4cv Sofica heater smells bad

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Stan W

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The heater in my 4cv smells bad - there seems to be a small amount of exhaust getting into it. There was previously a lot more exhaust getting into it due to a leak where the exhaust pipe connects to the autobleu manifold. I even took off the manifold to make sure it was sealed at the head. The muffler is not leaking, and it is sealed where it meets the pipe from the manifold. Has anyone else had this problem?

I am surprised that exhaust would get into the heater even with a small leak. I have all the proper radiator cardboard pieces in place along with all the sheet metal parts in the engine compartment. Would a slightly longer pipe on the exit of the muffler help?

The fan is running a little faster than originally. I have the voltage convertor set for about 8v and I get lots of warm heat in the car. This would be great if it did not stink!
 
Do you have fresh paint on any part of the engine that may be ,getting baked by engine heat producing fumes ,my 53 didn't have an electric fan but only used the engine fan to force air into the cab,[flaps on either side of the rad ] via a small flap under the back seat and de misting vents either side at the bottom corners of the windscreen ,i recall it having a particular smell but it wasn't offensive ,maybe a little oily .
 
Stan W said:
The heater in my 4cv smells bad - there seems to be a small amount of exhaust getting into it. There was previously a lot more exhaust getting into it due to a leak where the exhaust pipe connects to the autobleu manifold. I even took off the manifold to make sure it was sealed at the head. The muffler is not leaking, and it is sealed where it meets the pipe from the manifold. Has anyone else had this problem?

I am surprised that exhaust would get into the heater even with a small leak. I have all the proper radiator cardboard pieces in place along with all the sheet metal parts in the engine compartment. Would a slightly longer pipe on the exit of the muffler help?

The fan is running a little faster than originally. I have the voltage convertor set for about 8v and I get lots of warm heat in the car. This would be great if it did not stink!
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I'm glad you are getting heat! Be nice if you could test for CO and CO2 in the car to confirm whether or not it really is the exhaust. I'd be suspecting paint too. I know two other 4CVs with Sofica heaters and AFAIK they don't smell. Perhaps drive 50 -100 km with the windows down to really get things hot for a while. I guess it might be a bit cold your way though!

It certainly would be an improvement over the earlier type, as described by Mr Pugwash. Mine doesn't even have the windscreen vents or the rear seat flap, being a 1950 model. I do get a flow of warm air at my feet after 5-10 km.....
 
as mentioned in an earlier post ,i didn't realize i had screen vents till i saw smoke coming out of them, when the outlet pipe blew out of the fuel pump setting the engine on fire ,pulled me up quicker than a flat tyre ,actually i think that car was much later, could it have been a 59, disk wheels, dark grey paint, my first was a 54 ,one year younger than me .
 
Carbon monoxide sensors aren't that expensive (in Australia at least), which would help in diagnosis...
 
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Everything on the engine was painted, but the car has been running since March, so it has been up to operating temperature for quite a few hours. I did initially get some bad odors from paint, but that seems to have subsided. The heater core did get a dusting of paint, but again, I think that would have completely cured by now. The carbon monoxide sensor sounds like a good idea - are you thinking about the type used in homes? I once restored a 1961 VW and I had one of those stick-on CO detectors that would turn dark if there was CO present.

The 4cv I had back in the 1970s had the same heater and it did not have bad odors. I was wondering if there was some pre-disposition for the wrong type of airflow. It might also have something to do with driving at very low speeds, but it still shouldn't get exhaust in the heater. The heater cardboards don't seal perfectly around the heater core, but they shouldn't have to.
 
Stan W said:
Everything on the engine was painted, but the car has been running since March, so it has been up to operating temperature for quite a few hours. I did initially get some bad odors from paint, but that seems to have subsided. The heater core did get a dusting of paint, but again, I think that would have completely cured by now. The carbon monoxide sensor sounds like a good idea - are you thinking about the type used in homes? I once restored a 1961 VW and I had one of those stick-on CO detectors that would turn dark if there was CO present.

