[JFP in PA]

Originally Posted by rock88hard

JFP have you ever heard of or tried the Pentosin G12? On Amazon it's rated 5 out of 5 stars and there are a few comments of 911 and Cayman owners saying it works great. Amazon.com: Customer Reviews: Pentosin G12 Coolant For Aluminum Engines (1.5 Liter)

A lot of poeple say a lot of things work; unfortunately, we have also seen several brands that did not and resulted in one Hell of a mess where the coolant should be. The problem is that it is very difficult to get all the coolant out of these cars without doing multiple refill and dump flushes with clear water. Once the system is fully flushed (like three times), there are several compatible coolants that will probably work fine, but if the system is not fully flushed clean you could be running a risk.

Second issue is that a lot of shops only use the Porsche coolant (mine included) simply because it is a very capable and long lived product, and obviously totally compatible with the car's alloys. The OEM coolant is well known for not behaving well when mixed with some other coolants, so we only add distilled water to cars we do not know the history on. Not all shops do this, so it is possible that a shop could add Porsche coolant to an otherwise clean system that has another brand coolant in it, and promptly gell the system.

As I said, we only use the OEM coolant; it performs very well, lives a long time if installed in a clean system and only mixed with distilled water. It also in not all that expensive, and readily available.