How to Seal a Cracked Radiator?

Thank-you.

Thank-you.

If the crack is accessible, you might be able to solder or braze it. Beforehand, per Lyn's suggestion, Aluma-Seal or Stop-Leak or sodium silicate ("water glass") might work.

If the leak is at the tank, which is probably plastic, some other technique may be needed. More detail in the description might help.

The crack is right on top of the radiator where the radiator cap is located, along the seam. I hope this is the description you are needing. Thank-you.

Thank-you.

Or since Silfos has a fairly high melting temp use the pre-fluxed rod below.

Most raidiator walls are pretty thin and you may burn through it using silfos. Stay Brite solder and Flux would work too but it will have to be very clean.

Thank-you.

Thank-you.

I actually did that once and the results were unacceptable. Most Sil-fos melts around 1500F. Solder melts around 360F. So if the crack was on or near a solder joint the amount of heat you're applying causes all sorts of things to come undone. But you're right that brazing rods can be used successfully if the crack is a safe distance from a soldered joint.

It has been my experience over the last 40 years to just replace the unit with a new one. Unless it is was made when they used real copper and then you could repair. If you get on line you can find radiators for under $200.00 for most autos. Not worth hassle of being out in the middle of the night, know where from any where, trying to figure out how I am going to make it the next 20 miles home.

Thank-you the part cost will be over $200 because its an Infiniti.

Thank-you that is what I have decided to purchase another radiator.

It was good of you to take a minute and come back to say thanks

That is advice that is very useful for people who would never post on CR4.

If it's metal, clean up the affected area and apply lead solder to the crack. That's what the pros do. Make sure water level is well below crack so it doesn't boil out under your solder joint. I've had these repairs last longer than the radiator itself.

Thank-you.

I see a trip to PickYourPart in your near future...after you spend a few wasted dollars on "miracle stop leak" products <<band-aids.

I used the product I referrenced in a metal radiator that had a leaking solder joint on the side seam. That radiator gave me an additional 12 years of trouble free service. Maybe I just got lucky.

My lead solder bandaid lasted for 10 years. I guess we're both lucky.

PS- a radiator is one thing I won't get from a junkyard. If need one, I'm getting a new new one. Of course, I tend to drive my vehicles well past the decade mark.

Thank-you.

I've also used these products years ago. The problem I have with them is once the leak is stopped (if it's stopped) is that the rest of the junk is left to find a home in your cooling system. So in an emergency where you just need to get home, great. But I personally don't view them as a permanent repair.

Frankly, I didn't think it would last either. Yes, I agree that the rest of the gunk is still in there.

I'm not so sure I'd use it at all in a new vehicle, especially here in Arizona where street temperatures can reach 140°F.

Thank-you. You are right I decided to buy another radiator.

You can use DEVCON STEEL EPOXY which consists of 2 parts (squeeze tubes, A&B). One tube is epoxy the other is hardener. Mix 2 equal parts then apply. Be sure to clean or scrape the paint on the cracked side before application. Can be used on metal or plastic based housing.

Hope this helps.

Thank-you I have decided to purchase another radiator. I do not want the same problem again, I appreciate you giving me the name of the product I was speaking about.

If the top of the radiator is metal then solder it; if the top is plastic it is probably nylon and that can only be repaired with heat. Easier to replace the radiator. Before you repair the radiator make certain it is sound and not corroded or leaking. A new radiator may be the cheapest long term solution.

Dennis Waller

Thank-you I prefer to buy a new radiator. After reading some of the suggestions. I do not desire the problem to worsen to cause other problems.

Dipoxy-Steel. Comes with 2 tubes (Black + White) you mix them and they turn darK-grey. Apply this and it becomes like steel.

J B Weld

Sand the crack down to clean metal, wipe it down with lacquer thinner, cut a patch from a bit of copper flashing. (In a pinch you can use tin can steel, just be sure you cover the steel with the epoxy to prevent any rust.) Mix the epoxy with a popsicle stick, install, push the patch into the blob of epoxy to make sure you get a good mechanical bridge. This will outlast the rest of the car.

You can get j. b. weld at most any hardware store. Here is a link to the company.

J-B Weld is an extraordinary product. It will hold forever if you make sure the surface is absolutely clean and dry, and then warm it with heat from a heat lamp for the last five or six hours of curing time. 120-130 degrees Fahrenheit seems to work well

In 1974 it repaired a plastic eyeglass frame, broken at the bridge. This repair lasted four years, until it was time for a new prescription.

Some radiator shops will install a new plastic top and clean and rod the radiator cheaper than a new radiator.

Thank-you.

Before you repair or replace the rad with a new one, have the rad cap checked to make sure it releases at its over pressure rating.

Secondly if a head gasket has failed you might blow the new radiator as well. With the engine cold remove the rad cap and check for bubbles when the engine is revved up slightly to confirm this is not the cause, then replace the rad and the cap with new ones.

Good luck Elroy

Good answer....it is ALWAYS a good idea to ask yourself before you repair something a few basic questions. Like, "why do you suppose this broke" and "is what caused it to break still there, waiting to break it again?

(Like, just what blew that fuse anyway, and is it still there?)

j b weld but u r better off replacing with a new radiator and not used look online it could be mailed straight to you're house