JB-Welding Upper Radiator Seam - PeachParts Mercedes-Benz Forum

BenzDieselTuner · #1 04-08-2013, 10:01 AM

JB-Welding Upper Radiator Seam - anyone done this ? i have successfully used JB in the past to seal a cracked radiator (plastic part) on my '85 , when i couldnt afford a new radiator.....

this one started seeping after the second citric flush.....annoys me, i have to leave my cap loose now as well to not build pressure....

Simpler=Better · #2 04-08-2013, 10:17 AM

Do it and don't look back. I've repaired more than one radiator with JB weld, the trick is proper prep-clean the surface with brake cleaner and/or ether, and be sure to put some nice scratches in the surface for the JB to stick to.

Let it sit for at least 48 hours before giving it pressure. An incandescent bulb shining on it may help it cure faster.

charmalu · #3 04-08-2013, 11:34 AM

Applying three layers of $100 bills also works very well. A tube of it is pricy though.

I wondering if the plastic cracks in one place from age and heat, there is the possibility of it doing in another spot?
I know when the finances are tight, we do what we have to do.

If it works and hold the pressure, good, I hope it does. I would be keeping my eye open in the yards for a new one. new one`s, or fairly new, do show up if you look for a while.

I tried to JB Weld a cracked plastic grill on my 240, and it didn`t stick very well. Different plastic, or I didn`t prepare the plastic good enough.

Charlie

Zulfiqar · #4 04-08-2013, 11:35 AM

How about using the plastic radiator repair kits that come with a piece of fiberglas cloth and a piece of sandpaper too, The liquids use to seal it get really scalding hot to melt the fiberglass and itself into the plastic.

vstech · #5 04-08-2013, 12:08 PM

are you talking about JB'ing the plastic to the aluminum? I doubt that would work...

TnBob · #6 04-08-2013, 12:25 PM

My local jy charges $35 for a radiator

mach4 · #7 04-08-2013, 01:04 PM

I'm in the source a JY radiator camp. JB weld has its place (I use it a lot) but a plastic-aluminum joint with high temp deltas, I think is going to be a short term fix at best.

That being said, a tube is $5, and the radiator is bad anyway, so what's the harm? Silicone might be another option.

Simpler=Better · #8 04-08-2013, 01:07 PM

As I read it, he just has a minor leak-not a big gaping hole, which JB weld would be perfect for sealing.

BenzDieselTuner · #9 04-09-2013, 10:40 AM

Quote:

Originally Posted by Simpler=Better

As I read it, he just has a minor leak-not a big gaping hole, which JB weld would be perfect for sealing.

yes, it "seeps" the entire length of the radiator.....the upper seam, where it joins the plastic top part of the radiator......

obviously the only way to see if it works is to do it.....but yeah, i agree, i figured getting it good and clean with brake spray would be the way to go, if its going to work at all....

no 240 D radiators at the parts yard at the moment.....sucks, 6 months back they had an 85 euro 240 D, which has a BIG radiator, like a 300turbdiesel, and a comparatively massive oil cooler.....didnt have the money for that then though, and i didnt need it yet anyways....

vstech · #10 04-09-2013, 12:00 PM

Quote:

Originally Posted by BenzDieselTuner

yes, it "seeps" the entire length of the radiator.....the upper seam, where it joins the plastic top part of the radiator......

obviously the only way to see if it works is to do it.....but yeah, i agree, i figured getting it good and clean with brake spray would be the way to go, if its going to work at all....

no 240 D radiators at the parts yard at the moment.....sucks, 6 months back they had an 85 euro 240 D, which has a BIG radiator, like a 300turbdiesel, and a comparatively massive oil cooler.....didnt have the money for that then though, and i didnt need it yet anyways....

I was able to "pinch" the aluminum tight when one of mine started leaking...

BenzDieselTuner · #11 04-09-2013, 08:40 PM

Quote:

Originally Posted by vstech

I was able to "pinch" the aluminum tight when one of mine started leaking...

very interesting ! do you mind elaborating ?

FYVMMF · #12 04-09-2013, 12:31 PM

Sometimes the the metal clip that secures the plastic tank to the aluminum core can be squeezed tighter using a modified C clamp to clamp it tighter.

If you decide to go the epoxy route I would strongly suggest an epoxy called Fas-Stick #110 made by FASCO in Hialeah FL. This stuff is specifically formulated as an adhesive epoxy and it adheres tenaciously to whatever it's applied to. You're always well advised to clean, degrease and roughen the material as a preparation of course.

This stuff is the consistency of vaseline and when mixed 1:1 by volume it thins a bit to a cold molasses consistency. If you pull the radiator out to work on it that will allow you to get the epoxy deeper down into every crack and crevice, spread it around so there is a larger area of contact and it will hold better.

Here's their web site, I think they sell on eBay also, you can get a small kit for about $10, and the stuff lasts for years sealed up

Fasco unlimited

They make a number of other specialized epoxies maybe even give them a call and they might have a better recommendation

BenzDieselTuner · #13 04-09-2013, 08:42 PM

Quote:

Originally Posted by FYVMMF

Sometimes the the metal clip that secures the plastic tank to the aluminum core can be squeezed tighter using a modified C clamp to clamp it tighter.

If you decide to go the epoxy route I would strongly suggest an epoxy called Fas-Stick #110 made by FASCO in Hialeah FL. This stuff is specifically formulated as an adhesive epoxy and it adheres tenaciously to whatever it's applied to. You're always well advised to clean, degrease and roughen the material as a preparation of course.

This stuff is the consistency of vaseline and when mixed 1:1 by volume it thins a bit to a cold molasses consistency. If you pull the radiator out to work on it that will allow you to get the epoxy deeper down into every crack and crevice, spread it around so there is a larger area of contact and it will hold better.

Here's their web site, I think they sell on eBay also, you can get a small kit for about $10, and the stuff lasts for years sealed up

Fasco unlimited

They make a number of other specialized epoxies maybe even give them a call and they might have a better recommendation

good info, thanks ! i will look into them, that sounds very interesting, not just for this repair....

as far as "tank clips" are concerned, i never knew they had them, i always assumed they were "adhered" in some way......

97 SL320 · #14 04-09-2013, 06:39 PM

Quote:

Originally Posted by BenzDieselTuner

yes, it "seeps" the entire length of the radiator.....the upper seam, where it joins the plastic top part of the radiator...

There is a rubber gasket between the header and tank then shrinks as it ages. Crimping can help, ( do it when the rad is warm and not pressurized. )

If you use epoxy to seal this, go all the way around otherwise it will leak.

BenzDieselTuner · #15 04-09-2013, 08:45 PM

Quote:

Originally Posted by 97 SL320

There is a rubber gasket between the header and tank then shrinks as it ages. Crimping can help, ( do it when the rad is warm and not pressurized. )

If you use epoxy to seal this, go all the way around otherwise it will leak.

another thing learned ! i was not aware that these aluminum/plastic radiators have gaskets sealing the plastic to the metal.....so i assume this is something the local radiator pro could do ? (i assumed if i were to go there they would just say its no good and send me away) i would tell him to do them both, top and bottom if possible, but not to flush or brush out or pressure test anything, just leave it alone and do the seals......'think this is an option ??