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Cooling Flaps - revisisted
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PostPosted: Sat Nov 27, 2004 7:13 am    Post subject: Cooling Flaps - revisisted Reply with quote

My cooling flaps are having problems, once I attach the wire cable and rotate the lever rod; the left flaps "U" clip disengages from the rods attachment “U” clip. I'm not sure of how the whole mechanism works, except as the bellows heat up, the cable is lengthened. My Bentley cooling parts diagram seems to show the "U" clip facing rearward.

What is the proper setup for the cooling flaps?

When properly assembled, does the actuator rod close the left flap with a flush seal against the oil cooler shroud or will there be a gap?

Thanks
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ratwell
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PostPosted: Sat Nov 27, 2004 11:47 am    Post subject: Re: Cooling Flaps - revisisted Reply with quote

[email protected] wrote:
My cooling flaps are having problems, once I attach the wire cable and rotate the lever rod; the left flaps "U" clip disengages from the rods attachment “U” clip. I'm not sure of how the whole mechanism works, except as the bellows heat up, the cable is lengthened. My Bentley cooling parts diagram seems to show the "U" clip facing rearward.

What is the proper setup for the cooling flaps?

The cable stays the same length but the thermostat expands and this allows the flaps to move. You tighten the cable in the flaps closed position (max spring tension) and when the engine warms the flaps slowly open to the horizontal position.

The early Type 4 had a spring steel tab on the fan shroud to keep the rod in place:

http://homepage.mac.com/ratwell/.Pictures/Parts72Bus/31-FailsafeSpring.jpg

Quote:
When properly assembled, does the actuator rod close the left flap with a flush seal against the oil cooler shroud or will there be a gap?

The flaps are different left to right:

http://homepage.mac.com/ratwell/.Pictures/Engine2/06-AsymmetricFlaps.jpg

The passenger side flap is either closed or open. The driver's side flap looks open in the closed position but in fact it's not deflecting air into the cooler to allow the oil to warm.
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PostPosted: Sat Nov 27, 2004 7:21 pm    Post subject: Re: Cooling Flaps - revisisted Reply with quote

[email protected] wrote:

What is the proper setup for the cooling flaps?


How timely.
(I should wait for Sylvester75Westy or VWBusKid to answer this question for their final exam grade, since we were assembling Sylvester75Westy's engine today)

The Type 4 engine's right flap makes sense. Up is open, down is closed.
The left flap, however, looks opposite but isn't in fact. The left flap is open when pointing down. It divides the airflow in half, the air under the flap is directed directly into the oil cooler, the air flowing above the flap cools cylinders 3 & 4. When left flap is sticking up, it blocks 3 & 4 in a fairly apparent fashion, but the trick part is that the bottom of flap loops around and chokes off the air to the cooler as well.
Your link rod, the u-shaped deal, has sweged ends to hold it in the flap clip and the little intermediate link. Pinch the slots so the u-shaped rod can't escape. To orient the intermediate link and the flap and the actuating lever, move the actuating lever, the one that goes right across the engine, to the closed position, i.e. cable pulling it down, and lift up the left flap, the intermediate will then swing in the correct direction.

WARNING: Do Not Tighten Cable With Flaps Closed, as mentioned in the Bentley, unless you know your thermostat is correctly contracted!

To ensure proper cable adjustment, get under the right side of the cold engine and check your stupid thermostat which was not mentioned in the Bentley. Pull cable end of t-stat towards front of car against mounting bracket, does it contract like a little accordion and pull the cable when you do this? BAD thermostat, bad! You may go ahead and tighten cable with flaps closed with the thermostat squeezed. Might need an assistant to do the squeezing chore while you muck with the cable clamp. If you have a good thermostat, the cable end will already be as far towards the front of the car as it can get, and then the Bentley instructions are OK.
If you follow the Bentley instructions with a bad thermostat, your engine will die a horrible death with much smoke and terrible sounds of anguish and gnashing of valves and connecting rods, a pestilence will be unleashed upon your oil cooler. . . .
Colin
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VWBusrepairman
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PostPosted: Sat Nov 27, 2004 9:24 pm    Post subject: Reply with quote

Or just run it without the cable. The engine will heat up without the thermostat. I have a stack of old thermostats. Never have I ran one on the 2 liter.
I fire it up, take the time to roll a smoke (pretend smoke since I'm a non smoker) and I'm off to work/ school/ wherever.

