Because of all the extremely inaccurate articles and rumors, we have made thousands of temperature tests since 1971 and will continue to do so. These tests were quite eye opening and verified that the stock VW parts created the best cooling unless you were willing to spend far more for the cooling changes than the complete car was worth.

Our temperature tests showed that the VW was so well engineered that practically every change we made to the cooling system from stock ran much hotter. When we tested air flow inside the fan housing and cylinder shrouds, every change from stock reduced air flow to one location or another, causing higher temperatures at one location or another.

Removing the oil cooler inside of the fan housing (through 1970) raised the temperature at the 3/4 head as much as 50 degrees F above normal. That's right, it went up by 50 degrees, not down like the people selling outside coolers would like you to believe. In fact, upon looking at some of the ads for outside coolers they stated that the 3/4 head changed by 50 degrees, and never stated that it would cool better than stock. Air pressure (flow) was drastically reduced at the head and increased at the lower part of the 3/4 cylinders.

Even 1 and 2 temperature went up due to the lower restriction on 3 and 4. Further investigating inside the fan housing revealed that VW's air vortexes and directional vanes put the air in the exact locations needed at the correct velocity and that the cooler must be in place to direct the air over the cooler and along the top of the fan housing. This straightens it out to go down straight through the head and cylinder fins with the highest efficiency.

We even discovered that the thermostat shutters are directional devices to direct air to the proper locations through warm up and also when they are opened all the way to direct air to the most critical areas.

Speaking of thermostats, removing the shutters and the thermostat increases engine wear 15% to 17% and often causes cracked heads even in southern California. Naturally, the percentage is much higher in colder areas. The internal engine parts cannot heat up and expand together at the proper rate when the thermostat is removed.

The inside grows from heat and the outside is being cooled far too much and is kept small. This means valves, guides, piston and cylinders, pins and rod bearings are all being subjected to stress and abnormal wear without the thermostat and shutters. After all, you don't take the thermostat out of your new water cooled car do you?

The dog house oil cooler and bigger fan (100 CFM more air that will not fit most aftermarket fan housings) set-up introduced in 1971 proved superior in all tests by as much as 70 degrees F over aftermarket coolers or fan housings. It is even superior to the one that is made and imported from VW of Brazil that uses the smaller early steel oil cooler rather than the bigger aluminum cooler we normally see in the USA.

This is partly because the fan that fits the genuine VW dog housings is wider and supplies far more air. Every test was better by at least 30 degrees F. And the next best was the pre 1971 fan housing stock cooling set-up.

One interesting note was that when I installed the 1971 system in my 1967 VW, I had to add more air intake. The convertible louvered trunk lid was required to get full cooling benefit and take advantage of the higher CFM fan. Yes, I realize that these lids are hard to find and suggest propping the trunk lid open a couple inches at the bottom if you do not have the convertible lid.

Again, my suggestion is that you solve the overheating problem of the engine, which is causing the oil to overheat. After all, if your Chevy was overheating it�s unlikely that you would put an extra radiator on its roof, so why put a bandage on your elbow for the sore on your knee to fix your VW? The only thing that can cause overheated oil is an overheated head. Even if you cool the oil, the head temperature is still running far beyond normal, as you never fixed the source of the overheating problem. I have never experienced any overheating of any engine with the correct CR, carburetion, timing, distributor, and proper octane fuel regardless of HP output even 200 HP daily driven.

If you absolutely must hang a cooler on your car, ADD IT to a full flow system (remember, full flow comes directly from the pump) and maintain the original stock oil cooler. Do not substitute it for the original.

The more we tested, the more apparent it became that the heads are the source of the heat. We found the CR and volumetric efficiency of the engine is a large factor. When heads, CR, carburetion, exhaust and cam are all correctly matched to the engine so the volume of fuel (proper octane) and air is what the engine wants, the engine runs cooler and lasts longer. For long life, we recommend conservative compression ratios, especially because pump gasoline quality has been going down, down, down from the good old days.

Remember, in 1974 you could still get Chevron White pump gas that was rated at 103 octane and Union 76 purple gas that was around 104 octane and they had 3.0 grams of lead per gallon average. In those days we had street engines with 10.0:1 and even used power pulleys without cooling problems. For more about cooling order GB 801-COOLING, GB 801-CR, and GB 801-HEADS.

Note: I have had many people make adverse comments about my cooling and CR tests and recommendations. It is obvious these people do not daily drive an air cooled VW for over 100,000 miles of testing or have not considered that I do not make any money by recommending that you keep your stock cooling system that you likely already have or lowering your CR to match the octane of the fuel. I am committed to your engine running correctly and living as long as possible.