I remember reading somewhere that this stuff is the spawn of the devil - but I can't remember why

Someone has asked me to investigate a coolant leak on their car and I've just found the source

Another component has worked loose from a holding bracket and has chafed the back of the rad, damaging an area (slightly) around the size of a postage stamp

It won't be an easy or cheap job to replace the rad and I'm quite sure radweld or similar will plug the leak

Thoughts?

Evidence based please

 

Radweld from experience is only suitable as a temporary fix until a new rad is sourced.

 

The issue is that when it comes into contact with air, it sets .. I've seen (on a mk2 MR2 - which has a rad in the front and LONG coolant pipes to the engine) where the coolant system has air bubbles in, the radweld goes solid and then blocks waterways.

I'd only use it as a VERY temp measure (get me home), totally flush the system after (force water through the block) and only on a car I didn't want to keep much longer after.

 

What age of car are we talking about here? A beater or something more performance related that will be a long term keeper?

I used radweld on my old triumph herald back in the 90's. Worked fine. It fixed the leak, and the leak remained plugged even when i purged the coolant at a later date.

Ben's point about radweld going off when in contact with air is the main issue for not using it. But if it is an unsophisticated car, i would give it a try and then watch the temp sensor and coolant levels carefully thereafter.

 

it's a beater

uncomplicated for the most part, but I'm not inclined to give up a (unpaid) day of my time to fit a new rad, change the fluid, etc etc

I've used this stuff back in the day and I think in view of the comments I'll give it a shot and see what happens

the reason I asked about evidence is that I used the stuff plenty of times before and never had a problem

nor did anyone else I knew

 

I have used it on a few beaters with no problems ..

After using a couple of tins on my daughters first clio , it wasnt long after that the thermostat got stuck ( closed of course )

 

What he said.

It can be used longer term, but there is also the very real possibility that it will come into contact with air in the wrong place and restrict the flow of water around the engine.

This *can* lead to overheating, or hot spots around the engine, causing failure of other, more expensive to replace components (like the head gasket or the water pump). It could also be fine. But the problem is, you won't know until it happens. Or doesn't.

Not something I'd use, even in a beater.

 

I used rad weld in my old Golf, as the radiator was slightly leaking, and had no problems. Three years later it was still going strong.

 

it's fixed

used the radweld then once the leak was gone, refilled the system with fresh fluid

all seems fine