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I have done some important research regarding the importance of the engine tin/metal:

I hope this helps.


How to keep your Volkswagen Alive

A manual of step by step procedures

19th Edition

Author John Muir



Pg 430


“The engine compartment in a VW, along with the tin work surrounding the engine, is a closed system designed to keep air flowing around the oil cooler and cylinder and head fins. Anything that defeats this system will make your engine run hot. Air cooled VW engines run quit close to their heat limits to begin with so the margin of safety is small.

Keep ALL the tin in place , and make sure the seal around the engine is in place and well-secured.”


Pg 438


“If the upper part of the engine is not completely sealed from the lower half, not only will you spill valuable cooling air but the cooling fan will suck up exhaust gases and send it through the heater exchanges and into the car when you turn on the heat. These gases not only stink but can kill. And if the engine is on good tune you may not even smell these gases. Carbon monoxide, produced by all engines is odourless, tasteless and dangerous.”


Pg 361


“Air cooling: Air is sucked into the fan housing by a blower fan, which pushes the air through ducting inside the fan housing and over the heads and cylinders. Fresh air enters the engine compartment through louvers in the body or trunk lid.

Numerous sheet metal and rubber parts seal the edges of the engine against the body of the car. It is crucial that these pieces be kept intact. If the sheet metal piece that separates the front of the engine from the body is missing or fits poorly, hot air transferred from the transaxle will flow into the fan housing. If the apron or rubber seal that fits around the engine is out of place or even ripped, heat from the exhaust system will raise the temperature of the engine compartment. The little deflectors that fit between and under the cylinders and all other sheet metal protectors around the heads and cylinders are essential for proper cooling.”


The deflectors have been incorrectly replaced installed, there are no provisions for them to be screwed, they are hanging.




Pg 360


“If the fins around the cylinders become clogged with grease or even bits of litter hot spots develop.”


“The air - cooled VW engine depends on air and oil equally to keep it cool”


Pg 362


Every surface of the VW engine is part of the cooling system. Even the fins cast into the bottom of the case take heat away from the oil sump.”


One of the fins / body scoops at the bottom of the engine is missing or has been installed incorrectly, please refer to pictures.


Porsche 356

Service Manual


356  - 356 A - 356 B - 356 c


Pg 26




“The fan sucks air through the intake hole in the housing and directs in .downward over the heads and cylinders which are finned for greater heat dissipation. Metal shrouds contain the airflow and guide it properly”


One of the fins is missing or has not been correctly replaced, this is not helping with the heat dissipation. The metal shrouds are not fully bolted, this is not containing the airflow and not guiding it properly.


There are holes in the fan, these holes were created when the accelerator cable was repaired / replaced by the mechanic. The holes in the fan affects the suction capacity of the fan that sucks air through the intake hole.


Pg 26


Oil Cooling and Pressure


“The oil cooler is mounted on top of the engine and is under draft from the fan. Oil goes directly from the pump to the cooler through a by-pass valve. Regulated by pressure (viscosity) the valve either permits oil to be cooled or not, according to need. A warning light on the instrument panel is activated by a pressure device installed in the line between air the pump and cooler. If pressure drops below 6 to 8 lbs per square inch, the lighter will glow.”


As hot air and gases have been entering the engine compartment, the fan has been sucking hot air and gases through the intake hole, This has compromised the cooling function of the oil cooler. The light has been glowing when I start the car.


Pg 26


“Oil Circulation


Lubrication is maintained in a pressurised system. Oiling in the Porsche plays a greater part in heat-dissipation than it does in the conventional water cooled engine and is controlled more rigidly. The oil pump is in the crankcase and is driven from the driving end of the dam. Oil is taken from the lowest point of the crankcase and is forced into the lines by way of the oil cooler. Part of the lubricant is forced into the crank bearings, through the hollow crank and into the connecting rod bearings. Another part goes to the cam bearings, a third portion enters the hollow pushrods and flows up to lubricate the rocker arms and valve stems. Cylinder walls and pistons are splash-lubricated. Oil returns to the crankcase where it is cleaned by a strainer and magnetic filter before renewing its journey. A replaceable- cartridge is also in the system.”



Pg 191


“The inlet valves on the normal engine are vertical and the exhaust valves inclined, both operated by pushrod and rockers, a single camshaft centrally placed above the crankshaft having four cams on it which operate the eight valves, each cam working opposed valves. The whole principle of the engine is like the VW, which is not surprising as Dr. Ferdinand Porsche designed that particular vehicle, and the air cooling effect by a large fan on top of the engine and driven off the dynamo. This fan blows air through ducts to close-fitted shrouds around the cylinders and heads, the hot air escaping underneath the car.”


Pg 191


“ for no matter what the road speed the faster the engine runs the more cooling there is to the oil; this also applies in traffic driving”









There can be only one...!

