Cooling Flaps return spring.
Cooling Flaps return spring.
Quick question regarding the return spring.
Exactly where does the return spring attach to. The door flap end is straight forward.
But where at the thermostat top link plate area is it attached.
Is this spring absolutely necessary, given that the thermostat, expands and contracts,
effectively opening and closing the flaps. So where does the spring come into effect.
Thanks
Tim
Exactly where does the return spring attach to. The door flap end is straight forward.
But where at the thermostat top link plate area is it attached.
Is this spring absolutely necessary, given that the thermostat, expands and contracts,
effectively opening and closing the flaps. So where does the spring come into effect.
Thanks
Tim
- 937carrera
- Posts: 1190
- Joined: 7th June 2013 - 11:54pm
- Location: North Yorkshire
Re: Cooling Flaps return spring.
Are they like type 4 ?
Spring forces the flaps open, cable from thermostat pulls them closed when the engine is cool.
Spring forces the flaps open, cable from thermostat pulls them closed when the engine is cool.
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
- purplepeter
- Posts: 2338
- Joined: 8th August 2006 - 4:41pm
- Location: Bath, Avon
Re: Cooling Flaps return spring.
Yes Kaddy, It's vital!
Small hook on spring goes through a hole in Right hand flap, Bigger hook goes onto the relay lever (fairly self explanatory when you see how it lines up)
http://www.hallvw.clara.co.uk/type3/T3pbo/T3pb1-37c.htm
Small hook on spring goes through a hole in Right hand flap, Bigger hook goes onto the relay lever (fairly self explanatory when you see how it lines up)
http://www.hallvw.clara.co.uk/type3/T3pbo/T3pb1-37c.htm
Re: Cooling Flaps return spring.
So spring pulls them closed, and thermostat pushes them open.
But thermostat also pulls them closed when its cool and contracting ??
Academic because I dont have one on either engine. How strong is it,
is it stronger than a carb pull down spring?
Anyone ever arrive at a fix with an alternative.
Thanks
But thermostat also pulls them closed when its cool and contracting ??
Academic because I dont have one on either engine. How strong is it,
is it stronger than a carb pull down spring?
Anyone ever arrive at a fix with an alternative.
Thanks
Re: Cooling Flaps return spring.
Is the same spring as used in a type 1 engine at the back of the cooling tower.
Re: Cooling Flaps return spring.
Good article here that I have just found
https://www.thesamba.com/vw/forum/viewt ... mp&start=0
Clearly shows the connections of the substantial spring. But the spring looks to be pulling
the flap open a bit. And the thermostat pushes it open.
Why the need for the 2?
https://www.thesamba.com/vw/forum/viewt ... mp&start=0
Clearly shows the connections of the substantial spring. But the spring looks to be pulling
the flap open a bit. And the thermostat pushes it open.
Why the need for the 2?
Re: Cooling Flaps return spring.
If the themostat fails then spring holds the flaps open. Its so important to get some cooling air to the engine, its better they're forced open in a failure situation. Your engine will become a paper weight very quickly if the flaps dont open. The spring is also a helper for the thermostat to get them open when all is alive and well
The sultan of swing
Re: Cooling Flaps return spring.
But couldn't you just set the same amount of opening on the flap,
with the connecting rod, and leave the spring off. Even with the thermostat in the cold position,
there is very little pressure from the spring, and the flap is adjusted with the horizontal rod
to maintain a small opening. Spring on or off wont change this setting.
Am I missing something here ??
with the connecting rod, and leave the spring off. Even with the thermostat in the cold position,
there is very little pressure from the spring, and the flap is adjusted with the horizontal rod
to maintain a small opening. Spring on or off wont change this setting.
Am I missing something here ??
Re: Cooling Flaps return spring.
As we say over here, I think this needs another coat of looking at
Re: Cooling Flaps return spring.
