To undercoat or not to undercoat
#1
To undercoat or not to undercoat
I know this topic has been discussed numerous times but I'm looking for some fresh answers, I pulled my transmission out for the new one and was planning on undercoating the car before it goes in, there's a few rot holes in the drivers floor pan that I was gonna patch and prime before the undercoating, other than that the underside looks pretty good. I bought two cans of the rustoleum rubberized undercoating but am nervous to put it on after hearing it can trap moisture in and rot without being seen. I'd like to use por15 but don't really have the time to prep for it nor do I want to grind down to bare metal. Has anyone had any good experiences with spray on undercoating?
#6
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Car: '89 Camaro
Engine: LS1
Transmission: 4L65/70E
Axle/Gears: 9 Inch, 3.70 gears
Re: To undercoat or not to undercoat
Can't remember who did it, but fairly sure that it was on a LS swap car, but there was something about using low texture or he strained it before applying it. Either way, speaking from experience, don't use the rubber undercoating. It will not seal out the metal protecting it from rust, it will melt from exhaust heat, instead of scuffing up your hands it will leave a nasty tar-like spot on any skin or clothes. If not bedliner, use something that comes in two parts that you have to mix before applying it.
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Car: 1989 IROC-Z28
Engine: L98 - 350 TPI
Transmission: MD8 - 700R4
Axle/Gears: GH3/G80 - 2.77 POSI
My car was under coated from the dealer when we got it. Not a spot of rust under it 25 years later. Choice is yours.
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#8
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Car: 1983 Z28
Engine: 385 Fastburn
Transmission: T-5
Axle/Gears: BorgWarner 9-bolt posi, 3.27 gears
Re: To undercoat or not to undercoat
Same here, it's like anything, if you take your time and do it right then it will perform like it's supposed to. Clean and dry surface with a nice even coat and you'll be fine.
#9
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Re: To undercoat or not to undercoat
No it will not I have restored car that are 50 years old with undercoating and it did its job there was no rust now rust dont always start at the bottom of the car it can come from all points and truck bed liner is also good but if you ever need to take it off GOOD LUCK it is as hard as a rock and it will stand up to rock chips just like under coating
and also if you happen to miss sanding a spot undercoating will still stick to the car
and also if you happen to miss sanding a spot undercoating will still stick to the car
Last edited by Mirror Image; 01-27-2014 at 10:24 PM. Reason: add Info
#10
Re: To undercoat or not to undercoat
Thanks for the replies guys, I might just try the front floor pans for now and see how it holds up before I do the rest, can anyone recommend a good spray cleaner to get tranny fluid off the underside, a front seal blew and coated the underside
#11
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Car: '89 Camaro
Engine: LS1
Transmission: 4L65/70E
Axle/Gears: 9 Inch, 3.70 gears
Re: To undercoat or not to undercoat
I'm a fan of simple green, spray it on undiluted and let it sit. Spray it again and then start scrubbing it off. In the past I've used the kitchen brushes and scotchbrite pads for the really stubborn stuff.
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