I heard this ticking sound after exiting the highway and checked it and one of the studs that holds the exhaust manifold down is mysteriously and completely gone. It's the one that holds the number 3 cylinder (starting from rear). Local VOLVO deal does not have any in stock. Would it be safe to just put a bolt with a hex head on it and tighten it down until they arrive? Also, is there any danger I might tighten it too much and it breaks through the block on the inside? HELP!!!

From their site:

"948645 Exhaust Manifold Stud Lock Nut $1.25 MTC"

FCP Groton-Volvo 740/760/780/940/960 Turbo Hoses
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Norm Cook Vancouver BC; 1989 745T 204,000KM

See the 700/900 FAQ for stud dimensions: a bolt will work temporarily but don't exceed the stud length or it will bottom out and you may strip the threads. Get a new stud from a machine supply or fastener house, or online by Fedex.

Looked in the FAQs under EXHAUST . . . didn't see the dimensions of the stud (or temporary bolt). Anybody??

Sorry: it was in the Engine-Turbo section (where most of these stud issues arose):

Stainless studs are an excellent idea for aluminum heads. Try to find a local fastener supplier that offers high-strength metric studs (8mm x 46mm: (std pitch, 1.25mm), 45mm long with approx. 15mm thread on one side (head side), 25mm on the other and 5 mm of no thread.). They are hardened to 10.9 grade. Always use high-temperature nickel-based anti-seize on all studs. Search yellow pages under nuts & bolts.

I found one the correct length, it was only 8.9 grade though. I have to put something in here to keep from setting off everybody's car alarm's -- this thing is making so much noise. I will try to find a higher grade aluminum stud tomorrow. Thanks for the boost.

Oops: not aluminum! Get a steel one. Stainless is nice but not necessary if you use lots of nickel-based high temp antiseize when you reintall it and the nut. This magical stuff guarantees easy disassembly when you need to in the future.