It's not with the cooling system, but something to do with cylinder cooling inside the block. It is a design issue with the block and a larger radiator would not help at all. Apparently, it's a significant issue to fix (it requires a redesign of the block), hence the reason they haven't fixed it. I don't have the exact details or a source, but it came from a Ford employee on another Ford forum I follow.

 

Fordman, I generally agree with you on most things, but this sounds pretty far-fetched. The 6.2L block is no different than any other block - if it does generate more heat, the solution is to add a larger radiator or fan, just like any engine.

The 6.2L is available on the 350 C/C trucks. So what you're saying is because the payload and / or towing is higher on the 450/550 trucks, the additional "load" causes the 6.2L to overheat? That is not going to happen. It just means the 6.2L doesn't really have enough oomph to move those higher tow ratings well enough.

For instance, a 550 C/C with the V10 can only tow 1,000lbs more than an F-350 C/C with the 6.2L, conventional towing. Overloading the 6.2L with an extra thousand pounds on the trailer is not going to overheat the engine.

When you look at the commercial C/C towing guide, it becomes very clear as you look at the numbers they correlate directly to engine torque output. The V10 puts out 457lb-ft, and at a lower RPM than the 6.2L. That's why it is the gasoline engine offered in those heavier-spec C/C's.

 

It has to do with the (internal Ford) test cycles for medium duty engines, which is different than F350 on down trucks. To us lay folks, you would think you just add more coolant, but the coolant cannot extract that heat from the heads, it doesn't do any good.

Here is a link to one mention: No More V-10 450/550's, Sales Hold On 650/750 - Ford Motor Company Discussion Forum - Blue Oval Forums

The user 'theoldwizard' that is mentioned is a retired Ford employee. He is very knowledgeable and still has a lot of contacts inside Ford. Feel free to search that forum for more references. There's lots of info there.

I'm not BS'ing you dude. I don't make posts like that without decent information to back it up.

 

See, this is the area where I disagree. The company I work for designs plasma cutting torches, which are liquid-cooled. We know a lot about cooling and heat transfer, and have all the thermal modeling software. Granted, a torch is not the same as an engine, but both are metal that is heated by fire and cooled by the same basic anti-freeze solution.

If a cylinder head gets hot, it will heat the coolant flowing through it. The coolant pump pushes this hot coolant out of the head and into the radiator, where the fan draws cooler air through, transferring the heat out of the coolant and into the air. Next, the cooled coolant is moved back through the cylinder water jackets and through the passageways into the cylinder head. If the coolant is cold enough, it will transfer the heat away from the metals and cool them adequately. If the radiator did not cool the fluid enough, it will not be able to transfer as much heat away from the metal, resulting in the overheating you mention. Radiator size, fan size, water pump flow rate, and coolant capacity are the factors at play here. Sometimes, when a manufacturer tries to install a large engine into the engine bay of a vehicle designed for a smaller engine, they run into cooling issues (such as fitting a Mercedes V8 into the a C-Class, which was not designed for a V8). The answer to simply to install a larger radiator or increase airflow through the radiator.

It is possible that an engine could be designed so poorly that the coolant passageways do not flow coolant through the hottest areas of the engine, resulting in overheating. But this would be discovered during early testing stages. If the engine can cool adequately in a 350 towing 15,000lbs, then 3,000 more lbs will not cause overheating because of design inefficiencies. At the truck's curb weight plus 15k lbs, if the 6.2L can maintain appropriate engine temperatures during summer temps and steep grades, the cooling system is clearly operating well. It is transferring heat very well. The aluminum cylinder heads of the 6.2L transfer heat very well. I have seen the coolant passages in both the block and heads - they are very typical. I'm not calling BS on you, just on whatever source this came from. I guess we will have to agree to disagree on this one.

 

The thing is that the real world is not near as hard on the engine (and cooling) as the Ford test that the 6.2L failed. Likely, it would be fine in 99.9% of the cases in the real world, but the Ford test found that obscure case where it would fail.

It has nothing to do with ambient temperature. Yes, ambient temperature is important for the cooling system, but actually getting the heat out of the engine and into the coolant has nothing to do with the ambient temperature. Getting the heat out of the coolant and into the surrounding air DOES have to do with ambient temperature.

I think it is like you mentioned...a flow issue inside the block of the engine. Something that only rears it's ugly head in certain circumstances, hence the reason it wasn't caught early on.

And it's not a matter of the extra few thousand lbs. from an F350 to an F450, but the sustained loads at max HP for sustained periods of time. It's the internal test that increases the duty cycle for an engine to pass for a MD engine vs. a LD engine.

In no way would that sway me from buying a truck with a 6.2L, and in no way does it point to an issue with the 6.2L engines out there. If anything, Ford's test may just be too strict, and it tells us that if an engine makes it into the truck, we are able to trust it to do what Ford says it will do.

But, I'm not arguing, just stating what I know. If we don't agree, I'm good with that.

 

Chevrolet is not even in the mix. I wouldnt even bother. You want to know what tows the heavy loads just pick any campground and see what trucks are towing the 5th wheels.

bigdon68