Fumes from front vents

[Grunt]

Hi new 70 earlybay westy owner. We have taken her out several times now, covering over 1500 miles with no issues, until last week. We noticed the smell of fumes in the cab. I've visually checked the exhaust, heat exchangers but can see anything, but when I stop driving, either in traffic or a complete stop, exhaust fumes come out of the demister vents. Any suggestions would be greatly received

 

[Dave.P]

Could be your heat exchangers blowing inside the sleeve where you can't see, whip them off blow in one end while blocking the other to check maybe ? Are you backfiring when you let off the gas ? ( = exhaust blowing )
Could be your rear tailgate rubber seal letting fumes in too, worth a replace ment if its old and knackered

 

[Grunt]

Thanks Dave - no issues with misfires or poping. I'll get underneath tomorrow and give everything a good check over. Are you referring to the flexible looking connectors that come of the heat exchangers going to the duct

Cheers

 

[slow-lane-Matt]

If it is the heat exchangers that have rusted through you probably won't see anything, as they are effectively an exhaust pipe surrounded by chamber. It should just be fresh air in the chamber that gets ducted to the vents, but if the HE has failed exhaust gets into the chamber and ducted to vents.

Ypu can just see the back hole inside where mine failed

Are the fumes are coming out of the vents or from somewhere else. Turning off or blocking off the heating vents should prove that....



Where mine failed the soot was the obvious clue:




Photos from Beetle - but bus pretty much the same

 

[Tristan71]

Take the fresh air pipe of the fan housing put your ear to it then then block the tailpipe you'll soon know if there rusted through

 

[RichardAlexander]

i had a similar prob mine turned out to be the exhaust tail pipe seal wasn't tight so all the fumes escaping underneath the got sucked up by the fan pushing exhaust fumes into the vent, driving was fine cause they blew away, at standstill tho it would set the carbon monoxide detector off, all because the tail pipe seal wasn't right

 

[Grunt]

Thank you all. Some much information to take in a try.

I have visually inspected as many of the connects that I can see from under the bus and can see no sign of "carbon".

I'll try the removing of the air pipes from the fan hosing next, to see if that gets me a bit further, after that, I'm thinking of stripping down the exhaust and heat exchanger connects, just waiting on the exhaust fitting kit to arrive and the WD40 to work into the bolts and nuts..

 

[geordie]

Can you have the same problem where the exhaust and heatexchanger join?
Sorry to gate crash you thread

Geordie

 

[RichardAlexander]

Absolutely if the smell is coming from the front vent then it will be either rotten heat exchangers or the exhaust fume being drawn in and pushed through the hot air vents

 

[Tofufi]

Do you have all your tinware and engine seals in place? How about the engine lid seal?

 

[vwcanuck]

I had the same problem last week with exhaust fumes in the cab of my panel van more often than not. The problem was one of my fresh air tubes had come off the pipe from the heater box. Make sure they are seated well in the tinware with rubber grommets. Some people use hose clamps here too which would help keep them in place. Once mine was reconnected, I realised that I had lost much of my heat to the cab ... nice and toasty warm again.

Hopefully it's an easy fix for you