Anyone see anything obvious? Exhaust leak

[DSVW]

Hi,
The heat in my 1969 Ghia works great. It really blasts out of all of the ductwork.
My problem is fumes in the cabin area.
I replaced the rear deck-lid seal, the seal around the engine to body and the cardboard tubes are new. All of the heater boxes and the plastic heater tube underneath are rock solid.

Can anyone see by the attached photos why fumes would be leaking into the cabin only when the heat is used?

[CiderGuy]

You're missing the charcoal canister.

[DSVW]

OK.
Is that the reason why there may be fumes in the cabin?
I am not even sure what that would hook up to. I will have to look into that.
Thanks.

[Starbucket]

The Heat Exchangers may be burnt through or the tubes to the body might be leaking. Are you sure it's coming out of the heater vents. Lots of things to check.

[DSVW]

The Heat exchangers are rock solid and the tubes to the body are good. Only fumes in the cabin when the heat is turned on.

[xzener]

Could be a leak in the heater boxes.
_________________
My 70 beetle was totaled Now to build the Ghia I always wanted. Rest in peace Ruby, I will miss you. Hello <insert Ghia name here>!

[Starbucket]

If you have a lot of fumes in the engine compartment, an exhaust leak, or oil leaking on the exhaust components, the fan could suck them in and blow them across the heater box internal fins (where they pick up heat) and into the cabin.

[c21darrel]

Wasn't the charcoal canisters for fuel evap? Nothing to do with heating the interior. If the smell is coming in while say idling at a stoplight...its normal. The fan is sucking up exhaust fumes from the exhaust pipe and blowing in. If its all the time...ignore me.
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[DSVW]

Yes, I get fumes only when heat is on.
If the fan only takes air in through the vents in the deck-lid as well as whatever air is circulating around the engine compartment, could I be sucking air in from under the car? I don not have any oil leaks in the engine compartment but I do have a small oil leak under the car. I will have to research sealing up my engine compartment better. I am probably missing something that I don't know about.

[c21darrel]

[DSVW]

Thank you. Valve cover gasket. I will check that out.

[bhartwell59]

as everyone has said but i'd be looking at your muffler/heat exchanger connection.

had the same problem last winter until i plugged up some rotted holes in the exchanger by the muffler
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'74 Zambezi green Ghia vert, autostick, 101k
'87 Jeep Wrangler, 4.2, 330k

[swavananda]

Often with a decent exhaust leak, there is popping when decelerating in gear. any chance you been experiencing that ?

Can you hone in on the smell difference between oil and exhaust ? Oil baking on the heat exchangers smells a lot like a freshly paved road.

[sjbartnik]

Are you sure it's actually exhaust fumes?

Even on a tight car the heat has a bit of a smell, it's more of a hot metal smell rather than an exhaust fume smell.

If you've ever had oil leaks from the valve cover gaskets and the oil has made its way into the heat exhangers, you will get stinky burnt oil smell from the heat.

The air for the heater comes from the engine cooling fan via the vents in the decklid. If the car is sitting stopped, especially with a tailwind, it can pick up some exhaust that gets blown forward by the wind. This should go away when on the move however.
_________________
1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[DSVW]

Thank you, all.
The muffler/heat exchanger connection had a big gap where the clamp had come undone and separated. I tightened everything up. I haven't taken it for a test ride yet but I am pretty sure that was the issue since everything else is rock solid with no rust through underneath.

[brent bousman]

Next time you have the motor out replace that rear seal on the firewall as the fan is sucking air from under the car through that gap.

Also - reroute the gas line properly through the shroud with the grommet and metal line as you will eventually rub through that gas line and possibly cause a fire.

[DSVW]

Ok.
I fixed the gap from the exhaust to the heater box. The clamp had come loose. Everything else is rock solid with no rust. I also put in new valve cover gaskets with last oil change.

I think the only thing left that it could be is what Brent Bousman noticed with the rear seal on the firewall. I need to look into how to replace that. Must the engine be out of the car to replace it?

It is definitely an exhaust leak smell and not a burning oil smell. I drove it for 2 1/2 hours last night in 20 degree temperatures.....

[DSVW]

.....and I see that the tin that goes to the firewall is loose.

The gasket is ok, old but not brittle or broken.

I can not see how that piece of tin is to be secured to the firewall or tightened unless the gasket just goes over the tin and holds it in place? There are two screws holding the tin in on each end but the top of the tin is not secured and there is a large gap.

[70 140]

Since it hasn't been mentioned yet, you're missing the seals on the breast plate that go around the fresh air hoses to the heater boxes. There should also be one on the warm air intake hose but it's a different size if I recall.

https://www.cip1.ca/ProductDetails.asp?ProductCode=VWC%2D113%2D119%2D585%2DB2

[Starbucket]

With the motor cold, have someone start the car, while you hold both hands around the manifold per heat tube to exhaust pipe connection and feel for leaks as those gaskets tend to burn out if not tight. Careful it will get hot fast. The firewall tin should have two tabs that fit over the motor back there, one on each side near the top. Fit them over and tighten the screws at each end to keep it in place.