How to Fix a Cracked Radiator Plastic - JB Water weld 

I've done the same on my old car and my current jeep. No prep, I've gotten about a year out of the repairs. Actually going to do some prep this time! Good vid!

thank you having the knowledge to help others mechanically lost. thanks keep up the good tutorials

i fixed a crack in my BMW 330ci radiator with JB Weld - took a few shots but I now have a fantastic formula I recommend: 1. Get your engine warm and examine where the leak is. 2. Release the pressure and drain the coolant while it is still warm/mildly hot, but not too hot that when you seal the cooling system, it isn't blowing steam or air out of the hole you're trying to fix. 3. Once it isn't spitting but still warm - THEN apply the JB Weld and leave it for a few hours. Applyig it while the tank is still hot causes the glue to be drawn into the hole, caused by the internal vacuum when the hot air cools and returns from its exanded state. Exactly the same as when you fill an airtight tupperware with hot food and seal the lid while your food is still hot. By the time it's closed there's a vacuum inside ;)

Cool I’m trying this today. I also replaced the hose that goes to the reservoir with a clear silicone hose. I can see if the coolant is flowing to the radiator and reservoir tank.

Followed your steps. Sanded, cleaned, sanded again, cleaned. Made the patch. Let it sit and cure. It worked! Thanks for the tips. I’ll order the new all aluminum rad this week so it never happens again.

Ok I did the repair today on my 2015 Chevy Silverado. My crack is literally in the same side as yours. I spent alot of time hand sanding & cleaning mine. I didn't trust myself with an automatic sander. Once it was ready I mixed the stuff and I used a small art brush. I wanted to be able to get the seal in the crack. Then I put the fiber on top & added more. I decided to allow it cure for 24 hours. I will add an update tomorrow. I appreciate the tips.

I had a crack in my radiator(only a year old) as well. In a similar spot as yours and was obviously causing a leak. I used the JB Weld Plastic puddy instead of the water weld, but I have a feeling either would have gotten the job done. It worked incredibly well much like it did any time I used other JB puddy. This shit is the TRUTH.

I'veha good luck with that stuff ! prep is key for a lasting repair !

I appreciate your good video. Thanks for taking the time to do it.

Yea I used sum jb weld on my radiator hose and a crack on the radiator and it works like a dream! Been using for about 6 months now and only had to repair it twice

Thank you so much my brother I’m having the same problem and this video really helped I appreciate it take care peace

My Explorer got a crack at the same spot . I will use this method to fix it. Thanks buddy.

The VW 1.8T motors have a common issue where the coolant temp sensor goes or starts leaking. Being that it sits in a tube facing up so it can keep track of the Temps for the ecu and the instrument cluster often the case it leaks through the gasket as there is a clip that holds the sensor down with two split openings on each side of the pipe. Remembering vaguely years ago when it first came around someone said it fits but it doesn't stop the leaking so he gave my xwife an option as it was her car at the time and her father was footing the bill. Unfortunately 150k it has finally started acting up again. I only remembered when I has pulled out the sensor with a pliers after I pulled the pin out. So this time I'm gonna use roughly the same stuff just this waterweld version. Wanted to see what others thought. Thanks for the vid.

JB Weld is the GOAT

THANKS FOR THE VID! Ive been wondering if it would work on a small radiator crack!

You can wet your fingers or gloves or tools you use to press the epoxy down and smooth the epoxy to keep it from sticking and coming off of the repair

Thanks super video. Simple and confirmed after days. Ty

I will try on my truck, it is worth to try. To replace with new one is 2450 CAD + laborer

It would be best to drill a small hole at each end of the crack first to stop it going further otherwise it will just continue to crack out past where you have repaired it.

I use JB weld to replace the broken nipple on my plastic radiator with a brass one, it worked great but I did have to repeat the process a year later and every year from then on. But $5 each time was much cheaper than having a new radiator installed.

Jb weld is a good product for quick fixes like these, but yes I highly recommend taking the extra time to do the prep work first. I’m guilty for not doing the prep work before applying jb weld the last couple of times that I’ve used it, and i still got some good results from it. Just imagine how much longer it would last. Thanks for the video.

Thank you! This really helped

glad i came across this video... i have a small crack in the same spot as u had so im gonna try this.... mine isnt leaking to bad YET.... but before it gets cold i need to fix it and i dont have the 150$ for a new radiator... so...again... thanks for the info...

Thanks for sharing! Good video.

Why are all these radiator fixes right at the top where you can reach it 😂. Mine, can’t even see it. 🤨

I’m actually trying this right now as I watch the video. So we shall see 🤞🏾🤞🏾 12/30/2021

good work💯 I'm about to fix my Hummer 😁

I have almost the exact same hairline crack in the exact same spot on my 2004 ford ranger. I was gonna replace the radiator but I dont feel like spending the money during this time. I'm gonna try this quick fix in the meantime. Thanks!

Good educational vid. Unfortunately we don’t have JB Weld here. Will PC Fahrenheit Hi Temp work on plastic radiator; small crack

This putty weld just saved my butt from paying over 200 bucks!

Love the level holding the hood up lol

Thanks homie! I went and bought this product after your vid!

I don't want to spend money on new radiotar.... Thanks for the video I am just going to do that tomorrow

Muchas gracias he confirmado una vez más que con ese producto puedo reparar una leve fisura en el condensador ( parte plastica del mismo ) y así evitar pagar grandes cantidades de dinero por una reparación

I have an 07 ranger with what I'm pretty sure is the same radiator, and has a crack in the same place as the video...wondering if that's a weakness in this radiator model? Also if that's a sign thermostat is failing? But I did change my thermostat a year ago....

great job man....

