I was having trouble with the 6.8 gas 4wd truck going into limp or failsafe mode after loosing most of the radiator water through the cap so after making some changes it runs fine but won't keep water in the reservoir higher than 3" below the minimum fill line. Here is what I have done;

> Flushed the system and added 4 gallons of undiluted antifreeze.

> New thermostat.

> New cap.

> New bottom hoses.

> Cleaned the radiator and condenser front and powerwashed them.

The viscous drive fan seems to be working fine and spins the fan pretty good until it warms up (normal) and it never gets hot. It just won't stay higher than 3" below the min fill line. (It comes out the top and the tank is not cracked).

 

Still think you have a head gasket issue. Heads are lifting slightly and pressurizing coolant

Have you done strip tests?

 

I could only find strips that check anti freeze content.

 

Aren't you supposed to be underwater somewhere?

And Brent, is it still coming out the cap?

 

Just got done doing a RX startup. Getting back underwater soon

 

Yes but only if is up to the min fill line.

 

Did you check for crap between the radiator and condenser? Had a V10 puking, took it in under warranty and there was a bunch of crap down low blocking air flow and when the engine warmed enough i would puke.

 

Why are you using 4 gallons of undiluted antifreeze ?? When you mix it 50/50 it's able to transfer out the heat thru the radiator more efficiently.

 

Nothing in there, I cleaned it all real good.

 

Some puked out so and I replaced that with water so there is about 3.5 gallons (14 quarts) in the 28. 5 system....................50/50. That's not it.

 

I would do a leakdown test honestly. I have never heard of a head gasket failing in a v10 but it could be possible.

 

That will be my next venture, I kinda figured it would come down to that.......Thanks guys.

 

Do you have a way to monitor your engine temps? My scanguage II gives me accurate numbers to monitor.

How does the upper rad hose feel? When the truck is up to temp, squeeze the upper rad hose. Can you feel the coolant rush back when you release it? If not, your water pump may have failed.

 

Thanks I'll try that. I'm not going to buy a scan gauge to check it and it never gets hot and I can put my hand on the valve cover for a minute any time.