Can anyone out there assist this single female traveler (mechanically stupid) with the name of someone who is knowledgeable in the header/exhaust system issue? I am currently in Las Vegas until Tuesday, 14 September then plan on heading toward southern Utah but will drive anywhere within reasonable distance to have the system checked out. A new system was put on in a small town in Oregon only 3 weeks ago but am wondering if they really knew what's required. Any help is greatly appreciated.

Which engine ya runnin'?

Any details on what was done and what was installed?

What is the problem?

I have a 454 Chevy engine; a Mr Goodwrench replacement in 94. Barth is an 84, 29/30' The engine was overheating constantly and finally had to be towed in Oregon. The mechanics said that in order to really address the problem, I should have the exhaust system replaced with a larger one to pull the heat away from the engine. Having remembered hearing that previously, I told him to go ahead. Unfortunately, he did not explain to me exactly what parts he was using or how he went about accomplishing the mission. I have a new set of pipes though.

My concerns are: was the proper gasket used? is it possible to put in a system that's not compatible? is the fan doing its job because I don't hear it cycling on now? the bolts had already begun to work loose, were retightened in Ely, NV, and should I have them checked again? what's causing the backswoosh of air noise when I turn off the engine? I keep thinking it has something to do with the way the pipe is fitted; maybe the connection isn't tight and is allowing air to penetrate?

I'm sorry I don't have a computer of my own and so must locate one as opportunity and time allows. But I will keep checking back.

An exhaust system is not usually the cause of overheating unless it is really restrictive, as in blocking flow. Usually an overly restrictive exhaust system will cause a lack of power before it will cause overheating. However, a good set of headers and a less restrictive system will result in a little cooler running. On my 84, and an 83, I found the stock 2 1/2 inch tailpipes to be adequate. (John Geraghty says 2 1/4 is best) The stock mufflers actually gave a little more low and perhaps midrange power, with lower restriction mufflers getting the coach up hills a little better.

If you had headers installed, it is not uncommon to have to retorque them soon after installation. One more retorque and a leak check might not be a bad idea.

Perhaps the "backswoosh" noise on shut down could be what is called "dieseling" or "run on". This can be elusive. A hot engine will do it. If idle is too high, it will happen. Try letting the engine idle for a little before shut down. (this is a good idea, anyway) Then shut it down in reverse with the brake applied. Try higher octane gas. Does it make the noise with the dash air on or off, or both?

You say your fan isn't cycling. What temps are you running? It is possible your engine is running cool enough not to need high blow. My fan only runs high just after cold startup(for 30 seconds or so) and just before we crest a hill. Test your fan by blocking the radiator with paper and idling for a while. It should start to roar somewhere before the middle of the temp gage. If the fan clutch is more than a few years old, have a new factory one installed.

To save you the time searching, I have bumped up a previous thread on fan clutches that you might find informative.

quote:

Originally posted by bill h:
An exhaust system is not usually the cause of overheating unless it is really restrictive, as in blocking flow. Usually an overly restrictive exhaust system will cause a lack of power before it will cause overheating. However, a good set of headers and a less restrictive system will result in a little cooler running. On my 84, and an 83, I found the stock 2 1/2 inch tailpipes to be adequate. (John Geraghty says 2 1/4 is best) The stock mufflers actually gave a little more low and perhaps midrange power, with lower restriction mufflers getting the coach up hills a little better.

If you had headers installed, it is not uncommon to have to retorque them soon after installation. One more retorque and a leak check might not be a bad idea.

Perhaps the "backswoosh" noise on shut down could be what is called "dieseling" or "run on". This can be elusive. A hot engine will do it. If idle is too high, it will happen. Try letting the engine idle for a little before shut down. (this is a good idea, anyway) Then shut it down in reverse with the brake applied. Try higher octane gas. Does it make the noise with the dash air on or off, or both?

You say your fan isn't cycling. What temps are you running? It is possible your engine is running cool enough not to need high blow. My fan only runs high just after cold startup(for 30 seconds or so) and just before we crest a hill. Test your fan by blocking the radiator with paper and idling for a while. It should start to roar somewhere before the middle of the temp gage. If the fan clutch is more than a few years old, have a new factory one installed.

To save you the time searching, I have bumped up a previous thread on fan clutches that you might find informative.

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Thank you, Bill ... all you say, I've experienced. I will print this out and take it along with me ... and will utilize the useful tips. Will also have it retorqued and hope I've been worried over nothing much.