Thermostats on air-cooled engines...hmmm.
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PostPosted: Mon Nov 29, 2004 9:04 pm    Post subject: Reply with quote

Found one the problem, the Left flap was bent somewhat, so swapped with an extra, fixed the problem. Also reversed the direction of the "U" clip so the swaged tips faced toward the left of engine:?:

For the thermostat, I'm good per the heat test from the Bentley manual. To adjust the assembly will rotate the link rod forward (right closed); attach the cable, that's it?

Thanks again![/quote]
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Amskeptic
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PostPosted: Tue Nov 30, 2004 10:18 am    Post subject: Reply with quote

If your tstat is properly contracted, yes. I recommend that you hold the tstat bellows compressed as you secure the cable on your downwards facing lever. Check it for opening properly after warming up the engine. You can't be too paranoid. . . whose following me here?
Colin Very Happy
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VWBusrepairman
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PostPosted: Tue Nov 30, 2004 10:53 am    Post subject: Reply with quote

Amskeptic wrote:
You can't be too paranoid. . . whose following me here?
Colin Very Happy


Not to sound direspectful to you, my father-figure Colin, but is the tstat necessary? I mean for real...I've never had one...please enlighten your lost son.

Thanks,
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PostPosted: Tue Nov 30, 2004 12:40 pm    Post subject: Reply with quote

Lack of a thermostat will result in increased cylinder wear (aka lower compression over time) in all but the hottest climates. If you are breaking in a new engine you better have a thermostat attached no matter where you live.
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Schmooey
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PostPosted: Tue Nov 30, 2004 2:24 pm    Post subject: Reply with quote

I confess!
I don't have a thermostat on my bus.
My 67 bug ran for hundreds of thousands of happy miles without one, but the warm climate here may be a factor. Perhaps in the snow belt it's a big help, or in order to be TC (technically correct), but I'm not convinced.

As a matter of fact, I've owned about 20 aircooled motorcycles that lacked this feature, and they didn't seem to suffer too much. My BMW 750 had over 175K miles and the bores were still almost perfect. My brother is rebuilding his Harley 74 this week for the first time since he built it in 1973.


Last edited by Schmooey on Tue Nov 30, 2004 2:34 pm; edited 1 time in total
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PostPosted: Tue Nov 30, 2004 2:32 pm    Post subject: Reply with quote

Schmooey wrote:
but I'm not convinced.


How many German VW engineers would it take to convince you?

All of them?
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PostPosted: Tue Nov 30, 2004 2:50 pm    Post subject: Reply with quote

Well,
I'm not so sure nationality matters, but my German Zundapp and BMW motorcycles must've been designed by Germans. Neither had a thermostat. The BMW MC engine predates the VW by decades, and are legendary for high mileage.
My point is that preferences are sometimes personal and formed by exposure to many influences.

BTW, those sainted VW engineers waited quite a while to add an oil filter more useful that a piece of wire mesh. Some of us replace the points with Hall-effect modules and few of us are willing to live with the stock muffler.
We all inject our opinion into our hobbies. I enjoy radial tires and an FM radio as well. Wink
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PostPosted: Tue Nov 30, 2004 3:32 pm    Post subject: Reply with quote

How many persons in this forum are engineers? Anyone trained by Volkswagen as either an engineer or technician?

I want to see documented proof where a type IV engine requires a tstat for longivity.

I can only contribute my experience (as I am no mechanic, just a guy who builds type IV engines)- which has been without that worthless little thermostat. I start my engine, allow it to build oil pressure and off I go- never had a problem with worn cylinders, etc. I have only experience with a 2 liter, FI engine in a '78 Bus. I don't know about other engines.

