Repair radiator top tank leak?

1996 Honda Civic CX:

The radiator’s top tank leaks where it meets the main part of radiator. It’s a plastic top tank crimped on. Probably there’s a gasket in there. Is it feasible to remove that top, fix or repair or replace the gasket, and squeeze and crimp it back into place?

I would put in a new radiator, but I am helping a friend with no money and we are willing to experiment. He’s had this leak for some time and it seems that once the coolant level goes down a ways, there’s not much further loss. I say he’s been lucky.

Any advice on how to do this repair, what gasket material or goop to use, etc?

I’ve never seen anyone successfully repair a plastic tanked radiator. I hate to be harsh, but if this person can’t afford the hundred bucks or so a new radiator would cost, they can’t afford to own a car.

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I’ve seen just the plastic radiator ends for sale but I’ve never tried to replace just the tank. I doubt many people do it but it must be possible. Check rockauto radiator section and see what’s available.

Seems like the thing to do is buy a radiator for this friend and let them pay you 10.00 a month and just solve the problem.

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I wouldn’t try it unless you have the tool to do this.

Those tabs break off real easy.

Try adding ground pepper to the radiator to see if it will stop the leak.


I’ve seen this spray on stuff that is supposed to stop anything from leaking, even water lines under pressure. You can find it at Walmart in the “as seen on TV” display normally located near the check out lines. If that doesn’t work, a new radiator is probably the cheapest option in the long run. The labor to undo all those little tangs, replace the rubber gasket and re-crimp them would likely cost more than the radiator.

better than pepper or goop is Bar’s Leaks. The original pelletized formula.

I never had any luck with any bar’s leak what I did have luck with was alumaseal not sure I spelled that right,

My Corolla’s factory service manual says such a thing is possible to do, you have to take the radiator apart, replace some parts, and put it back together. Looks like it would be very difficult to do without special tooling though. The practical approach really is just to replace the radiator. The aftermarket radiator I purchased for my Corolla when it sprung a leak at the same place was less than $100. the aftermarket radiator doesn’t have the same fin density as the one that came with the car new, but configured with a manual transmission and no AC, works as well as a new radiator. And replacing the radiator was like a 30-40 minute job, very easy to do. If $100 is out of reach, you can probably get one from a recycling place like Pick N Pull for less than $50.

That plastic radiator tank is going to split open sooner or later. If you try to remove the top tank you won’t be able to reassemble the radiator. I remove the top and bottom tanks on radiators to recycle them and those old tanks crack very easily. A new radiator is $43 from Rock Auto.

I used to go to a radiator shop in my area that would re-core a radiator using your factory plastic top and bottom tanks. It was a better radiator than an offshore new one but he stopped doing it when new foreign radiators became cheaper than re-coring one.

In my opinion. if you try this, it will not be successful.