Long Story Short.... My 97 7.3L has quite a bit of miles around 439K but it had a rebuild in the early 300K. Here we go, i was building up little to no heat so i replaced the thermostat. the truck than began to run hot so i replaced all cooling hoses, the water pump, heater core, and the thermostat again still no fix it wasn't running extremely hot so i drove it for a week and noticed i was loosing coolant, i then notices i had some compression coming threw the overflow. i took it to a shop and he said there's 3 possibility's, One: head gasket Second: Cracked or warped head, Third: Block needs sleeved. Still ran fine so i put some Metallic Seal in it to see if it would help till i could break into it, it did but not for long, one day i went out to start it and barely got it to fire when it did it was BLOWING white smoke, and lacking power and knocking pretty loudly, so now there's two problems. The next day i wanted to see what it did when driving i made it 3 blocks the knocking stopped and started randomly and the fuel filter light came on and within minutes it died, started hard but persisted to die. this weekend i pulled the motor and tore it down to a long block, i am at a point of confusion. Any Ideas?



Thanks Jordan

 

About a month ago someone posted that they put engine restore in there van and it wouldn run right il see if i can find it but i think they changed the oil a couple times and it came out of it. Look at your tensioner arm to see if it is wore out. Might not be putting enough tension on the belt

 

This is way beyond my diagnostic ability, which I realize isn't saying much. I am, however, fascinated. Good luck with it, man, and keep us posted. I'm here to learn.

 

my belts tight and the water pump is working, i originally thought that could have been a reason, ive rebuilt many gases, this is my first diesel. im on a learning curve myself but as of tonight it seems like a diesel mech. i talked to said the oil cooler. Is there a way to test them? also he said that my power problem could be a bad injector or the HPOP, the thing that's got me puzzled is all the accessories are remans and the oil cooler in particular was replaced at 369K. any help would be great.

 

Definitely sounds like a head gasket leaking. It is hard to see any signs when taking it apart, especially if the leak is short lived. The white smoke and hard start on your first start-up after it had been sitting, is typical for a blown head gasket. The coolant fills the cylinders(s) and then has to push the coolant out to start.

Your head could be warped but not just all of a sudden. Did you let it get pretty hot for an extended period? Your t-stat could have been the culprit, they get old and stick, even brand new ones!!!. Hopefully it didn't warp the head. Check the cylinders for holes and throw a new set of head gaskets on and give it a go. Your other issue could be related, blown head gaskets can get worse pretty quickly. Good luck!!

 

Check your injector cups while you have it apart too. They can crack and let fuel into the coolant.

 

Would the cups allow compression into the cooling system?

 

Did you put the thermostat in up side down by any chance?

 

Or the wrong one? 97 takes the long stem thermostat. If you put the short stem in it will overheat.

This is the correct measurement on the long stem thermostat ...

 

No , Fuel in coolant is what you get with a cracked cup ..

 

Yeah it's the right thermostat, Im getting all my injectors tested this week I know one is bad the nozzle broke off on it but this happened in the removal. I'm just trying to figure out what would cause the compression out of the degas bottle. It's got me stumped. When I get home I'll post a picture of the head gasket so you all can tell me what you think on it also on the cups, are the cracks going to be easily noticed if any? Im a beginner on the diesel side of rebuilds and diagnostics.

 

Also the first mechanic I took it to said that it was probably a ticking time bomb and the old thermostat being stuck open was along the compression to just circulate and that's why nothing was noticed other than it not building heat. I just remembered. Is there any way to test what it might be I know there's gotta be some redneck ideas out there.

 

well it wont let me upload pics but heres the http for my photobucket:Trucks pictures by jtblack26 - Photobucket

 

I can't see anything glaring from the pictures you included. By the way, this forum won't let you upload pictures until after you have a minimum of 25 posts so that is probably why you're having trouble.

If you're getting compression in the degas bottle in my opinion it pretty much HAS to have been a head gasket or cylinder issue. Have you turned the engine over by hand and inspected all the cylinder bores since you have it out of the truck? A crack or hole in the injector cup will just put fuel into your coolant typically, and not compression gasses so I am guessing that isn't your issue. Inspect those cylinder bores very carefully and let us know what you find.

These engines are not prone to head issues, so this will be a rare case if that is, indeed, what it ends up being.

 

I cranked it by hand last night and everything seems I might be missing something, I'm going to pull the bottom end again and look underneath the pistons. Thanks for the help everybody.