Why does my car give me a headache?

[davidr]

I've noticed that, after driving my V12 coupe for a while I get a headache. There are no obvious fumes in the car but there must be something.
I did think that perhaps it was because the heater matrix had a slight leak and perhaps the anti- freeze vapourising into the incoming air was what was giving me a headache. I changed the heater matrix and the anti- freeze smell has gone but not my headache!
I wonder if exhaust fumes are getting into the cabin somehow. Anyone got any similar experiences or any ideas?
Regards
David

[J44EAG]

Perhaps use a domestic CO2 detector and see if the unit activates.

Poisonous gasses are often not smell detectable and can cause unconsciousness with potentially fatal consequences. Remember the Hawker Typhoon had a nasty habit of gassing its pilots!

You certainly need to find out if you have a dangerous gas issue with your car. Appears you may well have something of a problem with this issue.

Mike

[davidr]

Thanks Mike. Do you mean a carbon monoxide detector?

[J44EAG]

Indeed, David.

Reminds me of an old Cortina I had years ago with a worn out engine. Rings and bores gone. That gave me a headache at the time. Rebuilt the engine and no more oily crank case fumes within the car. No more headaches either.

Mike

[oldtimer]

David,
I am not too familiar with the XJ-S but am with the XJ 12 Series 2. There are similarities with the bulkhead. I've just been looking in my XJ-S parts book to try to find the heater plenum chamber drain pipes - bit late - no luck. The bare body shell diagram shows two stub pipes coming out of what I believe to be the drain from the plenum chamber onto which the rubber drain pipes connect. On my XJ these pipes have a ball shaped bulge on the end of the pipe with like two lips which seal the end of the pipe. The idea being that water can drain out but close to prevent gases being drawn in. I would suggest you examine both of them to ensure they close.

Bye the way, I believe it is crucial you take Mike's advise and get several carbon monoxide detectors. I would place one at each foot well outlet as a minimum.

Oldtimer

[steve_m]

My V12 gives me a headache everytime that I look at it and remember all the jobs that I have to do to it.
One of the jobs is strip out all the boot carpets (I have a new set ready to fit) and find and clear the tank vent tubes as it honks of fumes all the time.
Having said that I was stuck it in it for 4 hours on Tuesday (stupid Dorset Steam Fair) and I didn't get a headache.

[davidr]

Steve - the usual reason for fuel smells in the boot is corrosion in the bottom of the fuel tank. The tank sits on a foam insulator that retains condensation and so tends to rust the bottom of the tank. It may be that your vent pipes are blocked or not connected probably but the the likelihood I'm afraid is that your tank needs to come out.
Another job for your list!
Regards
David

[davidr]

Old timer - thanks for your suggestion. The scuttle drains don't have any kind of valve in them as far as I'm aware. They run down the side of the engine bay and exit through the inner wing into the wheel arch. I wouldn't have thought they'd pick up fumes from there? Anyway - interesting thought. I'll have a look at both my cars just to check. I might also try blanking them off temporarily as an experiment.
Thanks for your help - will let you know!
Regards
David

[steve_m]

Steve - the usual reason for fuel smells in the boot is corrosion in the bottom of the fuel tank. The tank sits on a foam insulator that retains condensation and so tends to rust the bottom of the tank. It may be that your vent pipes are blocked or not connected probably but the the likelihood I'm afraid is that your tank needs to come out.
Another job for your list!
Regards
David

I hate you already!
Actually it is more of an exhaust smell than petrol, or maybe a mixture of both so I am hoping that the tank is ok and the vent is just blocked or disconnected (another triumph of hope over experience!).
Also have to do the swirl pot when i am in there as there is a complete lack of performance when the tank is low; is this a difficult job?
Can't keep the tank topped up because a) it's a V12 and b) have to use all those stupid supermarket petrol vouchers to make it worthwhile filling up.

[davidr]

Have now looked at the scuttle drains on both my cars. Neither appear to have any kind of valve - both are straight forward pipes leading down to the inner wing.
I'm wondering whether exhaust fumes are getting in from the rear somewhere? Are there any vents in the rear other than the side vents in the buttresses?

[Iain-1980]

There are "vents" in the boot floor. My '93 4.0 has rubber pipes, angled 90 degrees backward, but on my old '89 3.6 they were just straight down. These could be blocked, holding fumes in the boot, does the boot smell of petrol?

Also the butresses mean that there is low pressure quite high up at the rear of the car meaning that exhaust can be drawn in the boot seal.

[ptjs1]

David,

If it's exhaust fumes (and assuming that you have no exhaust leaks anywhere in the system) it could be:

- the vent pipes under the car. I think unlikely but possible
- boot seal
- rear light aperture seals
- rear window seal

Good luck with sorting it. Apart from the potential danger, I'm sure it must be putting you off driving the car.

Paul

[davidr]

Paul - thanks for that. A few new ideas there.
The exhaust is fine and doesn't have any leaks. It's a new stainless steel one that I put on last year.
I think the rear screen seal is fine on the basis that it doesn't leak water.
I'm not sure about the rear vent pipes but will check
The boot seal is OK I think - it's in good condition..
What do you mean by the rear light aperture seals?
Regards
David

[ptjs1]

David,

I mean the rubber seal that fits around the rear light cluster units on each side between the light units and the body of the car.

Paul

[davidr]

I did the run up to Kemble today. On the way I kept the aircon fans switched off. I also pinched the carbon monoxide sensor from the kitchen and placed it in the car. It has a digital readout and read 0 throughout the journey. Only had a brief blip when I opened the door to reverse into a parking space at Kemble. So that eliminates any exhaust fumes getting in from the rear?
So on the way back I put the fans on and still it read 0 all the way home. Also didn't have any smell or headache on the way home. Just to make sure that the sensor was working it put it in the exhaust flow when I got back and it went mental! Wouldn't stop beeping for 15 minutes and earned me a bollocking from the domestic management!
So I'm at a loss! Doesn't appear that I'm getting exhaust fumes into the car but I guess I'll just have to continue investigating.
Regards
David