I have a 2001 4.0L XJ w/ 145K miles that was just diagnosed with a crack in the block. Does anyone have experience using engine block leak stop products like:

-K-Seal
-Bar's Liquid Copper
-Steel Seal
-Or something I've never heard of?

I just bought this Jeep in November for a little over $4K and I'm not interested in paying the mechanic $6K for a new engine. Even if I had the time to do it myself, I live in a high-rise apartment and have no access to a shop. I'm hoping for a Hail Mary with a leak stopper and squeezing some more life out of this XJ, rather than just selling it for a loss so quickly.

The crack is on the left side, starts at the top of the block between exhaust and intake ports for the #1 cylinder and runs at roughly a 45-degree angle to the front of the engine towards the water pump, but does not go all the way to the water pump. It's difficult to tell, but I'd estimate it is between 3/4 - 1.5 inches. It is very clearly leaking coolant external to the block; I've been topping off the coolant reservoir at about ~1/2 gallon per week.

The oil looks great and it passed a compression check beautifully, so I don't believe coolant is leaking into the crankcase or cylinders. I am going to get an oil analysis from Blackstone to be sure, though. I doubt it matters much, but I'll add that it has green non-HOAT coolant in the system currently.

Any input or feedback on experience using leak stopping products for engine blocks is greatly appreciated.

 

They work very well, they seal everything. You can pretty much plan on having no heat.

 

Ha! Good to know. Sounds like I should bypass the heater core for this procedure.

Any brand stick out as more effective than others in your opinion?

 

I've been wrenching for 40 years. None of that stuff has been proven to work in my opinion. They might work for a short time, but not for any length of time.

If your block is truly cracked, shop around for a replacement salvage yard engine.

The $6k estimate you got is not what you want to spend for a vehicle of this vintage.

 

$6k for an engine in an XJ, what has that mechanic been smoking? A reman engine should only be around $1.5k-$2k and maybe $1k labor to swap it out. You could probably get a good used engine for $500 or so (labor would be the same if you pay a shop to do the work).

 

I agree with TJ , no miracle fix out there (I,ve been wrenching for about 30 years lol) , But I have had limited success with a product called "ironTite"


might be worth a try...here is a link to the product (All weather Seal)

http://www.irontite.com/



This might buy you some time...I used this in a ford Bronco with a 351m engine that was cracked ...actually lasted a couple of years..
Good luck

 

OP listed Northern Virginia/DC for location, it's easy to spend $75 @ Dairy Queen for a quick lunch.

 

Should be able to get a junkyard engine swapped in for about $2k

 

As a hail mary I would personally CLEAN the hell out of the block around the crack and use some good epoxy on it.

If nothing else it will slow the leak down but if done right there's a good chance it will stop it for quite a while.

You must drain the coolant before doing this. Make sure the area to be epoxied is good and clean.

 

FWIW, I've used a product called AlumaSeal in the past. Stopped small pesky leaks really well and the heater continued to work fine.

 

You sure it's the block and not the head that is cracked?

 

It's a small hairline external crack with coolant leaking only to the outside? That doesn't worry me as much as an internal leak, provided you don't let it run low and overheat.
I'd be tempted to use a radiator stop leak like Bar's (or alumaseal like Djb suggested) either one might wedge in there and plug it without wrecking anything else. The cracked-block stuff can make a big mess that's impossible to remove.

Another option is to drill out the crack and stitch it:
http://www.locknstitch.com/Default.htm
But that's probably going to require the motor be pulled, in which case you may as well just swap blocks.

 

Moroso Ceramic Seal.
Follow the instructions to a T.
Bypass the heater core and flush the radiator separately.

 

x2

 

don't use cheap fluids. Find XJ motor for 500$ or so and swap all the good part onto one motor. You will only have to change timing chain and set the timing is the most difficult part. Which that is still simple. Cracked block is junk. Only other thing I see doing is find a good welder to seal it , but it wont last forever. Nothing does anyway. So Get a new block my friend!