so i have hydro lok. bad. bad enough that i broke the starter bell housing plate twice in 4 days!

obviously i need to rebuild it, so i tore it down. found out that the engine is a 91 jasper rebuild from a bus that is in a 94 e350 ambulance chassis with 310k miles on the chassis. engine mileage is unknown.

i completely expected to find blown head gaskets, but saw no sign of leakage to the cylinders so i sent the heads to the shop. one had 3 cracks so i replaced it with a reman from DHPS in lenoir city tn (near Knoxville). they are a ford factory certified head reman shop. the other head was crack free, got surfaced and a valve job.

i put the heads back in (engine stayed in the van the whole time) and filled the oil with water INSTANTLY. shut it down and pulled the engine assuming i bad messed up a gasket reinstalling the heads (changing heads in a van is a true B****!)

While the engine was out i inspected the engine bored thoroughly, saw no problems, reinstalled the heads, put it back in and it still leaks!

Here's the wierd part - it leaked a quart of water in the oil in the first 2 minutes of running, i shut it down, let it rest a minute, tried to start it - hydro lock BAD!!!

I have read plenty about pin holes and cavitation, but i'm getting tons of water leakage immediately, way more than before i started, and it happens before it even gets warm!! I have WAY more water in the oil and cylinder than could come through a pinhole, the head gaskets look like they sealed very well, and i even had the heads rechecked for cracks and they are good.

at this point i dont know what to do. I just dont see how it can leak that fast!! this last time, it didnt even get hot enough to seal the manifold gasket to the manifold and head. I just have a massive water to oil leak and I dont know where. I ve got 1200.00 in heads, gaskets, and oil, and about 70 hours in it. Now what??

im getting ready to pull the engine again, but honestly, i dont think there is enough of a block problem to cause this much water leakage this fast. Im afraid Im gonna tear it daown and find out there is nothing wrong with the block. this is my only truck and i havent worked in over a week, and i'm screwed.

please help!!!

 

the culprit cylinder is driver side second from the front (#4 i think). i looseden the injectors and that is the only one that shot water out.

 

Sounds like it's suffered from Cavitation.... pin holes in cylinders caused by lack of coolant additives.


Do a search on here on SCA's, Coolant Additives and Cavitation.

Have a GOOD read through this, and you'll understand what happened.

Cavitation Article


This engine will now have to be sleeved, and theres only 1 proper way of doing it, and not many places know how.

When the machine shop bores/sleeves the engine, they MUST leave a ridge at the bottom of the cylinder bore so the sleeve can sit on that ridge, and not drop in and hit the crank and cause massive failure.


I feel your pain on doing heads in a van. What year is your van? I did head gaskets in my '87 E350 and wow what a job!


How did you ever get the engine out of it though? I can't imagine how much of a PITA that must be....

 

That much water so soon, and I would suspect a cracked cylinder head somewhere other than the deck. I would suspect a frozen block (not enough antifreeze) if it was from farther north. The head can be cracked internally, say in the valve gallery, where they don't check for cracks. Best way would be to take that head off and have it pressure checked instead of checked for cracks.

One question....which head is which? You have one original, and one rebuilt, but you didn't specify which was which. Is the rebuilt head the one causing problems or the one that is the original?

 

charles: I thought the same. sent the head back to the shop that did it, which is a ford certified reman facility, and they did a "bubble test" on it today and it passed. They seal the face of the head and pressurize it with air while it is under water, which should show ANY water to chamber leak. I was hoping it would be bad, as this would have saved me from pulling the block. no such luck!

dieseljohn: yes, doing heads in a van sucks alot!! fortunately i have access to a forklift, so i made a fixture that goes over 1 fork blade and bolts to the intake manifold face and can rotate. It allows me to bolt up the head, lift it straight up, then rotate it flat to clear the exhaust manifolds away from the frame, then back it straight out the front. it goes in in the reverse, which allows me to set it down on the dowels without buggering anything up. the head weighs 105 lbs, plus the ex. manifold. I dont see how anyone could do this job wothout a special fixture like i described.

the van is a 94 ambulance, previously owned by a hospital. I dont know its history, but it SHOULD have had good maintenance. The engine is a reman 91 model from a bus, not the original 94 engine, so who knnows how it was treated.

I have read about cavitation, and will read your link (thanks for that), but im having a hard time believing that the block can leak that much water that fast from pinholes, and before it even gets hot. The cylinder in question has NO visible flaws or pits or cracks, but leaked more than 1 quart of water to the pan in less than 2 minutes.


Im pulling the engine now, it is going to the machine shop tomorrow, and they tell me they have sleeved MANY 7.3 blocks, so we'll see

 

oh i forgot charles, the new (reman) head is the one with the trouble cylinder.

BOTH heads were pressure checked and magnafluxed

thankfully, at least i'm dealing with machine shops that seem to know what they are doing!

 

That's still wayyy too much water too quickly to be a pinhole. If your head gasket sealed, and provided you followed the tightening sequence on your head bolts so your head didn't warp up, then you have more than a pinhole. If it is hydrolocking on the one cylinder, and you can't see a pinhole, you have a bad head. There isn't really a third choice. A quart in a couple minutes means about a 1/4 or larger hole.
I would suspect human error, in that the facility you took it too screwed the pooch.

 

well charles, it is 430 am, ive got it out and disassembled, and I think i have a combination of problems.

1. i replaced the water pump since it was accessible, and apparently the new pum casting has slightly shorter mounting bosses than the old one, and 3 of the water pump mounting bolts went too far in and broke out the back of the threaded holes. I found 3 nice sized pieces of cast iron kicking around in the water passages behind the pump. the broken holes wont let water get to the oil, but i gotta figure out how to plug them up.

2. i took off the front plate to replace the leaking front main seal, and i think the front plate didnt seal to the block when i put it back together, so im thinking that the large amount of water in the pan came from that.

long story short, the big water probably came from the bad seal on the front plate and the cylinder water is probably from a pinhole. the block is going to the machine shop in the morning