So basically the spring is for taking up the slackness of the connections of the flap to rod,
rod to lever arm, lever am to spring, and spring to flap, thereby maintaining connectivity
of all the important elements.
Makes perfect sense now, any vibration here could disconnect the flaps from the rod, and thereby
closing the shutters permanently regardless of a working thermostat or not. Spring stops this.
I think this sounds right.
Comments?
rod to lever arm, lever am to spring, and spring to flap, thereby maintaining connectivity
of all the important elements.
Makes perfect sense now, any vibration here could disconnect the flaps from the rod, and thereby
closing the shutters permanently regardless of a working thermostat or not. Spring stops this.
I think this sounds right.
Comments?
- 937carrera
- Posts: 1190
- Joined: 7th June 2013 - 11:54pm
- Location: North Yorkshire
Re: Cooling Flaps return spring.
You're missing the failsafe in the original design.
From the picture the type 3 has a rod, rather than a cable on the type 4, they work the same. There's still a difference though. Without the spring you are relying on the thermostat to push the flap open. With the spring, you are using the thermostat to close the flaps when the engine is cool.
In one mode the thermostat is compressing (pulling the flap against the spring), in the other it is expanding (pushing the rod). Sometimes things are just designed to work in one mode or the other.
I think you've got it now
From the picture the type 3 has a rod, rather than a cable on the type 4, they work the same. There's still a difference though. Without the spring you are relying on the thermostat to push the flap open. With the spring, you are using the thermostat to close the flaps when the engine is cool.
In one mode the thermostat is compressing (pulling the flap against the spring), in the other it is expanding (pushing the rod). Sometimes things are just designed to work in one mode or the other.
I think you've got it now
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
- purplepeter
- Posts: 2338
- Joined: 8th August 2006 - 4:41pm
- Location: Bath, Avon
Re: Cooling Flaps return spring.
Although the normal fail position of the thermostat is for it to expand, it's perfectly possible for it to fail not fully open & for the bracket etc to get fouled up with oil/road grime etc, making it sticky.
The spring ensures that the flaps open fully whatever the condition of everything else
Just fit the sodding spring & have confidence that it'll do it's job!
The spring ensures that the flaps open fully whatever the condition of everything else
Just fit the sodding spring & have confidence that it'll do it's job!
Re: Cooling Flaps return spring.
There is no way the spring can fully open the flaps if the thermostat is stuck closed.
It will partially open.
I,d love to fit the sodding spring, if I had one. Thats why I,m asking these questions about the spring,
to find a work around.
It will partially open.
I,d love to fit the sodding spring, if I had one. Thats why I,m asking these questions about the spring,
to find a work around.
- 937carrera
- Posts: 1190
- Joined: 7th June 2013 - 11:54pm
- Location: North Yorkshire
Re: Cooling Flaps return spring.
Try one of these - it may need some fettling, but if you get it functioning then it's a proven solution for other type 3 owners - you're not the first person to have this problem
https://www.machine7.com/product.php?xProd=15119
https://www.machine7.com/product.php?xProd=15119
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
Re: Cooling Flaps return spring.
Yep. Just took a spring from a type 1 1600 engine I have.
And same amount of coils, so good to go, I,ll try it.
Result.
happy paddys weekend folks.
Tim
And same amount of coils, so good to go, I,ll try it.
Result.
happy paddys weekend folks.
Tim
- purplepeter
- Posts: 2338
- Joined: 8th August 2006 - 4:41pm
- Location: Bath, Avon
Re: Cooling Flaps return spring.
It's worth mentioning also that you must use the copper bellows type of thermostat, NOT the newer waxstat type, which fails by default in the closed position!
Re: Cooling Flaps return spring.
Thanks, have fitted a good old school thermo. cant be doing with the new fang dangled tat
Re: Cooling Flaps return spring.
Happy St Irish Sunday, I had my fuzzy head last night so I wont be repeating that again this weekend.
The sultan of swing