What looks like an exhaust leak and smells
 

I just had some new Dynomax super turbo mufflers put on because my Flowmaster 40's were too loud.

It is definately quieter. However, now I am finding that I can smell something when the car is in the garage after driving/running it. At first I thought it could be the rebuilt Holley carb I just had put on. Maybe it's running rich, needs to be tuned. But it really doesnt smell like gas.

Today I had it running in the garage (door open) and started to notice something coming up from the pass side of the engine, looks like exhaust coming from the headers on the pass side? Could this be what I'm smelling and maybe a result of someone replacing the mufflers and moving the pipes around creating this leak?
Starting to wonder what I go into..:willy:

Does it smell like burning oil or something else? If you have oil leaking it could be burning off in that area and would smell.

I think it smells like exhaust. And right between the exhaust manifold and the bottom of the valve cover i can see some smoke, or probably exhaust coming out. This happened after new mufflers were put on so I have to image they must have twisted the pipes a little causing this issue? Does this sound likely?

Nope, sounds even more like oil to me leaking from the valve cover onto the exhaust. You dont normally see smoke with an exhaust leak. The best way to tell if you have an exhaust leak, especially right at the header, would be sound. Are you hearing anything in the engine compartment that sounds unusual? A tick or tapping noise that goes away or quiets down when the car gets warm is really common with an exhaut leak.

Take a papertowel and run it between your valve cover and header real quick and see if there is anything on it. Its not uncommon for those gaskets to leak.

OK, I'll try that. and report back Thanks

I took a paper towel and wiped above the manifold and below the valve cover. Nothing. However, on the side of the valve cover just around one of the bolts I see some grime that could be oil. But that's been there for a while. I keep thinking it has to do with exhaust. But you're saying if I see a little smoke that couldnt be exhaust ?

You can see what I'm talking about in the picture above. The left bolt on top of the valve cover. I don;t think that's my problem. it's been like that for months (I've only owned the car for 2 months now). Just started smelling something and seeing smoke (only once so far) since I had new mufflers put on.

Sorry, as for sound. not really sounding any different. Hmm, maybe you"re right. i'm just not sure why I would'nt have noticed this before.

I do know I have some kind of leak behind the intake manifold, it leaks a little back there. But that's not where I saw the smoke come from. Soundlike it might be a good time to pull the valvue covers and intake manifold off and put on new gaskets. Just wondering if I'm already in there if I should put on a new exhaust manifold gasket on both sides too.??

What do you think? Probably not expensive, just time consuming.?

Exhaust leaks are almost always audible... and unless your exhaust is producing white smoke out of the tail pipes, you wouldnt be seeing it there either. No cats to filter any of the burnt off fuel/oil/etc.

The leak behind the intake manifold..is it pooling on top of the bellhousing at all? I had the same issue not long ago and figured out it was my oil pressure unit on the back that wasn't sealing up. Valve cover gaskets are not a big cost or time consuming. Intake manifold gasket can be a major PITA since you have to pull the distributor.

Good luck :cheers:

did you take all the stickers off the exhaust before you installed it

FWIW, I've never used gaskets with rams horns.

Great, thanks. I just went back out there, I can see what looks like oil has been slowly accumulating under the valve covers. So I took a socket wrench and found that at least one bolt on each valve cover was not too tight at all. Tightened them up a bit. Wiped it down. Sounds like that may have been the reason I saw a little smoke. Not seeing it now.

As for the intake manifold, I wouldnt say it's pooling back there but there is definately some residue. My mechanic thought it had a small leak but he said it wasnt bad.

What I'm wondering is if this can be part of the reaon my car is hesitating off start and idel is a little ruff. I know I need to get a handle on vacuum (the reading I took was not steady) leaks. My mechanic said the car only pulls 7 lbs at idle which is low. He said maybe because of a heavy cam, but I'm wondering if I have a vacuum leak. I know my headlight go up and down slow so that's a sign of a vaccum leak but I've since unplugged them to see where else it's leaking. Ans finally, timing. I need to get a handle on that too.

Anyway, thanks for your advise and any other thoughts you have.

Forman, I had new mufflers put on. I don't see any stickers. But it wasnt the whole exhaust, just the mufflers. Looks like the small amount of white smoke may have just been a leaky valve cover.

Avette4me, I'm not sure what you mean.

He was saying that he does not use a gasket between the ram and the block - Lots of guys do it that way with the factory rams and it seals up fine.

If you have much of a vaccum leak or your timing isnt setup properly, then hesitation is very likely.. as well as very poor performance, back fires, etc.

You need to figure out where the leak is - if its on the manifold, the sender, or the valve cover leaking down from the back. I would start there then look at timing and vaccum issues. If you have enough cam to drop your vaccum that low and no leak, then a vaccum canister can be installed to resolve that problem.

Good luck! :cheers:

I see in your pic that you have a heatriser (unhooked) down there. I had the same problem as you, smelling exhaust while running, and found the heatriser to be the leaking culprit. The additional back pressure of the new "Quieter mufflers" could also add to the problem.....just something else to look at :thumbs:

When I put my Magnaflows and pipes on, for the first 2 hours of drive time there was a smell but it was just the anti-corrosion coating on the components burning off, but if you definitely saw smoke, it's probably oil. The heat riser suggestion is also a good one too. Time to get rid of it with a spacer...

Guys, great info. Thank You. I'm getting ready to go away for a few days. When I get back I'll take a look at these things.

Question about the heat riser. Should that be connected to a vaccum hose? I just got this 76 sb350 and this is how it came. I wonder if it was stuck and they just disconnected it.

If it needs to be tied into the vacuum line, do I just put in a T and connect it?

Thanks

There is supposed to be a metal rod (8") hooked to the ball stud on the heat riser, which is connected to a vacuum pot to activate the heat riser

http://i599.photobucket.com/albums/t...1/IMG_0057.jpg
Crappy pic to show this but its the only one I have....Just above the secondarys on the carb, and behind the curved breather tube that connects to the air cleaner you can see a small round cannister or vacuum pot, thats the heatriser actuator