# radiator leaking, would you use radweld?



## Melkor (Aug 16, 2012)

Hi all
My rad started leaking today, so I'm thinking of sticking radweld in until I can afford a new rad, I have read varied opinions, some saying it is safe and others saying it can damage the engine, any experiences on here? 
Cheers all.


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## PugIain (Jun 28, 2006)

I've never used it, although I have heard it can sludge stuff up..


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## HeavenlyDetail (Sep 22, 2006)

I had a radiator leak about a year ago and used it. Ive never had an issue since personally or lost any water now.


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## possul (Nov 14, 2008)

Its similar to fuel additives. Some use them some dont


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## Sh1ner (May 19, 2012)

Personally I avoid using it. It works but I have seen it block the heater matrix on a few cars over the years. Not so bad on a Vauxhall Astra, 15mins to change but usually requiring the entire dash to come out on say a Citroen.
It would depend on the type of leak in your radiator, swollen radiator, end cap seal or leaky core for example.
I have used Wynns radiator stop leak a few times and not had any problems. It is a bit like frogspawn and supposedly keeps in suspension and continually circulates around the system. Radweld has larger particles and will block larger leaks but I feel there is a higher risk of subsequent blockage.
I always reuse or replace the anti freeze after and when I get change the radiator I always flush the cooling system paying particular attention to the heater.
Radweld and no anti freeze is asking for trouble.


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## Melkor (Aug 16, 2012)

Thanks all
Shiner it would only be in the system for a couple of weeks until I get a new rad in, would it be ok I will flush the system when I change the rad.


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## Melkor (Aug 16, 2012)

It's a pinhole leak at the top part of the rad core.


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## Starbuck88 (Nov 12, 2013)

Just put some egg white in it...


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## danwel (Feb 18, 2007)

Used it before and done a great job


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## craigeh123 (Dec 26, 2011)

I personally wouldn't use it , ive seen it block stuff jam thermostats etc . If its a pinhole could you use metal putty on the outside of the rad instead ?


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## TOMMY_RS (Aug 2, 2010)

I used it on my old golf, worked a treat and never had a problem


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## danski (Aug 4, 2008)

I used radweld in the past and it blocked up the heater matrix as mentioned above.

Best thing I ever used was called Ce-lit. Cheap too, just has a quick look on ebay for you...

http://www.ebay.co.uk/itm/5-x-CE-LI..._Body_Shop_Supplies_Paint&hash=item51afc13db1


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## Sh1ner (May 19, 2012)

Melkor said:


> Thanks all
> Shiner it would only be in the system for a couple of weeks until I get a new rad in, would it be ok I will flush the system when I change the rad.


I think that is the problem with any product like this once it is in it is in. I know a few people who have been pleased with Ce-lit but I could not remember the name.
Perhaps with any product like this is any after effects that need to be considered.
If it is only a small leak then I would maybe keep a 5ltr container or two of anti freeze and water with me and top up as necessary if it is only for a couple of weeks. You soon get to know how much water it loses. I sometimes unscrew the radiator cap so it only partially/just seals so any pressure vents out rather than squirts water out of the hole in the rad. This only really works if you are not constantly stuck in traffic with the needle in the red but for driving a to b works just fine.
Craigh123s solution of gently pressing some chemical metal, I have seen isopon used successfully, on from the outside also works if done correctly and also avoids any internal hard to remove contamination but sometimes requires the radiator to be removed to do it,which may defeat the object.


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## Roswell (Aug 11, 2008)

if you can see the leak cant you solder it ?? after all thats how radiators are made ;-)


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## Sh1ner (May 19, 2012)

Most are aluminium cored with plastic tanks sealed with o'rings these days.
You can solder aluminium but is is not easy as it oxidises instantly. You need to scrub it with a wire brush as you solder to tin the surface and then solder the parts together.


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## craigeh123 (Dec 26, 2011)

What cars it on melkor ?


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## Melkor (Aug 16, 2012)

Hi it's on a lexus ls400, can't solder it as it is plastic along the top, I put the radweld in this morning out of desperation, but it didn't work and the rad has totally blown now, the car is undrivable, I have managed to get a new rad, but I need to try and fit it myself and im not really sure what I'm doing to be honest.


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## Sh1ner (May 19, 2012)

It is not difficult if you have the tools. Is your timing belt due for replacement as now would be a good time to do it whilst the rad is out.
There is some info here http://www.clublexus.com/forums/ls400/501875-changed-radiator-ls400-1990-a.html and here http://www.clublexus.com/forums/gx-first-generation/432090-radiator-change.html.


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## bidderman1969 (Oct 20, 2006)

Wish I'd seen this before, I was advised to use K-Seal when my rad sprang a leak, glad I did, haven't had a problem since


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## Brooklands (Jun 12, 2010)

Do not do it. Anything like that will only block your head, causing overheating and then headgasket failure. If funds are tight, look for a good used rad and replace with a new on one when funds allow.


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## carl robson (Nov 16, 2011)

Me being me i would buy a new one but then again my car gets what it needs regardless of cost (96 e36 )so it's not new ) tbh saves a load of hassle and possible expense 
Ok a new rad might not be cheap but using rad weld or k seal is only asking for trouble in the long run


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## bidderman1969 (Oct 20, 2006)

Haven't heard a single negative about k-seal yet


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## carl robson (Nov 16, 2011)

bidderman1969 said:


> Haven't heard a single negative about k-seal yet


I'm OCD with things like this I'm sure it's a fine product but at the end if the day I see these products as a temp fix only


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## Melkor (Aug 16, 2012)

Thanks everyone, right I have got a new rad,im going to fit it tomorrow, how can I flush the radweld out of the engine and heater matrix, do I just need to flush it out with a hose?


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## craigeh123 (Dec 26, 2011)

Id only use kseal etc on a vehicle not worth spending on tbh . Lexus rads pretty simple tbh as its in the bay . My advise would be look at the new one as a guide of what needs to come off . Where do you live ? Maybe someone near by can help (myself inc if im nearby)


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## craigeh123 (Dec 26, 2011)

Damn just seen your in Essex


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## Melkor (Aug 16, 2012)

Thanks for the offer Craig.
looking at the new rad it seems pretty straightforward, access is pretty good and the condenser and the fan are separate from the rad.


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## Melkor (Aug 16, 2012)

OK just to update 
I fitted the new radiator this morning, it was pretty straightforward, but after draining the system down the expansion bottle was still full up anyway I removed the tank and it was completely blocked with radweld, luckily this seems to have stopped it getting through into the engine and matrix, I flushed it through and all now seems well, so thanks for all your help.


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## craigeh123 (Dec 26, 2011)

Awesome , told you radwelds bad !


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## Melkor (Aug 16, 2012)

Yep lesson learned, cheers Craig.


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## alan_mcc (Oct 28, 2008)

Good to hear you got it sorted.


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