I need a little direction in tracking down a little overheating problem I had this week-end. Here's the deal. I was traveling on a little 3.5 hour trip down from NC, through SC, into Augusta GA. I went down Friday evening, starting about 7PM. The outside temp was hot, but not all that hot. About half-way through the trip, I was on I-26 in SC, and I was traveling with another F-350 dually like mine. We were tooling along at about 80 with the cruise set. Also, I had the AC on wide open. We had probably been going together for about 20 or 25 miles when I noticed my oil temp idiot light was on. I had never seen this before. I immediately got off at the next exit and pulled off the side of the road and let the engine cool off. All the other guages (stock) were normal, including the water temp. I set there about 5 minutes, then went on my way. I held it below 75 and had no more trouble. Once I got to my destination, I checked the oil and it was about 1 quart low, so I added some. BTW, the truck was about 500 miles shy of it's normal 5000K oil change interval.

Today, I made the return run. I didn't run as fast coming back, probably 75 max, but mostly a little under that. The outside temp was higher today. It was probably 93-95 degrees. Again, about half-way through the trip, the oil temp light came on. I was about 12 or 15 miles from a fuel stop, so I slowed way down (60-65), and turned the AC off. By the time I reached the fuel station, the water temp guage had shot up into the red zone. I let the truck set at the station until it cooled off, but it didn't take long for the water temp to shoot back up when I got back onto the Interstate. I ran her slow and the water temp finally came back down to the middle of the normal range, but it took a LONG time for this to happen - probably 20 or 30 miles.

Now, my question is this: Do I have a problem? I assume I do. What would it have been like if I had been towing or hauling anything? I have never had any trouble like this before. Where should I look first? Thermostat? Water pump? Something else? I need to check the coolant concentration, so I will report those findings after I have a chance to check it.

I apprecate any assistance in advance!!

 

Sounds like you have it covered:
1. Check coolant , SCA's, level, last flush?
2. thermostat
3. check sending unit
4. Pump
5. Acquire aftermarket gauges for crtical engine monitoring.

 

I should have said that the coolant level was right where it needed to be and the coolant is bright green, as it should be. I replaced the coolant and the additive a little over a year ago right after I got the truck. I have some strips so I will check the coolant either tomorrow or Tuesday, whenever I get the first chance.

THANKS!!


BTW....NICE avatar, Heat!!!!

 

OK, I checked my coolant concentration this evening. I changed out this coolant and additive right at a year ago, right after I first got the truck. Everything seems ok there. Freezepoint was about -45F, molybdate about 450 PPM, nitrite about 800 PPM, SCA about 1.7 units per gallon. I really don't think there is a problem with the coolant itself.

After thinking a little about what happened, I have to wonder which got hot first....the oil or the water. I know one causes the other, but during the first incident, I don't remember seeing the water temp guage out of the normal range. I have never seen my truck run that hot before. If running it hard like that is gonna cause a heating problem, then I definitely would be interested in some sort of oil cooler or something. For now, I would appreciate some advice as to what to check next. I know I mentioned thermostat and water pump. Where exactly is that sending unit? I definitely plan to add guages to my truck as soon as I can get around to it. I don't haul much or tow anything currently. Someday, I hope to have a TT, so I realize that I'll need to add those guages before I start towing.

Again, all advice is GREATLY appreciated!

 

Ya know, it sounds like maybe the thermostat might be stuck. Have you checked it? Its pretty easy to pull out.

 

The truck heats up in what seems to be a normal fashion to me and the stock water temp guage runs at about 3/8 of the normal range. I am considering doing that 203-degree thermostat thing, and replacing my radiator hoses at the same time. Not sure if a new thermostat would cure my troubles or not.........

 

I know that when it's that hot outside, this can be a beastly thing to do, but did you or can you try turning the heat on in the truck? If you can stand it. Dumping some of the excess heat into the cab might tell you if you have a thermostat or water pump problem. In the old days you could wait until the engine & radiator cooled off enough to open the radiator cap. Then you could restart and check for movement of the coolant across the top of the radiator. If no movement, you would drain coolant off until you could remove the elbow on the engine and run it without a thermostat, checking again for movement of the fluid (after putting back what was drained to remove the elbow or t-stat housing). Nowadays, with these "sealed" cooling systems, with your only access to the fluid being the overflow jug, you can't do this. Alot of parts countermen will tell you that a thermostat will always fail in the fully open condition. I've had some that have failed in the closed position. Remember that extremes in the outside temperature will show the weakest link in the system. If turning off the airconditioning didn't help, then you probably can rule out a failing compressor is making the engine work harder or slowing down the water pump and all the other accessory drives. Do you remember if the charging gauge (instrument panel) stayed in the middle, showing that the alternator was able to spin at it's needed rpm's to do it's job? For my 50 cents, I would concentrate on the t-stat and water pump. Any chance that trapped air is keeping the water pump from having a complete circuit of coolant to circulate?

These are just my humble opinions, and with them and a dollar, you can get a cup of coffee in most places.

 

When I bought my 97 f-350 it was used. The fellow was a part time farmer. First time I pulled my camping trailer the heat gage skyrocketed. When I got home I started looking. I found my rad to be plugged solid with bugs, dust and junk. I took the rad out, had it cleaned at the rad shop and she runs great. It will still heat up on a hard pull but cools off in record time now. I see you have a newer truck so a plugged rad may not be the problem. I know my dad drove through some major poplar fluff one summer and that plugged his rad on his car enough to cause it to over heat. Just look at your rad, see if the fins are plugged. Takes a few seconds and you can move on to the next check.

Ed

 

Did the cooling fan kick in? If the air from the radiator was hot enough, the fan should have started to engage.

 

What cooling fan? Are you talking about the fan clutch? Please explain.

THANKS for all the advice!!

 

Yes. The fan clutch.

 

The clutch fan when engaged will make a large fan roaring noise. In hot weather it will happen when you are driving empty, running the AC, and pulling away from a red light. You'll hear it roaring until the engine cools enough for the clutch in the fan to disengage. If it's really hot and stop and go traffic it will never disengage. If you are pulling a trailer in hot weather it will make a LOT of noise. Sometimes for the first couple of minutes in the morning it will be noisey whether it's hot or not. The silicone fluid that is in the mechanism needs to be centrifuged out. It settles in there overnight. (normal stuff).
If you DON'T hear any large fan noise at this time of year - you need a new fan clutch and then your overheating problems will dissappear. Let us know.

 

THANKS, Kwikk!! I will pay attention to it and make sure. I know exactly the sound you are referring to, but I don't recall whether or not I heard it lately. I will listen on my way to church in the morning.

If that IS the problem....about how much does one of them run?

 

I don't think the cooling system is really the problem here. The cooling systems on these things are way over engineered for the relatively light amount of work they have to do. Also, I think if your thermostat or fan clutch were bad, it would not have cooled off when you pulled off the interstate....it would have continued to overheat since you took away the airflow.

It seems from the nature of your posts that the cooling system is reacting like it should when trying to control an oil temp problem. I wonder if your oil cooler is plugged or maybe the low pressure pump is getting worn.

 

OK, cookie88....tell me where the oil cooler is, and how can I check that LPOP? The truck only has 69,000 miles on it. Hopefully that pump is still OK. Even today, my wife and I were discussing buying a TT.........