The 4cv I had back in the 1970s had the same heater and it did not have bad odors. I was wondering if there was some pre-disposition for the wrong type of airflow. It might also have something to do with driving at very low speeds, but it still shouldn't get exhaust in the heater. The heater cardboards don't seal perfectly around the heater core, but they shouldn't have to.
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Puzzling, then! I didn't have a particular type of CO detector in mind, just the principle. I've no idea how exhaust gases could get to the inlet to the heater, if indeed they are.
 
Is the Sofica heater the engine coolant heat exchanger type? Any minute leakage (or just seepage) of coolant will give you a pungent acrid smell through the heater outlets.
You may know this distinct smell well enough to eliminate it as a cause, I just mention it as a possibility.
Regarding the length of the exhaust outlet, yes, it can be significant. Many years ago, a particular model car at a dealership I worked in, had a factory recall campaign to replace the tailpipe with one about 100mm longer, just to get it past the panel under the rear bumper, as it was supposedly causing buildup of exhaust gases around and leaking into the luggage compartment and cabin.
 
well thats a thought ,you may not be going fast enough or have a tail wind ,i haven't noticed from your pics, if the exhaust exits at the back or side, were douse the Sofica get its input air from ,? the radiator shroud or elsewhere ,im not familiar with this heater ,i have seen them on dauphines ,but presume they might have been ,deemed unnecessary in our climate PS maybe re locating the inlet temporarily may help determine where the smell is coming from. just saying ,i must admit that a test drive on most U.S programs i have seen includes a prolonged burnout ,i presume this wouldn't be applicable in your case. Stan
 
pugwash said:
well thats a thought ,you may not be going fast enough or have a tail wind ,i haven't noticed from your pics, if the exhaust exits at the back or side, were douse the Sofica get its input air from ,? the radiator shroud or elsewhere ,im not familiar with this heater ,i have seen them on dauphines ,but presume they might have been ,deemed unnecessary in our climate PS maybe re locating the inlet temporarily may help determine where the smell is coming from. just saying ,i must admit that a test drive on most U.S programs i have seen includes a prolonged burnout ,i presume this wouldn't be applicable in your case. Stan
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The Sofica heaters were fitted to some quite late model 4CVs, maybe an option or on the upmarket versions. Maybe the North American ones got them in acknowledgment of the winters there?

The tiniest of coolant leaks would certainly give a distinct smell - hadn't remembered that.
 
I know the smell of coolant, so I do not think that is the problem - but I will not rule it out. The exhaust exits on the right side just past the edge of the lower body panel. It is on the same side as the sofica heater. The heater intake is just beside the radiator and has a cardboard panel to prevent hot engine compartment air from going back through the inlet side of the radiator. The cardboard panel is not a complete seal, it just helps keep the airflow correct. The Dauphine had the muffler/tailpipe assembly on the left side and the sofica heater on the right similar to the 4cv. I think most, if not all, US spec 4cvs 1956 and later had sofica heaters.

IMG_3498 - Copy.JPGIMG_3499 - Copy.JPGIMG_3500 - Copy.JPG
 
Stan W said:
I know the smell of coolant, so I do not think that is the problem - but I will not rule it out. The exhaust exits on the right side just past the edge of the lower body panel. It is on the same side as the sofica heater. The heater intake is just beside the radiator and has a cardboard panel to prevent hot engine compartment air from going back through the inlet side of the radiator. The cardboard panel is not a complete seal, it just helps keep the airflow correct. The Dauphine had the muffler/tailpipe assembly on the left side and the sofica heater on the right similar to the 4cv. I think most, if not all, US spec 4cvs 1956 and later had sofica heaters.

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It's certainly hard to see how you'd get exhaust into the Sofica, isn't it. That's very much the standard fitting. A friend of mine just fitted one to his 4CV and hasn't reported a smell.

