Running Warm Under Load; Using OEM gauge location vs Overtemp sender for gauge?

[ManBearPig]

I bought a 91 7.3 with a "factory" ATS turbo a few weeks ago. I bought it to pull our 9k pound travel trailer (near the truck's comfort level, I know) and haven't really had a chance to put it to work much yet. I bought the truck thinking it was a complete, mechanically sound project but soon found it was really closer to 80% there (for my standards, at least). I did take the rig for a test pull right after I got it, and found the water temp seemed to run pretty hot. It didn't have a "real" water temp gauge but during the short pull, it ran at the "L" in normal which I figured must be pretty warm. So I ordered a water temp gauge, 4-core aluminum Champion radiator, and a new Motorcraft thermostat. The radiator and stat got here before the temp gauge, so I unfortunately don't have any "before" data to compare to. I haven't pulled the load again yet, but I'm a little concerned about what I'm seeing during regular driving. Now granted, I've run the truck hard trying to get it warm even unloaded, but I was hoping I wouldn't be able to. Running 75 on the interstate in the hill country I have seen just over 210*. This is around 2500 RPM and it takes some boost to keep the truck at that speed. 5 psi or so. I realize 210* is very safe....but this is unloaded. If it runs anything more than 20* warmer than this when pulling, that's really about as warm as I want to see.

So my questions are...

I mounted the gauge sender in place of the overtemp sensor. While I realize that isn't as ideal as mounting it in place of the OEM gauge....I figured it would be pretty good. Does this spot show warmer than the OEM gauge location? Cooler? By how much?

How much warmer can I expect to see temps when pulling heavy vs normal driving? 10*? 20*? 30* warmer?

Thanks for the info, as always.

 

[Shawn MacAnanny]

I have mine in that location with 3 core aluminum, even with ac at 75mph my temp never goes above 200 with ac on now that I switched back to clutch fan. But I also have a cowl hood and intercooler radiator blocking airflow up front.

 

[whiteboyslo]

Seems slightly warmer than I would expect. Mechanically, my truck is identical to yours (same radiator and thermostat, too, and my sensor is also in the overtemp port), except I have the Banks turbo system. Unloaded at freeway speeds, I may see up to 205 on a hot day uphill, but otherwise it's about 195-200 under normal driving conditions.

The most I load mine is about maybe 3000lbs, but with half of that in the bed (motorcycles and gear). I've seen as high as upper 220s with the new radiator, but that's up a significant grade in the middle of the desert on a triple-digit day, and I was running it hard just to see what it would do.

Mike

 

[hesutton]

Any clue what your timing is at? How about a pyrometer?

I prefer the "real" water temp sender to be in the rear passenger's side head. There is a plug you have to remove and it's a PITA to get to, but after having temp senders in several different locations on these IDI's, that is the "hottest" place I've seen for water temp. I feel it gives me the most accurate reading I can have.

Anyway, EGT's are important when you are wanting to keep water temps controlled. The higher the EGT's the more heat is transferred to your oil. The hotter the oil the more heat your cooling system has to dissipate. EGT's drive coolant temps on these IDI's. Keep your EGT's less than 850-900 most of the time, and your coolant should stay in its happy place.

Timing (either too retarded or advanced) will make your EGT's less than ideal.

Turbo and how efficiently it moves air into and out of its self can help as well. Do you have the factory (squished/restrictive) downpipe? Upgrading would help power and efficiency.

Heath

 

[ManBearPig]

I've never seen exhaust temp over about 850 and the pancake down pipe has been replaced with what looks to be the biggest you could possible squeeze in there....I'm guessing 3".

I have no idea where the timing is at.

 

[hesutton]

That's good news.

Timing these is not something most diesel shops are equipped to do. I wish we all had a timing meter from Ford as part of the standard equipment, but it is what it is. I'm just up the road from you in BG, but I don't have the equipment. I usually get mine checked at the annual Rally. Most of the time, several folks have the goodie to do the job.