Information please, men & ladies
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PostPosted: Tue Nov 30, 2004 8:36 pm    Post subject: Reply with quote

I too would like to see a definitive answer to the question of whether or not a thermostat is needed.

I'm not an engineer.

I do know that Bob Hoover and Colin agree with the folks who actually designed these engines that the thermostat and flaps WILL make the difference between a short and long lived engine.

I'm not willing to take a chance and leave these things off my engine. They're not there now because the guy who built my engine swears they're not needed. They will be soon. I bought the missing parts from a couple of vendors and they are the next project on the list. I won't drive my van until this system is installed and properly adjusted.

I would like to hear from anybody with over 100,000 miles on their sans thermostat engine .

We all know that improvements can be made on 30+ year-old technology. Better seats, seat belts, etc. I doubt engine temperature control is an area we can simply delete.
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PostPosted: Tue Nov 30, 2004 9:01 pm    Post subject: Reply with quote

Schmooey wrote:
I'm not convinced.


one of the most significant reasons you need a thermostat on a type IV engine'd bus is because of the way the cooling flaps control the airflow to the oil cooler. without the t-stat you are getting maximum airflow to the cooler even with the engine dead cold, so the crankcase oil will take much longer to reach operating temperature. with the t-stat in place and cable correctly adjusted the flaps modulate the amount of air flowing over the cooler depending on the temperature of the engine.

richard is right about this over-cool oil inducing engine wear, and the engineers got it right to include the thermostat. anyone who has ever closely examined and understood the functioning of the cooling air flaps would never remove the thermostat.
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PostPosted: Tue Nov 30, 2004 9:25 pm    Post subject: Reply with quote

I'm not saying that the thermostat isn't useful to speed warmup in cold weather, and it may prolong engine life to some degree. No, I'm not trying to convince anyone else to leave it off.

The climate in my area is very mild, and I drove my very first car, a 1967 Beetle, for 245K miles. I rebuilt the engine at 115k miles because the oil pressure light stayed on and it was running crappy with a leaky#3 exhaust valve. When I pulled the engine apart, I couldn't find a thermostat. Apparently the PO removed it, as many VW fans did back then in the early 70's. As a matter of fact, I asked shops about the need for one and the consensus was, "You don't need it, and if it screws up your engine will fry."
Not my idea, but the prevailing wisdom at the time.
Image may have been reduced in size. Click image to view fullscreen.


When I sold it to a Swedish student 130K miles later, it still ran pretty darn well. When I bought my 71 Westy eight years ago, it had no thermostat, and my experience with the Beetle kept me from worrying about it.

I agree that the thermostat is an important part of the ACVW engine. No one should forgo this important part, just because I do. My confessed heresy is limited only to Type 1 engines.
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PostPosted: Wed Dec 01, 2004 6:27 am    Post subject: Reply with quote

I have a few thoughts about that infamous statement I have heard or read about 100 times..That statement "smarter than the team of Engineers". Well, for one I'm not a big fan of catch all phrases, but using that infamous term in reference to something like the T-stat assumes that there main reason was for engine longevity. And the other popular statement that goes along with it "VW wouldn't have put it on 1000's of vehicles a day if it wasn't needed". Well, consider this, in colder climates it will make the engine warm up and run more like the mass american market was used to,, maybe that is why they put one on 1000's of vehicles a day, could you imagine the dealer explaining to a potential buyer how this car warms up like crap cause we have maximum cooling all the time, we didn't want to spend the money on a t-stat.
Come on people, think out of the box, Bob Hoover is not a GOD.
Edited to add this,, also, maybe it was installed for emission too....
The oil being colder is going to make the engine parts wear that much more???,,,go pour some oil on a peice of metal when it is below 50 outside and see if you stick to it or slide???
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PostPosted: Wed Dec 01, 2004 12:05 pm    Post subject: Reply with quote

