Ford gold coolant has silicates. Silicates fall out of suspension and plug the oil cooler. Cat ELC is silicate free. And the thinner oil just flows easier when the motor is cold so the injectors fire easier. The injectors are electonically controlled but fired from high pressure engine oil.

those earlier 04 and previous lockouts were problematic. The biggest problem being they corrode here and almost become impossible to turn after a few winters. And they want so damn much from ford for them. They must think everyone is made of money. I agree, the warn kit/replacement is superior.

i have also had where the electric vacume pump got water in it and either seized ot bloaded from freezing..cracked impeller on the water pump i have sen cause not enough water flow..plastic impeller,,what a bad design.p.s. but i have only seen thias on the 7.3's with the vacume pump..cracked water pump impeller on the 6.0

one thing i found out the hard way was i thought warn had enough greace in their hubs to keep them from burning up..make sure you pack the backside with low temp grease or they may blow apart on the inside and you wont know until you go to use them..

I understand that, but why is the 5w40 not as good as the 15w40? They are both 40weights, right?

The 5w at the start is the measure of viscosity cold. So, the 5w-40 will move better cold than the 15w-40.

I just plug mine in when i get home and run 15w-40 motorcraft always. change every 3k and call it a day. i stop plugging it in when night lows are above 35 or so. It is just so much easier on the engine. Im pretty sure the heater element in the 7.3, 6.0, 6.4, 6.7 is a 30a heater. If you plug it in stone cold you will draw that amount max. if you plug it in when you get home right away and your ECT is 200 or so then the heater dosent have to bring anything up. it is actually a little colder than that. average ect when plugged in is 130. and the draw (which i have verified) is around 2a. So, it uses less current to plug it in hot.

So there is a thermostat in the block heater assembly that reads the coolant temps and adjusts a rheostat for the electric draw? I didn't know that. Just thought it was a dumb system that sent full power to the element all the time. And thought the element was a 1500 or 2000 watt element, similar to an electric space heater in your home. And I'm pretty sure I plug my block heater into a 120V outlet that is on a 20A circuit in my garage. Would the block heater work better on a 30A outlet? I think I could rewire the garage to do that, but would need to get a heavier extension cord. What gage wire is needed for 30 amp 120V service?

Once again, I know that. I just wanted to see what the other guys response was to it. He stated that the 5w wasn't good for the coolers, and that did not make any sense to me. I use the AMSOIL Series 3000 5w-30 in both my 6.0's. One has 250000 miles on it, and only two injectors replaced so far and the other 175000 (knock on wood) trouble free miles on it. I change my oil about 45-50,000 miles and filter changes every 15,000 miles.

There is more to the 6.0l head issues than coolant type. Im sure the fact that it has so few head bolts has something to do with it. Go to any diesel shop and they will tell you that the 6.0l keeps the lights on! Im all about sticking up for what you like but there is NO arguing the 6.0 is a fragile diesel. We see 1-2 a week with major issues. Some of those have different coolant with filters added and egr
Delete and fleet maintained and still dont last.

Just reading these posts makes my head spin.

With all the choices out there, why take a chance on an engine that has had so many issues?