Might be time to just hook up the TT and see how she does.

Heath

 

[ManBearPig]

Headed to the lake for the weekend tomorrow. Will be the first real time I have it hooked to a load for more than a few miles. Staying local-ish....will report back with how it goes!

 

[FORDF250HDXLT]

if you can't use it,what good is it?

it's not running warm at 210F.it's running correctly.running 235-240F is running warm.it's not a sissy engine.it's an old school medium duty truck work horse engine,designed to run @ upwards of 240F all day.run it.
some of you guys are way too skered.i'd have some of you ******** bricks working with me in a day.

 

[ManBearPig]

it's not running warm at 210F.it's running correctly.running 235-240F is running warm.it's not a sissy engine.it's an old school medium duty truck work horse engine,designed to run @ upwards of 240F all day.run it.
some of you guys are way too skered.i'd have some of you ******** bricks working with me in a day.

I'm not worried at 210*. What worries me is that if it runs 210* empty, it will run too hot when I'm working it. I'll find out in a few hours...

 

[laserjock]

Eh... its pretty flat around Nashvegas. Have to head toward down 24 to start finding grades. Something I've been thinking about is dropping a thermocouple into the radiator side of the cooling loop. If your thermostat is working right, the engine temp shouldn't budge much if the thermostat is working until you finally heat soak the radiator too. In the winter on my half ton truck I could see the thermostat open and close on my autometer gauge especially when it was getting warmed up. You'd see a temp spike down when it would let some cold water in from the rad. Personally, I'd be a lot less worried about my engine temps if I knew that My rad was still running cool. Once you get the point of really working it thought eventually you will come to equilibrium but it would be nice to know (pre planning based on how much head space you have on the radiator) where you stand before you hit the bottom of the mountain.

Just some rambling.

 

[BrianX128]

I put my mechanical gauge in the overtemp port and I think it reads around 5-10 cooler. I still have the factory gauge in and when it goes up to the n in normal that's about as high as it goes but I can always tell when the thermostat opens up because it will drop back down some on that gauge. When this happens my real gauge always reads right at 185-190 never above or below. Always right in that area. Highest I've seen my engine go was climbing a large hill in 4th with the ac on max my gauge said right about 210 so I'd guess 215-220. Just some random info, I think I'm interpreting my gauge somewhat accurately based on what I've read on here.

 

[ManBearPig]

Unfortunately, the truck ran quite warm today. It's a shame, I can tell there is more power to be had but I had to stay out of the throttle to keep water temp down. Made most of the trip around 55-60mph with water temp between 220-230. If I tried to maintain 65 even on relatively flat terrain, I would flirt with the 240* zone. Am I asking too much of the truck to maintain freeway speeds with 9k pounds behind it? I'm not sure what else to replace that would help. I don't think a new water pump would do much....fan clutch may be a good idea though. Even at 240* I never heard the fan come on. But even when working correctly don't they only engage around 235* or so? That wouldn't do much to keep me below 220* where I really should be anyway...

 

[Shawn MacAnanny]

Does your radiator have a full fan shroud? When I got my truck someone had cut half mine off to make it removable with fan in place

 

[Shawn MacAnanny]

Send a picture of your radiator fins too, maybe you just have 4000 bugs stuck blocking the fins. I noted my post ic Temps up about 15 degrees and found a bunch of bugs in my ic radiator. Washed them out and it went back down

Nevermind I see you have a new radiator I can t keep these overheating threads straight haha

 

[ManBearPig]

Does your radiator have a full fan shroud? When I got my truck someone had cut half mine off to make it removable with fan in place

It doesn't have much of a fan shroud but it looks OEM. This does remind me,though, that the fan shroud doesn't sit quite right on the champion rad. I could seal up the gap with some foam tape or something but I doubt that would keep me 20* cooler.

Side not.... EGT stayed around 700-800 most times. I did see almost 1000 once. Highest water temp I saw had the EGTright around 750.