Cooling fan evolution 1200 through 1600 late.

[Zundfolge1432]

Been questions lately about cooling fans so I dug a few out just to illustrate how they changed through the years. What you'll see is as the engines increased in size so did the CFMs of the fan. The factory also addressed this by allowing more cooling air into the engine compartment in a number of ways. So then cars have been modified over the years by people that do not understand the design and or think they know better than the engineers that spent countless hours and millions of dollars to perfect the design. Then you have a segment of folks that should not have a wrench in their hand. You know what I'm talking about, there are many threads here that witness the absolute hackery of previous owners attempts to patch things up.

Problems also arise when you install a larger engine in an early car which does not allow for the extra cooling or they've bumped up the displacement of a 1300,1500 to 1600 and larger. So just look at the photos they speak for themselves and if you think you know better than the engineers by all means do your own thing. From left to right we have early 1200 with the far right being the widest fan 71 and up doghouse.

The oldest ones on the left have those holes as a means of cooling the generator. The newer models have a different backing plate which faces down to the extract the heat. It's possible to install that wrong and you find that too. Good luck trust in the engineering not some nameless faceless Internet hack giving you advice. Don't believe me either read the manuals.

[Mr.Duncan]

Solid post.

This should be a sticky.
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Red 1971 Squareback Thread
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1966 Ghia (sold)
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1966 Red Beetle

[Zundfolge1432]

Here's an example of Vw factory cooling this deck lid had the thermostatically controlled door to open for added cooling. The tennis ball trick works too, use it

[Mr.Duncan]

I use the tennis ball in the summer time here in Texas anytime its 85F + out.

Mainly since I like keeping my 71' two slot deck lid, but we all know that 4 slot 72-79' deck lid lets the fan suck more air in much easier.
_________________
(Owner) www.vintagecarleds.com

Red 1971 Squareback Thread
Red 1966 Beetle Thread
---------------------------------------------------
1971 Green Super Beetle (sold)
1966 Ghia (sold)
1971 Blue Super Beetle (sold)
1966 Java Green Std Beetle (sold)
1971 Red Squareback (sold)
1966 Red Beetle

[sb001]

Please explain to me how, if I have a single port 1600 running hot, installing a doghouse fan shroud fixes the PROBLEM.

Not the SYMPTOM, the PROBLEM.

Could have sworn that even in 1970 when VW was using the 1600 single port (you know the exact same engine I have) they still weren't using a doghouse shroud. Not until 71 when they went to a dual port.

The tennis ball trick didn't help me.
_________________
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

[Mr.Duncan]

[iowegian]

[Mr.Duncan]

[Zundfolge1432]

The pics only show the evolution of the fan and what the factory did to control heat. Without admitting a problem VW knew they had issues and this is evidenced by the continuous improvement of the design, they called progressive refinements. The other well known issue of burned or worse dropped number 3 exhaust is also answered by progressive refinement. It's just info to be aware of that's all.

[Joel]

I'll just throw a bit of outside info in here as its relevant but not widely known as in the North American market from 71 the only upright type1 engine you guys got was 1600 dual port.
In other markets like here in Oz and Europe Beetles were also sold in the 70s with 1200 and 1300 engines.

VW never made dual port engines with the old single port style internal style oil cooler, the heads just ran too hot, so the 70s 1300dp engines also ran the same wider fan and doghouse oil cooler as 1600dp
However, the 1200s sold right up to the mid 80s were single port and still retained the old narraw fan and internal oil cooler.
So if you ever get someones frankenstein engine that has DP heads with an internal single port style oil cooler, don't expect a long life from it.
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Quick little bug, you got a Porsche motor in that?
1974 Germanlook 1303 2.5 Suba-Beetle

[concepts12]

Hey Zundfolge1432

Thanks for the pictures of the fans.

Just you make it clear Are you saying from left to right you have a 1200, 1300, 1500, 1600cc fans

[Zundfolge1432]

I've slept since then but I think from left to right its 36hp, 40hp, 1500, then dual port. I like the dual port fan and the matching shroud w/oil cooler etc. given a choice I'll take 75 and up fan shrouds with the directional or throttle ring on the back, I'll use this on a single port as well. I like stock but am not against mixing the various years to make a "better" cooling engine when I can.
Maybe this is a form of progressive refinement?

[Frodge]

Great post! Now if someone could further the discussion of how the different tins keep the engine cool.

[Tim Donahoe]

Steve, perhaps the tennis-ball trick didn't help you because your smaller fan could only provide so many cubic feet of air, regardless of the amount of air it has available. Also, the offset oil cooler in the doghouse provides a separate cooling system and hot air exhaust. Moving the oil cooler into its own air flow arrangement, also eliminated the pre-heated air going to number three cylinder. Nothing wrong with that.

Look at modern home air-conditioner systems. In particular, the condenser unit on the outside of your house. The fans and cooling-coils on those are far larger than, say the ones from the 1980's. However, the larger fans on the modern units use about the same amount of electricity as the old, smaller units--but they are far more efficient at removing heat from the cooling coils.

In other words, sometimes bigger is better. In this case, a bigger fan provides more cooling air, thus reducing heat more efficiently.

On a 1600 motor that is larger, more heat is produced than smaller engines. More heat requires a better--larger, more efficient--fan to dissipate the larger amount of heat generated. The addition of an off-set oil cooler was just a bit of genius added to the mix.

Tim
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Let's do the Time Warp again!

Richard O'Brien

[Zundfolge1432]

Here's a pic shows difference between the newer 75 and up left side pic and the 74 and down shroud on the right. The one on the left has the throttle ring and another hose attachment. The second photo show the provision for the hose,but no hose. More progressive refinement. They are blasted and primed with self etching primer awaiting a top coat of rustoleum semi gloss black.

[Zundfolge1432]

Here's another fan shroud and its 71-73 because it doesn't have the provision for the hose.

[67rustavenger]

[goober]

On the doghouse fan housing, part of the fans output air goes over the oil cooler and out of the engine compartment.

Does anyone know what percentage or cfm of the doghouse fans output is diverted over the oil cooler?

[Glenn]

[JKLNHYD]