liquid drip in passenger footwell?

[Barjavel]

I noticed some clear liquid dripping into the passenger footwell. It seemed to be water. (It wasn't raining out). It looked to be dripping from under or just below the dash, from the upper left of the footwell. There is some kind of cable sheathed in a green cover, it was dripping from around there.

Any ideas as to what to look for? Perhaps related -- a couple of my gauges are get condensation behind the lenses when operating in dry weather.

[18Fiatsandcounting]

That sounds almost certainly like the heater core, or its associated valve, has sprung a leak. Very common. Unfortunately, it doesn't fix itself, so the solution is to remove the passenger seat, lay down in that area with your head up in the footwell, bring along a 10mm wrench and 10mm socket/drive and some screwdrivers and pliers and some towels, and remove the heater valve and possibly the heater core depending on which seems to be leaking.

First, drain the coolant from the engine block and radiator, and do this with the heater valve in the on position (the center lever by the handbrake in the "red" position). That way you won't get coolant dumped on you when you're up in that footwell and loosen the connections.

Good luck as it's not the easiest job in the world.

-Bryan

[bobplyler]

And be sure to know a large number of Italian expletives.

[Barjavel]

Yikes, this sounds like a very unpleasant job. Thanks for the info. I may try to pawn this off on the mechanic.

[TX82FIAT]

As mentioned, the valve is a very common failure point. As an alternative to draining the entire system, you can bypass the heater with a barbed connector for the hoses prior to them passing through the two hole gasket on the firewall on the passenger side. This does two things. One, it allows you NOT to drain the entire system if you have clean coolant. Two, it allows you to drive the car why you do the repair without the leak. If you have not already done so, now is a really good time to install a Prestone flush and fill kit that has a coolant T with a removable cap. It is installed at the high point of the coolant hose that passes over the passenger side Cam box near the fire wall. The repair is not that bad as long as the tubes line up. I had to cut a new hose for the inside of the car as my new valve was slightly different that the one that was in the car.

[Barjavel]

Thanks for the "barb" advice. The car's at the shop right now but I would like to get the barb so that I can replace the valve on my own. Do you know offhand what size I should look for at the local Ace or similar (or order online)? I have no idea what size the relevant hoses are.

[18Fiatsandcounting]

Do you know offhand what size I should look for at the local Ace or similar (or order online)? I have no idea what size the relevant hoses are.

5/8" is the size of the hoses for the connection to the rear of the cylinder head, and the heater return pipe to the water pump, to the inlet/outlet pipes through the firewall to the heater core/valve. A hose barb for a bypass would also be 5/8".

-Bryan

[Barjavel]

Thanks much!

I just watched some YouTube videos on changing the valve; I am confident I can do that.

I also watched a video of the replacement of the heater core. That doesn't look hard either, but I am really hoping not to have to tear apart the interior.

[18Fiatsandcounting]

I also watched a video of the replacement of the heater core. That doesn't look hard either, but I am really hoping not to have to tear apart the interior.

The only interior piece that has to be removed is the center console where the radio/cigarette lighter/courtesy light are. The lower assembly of the heater box is held with 4 spring clips, 2 in the driver's footwell side and 2 in the passenger's side. Once those are popped off, the lower assembly swings down and the heater core can be removed. The core is essentially held in place by being pressed between the upper and lower assemblies of the heater box.

Removing the heater pipes that go through the firewall can get a little tricky, especially if the connections are rusted. Don't forget to use new o-rings for the heater valve and the attachments to the heater core. Those are round but beveled rubber or silicone washers.

-Bryan

[Nut124]

Usually the leak is in the valve, the only moving part.

I would not replace the heater core unless there is clear evidence that it, not the valve, is leaking.

[kilrwail]

I just finished replacing my valve and that's not a job I want repeat! Does anyone know the purpose of the big black wire that's soldered to the old valve? It looks like it has a rheostat behind it, but my temperature gauges still works. Can't find it on a wiring diagram. That (stainless?) steel tube is really hard to bend without an acetylene torch, which I don't have. Got it done with a propane torch and a big vise.

[18Fiatsandcounting]

Does anyone know the purpose of the big black wire that's soldered to the old valve?

Some early heater valves had a "thermal sensor" of sorts soldered to the valve on one end, and the other end was a copper tube that was coiled around and held against the underside of the heater core. It's never been clear to me exactly what this gizmo did, but apparently it was a very crude attempt at stabilizing the temperature inside the car. Kind of ridiculous in a convertible, but there you have it. Perhaps some previous owner tried to do something with this, and that's what you see?

The temperature gauge in the dash is solely controlled by the two temperature sensors in the top of the cylinder head.

-Bryan

[kilrwail]

Thanks Bryan. No issues on an 84 km drive, so it doesn't matter. Now I have some lights out, so something new to trace. There's always something.