Pressure in coolant tank.

Possible cracked liner allowing combustion gasses into the cooling system, have you done a pressure test? Are you loosing coolant? Could be a bad egr cooler.

 

A Pin hole in liner will do that, but you must ck. if any of your heater valves are air opp. an one of them can go bad and pump air into tank, next time motor is cool start it with cap off to see if air bubbles are coming out

 

There is a combustion gas test you can do easily on your cooling system. Will tell you what you need to know.

 

WTF seriously?

You're supposed to have pressure in your coolant tank!!

There is a pressure cap on drivers side for this purpose, excess gets bled off.

Pressure raises the boiling point of the coolant.

 

What this guy is describing is a possible fretted liner. He never said why he replaced the head and gasket, my best guess is that it was a liner that took out the gasket which in turn scored the head. Normally in a case like that, a complete in frame is required to properly fix the issue. OEM heads and gaskets rarely fail on their own now a days, there is normally another cause, like a busted liner or extreme high heat from a crap delete.

Here are the steps to check for a fretted liner...

Prior to removing the head, drop the oil pan and pressurize the coolant system to say 20 psi. Then wait over night, next day have a helper bar the motor, use a flashlight to look up into the cylinder liners from under the truck, you are looking for coolant. Odds are, this was not done, and the shop or owner just through on a new head never properly diagnosing the real problem. Seen it quite a few times, just peeing money away to save a dollar. Problem is, if it is a bad liner, that new head is more than likely shot.

If it is a fretted liner, a complete in frame will be required. When the block is in framed, the block needs to be machined to set the new liners. There is a ledge in the block that the liners sit upon, that is what is actually cut, or machined and where the shims sit. Shim and measure each liner for protrusion at the top of the block, a special tool will be required to make these measurements. On the Cummins, we are setting protrusion at 12 to 14 ten thousandths of an inch. The liners need to be measured at at four locations, 12, 3, 6 and 9 o'clock. Again, special tools are required.

Another test is a simple block combustion test kit, they can be bought at any Napa Auto Parts store for around $50. Test a few times with a warm motor, it may take up to 10 minutes or more, depending on how severe the damage, if there is any.

 

Take a good look at the tank itself. My friends was cracked internally and you couldn't see it because of the shape of it and it had darkened/discolored on him over the years...

 

GUYS!!!!......you're jumping to conclusions..... let's let him give more info..... He only said pressure in the coolant tank... Not air.

Pressure is NORMAL and needed as the coolant system heats up !!

**What you're jumping to is AIR introduced into the coolant.....he DIDN'T say that.....

How about a better description from the OP with what's going on...??... BEFORE jumping to conclusions and diagnosing some very very expensive repairs.....

 

No doubt... But, replacing a head, head gasket, compressor and coolant bottle tells me there is much more going on here... Like major pressure in the coolant system prior to these repairs and no one bothered to check for the real culprit, the fretted liner. Now, I bet he is having those previous symptoms all over again thinking these repairs and thousands of dollars had fixed the issue. Sadly, if my thoughts are correct, he was taken for a ride. Seen this happen more than a few times.

Let’s see what the op has to say.