New guy: smoke and smell at windshield

[RJExpress]

Hi everyone. I have recently been experiencing and strange chemical type odor(not antifreeze) and some smoke coming from the very front edge of the dash at the windshield. This only happens when I am towing a heavy load and going uphill for the most part. No change in engine temp or performance but it starts to burn my eyes if it persists too long. I know what antifreeze smells like, but this is not that familiar sweet smell. There is some residue on the windshield but not greasy. No smoke from the actual vents and window doesn't fog. Also stopped and lifted hood during this and saw no smoke and no noticeable leaks. Really stumped and becoming concerned. Any ideas? Thanks in advance for any suggestions.

[mxfever090]

What color is the smoke? Is the residue on the inside or out?

Well diesel smoke will make your eyes burn and water, the up pipe clamps are right up against the firewall, high boost temps/psi would cause exhaust leaks at the clamps.

Take a flash light and have a good look around the clamps. Soot streaks indicate a leak.

[RJExpress]

Smoke is white. Residue is on inside of windshield. Happened again today. Pulling around 22000 lbs up a 5 percent grade for about 1 - 2 miles. Smoke was pretty strong. Pulled over and dropped glovebox door down to see the heater box and part of firewall. NO SMOKE anywhere!!! Have decided like you mention, there must be too much heat from down pipe causing the firewall to heat up. Must be some insulation or something starting to melt and smoke. Had the down pipe replaced last year so I am not sure if the black soot on the firewall is recent or not. Some of the silver foil/insulation on firewall is damaged and/or missing after replacing turbo and down pipe. Thinking about making a heat shield to put between firewall and turbo/ down pipe. No obvious exhaust leak but it is difficult to see very well. Smell is very strange. Not antifreeze, oil, trans fluid, or any other common liquids used under hood. Can't think of any other cause or remedy at this point.