Rustproofing and undercoating tips to protect your car


The war against rust may be ultimately unwinnable, but rustproofing and undercoating can help win a battle and put off the worst. Rustproofing and undercoating can only defend against the onslaught of rust-causing road salt for so long. Victory requires vigilance.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2018/11/20/rustproofing-your-car-for-winter


The secret is to do some rustproofing before any problems start to show. I am about to attack my Honda Odyssey rear quarters, which at 220,000 miles are just starting to show through. After knocking loose what I can, getting dirt away from the rust, I will use PORs to convert the rust, per our story. But this 3M Cavity Wax with the applicator wand kit will be used to add a covering of the “cavity wax” 3M markets as a sealant/ rust preventative.


Here’s a link for the 3M Cavity Wax: https://www.amazon.com/3M-Cavity-Wax-Plus-Fluid


I bought trucks for light truck division of FOMOCO and noticed that after 3 months in the parking lot, never driven, rust started to appear on certain parts of the 73 Ford Econolines. Checking the areas rusting, I noticed no paint in areas parallel to the automatic assembly line paint spray heads. So, when I bought my 73 Chateau Club Wagon on “A” plan, loaded with every accessory available, I immediately painted those areas that either had no primer, or just primer and no paint, or bare steel. That was done within the first three days I purchased the van. Next was a trip to my local Ziebart dealer. Drilling rockers and doors, Ziebart, a mixture of heavy oil and paraffin was applied. The olde van has been on the road now for 46 years with over 400,000 miles on it. Areas Ziebarted near hot pipes and mufflers has dried out and flacked off, so I stripped those areas with mineral spirits and underneath, the factory undercoating primer was like new. I applied gloss black enamel, via spray can to those areas. Even with such a good undercoating system, frequent washes during the winter to remove salt and magchloride is a must. If I had not spent the $300 dollars back in 1973, when the vehicle had not yet been driven in the rain, today, there’d be nothing left to it, due to the ridiculous design of the underbody with lap and seem jointed welds that had no paint on them. I’m glad Ziebart is still around. It is an excellent undercoating system.

Regards, Joe Rybicki
Highlands Ranch, Colorado


I wonder where Joe and his van are originally from. Being a Colorado native, born in '61, we’ve never really worried about rust around here. (Though Fords were noticeably more rust-prone than other domestic makes.) Roads were never salted here; sand was used up until about 20-years ago, when the switch was made to magnesium-chloride, to reduce the “brown cloud” made by the traffic kicking up the sand dust after the roads had dried. And from what I’ve seen, mag-chloride does not induce rust; at least, not to any great degree.

Never-the-less, you are to be highly commended for keeping the Econoline for all these many years. Your post reminded me of the '72 E150 SuperVan panel I had some 30-years ago. 300-cubic inch six and three-on-the-tree manny. I sometimes wish I still had that thing…

Mark in Centennial, CO


The only reason I bought my F100 was for the body alone. Even after sitting in a gravel pit under a tree for several years the body had been taken care of previously. Floor, bed, rockers and doors were practically spotless all thanks to the truck having lived a majority of its life in southern Ontario and I believe being driven very minimally in the winter months. A good layer of wet under coating can still be found inside the doors and inside upper of the quarter panels.