My car has a crack in the engine block by the passenger side motor mount. It leaks a little puddle of coolant a night. I have to refill the overflow tank maybe once every 2 months, so it's not so bad.

However, I've tried to JB weld the outside of it about 6 times now, and the JB weld always cracks and does nothing. So now I want to try a coolant additive to see if I can plug it up from the inside. My only concern is if it will plug up sensors or anything? Also, what would you guys recommend for use?

 

I wouldn't do that. You need to patch it from the outside using something that can undergo the hot temperatures without melting/expanding/falling off.

 

always had good luck with alumina seal, silver looking powder.

never like the bar leaks with its giant chunks

But if you can get to it, id just be tempted to weld it. wouldn't go crazy, just close it up.

 

Well it's in a place we could probably weld but my dads friend told him that the weld wouldn't hold for some reason. I don't remember why but he told him that the metal wouldn't weld correctly....I may have to look into this. So far nothing on the outside has worked. We've tried JB weld, JB quick weld, and JB water weld all to no avail.

 

wheres the crack? I've used jb weld before with success. there are better products out there if you dont have the funds to fix it right. when my old man was driving truck he had a similar problem fixed it with jb weld and its still holding to this day with the new owner. how are you applying it? proper surface prep is necessary with that stuff

 

Crack is about 2-3 inches towards the front side of the car by the passenger side motor mount.

What we've always done is sand down the area so it's rough. Then we mix up some of the JB weld and apply it to the area. We try to get it as thick as possible but it always runs some. The resulting weld after 24 hours is maybe 1/4 inch think and it covers the hole. Then it leaks the first night after I drive it.

After it leaks we go under the car and get one of two results:

1. The weld never held and the piece just pops right off with a little pressure.
2. The weld was too thin and it cracks, letting the coolant go through it.

 

you can weld it. it will hold. call a couple professional welders in your area and see what they have to say. You just have to preheat it use a special rod and not let it cool down fast.

 

Id say sometimes, its best not to listen, I heard the same thing when I welded my cast iron heat riser valve, after I welded it. "you can't weld cast iron" well I did. [flux core mig]


weld away, just don't go nuts, make sure the block is drained well and dry, water will come out with the heat n screw with ya, maybe blow air into the crack to dry the area.


Could braze it too probably if he was not comfy welding, you can braze anything and its ok, just not as strong and the part must be HOT for it to stick well.

 

I agree with gumby about how its best not to listen sometimes you know what they say about opinions . I've welded cast iron multiple times and have never had a failure.

 

Alright, I always wanted to weld it but my dad was freaked out about it. I'll check into it, it would make me feel better about it. I'd really like this block to last for a while so I don't have to fork out a ton of cash right before I got into college (I'm a senior in HS right now).

 

You guys can weld cast engine blocks? Man my welding must suck lol.

 

It needs to be chain locked.

 

So my dad thinks that we would need to remove the motor, which he said at that point I might as well just get a new motor. Well I don't have the money for it and my mom won't buy me one so that's out of it I guess.

So here are my options:

1. convince my dad we can weld it while the engine is in the car.
2. Have my grandpa attempt to JB weld it.
3. Save up my summer money and hope I can get a new block.
4. Run something through the coolant.
5. Leave it how it is and deal with it...

 

try some aluminum seal if its as slow as you say, it should clogg it up.

 

there is also some stuff that we use at our shop for customers who dont have the funds to fix there water leaks and it its called ironnite it usauly gets them by for a few months but its a gamble.

but thats if your going to use an additive just another idea

 

Look for a 305 on craigslist. Ive parted a few thirdgens and couldnt get rid of a 305 to save my life. people will literally give them away. the last two I had spent 3 months on craigslist with me offering free delivery and they ended up going to the recycle place.

 

Drain your engine before you JB weld it. Get all the water out, give it a few hours to dry, try the JB weld again and let it cure for a good 24-48 hours (have access to a heated garage?) I think the antifreeze in the coolant prevents the JB from setting.

Or you could try welding it. A decent welding shop should be able to do it for a decent price.

 

removing and reinstalling to weld it isnt hard at all. maybe one full day for a novice if its really necessary. Did u drain the motor completely when you used the jb weld?

 

Ok so this is what happened. My dad and I tried JB weld again, it was a no go. So we got my grandpa over to try to see if he could get it to work for him. As he was cleaning the area off he noticed that around the hole there was a lot of black stuff. He took a pick and stuck it in the hole and got out a ton of grease. After about 30 minutes of cleaning, the hole was actually a perfect circle about 1/2 inch in diameter. It looked almost like it was suppose to be there in the block.

After we cleaned all the grease out, we stuck some jb weld stik in the hole and let it set. I think we got it now, I will report back though.

 

was the hole threaded?

and it seems you were trying to jb weld over grease? thats why it didnt work....

 

Had the exact same problem on my 89. I put blue devil head gasket sealant in it and it has worked great for over 3 years and 4k miles. I have had to replace the heater core though but not sure if it was age or the sealant that did it.

 

No that was the weird part. We were looking to see if we could see any threads, but there was none. It was almost like it was suppose to be there.

I wanted to get a picture of it but I was too late. By time I got the camera the JB weld was already in the hole.

 

Sounds like a freeze plug leaking to me.