JB Weld to fix cracked block, leaking coolant

[EmilA]

Does anyone have any experience/success of using JB Weld to fix a hairline crack in an engine block which is currently leaking coolant?

I have a small hairline crack in my block on the inlet side, we used a solution that goes in the coolant system which has managed to massively slow down the weep, but it's still there. I was loosing maybe 100ml every 5 mins before.

Since February this year, I've poured in 6.5l of coolant to keep it topped up, but have also driven maybe 6000 kilometres.

I plan on using that solution again in the coolant, but wondering if I should also or just use JB weld on the block.

From what I have seen, the best thing to do with JB weld is to use a Dremel to expand the hairline crack abit/rough up the surface to help the JB weld stick to the block

[GreenV8S]

You may have more success with a dedicated crack sealent like Oyltite.

[hellorent]

Years ago used araldite to fix leaking gearbox casing, worked ok until they sold it

[Lincsls1]

I used JB Weld to repair a leaking gearbox, where there was a hairline crack around the drain plug. Worked a treat.
I rate the stuff, certainly worth a try.

[richhead]

steel seal used to be the thintog use, not sure if you can still get it, it goes in the coolant, well you have to have no antifreeze in there and take out the thermostat, ive used it as a last resort in the past.

[alabbasi]

A friend of mine did this on a Cummins diesel block just had water instead of coolant and froze. It seemed to work.

[anyoldcardave]

If you get it to stick in can do the job, clean the area properly first time, I would not keep pouring stuff into the coolant .

[Sardonicus]

Much as I hate to say it I have known two head gasket type failures with all the symptoms stopped with Steel Seal (pressurising cooling system etc) and one still running around (Vauxhall) 4 years later , if you take care with the instructions inc their suggested coolants it works a P38 Range Rover 4.6 with suspected cracking behind a liner and a Vauxhall Zafira I did on request from the customers hack (no thermostat removal) I changed the water pump a short while back with no signs of gloop or strange residue or deposits in the water jacket often associated with leak stoppers etc however personally i'd look up Devcon products if sealing the block from the outside is a possibility a repair I would prefer over the Steel Seal or some other external method but thats just me

Edited by Sardonicus on Friday 5th September 09:49

[InitialDave]

Should work tbh.

As well as the Dremel stuff, I'd drill a small hole at each end of the crack to stop it propagating further.