So after replacing the top end of the engine (both heads), it turns out that the block has a crack somewhere as well. About a gallon and a half of coolant is getting into the crankcase over a 12 hour sitting period. Anyone have any experience with CRC's K&W Block sealer? Have already put it in, just wondering if anyone has had any positive results with it.

 

Post all you did to the engine..........so we can think of a possible cause.

 

Have replaced both heads, head gaskets, valley pan, upper thermostat and gasket, new exhaust manifold gaskets. The oil cooler is less than a year old. Would'nt have realised that the water was still getting into the crankcase if it wasn't for the fact that both the front and rear main seals are leaking and as the fluid level in the sump goes up, the seals start leaking by. While the heads were off, did a visual inspection of the cylinders and they all appeared to be in pretty good shape. The heads that were replaced were also both cracked. This all occurred due to the large coolant hose from the resevoir/fill tank coming off while we were trying to deliver 6 yards of dirt. Not sure exactly how long the truck was running while all the coolant was running out of the disconnected hose but it could'nt have been more than 3 to 4 minutes from the time we heard the hose give way until we could find a safe place to pull over and kill the engine. On a happier note, the engine starts right up now and sounds great, just can't allow it to run for any length of time due to the crack and fluid levels rising and lowering.

 

I found a good 3" crack in my block to tell you the truth you got more work ahead. with that high of compression if the block is cracked it is going to leak coolant. you can sleave the block though I would just start tearing it down before you have it lock up or somthing.

 

Before tearing anything appart I would do some tests......the main one would be as stated in this info I saved below. I do not know R Peter but his info is sound.

Cavitation Diagnosis
Source:
RPeter


--------------------------------------------------------------------------------
Updated November 7, 2001
As a 7.3L IDI & Powerstroke Ford technician I would like to clarify cavitation erosion diagnosis. I work on these engines all day every day and have developed my own test for this problem which has yet to fail me.

To accurately pinpoint the cylinder leaking the full steps are as follows:


Warm up the engine
Remove all glow plugs
Remove valve covers, rocker arms, and pushrods
Using an adapter that threads into the glow plug hole, attach compressed air (100-175psi)
Wait 3 mins for each cyl being tested.
A failed cylinder will make the Coolant level slowly rise and then overflow from top of radiator. It won't blow out of the radiator, but it will be obvious.
On Power Stroke Diesels a false failure may be indicated due to a leaky bottom injector o-ring. So, before you run off in a panic, consider that the o-ring may be defective, effect repair of the o-ring in that cylinder, then re-test.
NOTES:

Valve train should be removed to allow the piston, in the cylinder to be tested, to drop to BDC when shop air pressure is applied. This insures the valves will be closed and the entire cylinder surface can be tested under pressure.
You can purchase an air pressure adapter at most tool shops (they normally are sold to adapt a compression tester to the glow plug hole)
The cylinders that are most prone to cavitation are listed in order. #8, #7, and #4. Be sure to test all cylinders as I have seen some of the other cylinders occasionally deviate from this norm.
Most coolant leaks into the cylinder will show as the glow plug tip will be wet on the bad cylinder.
I have had very good success sleeving these engines in my business, but the key is finding a machine shop that has done this specific repair before. You don't want yours to be the machine shop's first kick at the cat!!.

 

or you could remove one glow plug at a time until it shoots antifreeze.

 

Shooting antifreeze only shows there is a leak somewhere......not cavitation necessarily.

double ott trep.... your sure you put the head gaskets on right side up......it is stamped in the gasket but hard to see.

 

I actually did not put the heads on the block, one of my friends had shown up about an hour before I got to the truck that morning and already had them in place. I have no doubts that he had installed the gaskets properly though. He is a navy diesel mechanic and a die hard power stroke nut with lots of ford engine experience. In any case, the K & W block sealer has had 36 hours to dry up in the water jacket now and were gonna refill the rad again this morning, fire it up and see what we got. I'll keep ya posted as to what happens later.

One other thing, the heater core hose connections on the firewall are in an over and under configuration on this truck and during the engine disassembly to pull the heads off, my friend mentioned to me that he thought the heater hoses were connected backwards. Which hose goes to the top of the water pump connection and which to the right cylinder head.

 

The coolant hose from the block (outlet) goes to the heater connection closest the fender and Ts off to the bottom of the rad if you have that one.. The waterpump gets the the return from the inner connection.

You say over under configuration, so which way it goes throught the core is irrelivant to my knowledge.......just hook the hoses in the right flow.

 

I quess it's all mute now anyway, water from cooling jacket (somewhere in engine) is leaking into the oil pan at about a quart every 15 minutes now. Must be a pretty signifigant crack. Anyway, thanks to everyone for the help and advice. Time to find another motor.

 

Sent email did you take any pics of the heads before installation........

 

I would do an air pressure cavitation test before I removed the engine from the truck.
You could have cooked an O ring in the oil cooler or there could be a pinhole in the front engine cover behind the water pump. The rubber on the head gasket could have even failed due to high heat.
It may be wishful thinking, but I would check all options before I went engine shopping.

 

I didn't get a chance to take any pics of the heads prior to installation. In fact, by the time I had gotten to the truck that morning, a friend of mine had already installed the gaskets and heads and started the first torque sequence on the bolts. I took over after that.


From your email...
Did your heads have open holes at the valley pan seal other than intake, there should have been a line of 1" holes with frost plugs in them, they are coolant holes. A friend of mine got a set of heads back and the repairer did not install them. The valley pan can on occasion seal those hole off but not always and it is direct opening into the upper area of the oil return gallery/lifter area.

Not sure I'm following ya on the line of 1" holes.
I don't have email privledges on FTE for some reason, guess not enough posts yet.

 

I looked at the cavitation test procedure and understand the theory behind the raising coolant level due to 100-175psi air, Do you think that pin holes could allow that much of coolant to enter the sump while the engine is cold? It is approx 40oz every 17 minutes or so.
I haven't taken the cooler off at all so the o-rings may be the problem. The head gaskets are new and have not seen coolant temps above 180 since installation as read by the temp guage.

 

I bought a reman engine that had a cracked block between the #6 and #8 cylinder.
No problems at first, but the head gasket failed shortly after I installed the engine.

When it was running it blew coolant out of the reservoir.
Put a pressure tester on it and it built 30 pounds of pressure in the radiator in 11 seconds after start. This was on a 6600 dollar 7.3 turbo upgrade motor. All I can say is thank god for warranties and they honored it.

After reading what you are going through, I would do every test I could to make sure the problem is really a cracked block. The cavitation test is how we found where to look for the failure. The gasket is actually where the leak was, and the crack was so small it would have been hard to find if we had no idea where to look.



The crack is between the black lines.

If I removed the radiator cap I could still run the engine and the only coolant I lost was out of the cap. If the cap was off when I turned the engine off the coolant loss was minimal. But if the cap was on, the pressure in the radiator filled the 6 and 8 cylinders with coolant very quickly. Even so it took a long time for it to drain past the rings into the oil pan.

This is what makes me think the leak is not in the cylinder area.
A hole in the timing gear cover gaskets behind the water pump would drop water straight into the oil pan. So would a failed O ring or gasket in the oil cooler area. The loss you are having would require a real big hole somewhere, it will not go past the rings that fast even with two cylinders failed.