Q – My Boxster is driving me crazy. I bought it at auction for a great price but three months later, the transmission failed. I only paid 12,000 for the car but the transmission cost me another 9 grand. So I’ve got $21,000 into the car and I was OK with that until it started overheating. I have never had any problem driving it until it overheated; and even after that, the engine still runs fine.
My local mechanic replaced the water pump and the thermostat but still after a few miles, the temp gauge starts to rise and then the heater quits producing heat! I took it back and now he is telling me that he thinks the head gaskets have failed. I have read all about Boxster engine problems on the web and now I am thinking that the engine might be bad. – Brian
A – Brian you have my sympathy. I understand why you would be worried. The water pump impellers do fail. They are made of plastic! And the thermostat is a good hunch too. And although it may seem simple to replace both parts, there is an added complication that your mechanic might not have realized.
Here’s the best news. I believe that the most likely problem is that cooling system has not been properly bled. Based on Boxster cooling system design, this is not an easy task and depending on where your mechanic got his information, he might have been doomed. The factory manual is vague on the topic (presumably they handle it in on-the-car training) and we have found that the Robert Bentley manual has the most detailed written & pictorial procedure.
It’s not easy or inexpensive but getting all the bubbles out sometimes takes a couple hours, a couple spirited road tests and even after that, a pesky air bubble may rise to the top and require a coolant top up. The key ingredient is patience.
Under the plastic trim panel where you fill and check coolant and oil, there is a bleeding port which is very well hidden. Porsche does not want the car owner to ever touch it and you shouldn’t. During servicing however, if the tech doesn’t find it, it can’t be bled properly.
Another cause of coolant loss (and potential overheat) is the coolant cap itself. The original cap on the early Boxster has been superseded to a newer, better design. If you have the original cap, check the number and buy the newer version.
So before you give up on the car, take it to a qualified shop and trust the process (trust but verify…make sure they know about the bleeder port first!). Even if your mechanic thinks that the engine is damaged, you need a second opinion. Based on the last Boxster engine swap I was involved in, if it actually needs to be replaced, it will cost what the car is worth, or more! I hope that is not the case. – MC