Ford Focus Mk2 - Cabin air intake vents

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Tue 31 Jan 2023 14:33
Ford Focus Mk2 - Cabin air intake vents - nowthenhonest

This is a general question about the air intake vent that runs across the top of the engine bay, just under the windscreen. My daughter's car has a slight smell inside the cabin. After driving with the blowers on for about half an hour, although I can't put my finger on the nature of the mild smell, I did start to taste something at the back of my throat. So, I started searching Youtube to see what people recommended. They were suggesting looking for smells in the a/c or fuel leaks or oil leaks in the engine bay (it does have an oil leak so this is my best guess) but what I can't understand is why any fumes from the engine bay would end up in the cabin. It seems bizarre to me that we can be so worried about exhaust fumes in the environment affecting people's breathing and yet accept the fact that fumes from the engine bay can end up in the cabin of a car. Is it impossible to shield the engine bay from the cabin air intake vent? Obviously there is that squishy rubber gasket that runs along the top of the engine bay. Does that work? Do fumes escape from the sides of the bonnet and end up in that vent? How do they get from the engine bay into the vent? Also, why don't they put the vents in front of the engine bay if this is a problem?

(While I have driven around for years not caring about a little oil leak here and there, my daughter has a newborn baby so this issue has come into focus.)

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Tue 31 Jan 2023 14:56
Ford Focus Mk2 - Cabin air intake vents - bathtub tom

Does the Focus use any coolant? Have you cleared all the twigs, leaves and other debris from the intake? Can the water flow freely away from this area?

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Tue 31 Jan 2023 15:10
Ford Focus Mk2 - Cabin air intake vents - Adampr

Wrote a long answer, then lost it.

Fix the oil leak, then replace the cabin air filter.

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Tue 31 Jan 2023 15:59
Ford Focus Mk2 - Cabin air intake vents - elekie&a/c doctor
Are you sure the fumes aren’t being sucked in from the rear of the car , either through the tailgate seal or the air extraction vents behind the bumper ?
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Tue 31 Jan 2023 22:39
Ford Focus Mk2 - Cabin air intake vents - nowthenhonest
Are you sure the fumes aren’t being sucked in from the rear of the car , either through the tailgate seal or the air extraction vents behind the bumper ?

I have no idea.

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Tue 31 Jan 2023 17:18
Ford Focus Mk2 - Cabin air intake vents - corax

Wrote a long answer, then lost it.

Fix the oil leak, then replace the cabin air filter.

This ^^. You really need to identify what the smell is, but I'm guessing it's hot oil. It will find it's way through any tiny openings through the bulkhead.

Then replace cabin air filter, which is not a pleasant job on a Mk2 Focus, so usually neglected.

If it's a musty smell after using air conditioning, the evaporator could have mould on it's surface. You can get an air con specialist to clean it, or use one of the many products online and follow the instructions.

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Tue 31 Jan 2023 22:40
Ford Focus Mk2 - Cabin air intake vents - nowthenhonest

Wrote a long answer, then lost it.

Fix the oil leak, then replace the cabin air filter.

This ^^. You really need to identify what the smell is, but I'm guessing it's hot oil. It will find it's way through any tiny openings through the bulkhead.

Then replace cabin air filter, which is not a pleasant job on a Mk2 Focus, so usually neglected.

If it's a musty smell after using air conditioning, the evaporator could have mould on it's surface. You can get an air con specialist to clean it, or use one of the many products online and follow the instructions.

So, are we saying that there is no possibility of sealing off the engine bay from the cabin?

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Tue 31 Jan 2023 23:13
Ford Focus Mk2 - Cabin air intake vents - Adampr

Wrote a long answer, then lost it.

Fix the oil leak, then replace the cabin air filter.

This ^^. You really need to identify what the smell is, but I'm guessing it's hot oil. It will find it's way through any tiny openings through the bulkhead.

Then replace cabin air filter, which is not a pleasant job on a Mk2 Focus, so usually neglected.

If it's a musty smell after using air conditioning, the evaporator could have mould on it's surface. You can get an air con specialist to clean it, or use one of the many products online and follow the instructions.

So, are we saying that there is no possibility of sealing off the engine bay from the cabin?

The only way to do that is to seal off the engine bay from the world. What you are.smelling in the cabin is what everyone else is smelling stood next to it..

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Tue 31 Jan 2023 22:37
Ford Focus Mk2 - Cabin air intake vents - nowthenhonest

Wrote a long answer, then lost it.

Fix the oil leak, then replace the cabin air filter.

Right.

