Explaination for rad failures

[Ficm]

Does anybody know what Ford's explanation is for radiator failures on the 6.4L engines? I am familiar with updates to the cooling system, ie updated coolant hoses, single port degas bottle and venture tee.

[Aaron]

I'm going with "MADE IN MEXICO" stamped into the top of the center of the core.

 

The thermostats and low coolant are currently the explanation, I think, aren't they?

[Ficm]

I'm no engineer but how does the thermostat cause the rad to fail, does it have something to do with a pressure spike? I suppose with low coolant, the cooling system runs hotter due to inefficient volume.

[Keith Browning]

The current cause as explained from Ford is as follows:

 

"Slow leaks at cooling system hoses/connections can lead to low coolant levels. Excessive hot and cold cycling associated with low coolant levels can cause stress within the radiator tubes, possibly resulting in cracks in the tubes."

 

I say current cause because this has changed as hyper-extended thermostats were once blamed for this concern. Maybe this is still true but I can not locate THAT TSB anymore. Engine calibrations have been updated to include a thermostat monitor that seems to do a very good job at detecting thermostat malfunctions ad turning on the check engine light. The idea is to correct the condition before other problems occur as a result.

 

And... I also think that the quality of the radiators leaves something to be desired.

[Ficm]

Thank you guys.

[Matt Saunoras]

I think body flex has a lot to do with it. I've killed 2 rads doing partial cab lifts because because my left rack arm lifts higher than my right and it torques the body when the rear remains on the ground.

 

Since then I just just 2 jacks but the point is there.

[lmorris]

The current cause as explained from Ford is as follows:

 

"Slow leaks at cooling system hoses/connections can lead to low coolant levels. Excessive hot and cold cycling associated with low coolant levels can cause stress within the radiator tubes, possibly resulting in cracks in the tubes."

 

Also known as "Thermal Shock"

[ktmlew]

Originally Posted By: Keith Browning

The current cause as explained from Ford is as follows:

 

"Slow leaks at cooling system hoses/connections can lead to low coolant levels. Excessive hot and cold cycling associated with low coolant levels can cause stress within the radiator tubes, possibly resulting in cracks in the tubes."

Also known as "Thermal Shock"

I've always believed most radiator failures, where the tank broke, was caused by "Thermal Shock". If you get the fluid boiling it creates quite a hammer effect. But "pushing the tanks loose" is likely a different issue?

 

I know the radiators suck but they ain't going back to 100lb brass construction.

[Fredsvt]

hey guys,

since I was curious about this, I've been following the thread.

 

I have a 2008 F550 that came in today, the driver (fleet) said it "overheated" and added 3 gallons of mixed universal junk, and then drove it, the level dropped again and it again "overheated", he added another 2 gallons.

 

By the time I got it today, it's halfway down the degas bottle, I put it under pressure which dropped, and the level disappeared. No currently visible external leaks. The oil level is about 15" over the full mark on the stick. The ccv separator is full of gooey black sludge.

 

I'm guessing so far, the front cover probably has cavitated. This unit has repeatedly come in low on coolant, averaging a gallon per 5-7k service. I see new upper and lower hoses, I'm guessing done at the Ford store on one of the services we didn't see. The rad is original, the best I can tell.

 

What would be the best approach with this? If we get the job, it may get brought to a Ford store.

[Aaron]

Mishimoto makes an all-aluminum replacement 6.4 radiator now.

 

It's pretty.

 

Lists @ $855 on their website.

[Aaron]

Among the front cover leaking, if it's been ran low/overheated I'd definitely check the EGR coolers for leaks as well.

[Mikill]

I still don't see how the coolant hoses leaking cause the radiators to leak because radiators have been leaking before the hose o-rings started leaking.

 

Radiators are just junk

[lmorris]

I still don't see how the coolant hoses leaking cause the radiators to leak because radiators have been leaking before the hose o-rings started leaking.

 

Radiators are just junk

The hoses leaking causes low coolant levels which usually goes unmonitored because you never see any coolant on the ground. Low coolant level is what causes the thermal shock that take outs the rads.

[ktmlew]

Originally Posted By: Mikill

I still don't see how the coolant hoses leaking cause the radiators to leak because radiators have been leaking before the hose o-rings started leaking.

 

Radiators are just junk

The hoses leaking causes low coolant levels which usually goes unmonitored because you never see any coolant on the ground. Low coolant level is what causes the thermal shock that take outs the rads.

 

I agree. It's a combination of the thermal shock hammering and the design of the aluminum radiators. A better radiator would probably just kill the engine quicker.

[Mikill]

I understand all that but the first coolant leaks I starting doing on these were radiators not hoses. This was back when the 6.4 first came out.

[Aaron]

^^ Yep.

 

And some trucks had a shit pile of rads, and some didn't.

 

And my truck hasn't ever had any coolant leaks, other than the radiator, which started to leak at 110k miles. On the updated thermostats for probably the previous 40k miles, venturi tee from day 1.

[mrbudge]

If you take a piece of cardboard, support it on it's four corners, place it in a vertical position, and shake up and down, it will not flex. Now incline the cardboard 30 degrees and shake up and down, watch it bend in the middle. Replace the cardboard with an aluminum radiator with plastic tanks, fill with several gallons of coolant (water weighs 10 pound a gallon, or so) and beat this thing down the road with your cushy 15000 gvw ride, I can't see how a rad can survive without eventually fatigue cracking.

 

This is just my theory, for what it's worth, but we have had rads, thermostats, and engines run with low coolant since the second world war, and now all of a sudden we have rads leaking because of thermal shocking and lack of venturi tees? So why are rads on 6.7's leaking now as well?

[Matt Saunoras]

Same reason. bumpy ass roads and a stiff suspension. I bet 90% of the 6.7 rads I did were in F-250s with 245 series tires.

[lmorris]

Having side tanks instead of top/bottom may be the actual issue here. 6L rads do not suffer this fate and frame structure has not changed that much in the last 2 vehicle changes. It could be possible that we are looking at multiple causes here. We have trucks that look like they never leave the highway that come in with rad leaks. On the other hand we get trucks that have spent their entire life on a lease road with no sign of a leak.

[mrbudge]

Having side tanks instead of top/bottom may be the actual issue here. 6L rads do not suffer this fate and frame structure has not changed that much in the last 2 vehicle changes. It could be possible that we are looking at multiple causes here. We have trucks that look like they never leave the highway that come in with rad leaks. On the other hand we get trucks that have spent their entire life on a lease road with no sign of a leak.

Rads in 6L trucks are almost vertical, and nothing gets run more with low coolant more often than an old 6.0 with a leaking cooler package. One day when I am more ambitious I am going to put my GoPro under the hood and go for a ride to see how much all of the cooler stack flexes on bumpy roads. We have lots of them here, no oil patch money to fill potholes for us.

[leavnon3rd]

I def. Agree with some of the posts looking at flex in the truck and it not being toally vertically mounted. As far as leaks all our 08's seem to be following a domino effect as leaks go.

New radiators, then upper hoses, then lower hoses (engine side ) , now degas bottles we see them in waves.

[jimmy57]

My theory is that they put a programmer set to "EXTREME" on the cooling system on 6.4's to handle egr cooling and increased engine output. All the parts are a bit overstressed. No room for imperfect coolant chemical balances for front cover, water flow rates that tax thermostats, and hydraulic shock that rads can't take.

 

I bet there are some folks that really know and forewarned of the risks. They are bound by confidentiality agreements as terms of employment and even worse.