Just wondering what you guys think about my crazy truck issues...

I just got done with a complete rebuild on my 03. And for a month or so had no issues, thot everything was good! Had to bore it out 20 over to get the scarred cylinder wall clean. Then found a crack in the block in the cylinder wall. So it was sleeved and rebored..

Now it has developed the problem of weird random overheating. So I thot maybe the new thermostat I put in was bad so I just took it out, let it run cold... haven't had the overheating problem since but I haven't pulled a load or went up any big steep mountains...
The coolant is constantly under pressure even tho its cold. I took the radiator cap off and let it run for awhile once and the coolant is frothy/foamy and slowly bubbles over the top.

I've heard that sometimes when they sleeve these things it can tweak the block??

I suspect the head gasket is leaking or there is another crack in the block???
A friend of mine said to try replace the water pump? Is there any way that could be the problem?

Please give me some GOOD news!!!

 

if the water pump isnt pumping good it could be. take it off and see if the fins slid on the shaft or something. normal things like rad. cap, water pump, fan, etc. check first. did you have your head decked when you rebuilt motor. my 6.7 done this and i tried everthing but i had a head gasket blowed.

 

You have compression getting into the cooling system! Now from where is the question!
Your first bet is to have the head pressure tested! If that passed then it's in the block but my money is on the head and or the head gasket! Sorry for the bad news!!

 

I have to agree. The only way you could get pressure in your radiater or your hoses is due to compression. the compression comes from the pistons. I'm sorry but it does'nt sound good. Don't think your alone. Bad out look but it can be fixed.

 

Thanks guys...

Yes the head was decked and completely gone thru when i rebuilt it...

So how do I pressure test the head?? And why would the head gasket fail within a couple months?

 

The machine shop should have done the test!! ASK them if they did! As far as the head gasket if it was damaged on install this would cause it to fail did you check the block deck for warpage possible but unlikely. Good luck!!

 

Are you running the common rail mls head gasket. If so the block and head deck surfaces not only need to be flat but smooth. I've seen some machine shops plaining and the surface is a little rough. If you could still see the machining marks is to rough.

 

it has to have a micro finish for the mls gasket to seal correctly

 

thanks for all the help... I called the machine shop where I had the engine and head. Talked to him for awhile and he is willing to refinish the head if it needs it, He is a really good guy!! I'm fairly confident that it was as smooth as it needs to be, but I guess we'll see.
I'm gonna take the head off and have it checked again. Also check the head bolts to see if they stretched. I guess while its apart i need to check the block and see if its warped... How do I do that? Can I check while is sitting in the truck?

Well I think before i do all that I'm gonna try a new water pump... About how much are they? Is it ok to get one from like napa or should that b a genuine cummins thing?

 

Any brand water pump will work! All the same one of the great things about this engine is the water pump is two bolts and under 80. and they rarely go bad! As far as the block you will need a straight edge to check it. read the book on how to check it!