The Mezger or GT1 engine is renowned as one of the best and most reliable engines that Porsche has ever put into production. Since this engine was based on an air cooled engine (the very reliable and excellent 964 engine), water cooling had to later be added in the form of cooling passages outside the engine block.
These cooling housings are made of aluminum but have steel fittings for hose attachments. This is where the weak point lies: these steel fittings are glued in the aluminum housings and over time the heat from the engine weakens the glue, which results in the fittings pushing out of the housing with the hose still attached! Once this happens, engine coolant will spray over the engine and most likely also over your rear tires.
If you plan to take your GT1 engine to the track or have modified the engine to produce more power, we HIGHLY recommend first pinning the cooling fittings. This helps avoid a sudden loss of coolant and also makes the car much safer.
For more info on how to deal with cooling issues for these cars, please refer to this coolant system article that Scott wrote for our local PCA chapter or just give our shop a call today. Our mechanics will help you with everything from scheduling an appointment to getting any issues repaired as quickly and affordably as possible.