Hole in exhaust manifold

[homerj1]

Hey folks,

My latest acquisition - 1990 Mk2 Jetta with an AAZ - has a dime sized hole in the cast iron exhaust manifold in one of the runners. I know replacing it is the way to go... but I was wondering if there was any way to seal it for now with some sort of sealing compound without taking it off? Basically a temp fix for now. Googled around  and came up with a couple of hits.

Hole is accessible from under the car, but not sure how much cleaning of the metal around can happen.

thanks

[theman53]

If it is round and you can drill I think the only option that would last would be a pipe plug.

[ORCoaster]

My thoughts exactly.  Drill, tap, plug.  You could reach up there with several drill bits to see which one was the tightest fit and upsize from there.  But honestly I would remove the manifold and do this all on a bench.  It would be much faster and a better fit when done.  The time taking off the mani will be paid back several times over when it comes to drill and tapping it.

[homerj1]

Yeah I figured that there was no easy fix that didn't involve removing the manifold.  Thanks for the help.

So my new question then is,

Is there anything I need to be aware of tips\tricks or don't do this...... when I remove the old exhaust manifold.  I suspect some of the bolts will be buggers to access since the engine is in the car.

 Although it is an AAZ the PO put a T3 turbo on it, but happen to have spare 1.6td manifold- so it should be a straight  R&R.

I'd appreciate any advice.

Thanks again!

[ORCoaster]

My advice is to soak those nuts on the manifold for a good 3 or 4 days before you start this repair.  Then be ready with a torch to heat them up a bit just before you put a socket on them   I find it really hard to get to the top ones but you can pretty much lay under the car and see up to the bottom ones.  Maybe not with the turbo in there. 

I use a 3/8 inch ratchet and a deep socket and that is all the room I can get as my car has a veggie oil heater in the same area you have the turbo.  Hoses and pump in the way.  Not to mention the flat plate heat exchanger. 

I ramp my car on those drive up ramps to get it higher in the air and get some clearance under it.  I have a nerve that just doesn't like me to lean over for long periods of time without giving me trouble for  days afterwards.  So get it up.  The car that is.

Can the turbo be taken loose of the manifold and just sit on the exhaust downpipe?  Not having one on my N/A I am wondering if that is better than trying to drag the whole bunch out of the top or out the bottom of the engine bay.  Anyone with a turbo that they play with a lot might be able to tell us what is the best way to go about removing the mass of metal. 

Good luck.   

[libbydiesel]

I'd pull the manifold and weld up the hole. 

[theman53]

I wouldn't pull the manifold to put a pipe plug in. I was just suggesting if you can get to it from the bottom that would be the only short term fix I would do. Weld or new would be much better. How in the world did it get a hole in it? Sure someone didn't put a pipe plug in it already?

[ORCoaster]

Yeah, how did that hole get there.  Those things are not generally subject to that sort of failure.  Kind of odd in that way.  EGT sensor? 

[homerj1]

The hole is on the bottom of the runner coming to cyl 2 - just above the exhaust manifold stud - I could see that the head of the nut was very black from the exhaust fumes.  So I'm assuming it was a egt probe based on location.

To clarify, does the intake manifold have to come out also?

 My major concern is getting out the upper exhaust manifold bolts - the ones that have a 6 mm hex head.. they're hard to see and hopefully the heads aren't stripped...
thanks

[theman53]

If it was EGT it should be tapped for some threads or able to get a clamp on EGT probe installed.

[ORCoaster]

You can take just the exhaust off but I find that the intake comes off easier and once it is out of the way I can work on the exhaust.  Removing these hex head bolts is a work of art.  I do most of it by feel and not look.  I think I used a #45 torx bit in place of the 6 mm to break them free.  Then I slapped on my 6 mm 3/8 in drive tool and backed them out with the ratchet.  I suppose you could get an extension on and get on them without removing the intake.  But I like to get the handle of the ratchet up above the work and hold it solid with one hand and turn it with the other.  Would you have enough room to do that if the intake were still in place?

[theman53]

My ex never had someone replace the factory studs with anything. If the turbo is small enough a 1/4" extension gets to all the nuts on studs pretty easily. If the turbo is bigger and you cannot get to the one that the cold side covers you can get to it from up top 1/8 turn at a time or less. I would still check to see if you could put egt or a "dummy" egt gauge in the hole.

[homerj1]

ORCoaster - just wondering why the torq vs the 6 mm?

theman53 - nothing in the hole had my finger in or on it...

You guys are also right shouldn't have rusted out?

Thanks again for the help!

Will take pics of mani when I get it out.

[ORCoaster]

Hex heads skip and the sharper points on the torx give a better bite.  But once loose I use the other so I don't wear the edges I depend on.  That's all.  Sort of like the difference between a 6 and 12 pt tool. 

[xsp2467]

Buy a new one for $130 from Boraparts.com
If you can't find it on their webpage give them a call. I have personal touched new AAZ exhaust manifolds at their shop.