The Porsche 997 coolant leak issues have been discussed on Porsche forums the world over. And while many discussions centre around the water pump and header tank, there is a more significant issue that is discussed less often. The corrosion and failure of the Porsche 997 coolant pipes.

Water pumps can – and do – fail on any car. It’s an item with a finite life and will certainly expire at some point, regardless of your care and attention on maintenance. However, in the Ninemeister workshops, we are seeing very regular instances of the coolant pipes failing on the Porsche 997, both 3.6 and 3.8 engines.

Many owners are dismayed to see pools of coolant leaking from the underside of the car and very often assume it is a terminal failure. After the initial trauma has subsided and the car arrives here at Ninemeister, frequently it is the coolant pipe fittings that are at fault.

Dissimilar metal corrosion attacking the 997 coolant pipes

Here’s an overview of what is happening, why they fail and a few thoughts from Colin Belton on the whole issue of 997 corrosion proofing.

Essentially, the failure happens on the joints that connect the various elements of the coolant system together. Constructed to speed up the assembly of the car and simplify production, the fittings are made of both steel and aluminium.

When subjected to the salt of winter roads, plus the internal effects of the coolant system circulating around at temperature, the two metal materials suffer what is known as dissimilar metal corrosion. In effect, they don’t get along and start to eat away at each other. Add in the perfect little micro climate of permanent moisture behind the plastic under tray and it’s a recipe for a corrosive environment.

Eventually, the joint fails. With luck, the owner isn’t somewhere remote or driving at high speed on track, though whatever happens, the problem needs to be solved.

There is no revised part available for this. It is principally a task of removing all of the corroded parts, both the pipes and the fittings themselves and replacing everything. It would be wonderful of course, if there was a lasting solution to this that ensures that it never ever happens again.

Fresh coolant pipes installed before Waxoyl treatment

Whilst Porsche don’t offer that, we do apply some common sense during the re-assembly here at Ninemeister. As we replace each failed part, we corrosion proof each one with Waxoyl automotive rustproofing treatment.

Waxoyl is a traditional rustproofing treatment that is well proven and has been in use for many decades. It’s an excellent way to protect vulnerable areas of any car.

Which, or course, poses the obvious question. Why don’t Porsche do this in manufacture and also, more importantly, what about the rest of my Porsche 997?

We believe that the reason why it’s not done in manufacture any more is quite simple. Times have moved on, manufacturers generally, not only Porsche, build cars with a lower expectation of a life of decades. With the majority of new cars being sold now on Contract Purchase agreements, the incentive from the manufacturer to create really, really long lasting build quality, such as the Porsche 993, is no longer there.

Another example of Porsche 997 corrosion

With drivers happy to pay to have use of the car for a monthly fee, rather that ever considering ownership outright, then future corrosion issues are moved down the line a few years hence. It makes sense from a financial viewpoint for any manufacturer. Why go to great expense – and it is expensive – to construct cars with stellar build quality when the world is moving on a such a rate?

It is generally considered that the Porsche 993 did not make any profit at all in the first few years of production, such were the remarkably high standards of engineering.

So should I be concerned about 997 corrosion?

Like any modern car, hidden corrosion is becoming something to consider. We are now seeing Porsche 997’s in our workshop and bodyshop with the beginnings of corrosion issues. These areas are generally well out of sight, in engine bay areas, behind the plastic under tray panels and in other hard to reach areas. Left unchecked, they will, for sure become a significant problem in years to come.

We will be writing more soon on the subject and also offering help and advice if you have concerns about corrosion proofing on your Porsche.