I have an Identical crack in my 2002 jeep grand Cherokee. So thank you I subscribed and liked. Least I can do if this does work.

Si señor! me ayudo! gracias

I used the JB Weld Plastic Bonder, hoping it works.

The top of my radiator is leaking water when i add some to the reservoir its coming out through the top of the radiator plastic part.

Will it work if lets say the crack completely broke like will this fix a completely broken part back together?

I used the JB WELD marine on mine today.. see how that goes. Holds up to like 5,000 psi or something insane like that. I sanded it , maybe not as much as you, but still, hope it works. Thanks for posting.

I have been wondering what is the spirit level for, I get it now.

Cool thanks my is on the back around middle of the radiator. It is leaking out of it so ill probably sand it down and use the water weld and ad some something else on top after it. Is that a good idea?

Nice thanks❤❤❤❤

great to see this video, the radiator is still working or did u replace it?

How long did repair last?

Good work, hope it lasts a long time.

it worked on a crack that was 7 in Long on top and my 2004 trailblazer LS radiator

Is that patch still holding?

How long did it take for the putty to actually get Hard. Completely cure. Let me know please.

It's three and a half years now, is it still holding up or did you have to do it again?

My radiator is cracked in the exact same spot I think that’s why I have a very slow coolant leak

Just have a small crack in myine ima try this out thank u

I’m looking this up because I took my ranger off a dirt bike jump and nosedived into the ground. Cracked my radiator, and bent my power-steering cooler. Was it worth it though? …yeah it was worth it

Nice, to the HomeDepot I go!!

Can you use it on a plastic radiator

How long did the repair last? Great video!!!

Guys after applying the substance for how long should I wait before driving ?

Good prep work cleaning the area w/ sandpaper and wiping w/ alcohol, this didn't show what kind of temperature the weld was rated for which is a concern. Since it appears to be just a thick epoxy, using a thinner, more liquid(fluid) epoxy may work as well for thin cracks. Glad your fix worked!

You are my main man. I can't afford a rad right now and only drive to the store, less than one mile. I've searched this a lot. It got confusing. Your vid is calming & to the point. Pre-prep is the most important. I looked into Waterweld seeing your vid. Yep. Heads up, someone commented to use a metal patch over the epoxy. 🤔

I tried this, it works first 40 miles, then i buy new radiator

أين احصل على هذا المنتج وهل هو مفيد للشقوق الاكبر قليلا من الموجود بالفيديو

Well tried this stuff because parts store guy asked what I was fixing and told him had crack in radiator and I had the original high strength that I’ve always used but he said this was better, well I call BS prepared it sanded and degreased it and crap never got hard, so take my word for it wasted time the best is the high strength one with steel particles in in 3,700 +PSI...

How long it be holding for

what does the JB package say is the max temp it can withstand ?

Did it last?

Hey I have a question !

Could you also fuse the plastic back together with heat?

In my hyundai Sotanata not worked.

Still sealed ?

Please only use this product if you plan on replacing the radiator in the near future... I had tons of radiators come into my shop that COULD have been properly repaired for 30-40 bucks that needed completely replaced because people used this product... Sure it seals the crack but it also clogs the tubes... It will also reduce air flow if it gets between the fins...

How long do you have to wait before you can drive it after applying?

Gonna do this to temporarily fix until I replace my radiator. That way I can drive it until I have the money for the radiator.

My radiator is cracked and I’m planing to fusion weld it with some PLA filament I’ve got from my 3d printer. Since the radiator plastic is nylon I’m a bit concerned about the two not sticking very well so I’m going to cover it with water weld once I’m done for extra support. I’m getting the car ready to sell and a new radiator for it is only $70. I’ll be informing the buyer about it so they can decide what to do about it once it’s theirs.

Your voice sounds very familiar. Do I know you?

great video is it still holding up.

I have the same exact crack in my explorer crazy youd think they did it on purpose

Did you drain the coolant?

Have the same problem

Still holding?

Mine had a big crack and when warmed it would steam out

Will it work for a Bmw e92? Guess I'm gonna try it since it's just a tiny hole in the top and I already spend £250 for parts and pick up truck last week 😂

No Disrespect...But Over The Years I Have Tried Everything...The Longest A Patch Has Ever Last Me Is 3 Weeks...Your Next Best Alternative Is To Get A Radiator From A Junk Yard....$20

I will try this on my chevy cruze water reservoir 👍

Thxs my mechanic has me fucked up if he thinks I'm replacing the whole thing just for a crack

Can you put in on the metal part of your radiator?

I try it on my car and after 2 days it's have cracked true the potty

Will this work on AC lines, in the car?

❤👍

Update it still didn’t work

I literally used every type of jb weld, it didn't work on my honda civic

Would normal JB weld work?

Did it stay on ??

So I can do this instead of paying $1500

Purchased this putty today. Hit me up if you wana know if it works. Follow the blue heart.

update? is it still working? thanks

anybody know how long we have to wait to dry. or we can drive rightaway

just so you guys know the proper repair for this is, you have to take a hot sautering iron and melt the plastic shut then you would put the putty on take as an added layer of protection unfortunateely i bought my car used and alrdy had sealan on it and there was a small pin hole, I patched it up and well see! might take it offer and melt some plastic if its even possible to take this stuff off lol

Still working?