I will be fixing a leak between the turbo and manifold, caused by loosened turbo mounting bolts. While looking for parts, I found a couple of turbo places that sell T3 gaskets that go between the turbo and the exhaust manifold. One style is just a thin piece of stainless steel, the other is more or less a spacer block. So I have a few of questions:

1- I was told that if I use a simple straight edge, bright light, and eyeball check, and see no daylight, that I will not have to send the manifold & turbo off to a machine shop to have the mating surfaces milled to flat. And I was told the areas around the bolt holes are the most prone to warping. Is this true?

2- It is it advisable to dress the mating surfaces by hand?

3- Is there a reason that Volvo didn't use a gasket?

4- Which type gasket is preferable- the SS or the "spacer"?

5- If the mating surfaces are flat, should I use the SS gasket anyway?

6- If I use the "spacer" type, will this have an negative effect on the assembly?

7- And finally, I guegs the leak have been there for maybe 8K miles. Can I expect any erosion in the gap?

thanks in advance.

Rick

Have you taken the turbo off the manifold yet? In my '82 Volvo watercooled T3 (and I think all Volvo T3s), there's a stepped ridge in there which acts as a gasket. Apparently 80's Fords with Garretts use a flat mounting surface and require a gasket but Volvos do not. I put a new center cartridge in the '82 about a year ago and didn't give the turbo to manifold surface a second thought. No leaks in the last 10K miles. I've read on Turbobricks where these guys want to use a larger turbo or Ford turbo on the Volvo manifold and have to have the step machined out of it. If you're just replacing it with a Volvo turbo or putting the original back on, I'd bolt it on, bend the locking tabs and forget about it.
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Nineteen Volvos
445-544-122-1800-240-740
Four turbos

Not yet- I'm trying to find the turbo to manifold bolts and locking plates- so I haven't taken a look in there. I wonder if all T3 water cooled Garretts have the same intake housing.

I'm pretty cheap so I wouldn't spend the $ for resurfacing, I would try to get the mating hardware as flat as possible, use your best judgement on how to do that. A DA (dual action) type sander will probably create the least amount of deflection if you're very careful.

You won't know if the surfaces are "guttered" until it's apart. Just loss of clampload you may be OK?

I would use the SS part even if it's flat since that's what I've seen used on Cat and Cummins diesel for over 30 years.
Don't know about a "spacer" gasket, is it graphite material? That's about the only material that would hold up other than SS.

How thick is this piece and could it create alignment problems with the plumbing?

Volvo didn't use a gasket to save money IMO.

The SS part is probably embossed and will conform to small amounts of deflection.

BTW I analyze failed gaskets for Victor Reinz gaskets so hopefully I haven't steered you in the wrong direction.

Thanks- I appreciate the input, especially the advice on the SS gasket.