My thermostat cable. (A rant)

[sb001]

For the past several months I have had an issue where my car was very difficult to start back up once warmed up, and although that is normal for these cars around summer season (if you don't think so just check the list of posters with the same issue for even just the past month) it just was happening too often for it to be just that. Also once the car did start back up, the first few seconds were touch and go as it would stumble terribly. Third, when I got home and popped the engine lid there was a significant gas smell.
(If you've never owned an autostick, just the typical characteristic of this system is to bog down after put into gear- due in no small part to the fluid coupling of the torque converter, on a warmed up engine the revs will drop from 950 to approx 750-780 rpms when put into gear. So this exacerbates the situation when the engine decides it's too hot.)

Anyway back on track- after dealing with this for the last couple months, enough was enough- I popped the engine lid and finally noticed that my thermostat cable had not pulled the flap inside the air cleaner snorkel open to ambient air- it was still open to pre-heated air. The deck lid handle, and everything inside the engine was roasting hot.
After some investigating, I discovered that instead of pushing and pulling the cable as it's supposed to when the thermostat expands, the flap arm the cable connects to on the fan shroud was pushing/pulling the whole cable sheathing. The clamp toward that end of the cable that holds the sheathing is supposed to prevent this from happening, but it was loose around the sheathing and no amount of tightening the clamp screw would prevent this from continuing to happen. There was another contributing factor as well- apparently I had too much cable length between the fan shroud flap arm and the air cleaner flap. This meant that even when the engine warmed up and the thermostat expanded, and the fan shroud flap arm pulled the lower end of the cable, the upper end on the air cleaner just stayed in place so the snorkel flap was open to preheated air. This also probably was the root cause of the sheathing being pulled instead of the cable.

The easy answer of course would be to adjust the cable length at the fan shroud end (loosen the securing bolt and pull more of it through the bolt then tighten the bolt back down.) This would be a great solution-- except that the cable to the fan shroud flap is COMPLETELY blocked by the intake manifold, as well as the fan shroud "arm" and the generator housing being in the way. There is absolutely NO way to get an open end wrench on the nut behind the flap arm to hold that side of the bolt and get another tool in to loosen it. Thanks VW!! Now I know EXACTLY why you went to a wax pellet thermostat on the air cleaner after 1970!!!

In order to accomplish this simple adjustment that should take 30 seconds, you would basically have to undo the whole fan shroud (and accompanying parts) and lift it up enough to clear the manifold, and even then it might not be accurate because you've moved the position of the fan shroud flap. The only other way is to remove the intake manifold- an impossible task on a single port with the engine in the car. After struggling for an hour with this mess, I finally gave up and cut that end of the cable and then pulled it off the air cleaner. Now I won't have my snorkel open to preheated air with the engine cold, but that's a small price to pay for this disaster of a design.

EOR
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I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[APPLEGREENVW]

Why not buy a new thermostat cable, grease the cable inside the sheathing etc.?
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Parts for sale https://www.thesamba.com/vw/classifieds/search.php?username=APPLEGREENVW

02/76 Beetle sedan

[sb001]

[APPLEGREENVW]

New cable available here. Also R & R type 1 engine is not a big job.

https://www.ebay.com/itm/VW-AirCooled-Beetle-Ghia-...1853329704
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02/76 Beetle sedan

[sb001]

[Tom K.]

Another option (that you probably already know about) is to throw in the towel and replace with a 1971 air filter with its own embedded thermostat. I have one on my '70 and it works perfectly.
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'91 Vanagon Westfalia
'70 Beetle Convertible
'71 Super Beetle Semi-Automatic: https://www.thesamba.com/vw/forum/viewtopic.php?t=714131&highlight=
'65 Ghia: https://www.thesamba.com/vw/forum/viewtopic.php?t=762478&highlight=

[sb001]

[APPLEGREENVW]

[sb001]

[Glenn]

Bummer.

Glad they switched to a better system.
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Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"

Member #1009

#BlueSquare

[APPLEGREENVW]

All I know is, its a easy fix, with the engine out of the car and using the right tools. Maybe someone else will explain that better to you. You make it sound like its a big hard project. Peace.
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Parts for sale https://www.thesamba.com/vw/classifieds/search.php?username=APPLEGREENVW

02/76 Beetle sedan

[Glenn]

[sb001]

[kpf]

[sb001]

[sb001]

[APPLEGREENVW]

[kpf]

[sb001]

[61SNRF]

While I can agree that the system is somewhat Victorian in design, I'm having a hard time trying to understand why a stuck TAC flap would cause your symptoms of hard starting and poor running on hot starts.
The fact that you smell fuel after being driven awhile doesn't make sense either. Sounds more like the common fuel drip into the carb throat on hot soak that is also very prevalent with these cars.

Another option you had to disable it was to simply remove the hot air hose off of the air cleaner. That would have been a quicker, easier and less invasive test to prove your theory.

As far as the adjustment goes, after 45 years as a pro mechanic I've learned some adjustments are not as easy as others and you just have to overcome and conquer whichever way is necessary.
Taking the intake off is not impossible nor is getting some sort of wrench in there to get to the bolt/nut. Sometimes you have to make the perfect tool even if that means cutting, grinding or bending a wrench or two.
Auto mechanics is an art form, not a science
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-Bruce

An ounce of prevention is worth a pound of cure.