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You'll find that FF/CMC and VS all had opening in the cooling time above the transaxle.  In addition to that open area, there was a piece of fiberglass cut to allow more air to the cooling fan in the shroud.  The engine lid grill with the rain shield does not provide much air to a bigger than a stock engine.  Even Porsche recognized that more air was required and they added a second rear grill in '62/63.  VW also did the same and added vents to the engine deck lid to supplement those vents below the rear window.  Many here also had louvers to the rear engine lid or make a prop to hold the engine (in the hot summer)  open 2-3 inches.

Image result for vw dune buggy air scoop


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  • blobid0
Highlander356 posted:

This topic is critical.

People have died due to this problem.

You can all joke about this and go on about your experience etc etc...

If you know of any reputable books or source material let me know.

i also have experience using the toilet bowl, unfortunately it doesn’t make me a plumber.

You just pulled information from how many pages of information from John Muir’s book and you’re asking for reputable material????

If Muir’s book isn’t reputable I don’t know what else is. 

And please reference one incident where someone died because they’re engine didn’t have proper cooling. 

You’re a bit dramatic. 

Engines have died due this problem.

I did several searches and could not find an incident where a person died as the result of an overheated air cooled VW or Porsche engine. Maybe I conducted lame searches.

If an engine compartment got excessively hot and the fuel filter melted that could mean a fire and maybe a driver or passenger couldn't get out and died. I tried that search too. Bupkus, nada, nothing, zip, zero.

Perhaps you could provide an example of this happening?

Last edited by Panhandle Bob

I've been avoiding this thread for a couple of days. I had put up and taken down a pretty incomplete and unkind response. I'm going to try to be more complete and reasoned with this one.

Like motor-oil, this is a subject where people have very strong opinions, but none of us (or anybody else) has any real data to back up those opinions. I'm not immune to the "everybody is entitled to my opinion" way of looking at things, so here's how I see it:

The Muir book is great... for guys with 100% stock VW Type 1s, and no background working on machinery of any kind. The title says it all: A Manual of Step-by-Step Procedures for the Compleat (sic) Idiot. While a lot of guys look at the Muir book as being the Bible of VWs, it's really a lot like the "Dick and Jane" books you likely learned to read with-- good, insofar as it teaches a person what they need to know to gain more knowledge, but not the final word on anything.

If you look at the Type 1 engine objectively, there is some real Rube Goldberg engineering, and all of it is centered around cooling. The oil relief pistons and flaps-n'-stats are the most Micky Mouse parts of an otherwise elegant design. It works, for sure-- but there would be no engineer anywhere in the world who would (or could) say that this setup is not prone to problems and ultimately to failure. It was the best Her Doktor could come up with at the time.

As I said above-- nobody has any hard data to provide a definitive answer to say, "this is best"-- just opinions and observations regarding what has worked for each of us (individually), and others (collectively). As it pertains to cooling, I truly doubt that even the Sainted German Engineers had the measuring capability to fine-tune the airflow across the heads and oil cooler back in the 30s and 40s (when the cooling was being designed), since the ability to do so was not even invented yet.

The title of this thread is "Air Cooling Research", which is a bit of a misnomer. "Research" means one of two things:

  1. Literary Research, which is pulling together information (considered opinions) from various sources, and collating them into a single cohesive narrative. I would submit that cutting and pasting from a single book written 50 years ago, by a guy who could not even spell trying to explain to "compleat (sic) idiots" how to work on an economy car. Such "research" would get an 11th grader a failing grade on a term paper, as does not rise to the standard of good literary research (3 or more independent sources).
  2. Scientific Research, which is performing experiments and looking for clues regarding why things act as they do. This is a lot harder than literary research because it involves accurate measuring tools and an open, inquisitive mind. It requires training in whatever discipline is the subject of inquiry, and involves lots and lots of time and work. It is my belief that the Sainted German Engineers with their labs and time did a bit (but not a lot) of this kind of research. Once they had something that worked well enough, they left it pretty much alone for another 45 years.

I'd love to actually see some scientific research into cooling, because at best, all we've got to work with is literary research. We all do what we think is best, based on the experiences we've had personally, and what we read from other people. Jake Raby did some actual scientific research into cooling systems about 10-15 years ago, but it was so expensive and took so much time that he was reluctant to give the data away. Some of us just took Jake at his word (because he generally doesn't blow smoke), but this is more faith than science.

The thing about the internet is that anybody can say anything, and if it sounds good, it's repeated until it becomes the accepted narrative. Gene Berg was a really smart guy, but he didn't know everything. The same can be said for all of the luminaries in the hobby today. All of them would readily admit that they know a lot, but have a lot to learn. This is what makes them good at what they do.

What I can say for sure is that almost all the good trial and error effort has gone into how to make more power, not in how to cool better.

That's a shame. Good research would be invaluable to all of us.

Last edited by Stan Galat

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