Normal Operating Temp Range
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Normal Operating Temp Range
Hello - just joined forum. Have done much reading on this topic here and on other ford forums.
Can someone help me understand safe operating temps and what is reasonable?
I have a 1990 7.3 IDI that overheated on a very steep, slow driving, 6 mile forest road a couple months back. Did research and seemed like fan clutch was probably bad. Replaced fan clutch and installed mechanical temp sensor. I can operate anywhere from 180 to low 230s. I have a lightweight (1000 pound wet) pop up camper mounted but no towing. Hit 230 a week ago up a long but mild grade outside of Boise probably going 50-55 in 2nd. I also thought I was lugging the engine when overheated first time, so I have started dropping into 2nd (E4OD) to climb a lot of the hills around here.
I can run 210 on highway at 70mph if the engine is already hot. I know dummy light clicks at 240 but just seems odd I can get so close to those levels under what seem to be very normal operating conditions. Makes me very nervous. I also never hear the fan "lock in." And never can find definitive evidence of whwhat temp it should happen at.
Can someone help me understand safe operating temps and what is reasonable?
I have a 1990 7.3 IDI that overheated on a very steep, slow driving, 6 mile forest road a couple months back. Did research and seemed like fan clutch was probably bad. Replaced fan clutch and installed mechanical temp sensor. I can operate anywhere from 180 to low 230s. I have a lightweight (1000 pound wet) pop up camper mounted but no towing. Hit 230 a week ago up a long but mild grade outside of Boise probably going 50-55 in 2nd. I also thought I was lugging the engine when overheated first time, so I have started dropping into 2nd (E4OD) to climb a lot of the hills around here.
I can run 210 on highway at 70mph if the engine is already hot. I know dummy light clicks at 240 but just seems odd I can get so close to those levels under what seem to be very normal operating conditions. Makes me very nervous. I also never hear the fan "lock in." And never can find definitive evidence of whwhat temp it should happen at.
Tuned
Joined: Jul 2010
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From: Kitimat British columbia
Definate problem under heavy loads and high ambient temperatures you should see that. Is your rad plugged? Is your thermostat stuck shut? You can drive down the highway with a stuck thermostat. Over heat on any hill, cruise fine. So check upper rad hose at operating temp should sit around 190-200 degrees. Fan should start kicking in around 210 in my experience usually. Otherwise water pump may not be flowing enough but still pumping.
i ain't rite
Joined: Mar 2005
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From: Marlboro Mental Hospital.
welcome to FTE.
ford or international dealer only for the thermostat.
aftermarket t-stats normally do not work in our engines and will give you an overheat condition like you are currently experiencing.
ford or international dealer only for the thermostat.
aftermarket t-stats normally do not work in our engines and will give you an overheat condition like you are currently experiencing.
Postmaster
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Also, when you replace the thermostat, dig the little ball bearing out of the upper thermostat housing/upper rad hose casting - It's "supposed" to be a little air bleed, but it doesn't really work right. Remove the ball bearing and clean out the port, and it'll bleed *much* easier.
It also doesn't seem to affect warmup times, even with the little 1/4" port bypassing the thermostat.
Cargo Master
Joined: Oct 2005
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From: NJ
Mine runs about 180*-210* depending on load. I forget exact temp but fan seems to lockup a bit over 210* as measured at drivers side head rear port, and when it locks it'll quickly drag temp back down to about 195*-200* before unlocking. Hottest I've ever seen it is just shy of 230* towing up a hill in low gear and high RPM. Towing in summer it can stay in the 200*-210* on fairly level ground at highway speed. Unloaded it tends to stay in the 180*-200* range.
Check thermostat, use only Ford or International parts for that. Check fan clutch operation, it get hot it it doesn't lock up. On mine it's easy to tell when it locks as it's usually towing uphill on the highway and right when I need all the power it has to offer that fan locks up and there is a very noticeable drop in power and of course the fan is very loud. If you don't have a good cowl to hood seal you'll also get a bunch of hot air out of the floor vents when the fan locks up.
