As a DIYer. what's the one thing that you should be doing, but most likely aren't?

[jluetjen]

I just wanted to share some learning that effects all of our Porsches, because I've come to the conclusion that it's important, and I bet you're not doing it.

This "Ah-HA!" moment came about as a result of working on my 2002 Boxster, but is just as relevant to my '69E. I bet that when you work underneath your car, you use things like Liquid Wrench (or something similar) to loosen bolts, WD-40 to clean surfaces, and if you're thorough, you may even use a parts washer with a solvent (I prefer mineral spirits btw) to clean parts up so that they are spick-and-span before putting them back together. I bet you than put everything back together, it looks awesome, and you pat yourself on the back and consider the job done.

What did you miss?

Surface protectant! I first learned about Tectyl from this forum a decade or two ago, and I've come to have a greater appreciation for how important it is. To cut to the chase, whenever we work under our Porsches, we should finish the job by brushing or spraying Tectyl or a similar cosmoline type product on the area. Ironically (or maybe ionically! ), the oily sludge that you cleaned off of the parts may actually have been preventing rust, and by cleaning this layer off, you are now creating conditions for rusts to begin. The "why?" is important.

All of our Porsches have made use of greater or lesser amounts of aluminum and magnesium in order to lesson the weight of the car. While magnesium will corrode just thinking about water, aluminum is supposed to be naturally protected from corrosion. Starting in the mid-80's, even our air-cooled 911's had their steel chassis galvanized to protect against corrosion. Rust shouldn't be a problem? Right?

The problem is that when you put all of those metals together in an assembly, you have a situation which is ripe for galvanic corrosion . In a nutshell, galvanic corrosion is when electrons are drawn from one metal to another. You most likely are thinking to yourself -- "I never drive my Porsche in the winter". But galvanic corrosion can occur in other situations too. For example as a result of chemicals used in cleaners. Even tap water which happens to have ions in it (I'm looking at you water softener!). Corrosion can occur even without salt water! There are numerous ways in which it can start. You can read more about it in the link. Porsche mitigated this issue in a number of ways:

• Isolating dis-similar metals from each other. This for example is why chromated hardware is required when assembling air-cooled 911 motors. The chromate provides a barrier to the passage of electrons.
• Special finishes on parts -- such as powder-coated springs or T-bars or chromating hardware.
• Separating parts with rubber bushings
• Grease between metal parts
• Coating the entire underbody and chassis in Tectyl or a similar product.

Over time, the Tectyl coating dries out or wears away. Here's a couple of examples of what it looks like when it does.



Once I recognized what I was looking at, it became clear that Porsche sprayed the undersides of our cars with Tectyl at the factory, and over time it's gone away.

But it can also be easily removed with penetrating oils, WD-40 and other such solvent products. Yes, WD-40 contains silicon, which can also provide a barrier to corrosion, but this barrier is quite thin. It might be adequate for a race car which rarely sees wet weather, but will be totally inadequate for long-term usage. The fact that Tectyl can be easily removed with solvents is not a bug in Tectyl's properties, but actually a feature. If you over-spray it or get it someplace where it shouldn't be, it can be easily cleaned off with any of those products. You can also easily remove an old layer before applying a new layer.

If you haven't recoated the underside of your Porsche, you are inviting galvanic corrosion to set-up house in your car. You may not see it at first, but it will start and can often be recognized by bolts seized in aluminum parts or springs or T-bars which have rusted through.

So the important point is that we should all be regularly refreshing the undercoating on our Porsches if we want to keep them clean of corrosion.

[GH85Carrera]

No doubt surface protection is vital in MA. I never drive my 911 if there is salt on the roads. I have my daily driver for that.

After 26 year of ownership and lots of miles the bottom side of my 911 has lots of road grime and dirt from driving in the rain, but no corrosion. I did clean the fender wells and then undercoat them. I know lots of folks spend hours to clean the fender wells and then wax them. Not me, my car is a really nice driver. With no fender liner, the fenders need undercoating to protect from rock damage from the underside.

I will admit that pretty much every time I have it up on my scissor lift, I do a complete inspection. No corrosion of rust is allowed.

[jluetjen]

Yeah Glen. This whole journey started because I used our 986 as a daily driver over one winter. Since the replacement cost is similar to VW Golf, I said "why not?". I wouldn't think twice about driving a Golf in the winter.

Undercoatings are not a subject which come up that often on this board, most likely because most people don't drive their Porsches in the winter, and it doesn't make the car faster or lighter.

But I've come to the conclusion that Porsche didn't include the sealant merely for use during transit to the dealer. It's there for year-round protection and part of the car's system. Any times that anything except de-ionized water comes in contact with the aluminum or magnesium of the car, electrons will move. When electrons move from the aluminum (or faster yet the magnesium) it will start galvanic corrosion.

Obviously the mental calculus is different for my 911E, and that never gets driven in wet weather if it can be avoided. I will be adding some sealant under the car the next time that it is up though -- most likely this winter.

[Jesset100]

The one thing that I haven't been doing is driving the D@%n thing. It's getting the typical front pan replacement repair and it's taking me too long. Hey life gets in the way.

[kimlangley7]

I use the ALU anti-seize paste... clean the threads, surface rust and paint that stuff on.. It has fantastic staying power - like lasts for years and protects the metal...

kgl