Radweld

[stuffedpike20]

My modern car (32 years old) has got a leak in the heater matrix. It would be a massive job to replace it. I am not even sure a replacement is available.

Would Radweld sort it out permanently?

I was told by a Toyota employee some years ago that each Toyota coming off the production line at Derby has a can of Radweld put in it.
There are a few different types of Radweld now. Which would be the best?

Thanks.
John

[MikeNash]

Corr! "Radweld"!
Until you mentioned it I'd forgotten all about it. At least 15 years ago I had a bad rad leak and used a can. It was a complete cure and that rad has had many flushes etc since without trouble. What type to use? No idea - in those day there was only one! In my experience use it with confidence.
Regards from MikeN.

[stuffedpike20]

Thanks Mike.

[Myrtles Man]

Barr's Leaks always used to be the stuff when I were a lad. Can you still get it?

[oliver90owner]

Barr's Leaks always used to be the stuff when I were a lad. Can you still get it?

Plus 1 for Bars leak. Yes, still available but not quite the same as I recall from yers ago. Likely marketed/presented better, these days. I was never confident with radweld 50 years ago. Bars leak has still done the job over more recent years.

Early radiator repairs included copious patching with P38/Isopon/Plastic Padding - particularly when the fan and radiator had made contact!

My most recent foray was to repair a rad, while a £350 replacement was sourced and fitted. After fitting the new rad (the old one had completely stopped leaking), the car was sold for not much more than the rad replacement. Such is life.

I was told by a Toyota employee some years ago that each Toyota coming off the production line at Derby has a can of Radweld put in it.

Obviously anecdotal, but doesn’t instil too much confidence in the build quality.

[kevin s]

I've used KSeal on a drip from my Range Rover Radiator, leak stopped and I hasn't leaked again in 3 years, An AA guy told me they carry it and it fixes virtually all radiaror leaks he comes accross.

[stuffedpike20]

Thanks Kevin.
I have found out that my leak is actually from the heater control valve, and not the heater matrix.

The bad news is that a new heater control valve is not available.

I will either have to try Radweld, or find some other valve that will do.

[myoldjalopy]

Well, here's a thing.....put some (I think it was Bars but not sure now) in a couple of years ago to cure a slight weep up one of the cylinder head nuts. And it did cure it. Then, this spring, I noticed a slight leak from a spot on the fins at the back of the radiator while I was at a friend's place. By the time I got home again, it had cured itself, so the Bars stuff still in there must have sorted it. But today I noticed the rad took a lot of topping up and there was a fine, dried spray over the plug leads, battery, dizzy cap etc. I noticed the leak had re-appeared in the rad (it seemed to be in the same place, as far as I could recall). I am gonna keep an eye on it and see if it seals up again, but maybe its time for a new rad - it is 68 years old, after all, and does look a bit worse for wear!

[stuffedpike20]

Radweld claims to not clog up any part of the cooling system that is not leaking.

What is the worst thing that can happen if I use Radweld to cure the leak in my heater control valve?

[oliver90owner]

Radweld claims to not clog up any part of the cooling system that is not leaking.

What is the worst thing that can happen if I use Radweld to cure the leak in my heater control valve?

The worst thing must be that it didn’t seal the leak, according to that claim. Just do it and let us know whether it works or not.

[stuffedpike20]

Ha ha! I used to be indecisive.....now I am not so sure.

[Sleeper]

I'm happy with...

https://www.ebay.co.uk/itm/234288356661 ... R4Tcp5_xYg

John ;-)

[myoldjalopy]

I'm happy with...

https://www.ebay.co.uk/itm/234288356661 ... R4Tcp5_xYg

John ;-)

The blurb is quite clear that it is a 'temporary' repair, and although I used a different product, which appears to have lasted on the slight weep from a cylinder head stud, it would seem that it was temporary when it came to my radiator leak (see my previous post above). I suppose I could try adding some more stuff but am moving towards the idea of a new rad, especially as the old one has definitely seen better days.

[stuffedpike20]

I looked at ce-lit too, and noticed that they themselves call it temporary.

Thanks for the suggestion though.

[stuffedpike20]

Just a quick update. I put Radweld in the system for a few days. Then I drained the system and re-filled with water and antifreeze.
The leak from the heater control valve seems to have stopped....for now.

[StillGotMy1stCar]

Just a quick update. I put Radweld in the system for a few days. Then I drained the system and re-filled with water and antifreeze.
The leak from the heater control valve seems to have stopped....for now.

I’ve successfully used the blue bottle version of Radweld a few times for leaks I can’t find.
I’ve always left it in the system, I thought that was the point of it, I’ve not got a bottle at hand, but I can remember it contains corrosion inhibitors.

Regards John

[stuffedpike20]

You are supposed to leave it in the system.
I was surprised how the little bottle of Radweld coloured the coolant, and worried about it forming sludge, so once the leak stopped, I drained it and re-filled.
If the leak comes back, I will put another bottle in, and leave it.

[StillGotMy1stCar]

I expect half a bottle would work.
I don’t know if it would form a sludge, but I do understand your concern.
I took the bottom tank off a radiator recently to resolder that had a copper coloured sealer in it and that had formed part of the sludge, a mixture of rust and sealer about 1/8th of an inch thick, too solid to become waterborne through normal flow.

Regards John

[myoldjalopy]

OK, so the rad leak I mentioned earlier started yet again and thus I decided to go for a brand-new rad than mess about with more Bars. Just as well, by the state of the old one when I pulled it out! I also confirmed that the water pump had quite a bit of play in the bearings so I replaced that at the same time (luckily had a new spare one on stand-by ).
I'm wondering if it would be worth re-furbing the old rad (not that I'll need one if the new one lasts another 68 years, but it seems a shame to scrap it in a way). What do you guys think?

2023-11-22 15.49.44.jpg (643.72 KiB) Viewed 326 times

[geoberni]

High Top Radiator are expensive, if it's salvageable, then do it.
I've seem complete wrecks go on ebay as 'Spares or Repair'.
My Series II had a regular Radiator, it took me years to find a reasonable replacement.
Luckily I spotted it on ebay from a guy clearing his late father garage; it was a reconditioned one from the 60s or 70s, still with fabric tape over the hose connections. His dad had brought it 'just in case'.
There's even little brass plate from long since gone place that reconditioned it

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