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Tue 31 Jan 2023 22:36
Ford Focus Mk2 - Cabin air intake vents - nowthenhonest

Does the Focus use any coolant? Have you cleared all the twigs, leaves and other debris from the intake? Can the water flow freely away from this area?

Not that I am aware of. Yes, the intake is clear and water does flow freely.

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Tue 31 Jan 2023 23:07
Ford Focus Mk2 - Cabin air intake vents - Big John

Where is the oil leaking? Could this be a crankcase breathing type issue be it something blocked, PCV valve, split pipe. I had something similar on my Superb when an oil breather pipe wasn't fitted correctly after a service(not easy to see as buried under all sorts of gubbins. After a while on a run you could detect a very slight background oil fume smell.

Fortunately I then moved my servicing/MOT to a great local independent(used ever since) who quickly found the issue. It's the driving after 30 minutes(fully warmed up) that makes me think it's oil, although it also could be coolant. When it's making the smell find a place to pull up and pop the bonnet and have a good looksee & smell, keeping the engine running (beware moving parts though!)

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Thu 2 Feb 2023 17:54
Ford Focus Mk2 - Cabin air intake vents - JONATHAN_11_80

This will be the aircon smelling. Get some air con cleaner. Had this on my old focus mk2.5.

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Sat 4 Feb 2023 03:02
Ford Focus Mk2 - Cabin air intake vents - nowthenhonest

Where is the oil leaking? Could this be a crankcase breathing type issue be it something blocked, PCV valve, split pipe. I had something similar on my Superb when an oil breather pipe wasn't fitted correctly after a service(not easy to see as buried under all sorts of gubbins. After a while on a run you could detect a very slight background oil fume smell.

Fortunately I then moved my servicing/MOT to a great local independent(used ever since) who quickly found the issue. It's the driving after 30 minutes(fully warmed up) that makes me think it's oil, although it also could be coolant. When it's making the smell find a place to pull up and pop the bonnet and have a good looksee & smell, keeping the engine running (beware moving parts though!)

The smell is from the side of the engine nearest the windscreen. I think it is oil smouldering but I am not certain. I doubt my ability to find the source of the leak. There is plenty sat on top of the gearbox, although that area doesn't really smell. I wonder if there might be a slight leak from the exhaust.

I have had a go with a foaming aircon cleaner (K2 I think( and was surprised by its effectiveness. I also replaced a very black cabin filter with a nice new one with activated carbon. It is definitely smelling much better in there now. I wonder why a filter is not also placed over the rectangular intake below the windscreen (maybe 6 inches across). I am tempted by that idea. I don't know if it would cause the fan to work too hard.

It seems that Ford did not want anybody to change that cabin filter EVER. Unbelievable place to put it.

Edited by nowthenhonest on 04/02/2023 at 03:03

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Sat 4 Feb 2023 14:34
Ford Focus Mk2 - Cabin air intake vents - corax
The smell is from the side of the engine nearest the windscreen. I think it is oil smouldering but I am not certain. I doubt my ability to find the source of the leak. There is plenty sat on top of the gearbox, although that area doesn't really smell. I wonder if there might be a slight leak from the exhaust.


I have had a go with a foaming aircon cleaner (K2 I think( and was surprised by its effectiveness. I also replaced a very black cabin filter with a nice new one with activated carbon. It is definitely smelling much better in there now. I wonder why a filter is not also placed over the rectangular intake below the windscreen (maybe 6 inches across). I am tempted by that idea. I don't know if it would cause the fan to work too hard.

It seems that Ford did not want anybody to change that cabin filter EVER. Unbelievable place to put it.

Hot oil has a distinctive smell. Once you know what it is, you won't forget it. Crankcase fumes are worse, there is an underlying smell of petrol within. It's actually pretty dangerous to breath that in for too long. I've been in cars with that issue, and it can make you feel quite ill.

K2 is what I use for aircon, it's a great cleaner with a nice lemon smell. I only use around a third/half of a can at a time, then keep it for next time. The first time I cleaned my old Toyota Avensis system, I followed the instructions to use the whole of the can and it was way too much. I stopped because there was foam starting to come out of the vents, and bear in mind I was spraying from the evaporator drain, right at the bottom.

The cabin filter on the Focus is OK if you like to spend some time with your upper torso wedged in the footwell, and your neck craned around to see the pollen filter cover, while dislocating a shoulder trying to remove said cover. Even then it doesn't want to come out easily, and you have to squeeze/fold the new one to get it back in.

On my Avensis, it was one screw to remove the glovebox, then sit on the passenger seat with everything visible in front of you, about as far removed from the Ford as you could get, and no visit to the chiropractor afterwards.

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