hoosier58

I just did a Seafoam treatment through the brake booster line. While I was still pouring the stuff in, I started getting heavy smoke under the hood --- from between the engine and firewall. It was too thick to see where it was coming from.
Any ideas?
A vacuum leak?
An exhaust leak (it was also smoking out of the pipes, and doesn't sound like it has an exhaust leak)?

Thanks for any ideas in advance.

scENFORCER

Isint excessive smoking part of the process?

hoosier58

I thought the smoke was all supposed to come out the exhaust. I did my van the other day, and that's what happened with it.

I actually did a first and second treatment, prepared for smoke the second time, to try to see where it was coming from. Unfortunately, I couldn't tell. I had the RPM just over 2K (propped the pedal with a snow scraper), which was a little higher than the first time. It smoked quicker and thicker than the first time. I shut down, which is when I came in and wrote my post. There was smoke gently curling out of the pipes in back.

The first treatment, when I shut down after pouring the Seafoam in, the car kept dieseling for a while before it died. I waited a few minutes, then fired it up and drove aggressively for maybe 4 miles. It smoked hard for probably 3 1/2 of them. It was running nice after that, but I thought if it had the much crap in the high miles engine a second treatment wouldn't hurt --- and I was hoping to identify the location under the hood where the smoke was coming from. No luck on the later score, but the second treatment demonstrated how much the first one had done. That time it didn't pour smoke for nearly as long. It must have loosed up more carbon though, because the second treatment did apparently foul my plugs (drats!).

WadeLovell

iTrader: (5)

When I did this it appeared the smoke under the hood was coming from the EGR valve which I took to mean I had a problem there. I replaced the hoses and could not repeat the problem on a subsequent treatment. Check your vacuum hoses and connectors first.

hoosier58

Thanks, Wade. You replaced hoses, but not the EGR valve?

Nova

iTrader: (21)

sounds to me like you have a vacuum leak somewhere. i seafoamd my 96 with only a little smoke coming from the cat/midpipe flange which i took as have a small leak there. other then that all the smoke should pour out of the exhaust and no where else

hoosier58

Thanks Nova.
It's turning cold and nasty again tonight in Denver, but is supposed to get back up near 60 degrees before the weekend --- I should have a good day to check vacuum lines.

Here's a question for anyone that wants to answer.
Service manuals regularly say that vacuum hose is color coded, and that the wall thickness is important for the function of various vacuum controlled systems. I've always ignored that, and used whatever hose would fit.. So far it never seemed to bite me in the backside.
Does anyone think I'm way off base to take that approach?