View Full Version : Should I oil spray my car to prevent rust?

12-21-2004, 10:09 AM
I recently bought a 2000 Dodge Grand Caravan. In the past I always got the hot oil spray treatment where they jack your car up and drill holes in the bottom and so forth. Since my cars were always older I figured it was the correct thing. Plus, it's now winter and the snow, slush and road salt can play hell with metal.

Now I'm told by some friends that the newer cars don't need this as the compunds the underside is built of/coated with mostly do the same job and the good old hot oil spray is not needed.

So what is the best thing to do?

12-21-2004, 11:22 AM
Generally, it is fast money for the applier and not much for you.

See this.


Additionally, use the search function there to search on 'undercoating' or oil coating.

Whatever variant of undercoating, they don't seem to do much. Some do harm.

12-21-2004, 01:03 PM

I kept using the search for varients of "oil spray" and the not-safe-for-work sites kept coming up. :D

12-21-2004, 01:50 PM
Over at Car Talk, they aren't crazy about undercaotings, and loathe the oil coating.

The generally stick to this theme of saying, "They don't do much....cars are pretty well protected now...., it is easy money for dealers and distributors, etc"

In one case they say 'if you must', more or less, and recommend finding a good mechanic who can apply an aftermarket undercoating while not spraying everywhere to the point that it clogs drainage holes.

12-21-2004, 02:57 PM
Better-quality galvanized steel, and "cold-dipping" the entire car frame/body after assembly has all but eliminated any need for aftermarket rustproofing. IIRC, way back in 1985, when my mother bought a new car in Chicago, the cold-dipping (a means of coating the metal with zinc to prevent rust - the main idea is it gets zinc on all the cut edges, whereas the galvanized sheet metal is coated only on its sides) was a major selling point and the dealer said she'd never need rustproofing.

The two main problems with "rustproofing" are that the car STINKS for a good while after, and more often than not, the drain holes in the body panels get clogged, allowing water to pool up rather than go away. Oh yeah, as Philster said, it's a nice money grab.

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