Possible Cracked Engine Block
 

Hello all,

I am posting under my roomate's name, so that there isn't any confusion with his profile setup

I am currently faced with a large dilemma. I have a 2.5L 94 YJ that is getting coolant in the engine oil. This problem stems from a couple of weeks ago when the thermostat stuck and the engine overheated. I took the head off, got it tested and planed and came back in great shape. Put a new head gasket on, bolted everything back together. I ran bar's stop leak thru the block and changed the thermostat again.

The engine fires up fine, but it is not cooling well at all. The cooling system never works well enough to cool the engine when driving. (good thing its -15 degrees up here most of the time in Potsdam, NY) Every time I start the engine, about a minute later I get bubbles running thru the radiator It is ok when idle in the shop, but not for a long time. I am getting plenty of heat thru the heater core though.

Now to my question... Could this problem be anything but a crack in the engine block? I have a replacement about 2 hours away from me, but before I perform this large project, any suggestions on things to check beforehand are much appreciated.

Thanks in advance!
Tim
94YJ, 2"BDS Lift, 32" BFG All Terrains

Re: Possible Cracked Engine Block
 

sounds like a cracked block. I just went through the same thing with a toyota 22r motor. We thought it was just a blown head gasket, and didn't look super hard at the block. We went to all the trouble of doing the head gasket( toyota doesn't make them easy to work on like Jeep) then fired it up and the problem was still there. When we pulled the head the hair line crack was apparent in the #3 cylinder.

Look hard at you cylinder walls, turn the engine over with a breaker bar and watch each cylinder individually. I bet you will see a crack. One thing to look for is "scratches" going the opposite way of the piston, side to side, instead of up and down. That is a give away, because it wouldn't be possible to score the cylinder wall that direction, that is how the toyota crack looked.

Good luck, hopefully it isn't your daily driver, so you don't have to rush through the engine swap.

tony

Re: Possible Cracked Engine Block
 

How did they test the head? Magnaflux,zyglo,pressure? Makes a big difference. Overheating doesn't usually crack a block but will warp and or crack heads. Take the head off and look again at both.

Re: Possible Cracked Engine Block
 

They pressure tested the valves, and then checked to see if the head was warped at all. After everything came out well within specs, they milled the surface flat. The head visually looked to be in good condition.

Thanks for the replies!

Re: Possible Cracked Engine Block
 

It is a real bummer to have torn the whole thing apart, and to then have to take the whole thing apart again. I don't have any experence with cracked blocks or heads. But I do feel your pain, and at least this will bump your post BTT.

Re: Possible Cracked Engine Block
 

Magnaflux will pick up cracks that others miss. Take the head to the shop and explain the symptoms to them. If they aren't capable of checking with magnaflux then take it to someone who can.