Recently I’ve noticed that when the car is stationary and the air conditioning is running I am getting exhaust fumes in the car, it stops immediately if I switch off the fan, I’ve had the car for a few years and it hasn’t been a problem before, it happens when there are no other vehicles around so it is drawing in its own fumes. Does anyone know what’s causing it and how to stop it? The car is a 2012 1.2 Tsi Monte Carlo

Thanks

You may have an exhaust leak in the engine bay; suspects might include flexible joints in the exhaust near the engine, EGR pipe/connections, turbo to downpipe connection.

Is the engine noisier than it used to be? More tractor-like? Has any work been done on the car recently?

 

You should also check the sealing between the so called 'water box' (the compartment under the wipers where the cabin air intake is) and the engine bay: it should be quite well isolated with rubber seals so that all the cabin air comes from outside the bonnet, not engine bay air. Safety first.

 

 

Following on from Wino, I would almost certainly stop driving the car until I have sorted this issue as the fumes may well be dangerous and knock you out mid journey!!

 

The fact you mentioned stopping after switching off the fan may only be due to the fan drawing the fumes in at a faster rate of knots so don't rely on driving around without the fan on, thinking it will be safe. If the fumes are coming in from a leaking exhaust, etc, it will not be safe!

 

Please take care and get it sorted asap.

I think I have found the problem which is a small pipe from the engine rocker cover to the air intake, it has broken at the rocker box end where it connects to a non return valve so I’ve ordered a part to replace it, once I’ve fitted it I will post an update. With reference to Wino’s reply though it sounds as though the air intake for the cabin shouldn't have been able to draw these fumes in anyway so I will have to have a look at the water box seals too. I think I might change the pollen filter when the fumes problem is solved so does anyone know how to get to this please?

I don't think that broken pipe you've found will be the problem unfortunately. That will be sucking air into the crankcase, not pushing fumes out. (Unless the NRV is broken too).

Oh dear, what's an NRV?

 

Non Return Valve.

Oh yes, it's the pipe on the non return valve housing that's broken so I think that a new valve comes with it anyway, part is due today so I'll update you when it's been fitted, thanks

Out of curiosity, can you please post a photo of old and new once you have it?

The pipe from the air intake was loose at the rocker cover end and when it was removed to fit the new one you could see that the plastic pipe from the vale housing to the rocker cover had snapped off, I removed the rubber seal from the rocker cover which still contained the rest of the plastic pipe and then pushed the new one in, it's a bit tricky to get to and I had to use a forked trim removal tool to get the rubber seal out of the engine but it only took a few minutes.

Ah, in that case it could have been letting fumes out.

Well done.

Thank you for this. Had the same problem and it turned out to be the same culprit. That's the last time I take it to a cheap mechanic for a service. It's obvious that they have just yanked it all out when changing the air filter.

What was that part called ? Or do you have part number?

The part number for the non return valve was K030103175B. 2012 Monte Carlo. 
I didn’t need to replace the vent hose. 

Thankyou

Awesome help. Thank You :-D

I had that on my Roomster and I had it replaced last month. It is the PCV valve and a very common problem. I had a major service and the air filter was replaced. This meant lifting the lid of the air box and must put leverage on that connecting pipe which in turn bends the PCV valve in the rocker box cover and breaks it. After the last service I felt that the engine was not as smooth and not so responsive as before the service. I recommend that the technician disconnects the pipe before lifting the airbox next time the air filter is replaced. Such a bad design: the connecting pipe must be made longer and corrugated to be flexible. There must be many people running around with a broken PCV valve. I only spotted it while cleaning the engine and found a residue around the valve insert. I lifted the valve to wipe under it and it broke in my hand.

Misery! The broken of piece is missing. Surely it has already gone into the engine 😲

Now what do I do 😩

 

I have also found that if I reverse, that is when I get fumes and even petrol smell