Wax oil, should i use it?

[Chris KC]

Just don't use silicone sealant on your engine!

No seriously, the black brush on stuff is jolly good. My car had nothing else on the underside for 30 odd years (i.e. on bare steel) and it only rusted when the coating started coming away - it does eventually dry out and fall off if not re-coated. I agree with Hedd though, paint then apply over the top. Then take a look underneath once a year or so and address any signs of failure.

Check you don't need to weld anything before you apply it rather than after!

but doesnt wax oil stay supple? i thought the really old stuff that people put on that was like a tar, i thought that eventually dried out, but i thought wax oil stopped.......well,  waxy?

The stuff I had on for the last 30 years was, I think, 'Spectra Brushing Underguard'. It eventually hardens, probably wouldn't have done had I given it an occasional re-coat. I have now applied Hammerite Underbody Seal 'with added waxoyl'. This goes on nice and easy with a brush and gives a neat black finish which I expect to remain flexible for some time. I did my wings and running boards separately some ten years ago now and they still look like new. The spray-on waxoyl is a clear liquid wax, I don't have direct experience of keeping it long term but likewise it will probably benefit from an occasional re-coat.

[Andy Bennett]

I think the general agreement these days is that the old style bitumen based underseal is bad as it cracks and harbours water to rust everything behind it. However, the newer wax based underbody protection (not cavity protection) grade stays waxy and so self heals over any damage, with the occasional top up. I have used the spray can version and am v happy with how it looks and appears to wear well.

I just bought an extra can to top up ad again am happy with the ease of application and the coverage from 1 can, usual disclaimers:
https://www.ebay.co.uk/itm/Car-Truck-Van...2749.l2649

Andy

[Chris KC]

Just don't use silicone sealant on your engine!

No seriously, the black brush on stuff is jolly good. My car had nothing else on the underside for 30 odd years (i.e. on bare steel) and it only rusted when the coating started coming away - it does eventually dry out and fall off if not re-coated. I agree with Hedd though, paint then apply over the top. Then take a look underneath once a year or so and address any signs of failure.

Check you don't need to weld anything before you apply it rather than after!

Interesting your point regards to Silicone Sealant C KC, I've seen a car for sale, and it looks like it has blue sealant here there and everywhere, sorry to go off thread a little, but have you had a bad experience we should be aware of, I'd like to know please. I personally hate the stuff too, but if I'm looking at a car that has had loads, I'd love to know what your bad experience may have been. Other than it just looking wrong, and quite frankly in my experiences, if you use a decent old fashioned suitable paper or cork gasket... it seals ok.


On the wax oil question, I'd agree. Its a good product, clean things down first a little if you can, it certainly helps to repel water etc.... I've seen bad experiences with cars that had Ziebart on over the years, where the parts missed had became like an anode on a boat, but that was some years ago...


Regards


M-M.

No I've not had a bad experience with silicone and personally I have yet to find any combination of materials which will keep my engine oil tight. (Running a pressure-fed crank at 50 psi probably isn't helping).

My intended meaning was that many cars have survived which would possibly not have done if their owners has succeeded in getting their engines oil-tight. Large quantities of oil coating the frame and underbody do wonders in preventing corrosion.

As an aside I did once have to abort a holiday (at Southampton docks, as luck would have it) when my oil pressure gauge dropped to zero and stayed there. The subsequent strip down revealed a lump of hardened red hermetite blocking the take-off to the oil pressure gauge. Heaven knows where it came from but it demonstrates that sealants of all kinds must be used (and removed) with care.

[Dennis Nicholas]

Bilt Hamber products come out tops in (all) tests done by various magazines etc. They do a wax protection.
I have previously had a not so good result with WAXOIL on the rear end of my Scimitar........it has been subject to salted roads but still disappointed by the rust beginnings.
There is also another make of similar waxy protection (can't remember name and too late at night to start searching around) which has been commented as being superior to WAXOIL.

Dennis