Thermostat cable adjustment

[tractoman]

My cable seems to come off the pulley between the thermostat and the lever for the flaps once in awhile rendering the thermostat useless and the flaps open. What is the proper method for adjusting the cable?

[Amskeptic]

My cable seems to come off the pulley between the thermostat and the lever for the flaps once in awhile rendering the thermostat useless and the flaps open. What is the proper method for adjusting the cable?

I do not use the Bentley method! It assumes that your thermostat is el-perfecto.

Unscrew the thermostat from the bracket. Pull cable around pulley and draw it up through the clamp on your **open** flaps, the fail-safe spring should spring them to open position with a clank after you do a test push towards closed. Secure cable in clamp with that pathetic 7 mm bolt going through that even more pathetic rectangular piece of annoyance. Check that thermostat is pressed against the rear side of the bracket. This is our default no way that cable adjustment will ever accidentally have flaps partially closed.

Have assistant push lever/cable/clamp (wear gloves for comfort) forward to close flaps - forward as in towards front bumper. You now make sure that the cable is inside the pulley wheel groove and pull thermostat towards bumper and re-install 13mm bolt that goes through bracket into the thermostat end. Make sure rectangular thrust washer engages with the rectangular cut-out in the bracket. This prevents tightening torque from twisting the thermostat pleats in any way.

Button up lower tins, start engine, drive four miles, check for lever moving from tilted forward to about vertical. After a good ten minutes, you should be able to test push lever and hear it clank back to fully open with a cable that is now taut enough not to fall off the wheel, but not so tight as to interfere with full opening of the flaps..
Colin

[tractoman]

Will this cause the thermostat to stretch open at all while it is being remounted to the bracket or just tension the cable against the wheel? Just curious. Does the bracket limit the thermostat to only expand so much?

[tractoman]

I'm done now and see there is no expansion of the tstat when installing per the Colin method, but just a little extra tension put on the cable.

[Amskeptic]

Will this cause the thermostat to stretch open at all while it is being remounted to the bracket or just tension the cable against the wheel? Just curious. Does the bracket limit the thermostat to only expand so much?

Answering for the Readership here, a fresh new thermostat would indeed go to war with you as you tried to mount it to the bracket. In this case, we slacken the cable clamp to allow a little slip at full close until it is bolted up.
Colin

[72Hardtop]

For a used but operable T-stat it will likely expand slightly when putting onto the bracket (engine cold). More so if the cable has been cut to shorter length not allowing for much lead way.

When I adjust the T-stat I use some vise grips to hold the flaps closed (bracket towards front bumper) and pull the cable thru the bracket clamp until there is no slack. Then tighten down the cable bracket clamp nut. All while the engine is stone cold. Once driven 10 mins or so the clamp should be vertical or as near to vertical as possible.

[Amskeptic]

For a used but operable T-stat it will likely expand slightly when putting onto the bracket (engine cold). More so if the cable has been cut to shorter length not allowing for much lead way.

When I adjust the T-stat I use some vise grips to hold the flaps closed (bracket towards front bumper) and pull the cable thru the bracket clamp until there is no slack. Then tighten down the cable bracket clamp nut. All while the engine is stone cold. Once driven 10 mins or so the clamp should be vertical or as near to vertical as possible.

This may guarantee that the flaps are closed when cold. I like to guarantee that the flaps are open when warm. You need to hear the fully warmed engine's flaps clank in the full-open position.

I have also discovered that people have so much trouble getting this mess to stay together when they are reassembling the fan housing to the engine, that sometimes the cross shaft gets twisted and bent. You can make sure that when the left flap clanks on the oil cooler duct, that the right side flap is tapping the upper cylinder tin. If they miss, you can re-twist the cross shaft to synchronize them. Then you re-check thermostat travel.

I hear that there are new Wahler tstats being made?
Colin

[72Hardtop]

New T-stats =D> I'm up for a purchase. When and where? I'd like to get my hands on another T-4 fuel pump rebuild kit as well...I know they're out there ...somewhere. I always confirm the flaps operation prior to putting the top tins on (shroud in place) by working the T-stat and watching the flaps. If any adjusting needs to be done it can be done easily at that point.

