Fume galore

[Iain T]

Do you suffer from gas?

Sorry I meant exhaust and engine fumes getting into the cabin. Whereas I admit I might have personally contributed my cabin does fill up with nasty fumes that can quite quickly give me a headache. Not so much of a bother in summer as we always have the windows down to try and cool us down. So today I looked at the bonnet to windscreen lower panel seal. There was a telltale black line on the bonnet but nothing for about 12" in the middle. Could fumes be escaping and then be sucked into the fresh air vent? I've put layers of thin foam tape on the bonnet in an attempt to seal, hope it works. I've also made sure the bulkhead grommets are in place and the boots on the master cylinders are fitted correctly. 

Any other suggestions as a nose peg won't work...... 

Iain 

[JohnD]

Almost certainly:

1/ exhaust leak in engine bay

2/ Some/many of the holes in the bulkhead  are no longer sealed with grommets.  Either fallen out, perished or not replaced by your DPO.

 

Get under the dash, get your assistant to shine a torch at the bulkhead.    I'll bet you see lots of light!

John

[Paul H]

Are fumes coming in via gaps in the gearbox cover ? 
Paul 

[Iain T]

When I sorted out the dash wiring I put sound deadener on the bulkhead and made sure the various holes were covered. 

Ah yes the gear box cover. I'll take another look and if necessary gaffer tape around the perifery. 

As to exhaust leaks the phoenix 3 to 1 collector is infamous for leaks. I used exhaust paste and welded tabs on to bolt up each pipe. 

At the moment it's rather noxious and the wife wasn't impressed when we did the Sainsbury run it it this week. 

[Paul H]

I found my fibreglass gearbox cover in my Vitesse was a terrible fit and heat / fumes a significant issue. The gearbox cover even had a cut out for the heat diverter box so impossible to seal . I’ve filled the cut out and I’ve made oversize (width) hardboard gaskets one for the cabin and fire wall ( they are silconed in ) . The matching gaskets siliconed to the gearbox cover .  I haven’t tested it yet though confident fumes will be reduced significantly or completely eliminated . Between the hardboard gaskets I’ve glued lengths of inner tube to make the seal airtight 

Paul 

[trigolf]

As I recently posted, I'd been trying to trace the source of the fumes, whilst corking up all the various holes through the bulkhead. Various knackered grommets replaced, and replaced the seal on my fibreglass gear tunnel-the bottom flange is about as flat as my arse! Only after peering at the exhaust manifold closely did I spot the hairline cracks, now replaced with a serviceable spare. Interestingly, since replacing the manifold, a noisy 'tappet' noise has now disappeared. I'd checked the tappet gaps several times, but could never pin it down. It would gradually quieten down as the engine warmed up - probably as the cracks closed up?

[Iain T]

I've used some 12mm square high density foam I nicked from work. I needed to raise the fibreglass g/box cover or it hits the bellhouse. Must be a peculiarity of my cover? However this means I haven't yet been able to screw the cover in place so I used duck tape around the cabin side and as much as I can get engine bay side. I noticed the rocker oil filler was loose so bought a new one which fits nice and tight. I'll also get underneath and check the exhaust. I was going to grovel underneath anyway as I want to install an small silencer in the straight to quiten the barrow boom. 

Another thought is the gap around the gearshift gaiter. Not sure how I'll seal that. More investigation required. 

I'll persevere as its not making driving a pleasurable experience. 

Iain 

[Pete Lewis]

a full lenght heater /plenum/bulkhead  flange seal with a deep flip  should keep engine fumes entreing down the heater intake 

the basic design is a bit limited , not too deep or you wont close the bonnet , but does need to run across the full length 

ive tried a balloon type seal in the past but it offers too much resitance 

to eleiminate while you have your gaffer tape at work   cover the air intake as a test

Pete

[Iain T]

6 minutes ago, Pete Lewis said:

eleiminate while you have your gaffer tape at work   cover the air intake as a test

I'll see if my thin foam strips on the bonnet work first then tape up the vent if it's no better. 

 

[Iain T]

14 hours ago, trigolf said:

spot the hairline cracks

I don't think it's cracks or splits but I'll take another look. 

My money is on the hood seal. 

Iain 

Sorry been using American auto language too long for hood read bonnet. I must get the rubbish out of my trunk.... 

[Pete Lewis]

whilst older engines can be far more smelly than a modern it shouldnt gas you out or cause a problem 

is the breather system working ok ??

the 3.2.1 is a good leaker but its below the engine and should just go under the car rather than down the heater intake

check the tail pipe if its too short you get exhaust flow back into the car via the boot seals etc.

Pete

[trigolf]

If your fibreglass cover is as badly moulded as mine its the likely culprit for letting the fumes in. See pic of mine-offered up without any seal fitted to assess the gap to be filled. I tried a  12mm x 25mm foam strip, but I found it wouldn't compress enough where the floor was flat and still fill the various bigger gaps, so went back to a bubble section strip, which seems to have worked ok.

[Paul H]

My money is on the bad fitting fibreglass gearbox cover being the source of the fumes 

Paul 

[Pete Lewis]

i used strips cut off a dunelm foam slab   easy to compress and fills the undulations  ... very cheap fix 

it doesnt have to be closed cell   foam 

Pete

[Iain T]

The two main culprits are probably gb cover and bonnet seal. I did tape up the cover last year and although better it still stank so it's still the vent that I think is letting in fumes. 

I'll have a look at the weekend but a bit busy getting the in laws new retirement place sorted. 

Cheers 

Iain 

[dougbgt6]

Ian,

The guys all make valid points however I had exactly what you describe on my GT6 and it was the seal. It didn’t make contact with the centre of the bonnet, the back end of the “power bulge”. Fumes were getting in through the air intake. I padded out the power bulge section with draught excluder, later SilientCoat.

Doug

[Iain T]

26 minutes ago, dougbgt6 said:

I padded out the power bulge section with draught excluder, later SilientCoat.

I've stuck a few layers of some 1mm thick dense foam/rubber tape along the same area. I really do think the seal is the culprit. I have some 12mm square foam but it's quite dense and I'm afraid it will not squish enough. If the weather is nice I'll go for a spin on Sunday and get the wife to do a sniff check🤪

Iain 

[Dave the tram]

I have similar problem but mines a GT6 and, because I don't thinks it’s from the front, I suspect the rear hatch seals and fumes being sucked in from the tailpipe (as per Pete’s comment above). Main reason for thinking this is it’s ok with windows shut, but noticeable with any window open surprisingly. Rear quarter lights will definitely suck out but I think the overall effect of the main windows open is to create a slight vacuum, even though you think it’s blowing in. New hatch seal when I finish current restoration. As for the gearbox cover, I never trust the seals and the fit so double up with gaffer tape all the way round the inside before fitting the carpets.

Dave

[Iain T]

It could be from the tail pipes as disturbed air does roll around the rear of the car. It's a sunny day tomorrow time for a spin and report back. 

Iain 

[johny]

Would have thought you can slide a piece of paper (or card if gap big enough😲) around the tailgate seal to indicate how good its contact is?

Of course even better would be one of those non noxious smoke generator they put inside a DB8 on Wheeler Dealers to look for cabin leaks although Im sure with a bit of ingenuity some cheaper alternative could be rigged up - gardners insect fumigation bomb anyone🤔...

[Iain T]

29 minutes ago, johny said:

Would have thought you can slide a piece of paper (or card if gap big enough😲) around the tailgate seal to indicate how good its contact is?

Or if I clear out the boot the wife could get in? I'll ask her and run...quickly. 

Saying that a few years ago for our modern we had a boxster and so that we bought the maximum size suitcase (norra lorra room) she volunteered to get in the bonnet with a tape and torch to measure while I locked her in. I sold the car, as far as I no she's still in it...😂😂

Iain 

 

[Dave the tram]

I did the sliding paper thing to check the seal on my GT6 -  and the seal was rubbish in places so hoping a new seal will do the trick when the car is back together. Question is, do I trust the Rimmers new one will fit ok or have a chat to COH Baines after my experiences with windscreen seals.

Dave

[Iain T]

Dave, I suggest Baines they are manufacturers. 

Iain 

[johny]

1 hour ago, Dave the tram said:

I did the sliding paper thing to check the seal on my GT6 -  and the seal was rubbish in places so hoping a new seal will do the trick when the car is back together. Question is, do I trust the Rimmers new one will fit ok or have a chat to COH Baines after my experiences with windscreen seals.

Dave

Not had any experience with the GT6 tailgate but with door seals Ive had to bend the seal mounting metal lip of the door surround in and out to get a good and uniform contact all the way round.

I would suggest that, unless your seal is damaged in the places it doesnt make contact, putting on a new hopefully thicker seal could make closing more difficult and when you adjust for that the seal is lost elsewhere so youre back to square one☹️ 

[mark powell]

Temporarily block off the heater air inlet to exclude that possibility?  The only fumes I get in my Herald pick-up come through the aftermarket gear lever gaiter when a slight oil weep from the gear box heats up on the exhaust.