[JFP in PA]

Originally Posted by saturk

I have followed the various questions regarding Boxster coolant. A new owner of a 2001 S, 80k, purchased in Oregon, but live in Helena, MT. Did a a dumb thing bringing the car home. Before leaving Oregon, the coolant level light blinked and the coolant level was below the level on the coolant reservoir. Being ignorant, purchased a gallon of PEAK 50/50 and proceeded to, apparently, overfill the tank. No problems until 650 miles later, at home. After driving it from Oregon all the way home, and after driving thru rush hour traffic, I stopped the car at home and had the proverbial anti-freeze dump from the system overflow tube. This lead to more PEAK 50/50. Then discovered the 986 forum and the coolant discussions. Had one more incident of blinking coolant light, and brought coolant level to minimum with distilled water. A new cap is on the way. No problems since. I am a long ways from a Porsche dealership and not sure about the potential independent in the area. Not wanting to flatbed it to Spokane with oatmeal in the engine as the worst case consequence for my actions, should I do a coolant flush and replace with an approved coolant? Willing to accept all the sling and arrows for ignorance, but after which would appreciate suggestions. I am reasonably handy and believe I can manage the flush and replacement, as shown on the forum. Thanks, in advance.

The first thing you need to look at is where the coolant is going……. If there is a leak, you need to fix it first. The most common leak issues on the Boxster are with the coolant reservoir tank, which tends to develop cracks. A decent pressure test should tell you if you have a problem.

The “where’s and why fore’s” of draining and (if required) cleaning the system have been discussed “ad nauseum”, so run a search for the details. The Bentley manual also covers it pretty well. As for what coolant to use, the answer is simple: Use the Porsche product. It is readily available for about $20 a gallon, is known to be long lived; so “cheeping out” to save a couple of bucks makes little sense. Mix the OEM coolant with distilled water only; do not use tap water which contains minerals that shorten the coolant’s life. Again, distilled water only costs about $0.80 a gallon in most supermarkets, so why mess with anything else.

As for determining if you need to actually clean out the system; collect all of the drain coolant and look for particulate mater or gel clumps, as well as cloudiness in the coolant. If the drain coolant is clear and free of solids, you should be fine with just refilling with a fresh 50/50 mix. Because the M96/Boxster design makes changing the coolant a bit more of a time consuming project, you really do not want to skimp or cut corners. Once done, the car will be ready for years of service……………