Exhaust fumes in the cab

[nicktheknife]

All right, I am getting some serious exhaust fumes in the cab, its to the point where I shouldnt be driving it, by the time I get home I am nausiated and feel like I am going to pass out. My question is, the exhaust ports on my headrs are rectangle, but the holes on my headers are oval, should I use a gasket that is rectangle, oval, or both? Also, where would it enter the cab? One guess is through the holes on the heater core housing where the two hoses go into it, theres a gap, but does that go directly into the heater duct? Should I plug those holes up with some type of sealant? Please help.

[cdowns]

where does your exhaust end?

[nightmare]

I have that too, but only when my windows are open. Mine exits straight out the back of the truck, right at the end of the bumper. But I also have a camper shell on there, with the back window sealed to the camper shell. I also think that I have an exhaust leak at the joint where the header collector is and the rest of the pipe connects. Do they make a thicker header collector gasket?

[kcjones]

If you've got collector leaks and your flanges are straight, time to switch to steel laminate instead of the cardboard/paper things. Most often it's that the flange bolts were over tightened, and bent one of the flanges.

[nightmare]

do they have the steel laminate collector gaskets at the local auto parts stores?

[nicktheknife]

My exhaust exits behind the rear tires, and I just changed the header and collector gaskets to the copper ones. I know I do have an exhaust leak on my left header cause I can hear that clicking noise. So you think if I exited the exhaust out the back it would help with the fumes in the cab?

[68gmsee]

I had a similar problem once. The muffler guy told me that exhaust fumes are primarily caused by leaking connections -of course he was trying to sell me a welded stainless steel exhaust.

Mine was a leaking exhaust donut. Fumes were coming in through some open holes in the front firewall -torn clutch boot and no boot in the brake pushrod opening. Got the donut fixed and sealed up all of the front holes just in case.

Only other time I've had that happen was with the rear vent window open or in slow traffic behind a vehicle with my front vents open.

[kcjones]

Originally Posted by nicktheknife

My exhaust exits behind the rear tires, and I just changed the header and collector gaskets to the copper ones. I know I do have an exhaust leak on my left header cause I can hear that clicking noise. So you think if I exited the exhaust out the back it would help with the fumes in the cab?

I wouldn't think so...if after changing gaskets you've still got the smell, either:
1) There is still a sizable leak in the header/head area or collector
2) You're misinterpreting the smell...it's actually coolant being burned (bad head or intake gasket), oil being burned (dripping or seeping onto hot engine or exhaust parts), something in your vent/cowl area that is getting hot and sending the fumes into the cab. I'm sure there are other possibilities, too.

What's weird to me is that even with an exhaust leak at the head or collector, there wouldn't be so much exhaust entering the cab to cause the bad smell and nausea. I'd go after the clicking noise, maybe even let an exhaust shop track it down and fix it, then move on to searching out all the cab holes and working towards sealing them up: heater core/blower area, speedo cable, master cyl, steering column, wiring harness, gas pedal, etc.

Good luck, man, that's a tough one.

[cdowns]

in back of the rear wheels is about the best exit i've found for pickups/i agree with wotking on the exhaust to seal leaks and sealing up any and all holes in the cab// i've found over the years the number one cause of heavy exhaust smells is a poorly installed/tuned carb

[Lippyp]

Do you still have the gas tank in the cab? If so are you sure its exhaust fumes and not gas fumes from a leaking sender gasket? Mine used to leak as it had the wrong gas cap so when the tank was ful it slopped and ran down into the cab past the gasket, new cap, new rubber and it was fine.

[ChevLoRay]

It may be from blow-by. Oily smoke accumulates under the hood and filters into the cab. I'm not saying it isn't exhaust gases, but offering an option. Another possiblility is a rich fuel mixture. Before I pulled the old carb off of my engine, it was jetted rich and the exhaust gas would bring tears to your eyes. It's another possibility.

[nicktheknife]

thanks guys, looks like I got some work to do