[SlowLane]

Just got around to installing my new Awesome Powdercoat thermostat. Got tired of waiting for Bus Boys to get around to my request for a rectangular washer, so I made do with a dead-bolt striker plate from Lowes.

In the process I took the time to measure the amount of cable pull necessary to pull the flaps from fully open to fully closed. Though imprecise, I measured about 12.5mm (+/- 0.5 mm).
I then measured the amount of free movement that the thermostat had to open in the bracket (with rectangular washer correctly mounted outbord of the bracket). That came out at about 13.5 mm (+/- 0.5mm).

So that means that there is about 1 mm of extra play that the fresh thermostat has to work with, meaning that one can adjust the cable as per Bentley without trepidition on a new thermostat. As it ages and relaxes, however, that extra play will get "eaten up" by the increasing cold resting length of the thermostat. At that point, Colin's adjustment procedure makes a lot more sense than Bentley's.

[72Hardtop]

I to purchased the new thermostat (Powdercoat). I know originally the square washer was mounted between the bracket and thermostat (confirmed from a former (VW dealer/Independent) mechanic 35+ years. But he also confirmed that the new thermostat is slightly different at the base therefore requiring the T-stat washer to be placed on the outside of the bracket. Placing it inboard won't allow the T-stat to open fully when adjusted cold. I checked initially and he was correct it would only open about 95%. The new one will likely outlast the OEM one due to it's better thermal resistance with the newer material. I highly recommend it when replacement of the T-stat is needed.

Especially useful for quick even warm ups, reducing thermo shock when engine is operating as well.

[Amskeptic]

I to purchased the new thermostat (Powdercoat).
The new one will likely outlast the OEM one due to it's better thermal resistance with the newer material.
I highly recommend it when replacement of the T-stat is needed.
Especially useful for quick even warm ups, reducing thermo shock when engine is operating as well.

Link? Price? Does it warrant a position in the Parts Known To Be Acceptable thread?
Colin

[72Hardtop]

http://www.thesamba.com/vw/classifieds/ ... id=1036746

[Amskeptic]

http://www.thesamba.com/vw/classifieds/ ... id=1036746

Now in the Parts known To Be Acceptable thread, thank-you.
Colin

[cegammel]

Just got my thermostat on, which was a bear, but easier than I anticipated. So, a couple of questions: 1) How tight should the spring be? My flaps now sort of gum their way open rather than clanking. Can I safely wrap that little spring another turn without breaking it?
2) the cable that came with my used thermostat was too short to reach, so I spliced another onto it...I know...I know...I'll order a proper one with my next load. It seems to work fine, the splices don't interfere with the wheel or the flap. Anything else I should watch out for with a splice?

Thanks!

[Amskeptic]

Just got my thermostat on, which was a bear, but easier than I anticipated. So, a couple of questions: 1) How tight should the spring be? My flaps now sort of gum their way open rather than clanking. Can I safely wrap that little spring another turn without breaking it?
2) the cable that came with my used thermostat was too short to reach, so I spliced another onto it...I know...I know...I'll order a proper one with my next load. It seems to work fine, the splices don't interfere with the wheel or the flap. Anything else I should watch out for with a splice?

Thanks!

Heck, I wrote you a novel in PM, but the same question is right here. Well, so's the answer:

The shaft must end up with a perfect parallel between the fan housing saddles where the plastic bushings seat. You can gently bend the shaft to achieve this parallel. If you have garage door or silicone grease, hit the plastic bushings with it.
The u-shaped link needs grease too, if it is not too late, as do the pins that the flap pivots on. The plastic cable wheel's bolt has a smooth bearing surface that should be lubricated with silicone or garage door grease.
(all of this in the name of low friction, a great thing for all of us to aspire to)

Do not over-tighten the spring, it will wear everything out. There are supposed to be two spring steel tabs that hold the cross shaft/bushings in their seats. They screw into the fan housing bosses. Look for the two shiny circles along the fan housing edge, the left side has the reverse inline fuse clip, but I think you can see the actual tabs painted black: