Does anyone know much about the thermostat on a bug. Is it possible to simply remove the levers etc from the shroudand simply allow full time air flow to the fan? Idont drive the bug in the cold so just curious if this is possible ?:beer

im surprised u still have one fitted

most ppl rip them off during rebuilds, so most of the vws getting around dont have them anymore and the ones that do very few still have working thermostats

the thermostats are almost impossible to get now as they are a NLA part and good 2nd hand ones are rare

even if ur thermostat is dead a few ppl say its agood idea to leave the flaps in as they direct air to the heads

but i'm abit sceptical on this as when they are fully open they are perfectly vertical so it makes no differnce if they are there or not

ive got a working setup on my bug only coz i got a perfect thermostat off ebay but even in the middle of winter it doesnt make much difference about 2 mins and its fully open

they were designed for snow temps in germany

-Joel

I've seen those thermo jobbies on maybe three engines in 20 years.. you'll be fine without them

Many thanks. Thought was probably the case as its for a convertible that only gets driven in warm weather !

Hi,
Most VW Mechanics say the flaps should be left in, as they do direct the air
to where it should go..
they do just point down as You have said,
but without them being there the air can go where it wants to..
I agree...
I bought a new thermostat kit from the USA and have fitted everything except the thermostat itself..
it does get cold here in the winter, so I will fit the thermostat then...
also because I run My engine lid open at the top, the engine would tend to run a bit cool in the winter...

Do You want to know what happened to all the thermostats?
At the first service the VW Mechanics were instructed to take them out and chuck them away...
same thing happened in parts of the USA too..
so, most engines are doing without them...
but with temps below zero in winter, it has to better for the engine...

cheers

Lee - 68autobug - Scone.

http://community.webshots.com/user/vw68autobug 

Hmmm interesting. My main worry was if I kept the flaps in without the thermostat they might inadvertently end up in a closed position at some point and cook the engine....assume if the connecting rod is removed that links the flaps then this cant happen?:beer

Taurine,
The genuine VW ones fail in the "open" position, so no probs.


Ctefeh

There is a very good reason for leaving them in: they allow the engine to warm up quickly to normal operating temperature, which is important for getting the oil flowing properly. If yours is missing then your engine takes a long time to reach normal operating temperature, and therefore it is suffering from increased wear. Bottom line is the thermostat and flaps make your engine last longer.

Make sure the spring is still attached to the bar at the back of the fan housing...
the spring will keep the flaps open all the time...
make sure you have little circlips [e type] holding the shafts to the bar.. or some VW type round clips..
I have had 3 different clips on the shafts... none fell off,
but during My pulling the engine out a few times and repainting the fan shroud etc.. I didn't like the wire clips,
the e type circlips were Ok and the round push on, never come off clips should be the best...

If You don't have the spring, just use any spring that will pull the flaps open all the time...
if you don't have the flat shaped bar that holds all the flaps open, just clean the shafts from the flaps so they are very clean and apply some silastic to them...
I did this with mine...
then I found a bar and spring, and had to remove the silastic!!
and now they are attached to the rod poking underneath the engine waiting to be attached to a new thermostat..
with the spring keeping the flaps open all the time...

cheers

Lee

http://community.webshots.com/user/vw68autobug 

[ Edited on 14-11-2006 by 68AutoBug ]

hi folks, thanks for all the replies. Looks like I will keep the flaps in. The thermostat is long gone but the bar and spring are still there and 3 of the 4 clis were attached so Ive made a new clip and I've tested it a few times and it positively pulls flaps to the open position and they stay there so all is well! :beer:beer

everyone reckoned they werent needed in average climates
only in snowy germany like i said b4

i have seen an engine fried by faulty thermostat flaps
as usual the thermostat had long since given up which is fine but over the years the vibration wore the hole the return spring goes thro bigger and bigger till it finally wore all the way thro and they fell shut

i took a few pics a while back when i put them back on my motor
but even in the middle of winter ive noticd no difference what so ever
its fully open with in about 3 mins
and it only regulates flow to the cyinders and heads not the oil cooler so the oil is always being cooled









this spring must be in good condition and the hole in the rod and tinware in good nick or ur in big trouble


the stats on the left are all buggerd the one on the right all compressed is good


-Joel

Hi Joel,
Well You have more thermostats than most people have ever seen...
I will admit that the thermostat , bar and spring wasn't really made to last long time, and they don't really look like they were engineered to last..
no bushes for the bar or flap shafts, the hole for the spring in the fan shroud wore away, if the spring didn't wear thru first.. and the most important part, the thermostat was held on with one bolt...

The oil doesn't go thru the oil cooler all the time...
I was just reading My bentley manual, and it shows the 3 positions of the oil pressure valve...
very intersesting...

I can also remember reading an Article by Larry Perkins who Rallied Beetles in Car Rallies years ago, and He said "VW spent a lot of money on inventing the Beetles thermostat, so they should be left in place"

I also know many people who discarded their thermostat flaps years ago, and the engines don't seem to have suffered without them...

cheers

Lee Noonan

Did the last of the Mexican Beetles run them? (thermostats)

i did end up finding a bit of info on the new style ones
but theres not much of it and i havent heard to many positive reports on them

-Joel

[ Edited on 13-12-2006 by DUB74L ]

What this thread needs is some facts.

Here is a graph showing the heat-up curves for a VW engine with and without the thermostats. I'm not sure what ambient temp it is.


The critical time is the time required to heat the cylinder above 70 degrees. This is because the most wear occurs below this temperature. Below 45 degrees is very bad because you get combustion by products condensing on the cylinder walls (like sulphur trioxide).

You can see there is almost no difference in time required to heat the cylinder above 70 deg C, therefore I'd say the thermstats don't do much for normal warm-up.

This next graph is a VW driving along a hilly test circuit with an outside air temperature of a very cold -5 deg C!!!


You can see the thermostat has a lag to respond. So with the thermostats it makes the engine run hotter. But, on the long down hill runs it also stops the engine getting too cold. The engine without the thermostats actually ran for 6kms with the cylinder temp below 60 degrees (causing excessive wear). But remember, the outside air temp was -5 deg C.

So if you are in QLD I would say you'd be better off without them (because you don't want the lag and high temp spikes). In you live in Tasmania then you probably don't want your cylinder temp getting too cold, so perhaps you should run them.

So there is no clear answer

Info shamelessly copied from Air-cooled Automotive Engines by Julius Mackerle (former chief designer of Tatro motor works).

I don't really want to sound argumentative, as the Julius Mackerle stuff is really interesting. However, the book was first published in 1961 and then updated in 1972. Would his tests be on the old thermo system of the later one? I think there would be some difference.

I do remember reading in one of the official VW maintenance manuals that the thermo system was effective even in hot or warm climate conditions, though it is obvious that as the ambient air temperature increases so the 'effectiveness' decreases. It may also be a case of some obscure VW thought processes, which they were very good at implimenting but very bad at explaining.