75 CDTi - Smell (and headache) from air vents

[Vantheman]

Hi All
Apologies for the long message but I have tried lots of things.

I am getting a smell through the air vents which I think is diesel but I might be wrong. It is slightly sweet and doesn't have the burnt smell of exhaust. It gives me a headache and it's been getting worse over the 2 months I've had the car.

It's an 04 without the under bonnet fuel pump.

I don't get the smell when running the blower with the engine off, but it appears not long after I start the engine, even with the car stationary. When driving, I get it without the blower on, but I think it's worse with the blower running. I don't think it's as bad when I set it to recirculate.

I had a very slow leak from the fuel check valve just behind the filter, but I've sorted that out. I've tried to wash away any diesel from the surrounding area/top of the gearbox.

I've looked underneath and the exhaust doesn't seem to be blowing (at idle) and I couldn't see any sooty marks/evidence.

The various drain holes from the plenum have the correct flappy things which should reduce fumes being drawn in from underneath. The seal along the front looks OK and I've tested it with double sided tape.

There was some oily/dirty residue around injector 1 including on the head of the end inlet manifold bolt, but it's also around the oil filler so I think it's left over from a previous topping up. After a drive it wasn't wet again.

I've looked all round the EGR, injectors, pipes between injectors, for signs of a leak but can't see anything or feel any wetness or smell anything.

If I run let the car idle with the blower on long enough for it to happen, then have a sniff around under the bonnet and the plenum chamber, I can't smell it.

Now there are a couple of things I don't understand (being new to diesels and in fact anything remotely modern).

There is some oily/dirty residue around the pipe from the top of the intercooler. I've read all about the o-rings and I'm going to get some and change them. But I don't see how this could cause the smell as nothing diesely goes through there. Please correct me if I'm wrong.

Also, the plenum seems fairly well sealed from the rest of the underbonnet area, so what route could the smell be taking to get in?

Any suggestions would be really appreciated!
Van

[Ian G]

Air con needs a service maybe
Have a read
https://the75andztclub.co.uk/forum/s...d.php?t=194849

[trikey]

Check the EGR pipework (The concertina metal bit on the rh side of the engine in between the battery box and the cam cover) This can fracture easily (Especially on auto's that have had an EGR bypass fitted)

Also whip off the engine cover and see if the top of the injectors are wet, if so you have diesel bypassing the copper washer at the base of an injector(s)

Have a look quickly, and get it sorted, this is not good for your health!!

[Vantheman]

Thanks Gents

Ian - interesting read although my smell is more fumey than mouldy... might give it a go some time.

Trikey - Cover is off already and can't see anything untoward there. I've just started the car and can't feel anything blowing from the concertina bit, or between there and the valve, but will have a better feel tomorrow in the daylight. I suppose there could be a problem at the other end - I've looked on the Rimmers site and see it has a 2 bolt flange but where does it go?

Cheers
Van

[trikey]

The two bolt flange bolts to the end of the exhaust manifold (RH side as you stand in front of the car)

I have never seen a leak of exhaust gases from this area, your best bet would be to get the car up on ramps and get underneath, look for any sooty deposits around the turbo / back of the block area.

[LeRich]

Is there any sign of moisture in the interior - steamy windows etc? I wonder if the heater matrix might be leaking and it's coolant you can smell.

[Mike Trident]

I was also going to say, possibly a coolant leak. Any leakage of coolant will dry without trace, but antifreeze does have quite a strong wiff if it is dropping onto a warm engine part.