Q – My 1968 912 is running hot. My mechanic suggested that the oil cooler is clogged since I live on a dirt road and for quite a while, the engine compartment gasket wasn’t doing it’s job. I believe him but wow is it expensive to take it all apart. I guess I should be glad that it is not a 911. Peter
A – Well I agree with your mechanic. His method is foolproof but expensive. But I have had some success by using a chemical called “Gunk Engine Brite”. I sprayed it into the cooling fan on a cold engine (about ½ can) and then let is sit and soak in for about an hour. Then I started it up and held the engine speed to about 2,000 while spraying hot water into the fan. No, the engine did not stall (I was surprised) and once the process was complete, the engine ran at normal temperature, never exceeding the ½ way mark on the gauge. As you would expect, this was a fairly cheap, “Band Aid” process. My client and I were tickled pink that he could spend his money on other fun projects. Hooray!
If this does not work in your case, you better consider avoiding long drives and changing to synthetic oil that can tolerate a lot more heat than regular oil. I have seen oil coolers expanded to the point that the vanes in the cooler were so bloated that air could not pass through them. Oh yeah, and about the question of the faulty gauge…trust the gauge and save your engine. – MC