On the return trip from our Memorial Day weekend, we were climbing a good sized hill and things got hot. Engine water climbed to 250 degrees, engine oil reached 310 degrees and transmission fluid temperature reached 220 degrees. These temperatures seem to be at the upper limit of what is safe. The alarming thing for us is that we are in Minnesota, often thought of as flat land country. What happens when we travel in the mountains some place? What are the safe limits for these temperatures? And what can be done to our truck to help avoid such high temperatures in the future? Are there oversized radiators and transmission fluid coolers available? Or better fans for these units, etc.? The truck is a 2004 F350, V10 gas, 456 gearing, pulling a 10,500 5er.

It's 14 years old so core/fin separation is a possibility. As the radiator ages the fins can start to deteriorate and not shed heat. It's one thing to consider and it often starts in the corners.

You went way beyond what is safe for an eng IMHO (this is the internet so I'm sure someone else person will say they run theirs up to 350 degrees daily but I wouldn't). Next time stop and pull over so it can cool. Your lucky you didn't lose a head gasket and you still may.I would start by a total servicing of the cooling system. Have radiator boiled out and checked, change antifreeze and thermostat (use OEM stat). Replace any belts hoses that are suspect.Also, change that eng oil regardless of miles.

^^^^^^Oh yeah, that oil needs to be changed and it wouldn't hurt to change the transmission fluid too. Those temps are definitely not at the upper limit of what's safe, they are a ways beyond. Obviously the engine isn't going to fall apart tomorrow, but that oil is just about used up and won't do it's job well after being at that temperature more than momentarily.The reason they put gauges on there is so you can back off when the temperatures start climbing, not to see how high it finally gets.

If me I would confirm gauges were correct. A "scan gauge" would be my choice to see if there might be an elect problem. Not to much money and good second back up just in case

Hopefully you changed ALL those fluids if gauges were working properly.

High Fluid Temperatures | Good Sam Community

21 Replies

1Wheeldrive
Explorer
Jun 14, 2018
Another potential problem with a vehicle of that age is that over the years, there is a build up of bugs and other debris in the radiator, tranny oil cooler, AC unit, etc..
My 2003 Silvarado Duramax at about age 10 started overheating where it had never done so before, took it to my mechanic and he checked it out and said it needed a "stack cleaning". There was a lot of "stuff" in the various heat exchange units, including a lot of cotton wood cotton. Overheating went away after the "stack cleaning".
laknox
Nomad
Jun 14, 2018
One thing that can also cause overheating in a gasser is lugging the engine, i.e. trying to run in a higher gear, rather than letting it rev up a bit. I found that out by experience, when my dad and I took a GN trailer up over El Cajon Pass with my old 3/4t truck with a GearVendor OD. Dad could consistently out-mileage me and ran cooler because he'd run a gear lower, and rev about 600 rpm higher. The engine was just running "more free" at the higher rpm. With a gasser, you simply can't be afraid to rev it up to 4-5k. If this means slowing down, then slow down.

Lyle
larry_barnhart
Explorer
Jun 14, 2018
Gearitis wrote:
Back when I had a V10, it started reaching temps that were higher than normal. As the OP, took it to an independent mechanic and we found that the tranny fluid was cooled by the radiator and a small factory external cooler. They also found that the radiator needed to be rodded. So they removed it and took it to the local rad shop and they boiled it, cleaned it and rodded it. Never had an issue after that, in fact temps very seldom moved even over Wolf Creek and Monarch Passes in Colorado pulling my 12k 5er. I have always used Scangauge to monitor temps exactly rather than trusting the in dash gauges. Just my 2 cents worth for others.

Just for information. a few years ago ib516 posted he had his scanguage send in and had their up grade. I was near their store in chandler Az last winter had the up grade for free. The $25.00 charge is for the mail . New items were added and the screen was made brighter. Trannie temp was added. I have tested it with our trannie gauge and both read the same. Our scanguage was several years old so might be the newer models have this.

chevman
Gearitis
Explorer
Jun 14, 2018
Back when I had a V10, it started reaching temps that were higher than normal. As the OP, took it to an independent mechanic and we found that the tranny fluid was cooled by the radiator and a small factory external cooler. They also found that the radiator needed to be rodded. So they removed it and took it to the local rad shop and they boiled it, cleaned it and rodded it. Never had an issue after that, in fact temps very seldom moved even over Wolf Creek and Monarch Passes in Colorado pulling my 12k 5er. I have always used Scangauge to monitor temps exactly rather than trusting the in dash gauges. Just my 2 cents worth for others.
colliehauler
Explorer III
Jun 14, 2018
Sounds like your ready for the road again.
4x4ord
Explorer III
Jun 14, 2018
I have never seen the engine oil run that much hotter than the coolant. Does your truck have an engine oil cooler? 250 degrees is generally the red line for oil.
time2roll
Nomad
Jun 14, 2018
Did the Ford temp gauge move at all? If not I say all is good and normal.
klr650goldwing
Explorer
Jun 14, 2018
Well, I took the truck to an independent repair shop. They flushed the radiator and transmission. The fan had a broken blade. They replaced the fan clutch. The aftermarket water temperature gauge was reading 40 degrees too high. So, over all, I think the truck is okay. I'm going to replace that gauge and should be good to go. Thanks for your help everyone.
klr650goldwing
Explorer
Jun 06, 2018
I do use full synthetic for engine oil and ATF, so maybe that will help avoid major damage. Fingers crossed.
colliehauler
Explorer III
Jun 06, 2018
klr650goldwing wrote:
Thanks everyone. I changed the engine oil today, and have an appointment to flush the transmission tomorrow. Plus they will change coolant, check the fan clutch and then we will talk about radiators etc.
That was going to be my suggestion a new fan clutch and radiator, not that expensive.

Just put a new fan clutch on my 06 Ford F-250. My mechanic flushed the area between the radiator and A/C condenser.