How difficult is it to replace exhaust manifold gasket (M30)?

[Adnan]

Hi,

Some of you may recall that I had asked about a flapping noise under acceleration in my '91 535 a few weeks ago. Well, it turns out that the exhaust manifold gasket is leaking at the head on the rear cylinders.

How difficult is it to replace the gasket? I assume I should do both the front and rear gaskets. Should I also replace all the studs and nuts? I suspect the studs won't budge so it may be best to leave them alone. What other parts will I need for this job?

What's the best spray to get those nuts loose?

Thanks in advance,
Adnan

[winfred]

i like this stuff http://www.blasterproducts.com/store/moreinfo.cfm?Product_ID=1 it can be had in many stores. id just do the 12 nuts going into the head and leave the 4 nut/springs alone, soak em a few times over a couple hours and go for it

[winfred]

ps i just reuse the old hardwear

[Sean H]

How difficult is it to replace the gasket?
Well, it ain't fun, that's for sure. But it is possible. If you can get under the car, it makes getting the bolts at the back much easier.

Should I also replace all the studs and nuts?
I'm going to defer to the experts, but I will add in my experience I left the studs as-is (unless they came out) and replaced all the nuts.

What other parts will I need for this job?
I think you're good.

What's the best spray to get those nuts loose?
Zepreserve is what I've used, but that's jsut because it was what was laying around.

[Adnan]

.

[Mr Project]

I did this when I had the head out, and I replaced all the studs and nuts. I figured for $15 it would be nice to be able to remove them more easily in the future. Some of the nuts were in pretty bad shape before.

[Mr. BILL]

I agree with winfred. Loosen it at the head and use PB Blaster...works WAY better than WD40 and Liquid Wrench.

[Craig]

I've done this three times in the last 6 months trying to get my turbo installed. I can do it in about 20 minutes by now. ;)

It's not as difficult as it first appears. You'll have to crawl under the car and remove a heat shield that sits over the steering linkage. This make access to the header-downpipe bolts much easier. It's not necessary to remove these but it makes it much easier to get the manifolds off. Also, you WILL break these bolts so buy a set of 4 new ones just in case. Also get new nuts for them at the same time, they are pretty cheap from BMA.

Once you have the downpipe disconnected the exhaust manifold nuts are not that hard to access. You can do this from the top or bottom of the car. More than likely several of the studs will come out, and the locking copper nuts are a bitch to get off the studs so just buy all new parts and save yourself the hassle, they aren't that expensive.