Check thermostat, use only Ford or International parts for that. Check fan clutch operation, it get hot it it doesn't lock up. On mine it's easy to tell when it locks as it's usually towing uphill on the highway and right when I need all the power it has to offer that fan locks up and there is a very noticeable drop in power and of course the fan is very loud. If you don't have a good cowl to hood seal you'll also get a bunch of hot air out of the floor vents when the fan locks up.
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Thanks for all the advice. So I replaced the thermostat with the ford dealership thermostat and replaced all the coolant. Go out and take a big hill and I'm back at 230 in no time. The upper radiator hose is getting hot so I know coolant is getting through the t stat. The radiator is hot all over. Fan clutch is brand new. I'm at a total loss. It seems like if the water pump were the issue the radiator and upper hose wouldn't be getting hot? Or it's just not circulating fast enough?
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Postmaster
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This is just my own experience, but try doing a timing-by-ear job on the truck. Chances are, it's retarded due to wear, and retarded timing results in high EGTs and water temps(because you are using more fuel for the same work done).
Timing by ear is basically a matter of advancing the timing a bit and seeing how it drives. The more power it has, the better. You can easily just keep advancing and driving until it feels like it /lost/ power, then back it off a little.
Also, if you see smoke under acceleration: Blue, gray and white is retarded timing. Black is advanced or OK timing; you never want to see any smoke other than black.
Timing by ear is basically a matter of advancing the timing a bit and seeing how it drives. The more power it has, the better. You can easily just keep advancing and driving until it feels like it /lost/ power, then back it off a little.
Also, if you see smoke under acceleration: Blue, gray and white is retarded timing. Black is advanced or OK timing; you never want to see any smoke other than black.
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I disagree with mac here. Better to be a little retarded than advanced at all. Sounds like a plugged radiator to me. Is your fan clutch engaging? The quality control for them is terrible. Bought one and it would never lockup, bought another, it wont unlock. Mine with a freshly rebuilt radiator gets warm too, and my timing is dead nuts, fan clutch wont unlock. I have no idea, gave up on fixing it tbh. I just drive by the temp gauge.
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I should also mention I lost a bunch of coolant yesterday when I took the truck back out after thermostat replacement. I would park the car and with it running / also when off, it was pretty quickly draining coolant directly under the engine. Let it cool down and took back out after my last post here and took a big hill and did same thing, losing coolant. To the point of sucking the nearly full overflow tank dry and this morning can see the fins on radiator.
I first thought I had overfilled with new coolant but I'm not sure how it could be exiting the system below the car. Have never had coolant leak before. Trying to figure out where it was coming from. Only thing I can think of is water pump weep holes.
I first thought I had overfilled with new coolant but I'm not sure how it could be exiting the system below the car. Have never had coolant leak before. Trying to figure out where it was coming from. Only thing I can think of is water pump weep holes.
Postmaster
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Check hoses - upper, lower rad hoses, and the two heater hoses. You might have a hole in one.
I'd probably start off by filling everything up, popping the hood and letting it idle from cold. As it warms up, it will naturally build pressure in the cooling system, and you should see the leak.
Edit:
Also, your choice of coolant will help with this.
Personally I believe in and use Zerex HD ELC coolant for all my IDI trucks; it's bright pink and leaves behind a white/pink residue as it dries.
So it's pretty easy to see when there is a leak, from the white/pink trail.
I'd probably start off by filling everything up, popping the hood and letting it idle from cold. As it warms up, it will naturally build pressure in the cooling system, and you should see the leak.
Edit:
Also, your choice of coolant will help with this.
Personally I believe in and use Zerex HD ELC coolant for all my IDI trucks; it's bright pink and leaves behind a white/pink residue as it dries.
So it's pretty easy to see when there is a leak, from the white/pink trail.
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Coolant is leaking frown somewhere around/above the starter. My block heater is in one of the freeze plug ports right there but doesn't look to be coming from there. Can't tell if it's just running down, but it almost seems to be leaking from the valley pan seal. The biggest flow is from right at the seam. I have heard of this problem before just funky it happened right after changing the thermostat and new coolant. I guess it could also be a freeze plug blown out somewhere else or a cracked block, I hope not. Potentially also a headgasket I would think.
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