I own a 2008, F450, with the 6.4 Diesel engine. Over the past year I have had some cooling system problems. It began, @ 12K, with a leakng radiator that was replaced. Next the recall, done during a regular service, Then in May a plastic "Y" conector leaked coolant. All repaired under warranty with minimal dwon time. Since then I have noticed that coolant sometime splatters from the expansion tank. And, twice for not reason the temp gauge went up and then down again quickly. Yesterday, the cooling system let me down with a full blown sudden rise in temp and the dash warning light coming on. I slowed and pulled over, steam was coming out of the expasnsion tank. I have had the truck towed to the nearest dealer for repairs. This is disapointing and frustrating. We are full time RV travelers and need our truck to be reliable. Has anyone had similar problems? If so, what was done to fix them and has the fix worked?

 

Sounds like it could be a bad egr cooler or blown head gaskets. Check down in the 6.4L section or maybe a moderator could move it for ya.

 

Thread moved to the 6.4L forum. And WELCOME to FTE!

 

6.4's are pretty strong in the head gasket department - no failures I've seen so far.

Cavitation behind the water pump in the front cover is pretty common, is there oil in the antifreeze?

 

Have read elsewhere that some '08 450's, particularly earlier job, have randomly developed sticky theremostats. No pattern yet.

Your earlier symptoms fit the description. Hope that no damage was done.

 

Sounds like a t-stat to me. As important as t-stats are they are probably the cheapest built part in just about any vehicle made.

 

Job 3 F450 here, constantly towing 20K with my foot on the ground 81mph and havent had a temp issue yet, even when climbing 7-9% grades in 90F ambient temps.

Hopefully it's a quick fix for you, and you're back on the road.

 

It would not surprise me if it was a thermostat. Only way to tell is probably going to be pulling it off.

Others that have had the failure, the t-stat was broke into two pieces.

Have them check it in some hot water and see if it works in the proper temp range.

 

I had the opposite problem from my one of my thermostats. It was stuck part open and engine never reached normal tempeture. Since it never got to normal operating tempeture it did not go into regen. This in turn caused my DPF to plug so bad it was replaced under warranty.Turned out to be a piece of pipe dope stuck in it.

 

No oil/water mixed. No white smoke. Just sudden temp gauge pegging and loss of power, then very quick recovery.
ONLY when towing a load (empty trailer doesn't seem to do it).

 

couple of things to check. What is the level on the degas bottle.


Did the clutch fan engage on high and sound like an airplane?


Did you scan for codes or have a check engine light come on and did the wrench light come on?

 

get a new pressure cap

buy a coolant viscosity tester and check your coolant density

sources of cooling problems not mentioned above is the oil cooler/coolant exchange unit which is known to clog.

if this is just happening with a load, I would recommend you spend the 500 bucks for a water/methonal injection unit. The AEM (30-3300) V2 system is very simple to hook up. you set the spray for the boost range (start at 20 end at 35, etc) and you will get cooler operation, cleaner combustion, better mpg, fewer regens, cleaner top end.


you can run water during spring/summer/fall, but you need at least windshield washer fluid during the winter due to freeze protection needed.

 

I am having the same problem with my F-350 6.4L DRW. I just had the timing plate, oil pump, and water pump replaced because I had a small hole in the timing plate that coolant was shooting out of. I drove about 500 miles over the last day pulling my RV from Missouri to New Mexico when it started over heating. The terrain was hilly but not nearly as bad as it was a week ago when I was driving from NC into TN. My check engine light (wrench) came on and my coolant temp gauge immediately shot from "Normal" range to "Hot". I immediately pulled over and shut it off. I immediately turned the key on and my temp gauge was back to "Normal". I was in the middle of BFE in New Mexico so I had to get to the closest town. It happened four more times. My coolant is at the "Cold Fill Line" and it isn't leaking anything. Any ideas? I plan to drive it into the Ford dealer that is 3.9 miles away tomorrow. I need to get to CA quick.

 

did you hear the clutch fan engage on high and sound like an airplane? If not then I would suspect that there maybe an issue with it.


Got to read the codes and see what you have.

 

I would suspect the coolant temp sensor, we have seen this a lot especially on older trucks with higher milage. If you have a temp gun check the actual temp, the gauge is a glorified idiot light it reads normal from around 150-229.....at 230 it moves from norm to hot past 229 in sec's this can also happen if the oil temps are over 229 as-well indicating a oil cooler or sensor issue there as well. Its best to take to to a shop that has a ford IDS system and can monitor the pids to see whats actually happening.