repairing plastic radiators

Sorry to answer my own post but I just found out the tanks are made of nylon and fiberglass. Nylon is the media. I will practice welding nylon when I go in to work today.I have plenty of 1/8" x 1" nylon scrap. I'll use large nylon tywraps as rods. This should be intresting. Hell I may learn something.

I hope you will share the discoveries, I encounter lots of cracked nylon parts. LS

If that crack is not back by the radius of the neck you might be able to tape it or make a thin sleeve to go over it (with sealer/adhesive). I'd drill a tiny hole at the end of the crack to relieve stress and stop the crack from projecting further. For $200 I sure would give something a try too.

Messing around with 2 types of nylon today. I found that the ty wraps only stuck to one type securely. I got better results fluttering it with a pencil torch. I have received info that rad shops have glass rods for this purpose and that tank replacement is common practice. Gonna call today and ask what it will cost to fix it.

Thanks for the tip. Good idea

I used a 25W soldering iron but covered its tip with aluminum foil to prevent sticking. I melted a deep groove along the crack and then filled it with plastic taken from the tank itself. Radiator tanks are made of nylon, but I learned that there are different types, and test welds made with black and white nylon ties seemed to break off too easily when flexed (yet they held well when I earlier repaired small nylon gears with them). There are fiberglass reinforced nylon welding rods made specifically for radiator repair but I didn't know about them at the time, so I used strips of nylon cut from the corner edges of the vertical reinforcement ribs of the tank. I believe any repair you make by welding this material will be last because my repair was still holding when I sold the car a few years later, and the crack had been at the intersection of the tank and the plastic pipe molded into it for the upper radiator hose.

| Does anyone know a method of repairing a hairline crack in a plastic radiator |side tank ? I know there are some commercialy available kits to weld plastic |radiators. |I may already have most of the irons and tips as I use them for urethane belt |joining at work. I have already planned to shell out $200 for a new radiator, |So if I mess it up, it's no big deal. My concern is the proper way to do it and |what type of material do I use.How hot should the iron be? I am thinking it |may involve carving a v trench with the iron along the crack line and fill it |in with a like plastic. This radiator is like new so I'd like to give it a |shot. Whoever installed it ditched the factory spring clamp for a worn drive |clamp. I suspect this is why it cracked in the neck area .It may have been over |tightend. I havent asked the opinion of a radiator shop but I guess I should. |Any thoughts on this from someone with experience is appreciated.

I've used JB Weld a number of times, has always worked fine and held up for at least a year.

Rex in Fort Worth

the car a few years later, and the crack had

Some good ideas here. I have various soldering guns I can use for this type of job. I also have small butane torches. I took a butane soldering iron apart and robbed just the tiny torch for small repairs. The flame is only about

1/8" wide and 1/4" long which helps do fine work without damaging the substrate. I almost wish I had a cracked radiator to work on.

JB Weld is epoxy, and epoxy doesn't stick well to most plastics, including the nylon used for most plastic radiator tanks. So I wouldn't rely on it where tensile strength is needed, such as near or at the edge, but only where there's plenty of plastic all around and the epoxy will act only as filler under compression. Just passing a hot soldering iron over the crack is probably going to give a stronger repair.

I say bah humbug to plastic radiators. Just replace it with an all metal aftermarket radiator.

|I say bah humbug to plastic radiators. Just replace it with an all |metal aftermarket radiator.

Good luck finding one. The replacements are like the originals. You would have to make something else fit from an older model.

Rex in Fort Worth

Granted. You improve the odds a lot with prep and reinforcement. I rough up the plastic with a hand or rotary rasp (low speed). I also imbed either aluminum screen wire or formed sheet metal cut to fit or other bits of metal, depending on the shape of the cracked area. If it is cracked into a mounting boss, a washer is often the best thing. So far I haven't had a failure.

Rex in Fort Worth