jb weld / plastic radiator inlet


Old 10-14-06, 06:17 PM
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jb weld / plastic radiator inlet

'84 BMW 733i crack in the plastic radiator inlet just past the hose .

Im looking online and it looks like replacement radiator 225 +

what about jb weld on the crack anyone have experice with it ?

im thinking of using a drmell tool to rout a v over the crack for a little more surface area .
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Old 10-14-06, 06:54 PM
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From my experience, don't bother trying it. The expansion and contraction of the plastic heating/cooling must be a factor. It just doesn't hold.

There is also some plastic radiator repair stuff that's made just for what you're describing. I tried that on my Celica (about four times before I gave up and bought another radiator). I never could get it to hold. It would be OK for about a week in the winter. Then it would start leaking again.

I also found out local radiator shops (there's a lot of them in Des Moines) wouldn't try to fix the plastic parts of the radiators either.

Hope this helps,

Old 10-14-06, 07:47 PM
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I've used JB Weld (water based stick) on my mother in-laws radiator hose coming out her water pump. It was cracked. It's been holding fine for about 6 months now. You could go to a junkyard to see if there are any radiators in decent shape there.
Old 10-15-06, 07:05 AM
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my 2 cents

The secret here is part must be totally clean and then it might not work because of the expansion issue.But I would give it a try just dont make any long trips and keep a jug of water close.
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Old 10-15-06, 10:24 AM
Join Date: Jun 2006
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To fix the problem you need to weld it. Use a pencil type soldering iron. Get s similar type plastic, plastic scraper, spray paint cap(not the shiney type) and cut some small strips(these are your welding rods), brittle type of plastic will not work. Now with the area clean using the soldering iron start a small puddle just beyond the crack with a small circular motion, now start introducing some of the rod(the plastic strips) into the melted plastic, slowly move along the crack(in a small circular motion) going about 1/4" wide in total, go slightly beyond the end of the crack. Now using just the soldering iron go back over the weld to smooth out the weld and to insure the two plastics are blended well. I usually use a different color plastic for the welding rods so I can tell when they are blended. The key is to take your time and make sure the 2 plastics blend together, you do not want the melted plastic to just set on top of the crack, it won't work. You are now finished and you have just saved yourself a bunch of money. Have a nice day. Geo

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