Plastic welding a radiator end tank

The plastic end tank on my WJ Jeep Grand Cherokee has developed a hairline crack near the inlet. I couldn't figure out where I was losing coolant until tonight when it started leaking enough to see.

Searching the Internet shows it's a common issue and a replacement runs from $85 to $550. The factory core isn't anything special at 1" thick but this vehicle has had all the coolant changes done regularly so it's pretty clean.

I also found a reference to plastic welding cracks like this using an airless welder that looks like a soldering iron and some nylon filler. Have any of you guys used one of these with success or am I just asking for more problems?

The current radiator is original and I have 130k on it.

Thats what I would do, following the instructions for cleaning and such beforehand.

I once tried welding a small crack on a radiator tank with a 100 watt soldering gun and a zip tie, it leaked less, but didnt stop entirely. So I bought a used one from CL for $50 instead. You might have better luck with a plastic welder proper.

Personally, I don't think they're worth repairing, if its brittle/thinned out in one spot, its gonna blow out someplace else soon enough.

What broke said. I fixed a hairline crack in a plastic endtank once with the "quickset" jbweld. Held up fine forever, even "sharpie color matched" it black!

I fixed a 93 mopar plastic endtank with jb weld, standard stuff. Just got it degreased and clean, provided adequate dry time. (had used a non standard too long bolt on a bracket and it punched through, plugged with jbweld.)

Held fine for years.

As you have a crack, perhaps grind with a dremel for more surface area for the epoxy to grab and prevent a raised surface if it is near a sealing surface.

I have done it a number of times with zip ties and propane torch/soldering iron and a cheap chisel (chisel to heat and gouge or just to smooth the nylon globs). You can't have coolant still in the rad, and you have to melt the crack into a V shape. Melt 95% of the way through the rad and start melting in zip tie. It helps if you have ever welded metals before, it a very similar process

Begging for trouble, buy a new one.

Plastic tends to crack because it's lost the plasticizer ingredients which make it flexible. Welding it doesn't give it back those ingredients or the flexibility it once had. At best, you're borrowing time.

Even though all of these radiators crack in the same spot it sounds like repairing it will be a 50/50 proposition. Most likely it would crack again or in a different spot when SWMBO is driving and I'm 1000 miles away. She has a tendency to continue driving regardless of whether the tires have air or there's steam coming out of the hood like a freight train.

While I would like to upgrade to a larger radiator those are $550. I'm hoping an aftermarket OEM style radiator will have been improved to avoid cracking in this area, all of the ads claim "better cooling than OEM" yet use the same size core.

Are there any recommendations for manufacturers? eBay has a bunch priced at around $90-$180 shipped (mystery manufacturer or Mishimoto), Amazon has TYC/Spectra Premium, Rockauto is $90-$120 plus shipping, and the local Autozone is $148 (Spectra Premium).

I am thinking about adding an auxiliary transmission cooler in addition to the factory one while I have everything apart.

The radiator is a real PITA to get out of this Jeep so I'd like to avoid having to redo it if I can.

In reply to bluesideup:

There are a lot of people using the Mishimoto, just make sure to change the cheesy rad cap, that goes for any chinese alum rad. I have used those $100 larger than factory all aluminum chinese cores. The first one had the wrong size too small inlet/outlet they sent rubber hose segments to adapt the larger factory hose to the smaller rad pipe. Worse cooling than the smaller factory rad. Pay good attention to inlet oulet sizes and thickness of the cores. I ended up accidentally punching a hole in that above rad and getting another from another vendor. The second one had the right sizes and seems to work fairly well. I think it says godspeed on it if that helps any

Lately I find very few radiators that can't be replaced with a sub-$200 all aluminum racing radiator from Speedway.

I used several coats of original jb weld on the plastic tank on my old accord. It held fine for the last year that I had the car. I just roughed up the area with sandpaper and layered it on.

As stated by several others, it is possible to repair the plastic tank but I would consider it a short term fix until I could save up for a replacement. If possible, try to find a replacement with metal end tanks.

As far as the replacements claiming better cooling with the same core thickness, they alter the tube size/shape to increase the tube perimeter to volume ratio and also adjust the fin count to allow better heat transfer away from the tube and into the air flowing through the radiator. Usually this helps when the vehicle is in motion, but it may not help when idling in traffic. Really depends on the manufacturer. I haven't had anything to do with radiators in about 20 years, so I can't say who makes good quality at reasonable prices anymore.

I'd get a new one if I was in your situation. No reason to tempt fate.

If it was my SWMBO I'd go with the cheapest option that wouldn't cause more issues later. Then again she knows better than to drive her car with an obvious issue.

What's the price of getting stranded, lost time, a tow and then replacing it.

I'd replace w/ new aluminum like oldopelguy said and be done w/ it.

fasted58 wrote: What's the price of getting stranded, lost time, a tow and then replacing it. I'd replace w/ new aluminum like oldopelguy said and be done w/ it.

This.

ESPECIALLY if SWMBO is going to be driving it.

Do you really want to have the "I cheaped out on a repair and that's why you were stranded" conversation?