I'll jump in here! I'm in Iowa and it gets as low as -35° F and as high as 100°F! At low temps even 10w oil is like honey and the pump may cavitate and pump nothing. This is especially a problem in my Vanagon diesel, but that may be an extreme case. the oil light will come on repeatedly for the first minute.
Oil really needs to be at about 180°F to be effective. It needs to get hot to boil out gasoline and water from condensation.
To compare your Zundapp (is it a 4 cycle Zundapp?) or BMW motorcycle is not very relevant because they are not used in very cold temps and were never designed to use cooling fans.
Thermostats fail in the open position anyway. People who leave them out wreck engines more than any positive benefits.
Sure, it works in Souther California, but what if you drive up into the mountains for a few days? Every time you start it could you get some gasoline in the oil.
What is the upside to this except about $20 worth of parts and mostly being hardheaded?
There is extensive documentation I have seen of damage from engines running too cold.
And yes, Bob Hoover IS god (small g)!
Al
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PostPosted: Wed Dec 01, 2004 12:43 pm    Post subject: Reply with quote

This really is a religious cult! Laughing

I'm doing what has proven to work for me over a course of many years and miles between 1972 and 2004. If you disagree, I won't call you a hardhead for having a different point of view. I would definately use a thermostat to get the oil warm in seriously cold weather.

My BMW ran well in Alaska, Minnesota and Wyoming snow. Warmed up fine after a minute or two, not much slower than when camping in the desert.

Not trying to insult anyone with different views or attempting to change them. Apparently there are other heretics among the crowd.
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PostPosted: Thu Dec 02, 2004 11:29 am    Post subject: Reply with quote

I'd like to give an engineering approach on why the VW engineers opted to use a thermostat.....(I am a mech eng, and believe it or not we are trained to think of things in a certain logical way). But of course it is only my opinion.

a) For an application such as this, the physics must back it up.
And we already agree that it does - i.e. the oil will reach operating
temperature quicker - less wear etc. This can only be good

b) The original beetle was to be the 'peoples' car. The average person
didn't want to sit in their car to wait for it to get up to temperature.
They wanted to zoom off.

c) They may have known that it was more needed in the colder climes of
harsh winter in inland Europe/US than the SoCal desert areas but it
would most probably have been easier to keep it standard. Different
options can be a nightmare to control

d) Once it was within budget, and proven to be of SOME assistance, they
would have moved on to something else

In summary, there are many things that an engineer will factor into a design that may or may not be needed all of the time. Especially when the 'people interaction factor' comes into play. Not having a thermostat may not make much of a difference for say a VW industrial engine, which might be operating under steady loads for continuous periods every day.
Nor may it make as much as a difference for the average person who is reading this, for they are likely to be the type of person who is some way VW knowledgeable. But for the millions of others out there who aren't engine savvy, and who operate their equipment all over the world in different climates, it would have been seen by VW as a useful addition to aid the longevity of their engines.

Rob
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PostPosted: Thu Dec 02, 2004 6:16 pm    Post subject: Reply with quote

Many of the other systems in a VW are designed around the thermostat. The choke opening rate, the preheated air thermostatic valve, the fuel injection system, the central idling enrichment box and thermostatic accelerator pumps on the dual carb buses, the distribution of cooling airflow between the barrels and the heads not to mention the oil cooler on all Type 1 engines, the oil pressure relief valve, all depend on a functional thermostat. So does the crankcase breather which can gum up with condensation-induced sludge. My current crankcase (at 391,378 miles), original crankshaft and connecting rods (which were within spec at 419,000 miles), and my original cylinder heads (at 473,000 miles), all have given me many more miles than I ever expected. How much of this absence-of-wear was due to a functional thermostat? I don't know. Are there any others here with 400,000 miles on their non-thermostatted VW engines to help figure out if my thermostat contributed to longevity? I can vouch for the fact that my car has given me 25 years of excellent cold weather driveability which I think stems from the thermostat's contribution.
Colin
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