Does your car have the air scoop on the left side of the radiator? Not that it would have much effect on getting smell to the heater or preventing it for that matter.

It'll be obvious to all of us once you have found it of course! Good luck with the hunt.
 
I have the air scoop on the left side of the radiator, but I have not put it on the car yet. I thought that piece would be more for getting additional air through the radiator at high speeds (relatively speaking). I should put it on the car anyway. The leak at the manifold outlet made the heater smell REALLY bad even though it was on the opposite side of the engine. Maybe I did not get it completely fixed. I will do more checking when I have time and report back.
 
Stan W said:
I have the air scoop on the left side of the radiator, but I have not put it on the car yet. I thought that piece would be more for getting additional air through the radiator at high speeds (relatively speaking). I should put it on the car anyway. The leak at the manifold outlet made the heater smell REALLY bad even though it was on the opposite side of the engine. Maybe I did not get it completely fixed. I will do more checking when I have time and report back.
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The early cars didn't have the scoop - I've absolutely no idea how much good they do, but yes, I'd reckon it wouldn't do much on the golf course!
 
maybe the smells coming from the ducts in the car ,mouse nests etc, can you run some kind of freshener[ like you would use on household air con] , spray through them using a vacuum cleaner ,presume there must be some kind o fduct or tube from the unit to the ducts in the body ,
 
Baking hot today in Perth so I took the 4CV out, as you do! I forgot to open the heater flaps so it ran pretty hot (stupid) but it was an interesting smell test. There was a gentle blast of hot air at the foot level vents and a slight but distinct smell of petrol. My suspicion is that there is enough turbulence inside the engine bay to get carburettor and/or exhaust smells around the sides of the cardboard air screens. And yes, I have one across the top of the radiator too. I'll test it again later with the heater flaps open at the radiator and closed at the feet!

I reckon air goes straight through the radiator and out but a wee bit circles around on each side. I do have the full set of engine trays btw.
 
The exhaust is not leaking at the manifold exit. I sealed the area above the radiator and around the top of the right side cardboard. I sealed the heater core to the cardboard. I also slowed down the fan (adjusted my voltage convertor) since I was running it a good bit faster than it would be on 6v. It might be a little better, but I am not sure. It has been unseasonably warm here recently, but I will get a better test next week when it will be cold. I might also seal the top of the cardboard on the left. to keep a bit less engine compartment smell from the radiator intake. It would be interesting to know exactly what the airflow does in the engine compartment. I suspect that air circles around the edge of the radiator anywhere it can.

The heater duct is new - I had a rubber duct, but changed it to aluminum just in case the rubber was the problem. It did not make a difference. I also need to make sure there is not any petrol seeping out on the top of the gas tank. There are no drips or stains on the side of the tank, but the tiniest amount would make the heater smell terrible.
 
Stan W said:
The exhaust is not leaking at the manifold exit. I sealed the area above the radiator and around the top of the right side cardboard. I sealed the heater core to the cardboard. I also slowed down the fan (adjusted my voltage convertor) since I was running it a good bit faster than it would be on 6v. It might be a little better, but I am not sure. It has been unseasonably warm here recently, but I will get a better test next week when it will be cold. I might also seal the top of the cardboard on the left. to keep a bit less engine compartment smell from the radiator intake. It would be interesting to know exactly what the airflow does in the engine compartment. I suspect that air circles around the edge of the radiator anywhere it can.

The heater duct is new - I had a rubber duct, but changed it to aluminum just in case the rubber was the problem. It did not make a difference. I also need to make sure there is not any petrol seeping out on the top of the gas tank. There are no drips or stains on the side of the tank, but the tiniest amount would make the heater smell terrible.
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Second hot running test, about 36 degrees I think, and the car ran a bit cooler (better to say "a bit less hot") and there was no smell at all. The radiator flaps were open and heater vent flaps were shut.
 
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