OK... I have asked a lot of questions about over heating, no interior heat, excess pressure in the cooling system, and "magical" coolant loss...

Lets add to that! The coolant is being pushed into the coolant overflow bottle from the rad, filling it up, and making it overflow...

I know it has not been the response from all you, but I am fairly sure that compression gasses are finding their way into my cooling system!

I know on gas engines you can take a 4 gas analyser and look for HCs in the rad, can this be done on a diesel too??

If this is the case what are my chances its a head gasket?? the engine has 240 000 miles... I have never seen a puff of white.....

Thanks for the help!!!
Bob

 

When the engine and coolant is cold, someone said that if you remove the radiator cap and place your hand over it and you feel pressure that it is your head gasket.
Next time I have time to fire up my truck I will check mine also.

 

I dont know if this would work but you could try to put the overflow hose into a clear container, run the engine to normal temperature and see if any air bubbles are coming out of the hose?You may be blowing exhaust gases into the coolant but not sucking any coolant in the cylinders, maybe that's why you don't have any white smoke.My bet is that you are in need of new head gaskets.

 

Careful with that "magical" coolant loss. If coolant starts leaking into the cylinders, you will snap a connecting rod and possibly a few other things. Keep in mind, coolant does not compress. Not sure if I remember this right (hopefully one of the guys will confirm this) but after the truck has sat for a while and when you get the chance, change the oil and see if there is any coolant in the oil pan. That should be a good sign that the headgaskets are gone from what I remember.

-Dave

 

Being a 6.9 I'd say you're right, head gaskets. If they get too bad you won't be able to keep any water in it at all. I had a 7.3 in the shop that was overheated and developed cracks between the valves. That thing would empty the whole radiator in 10 seconds with the cap off.

 

If you think you have coolant in the oil,try draining a bit of oil from the oil pan the coolant will come out first.

 

If you have the time. Do a oil analysis. This will tell you if there is water/antifreeze in the oil.

 

Look for the coolant by either of the back glow plugs.
My original engine would run fine for a while then suddenly lose coolant that never showed up on the ground. It was pooling in the intake web at #7 glow plug.

I would say if you are running the coolant recovery tank over, you need head gaskets.
A cracked block or cracked head could also be the cause.

When I cracked one of the 7.3 blocks I had, it would build 30 PSI in the radiator in 15 seconds running. It would also blow the cap off the coolant recovery bottle.

 

How hard is it to spot a crack in the bolck?? I will assume that I have 20+ LBS of pressure in 20 seconds or so....

 

Usually not to hard after you get the deck of the block cleaned up.



This is a little hard to see at the low resolution I had to use to meet the picture size requirements.

 

I dunno what I will do...

found a guy with a 6.9L and ZF that he will be pulling out of his F350 to replace with a Cummins...

I guess that if the price of the engine and trans together is good ( I want the ZF anyhow ) I may just do that and keep mine, tear it apart, and see what I got... re-build it and put it in when done...

Stupid truck!!!!

Bob