Restoring Engine Bay Rubber Pieces

Jim Carroll -
MiataNuts of Hampton Road

So, it's Spring coming on, time to freshen up your Miata in preparation for "topless" motoring on the Highways and Byways! You pop the hood to check on the fluids, and do a quick air cleaner check, and WHOA!, what's all that brown crud on my air intake tube?! What you are seeing is oxidation of the outer layers of a rubber piece that will occur with heat and outgassing of the volitles as it ages. Upon closer examination, just about all flexible rubber parts under the hood will show this damage, including heater hoses, wiring grommets, radiator hoses, and vibration isolators. Left unchecked, they will stiffen, crack, and eventually fail.

Some people I know have tried ArmourAll on these parts, but to no avail, the parts don't appear to like the stuff, get really greasy, and in some cases have caused earlier damage and failure.

I happened to remember something I saw and asked about as a Kid. (Don't even ask when!!) A local car lot specializied in Sports Cars, MGs, Triumphs, and Alfa Romeos. I loved the cars, and would go there to hang out, get odd jobs, and listen to anyone about the cars who would talk to me. One of the detail guys would always wipe down the hoses with a rag he dipped in a pail he kept in the paint locker. Since I was his helper for the day, I asked him what it was. He was a good guy, and told me it was used Power Steering Fluid. He asked me why I thought he did this, I drew a blank, so he explained.

It turns out one of the main jobs power steering fluid and automatic transmission fluid do, is maintain the seals in their respective systems. These seals are made of the same material that the hoses were, and so it helped restore some of those volitiles mentioned above.

So, I took some NEW power steering fluid, put some on a rag, and tried it on a 2" square patch of the intake tube. The more I rubbed it in, the more the brown disappeared, and the heathier the tube felt, softer and pliable. I drove the car for a week to see if something bad would happen.

No problems, so I did everything in the engine bay I could reach. The results were parts with a deep black color, a soft resiliancy, and a good looking Miata that I wasn't ashamed to pop the hood on. Cost? $1.09 for the Power Steering Fluid, and an old cotton sock!

Back to the Garage

17 July, 2003