet bugger all at the kind of temps the headers get to. if you're worried about bolts loosening off you can always chuck on a set of good spring washers and keep them nice and tight. one thing you should do is put a metal ruler or another very straight surface agaisnt the inside surface of the header to make sure its not warped

6 bolts per side, 2 per port.

Loctite does bugger all? Hmm, interesting:
I never bothered with it when I put the rebuild V6 in my VN, because I thought exactly that.
All my header bolts were loose, some half out, in a matter of weeks.
I loctited them, put them back in, no more loosening months and months later.


Just my observations.. of course 12 bolts COULD be 12 separate coincidences but I don't like the odds of that.


Still, spring washers probably a better idea. I didn't have any handy and cbf getting any.

Sam.

[purrVN]

oh well i could be wrong, i'm just going off what i've been told as i have the same problem with my header bolts only being finger-tight within a matter of weeks and end up with a crazy exhaust leak. not entirely sure why they loosen themselves off like that and the only thing i can think of is that it's something to do with the fact that my engine, as apparently many are the same, came without manifold gaskets. however they were added in when the extractors were installed. other than than its real strange and i wouldn't have a clue

[Not_An_Abba_Fan]

Personally, I've never used loctite on any exhaust bolts and never had any come loose. Maybe you just didn't do them up tight enough? Spring washers are never fitted from factory either, there is a reason for that, the steel loses it's 'spring' when they get hot.

After installing extractors you need to go over all the baolts about a week later and tighten them all up. The extractors expand and contract and then 'settle' so do the bolts, nipping them up a week later when the engine is cold usually prevents them from coming loose again.

[savage1987]

After installing extractors you need to go over all the baolts about a week later and tighten them all up. The extractors expand and contract and then 'settle' so do the bolts, nipping them up a week later when the engine is cold usually prevents them from coming loose again.

That's probably the bit I tend to miss out on to be honest, cheers

OP, do this and you should have no more problems

[crazy.vr]

I have replaced about 6 motors ranging from the V6 to the V8's and never used that loctite on the bolts. I use anti-seize on those bolts or any exhaust bolts and do the bolts up to around the specified torque. I don't know why people are having all these bolts come loose. Looks like the installer doing something wrong.