Radiator

what is a good sealer for a small leak at the bottom of a plastic radiator.

If you remove the radiator and completely drain it…black 2 part plastic epoxy will be the job. Make sure you sand the area to be repaired. I fixed a 1996 Jeep Cherokee with this technique a few years ago and the vehicle is still on the road. The best “fix” however would be to replace the radiator with a good used one or better yet…a new one. They are inexpensive for some vehicle models.

What kind of car do you have?

I would try some of the granulated sealer found at the parts stores. Other than that, I would follow missleman’s advice of remove the radiator and completely drain it. At that point I would deviate from it and install a new radiator. They’re pretty cheap nowadays unless you drive something exotic. And if you’re going to the trouble of removing one to attempt a repair, why wouldn’t you put a new one in and not have to wonder how long before another leak opens up?

I’ll throw another idea out there . . .

Some radiator shops will replace the plastic side tanks

That said, I don’t see how it makes economic sense to replace the plastic side tank, when the core itself might be in marginal condition by now. Not to mention the radiator shop will charge some labor to replace the side tanks.

If you want to be economical, you kill 2 birds with one stone. Go to a local mom and pop radiator shop and buy a radiator from them. Not only are their prices lower than Autozone, oreilly, pep boys, etc., they will almost certainly have the part in stock, provided it’s not some exotic Ferrari or custom job

I’m with db on this, except that I’d suggest price shopping amoung local radiator shops. I’ve found a wide variation in the cost of replacement radiators with no difference in quality.

Gotta also agree with db on this. First, radiators are pretty cheap now so why mess with it? I have just replaced the plastic tank part for like $35. Its a crap shoot that it won’t leak or you won’t break a tab, but if you are careful it can work, but generally just replace.

As a price point, I purchased a new aftermarket radiator for my Corolla for less than $100. Might be interesting to see if the OP’s radiator can be fixed with epoxy though. Worth a try anyway. If there are no inexpensive aftermarket radiators for the OP’s car available, and the epoxy doesn’t work, definitely consult the local radiator shop to see what they can offer as an alternative.

The places here that used to re-core factory plastic tanks have not done so in a long time because a Chinese tank is so much cheaper.