Normal operating temperature
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Normal operating temperature
What is the normal operating temp of my 86 300?
This is what I know and verified:
Low end of gauge N of normal is 200 degrees while the L is 260 degrees.
Thermostat is a 195 degree from part store. Water pump spins and doesn't leak.
At highway speed gauge reads at O which is about 220 degrees.
On warm days sitting in traffic the needle goes to A...L and above, therefore the actual temp of engine is rising close to overheating and may if I sit long enough (don't want to find out).
Next purchase would be the radiator. Is this most likely to cause this problem?
Should the operating temp stay constant +/- 10 degrees or so? (not 50 degrees) Other vehicles I have stay constant +/- 5 degrees.
This is what I know and verified:
Low end of gauge N of normal is 200 degrees while the L is 260 degrees.
Thermostat is a 195 degree from part store. Water pump spins and doesn't leak.
At highway speed gauge reads at O which is about 220 degrees.
On warm days sitting in traffic the needle goes to A...L and above, therefore the actual temp of engine is rising close to overheating and may if I sit long enough (don't want to find out).
Next purchase would be the radiator. Is this most likely to cause this problem?
Should the operating temp stay constant +/- 10 degrees or so? (not 50 degrees) Other vehicles I have stay constant +/- 5 degrees.
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Junior User
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Yes, Yes, Maybe, Yes. I have used water(garden hose) to flush. Seem like there is enough flow.There just seems to a large swing in tempeture.....not nearly as large since I rebuilt. Other vehicles I own don't have that swing. I assume part of it may be the response time in the sensor or electronics. Does the block or coolant heat that fast? From low temp(200) to higher temp(260) under a minute a lot slower to cool to lower temp after moving. And yes the fan is working(spinning).
Would a lower temp thermostat like 160 help or hurt? Does this engine need to run this hot for proper operation?
Would a lower temp thermostat like 160 help or hurt? Does this engine need to run this hot for proper operation?
New User
Joined: Jul 2004
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I had the same problem with my E-150 van ,it has a 5.8 v8, I have istalled new water pump,new 195 therostat and new after market thurmal clutch fan with no luck still ,Let me back up here in the driveway the temp hits 195 then floatsdown to 192 after thermal stat opens that good, But then start driving down the road and the temp will rise to 221 to 225 it too hot. Need help .Ford over chevy
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Bought a new radiator. Replaced the thermostat to 160. Engine runs cooler overall, but still can go up to 260 . I have to watch temp if I am using the A/C. Can the compressor put that much of a load when it still feels cold and the low and high pressures are correct? Doesn't sound or feel like it is loading the engine when turned on. Is there a check for this?
What about the tempeture of the transmission fluid running thru the radiator. Lines don't feel hot.
What about the tempeture of the transmission fluid running thru the radiator. Lines don't feel hot.
Fleet Mechanic
Joined: Nov 2003
Posts: 1,372
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From: West Cornwall, CT
Proteks, from your description the truck runs hot at low speeds, at idle and when the AC is on at low speed. Does it seem to run closer to normal temperature when you are driving?
With a good radiator, thermostat and radiator cap the most likely problem is your water pump. The pump is a centrifugal unit and, if worn or corroded internally, will not pump well at low speeds. This can cause the overheating you are seeing.
A water pump replacement on an I-6 is not too difficult if you remove the radiator and shroud to get decent access. Make sure the shroud is reinstalled when you are done. I would not use the 160 degree thermostat. Your truck will run better with the hotter stock unit.
Lou Braun
With a good radiator, thermostat and radiator cap the most likely problem is your water pump. The pump is a centrifugal unit and, if worn or corroded internally, will not pump well at low speeds. This can cause the overheating you are seeing.
A water pump replacement on an I-6 is not too difficult if you remove the radiator and shroud to get decent access. Make sure the shroud is reinstalled when you are done. I would not use the 160 degree thermostat. Your truck will run better with the hotter stock unit.
Lou Braun
Tuned
Joined: Jul 2002
Posts: 479
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From: Louisiana
Have you ever changed the fan clutch?
I just changed mine at 112K original miles on it. I had the same type of problem, temp would spike all the way to the "A". Now the fan really blows. I use to stop the fan with my fingers after the initial "roar" when the truck was first started, that's how slow it was turning.
I just changed mine at 112K original miles on it. I had the same type of problem, temp would spike all the way to the "A". Now the fan really blows. I use to stop the fan with my fingers after the initial "roar" when the truck was first started, that's how slow it was turning.
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Posting Guru
Joined: Dec 2003
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From: Northern California
Thats a good idea byronbgs, a proper working fan clutch is a big key in assuring good cooling. On the subject of what Lou Braun was speaking, on water pumps being internally corroded, I have seen that condition several times. You will have externally what appears to be a perfectly good water pump with no staining beneeth the "pee" hole. I've removed these "good" pumps before and found that the impellers are corroded away on them, leading to all of the overheating problems. A water pump change is often the ticket in these hard to find overheating issues, give it a try.
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New User
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Same Problem but on my van. Replaced water pump, T-stat(3 times), radiator, sending unit, fan clutch. Rechecked timing, tested heads for leak, flushed block.
Nothing worked. The gauge goes to the (R) with no a/c and to the (A-L) range with a/c. Even higher if stuck in traffic. I dont know what to do short of ripping the whole thing apart looking for a restriction in the block or intake.
Please does someone have any ideas I can try. I am truly frustrated and at my wits end.
Thanks,
Tsunami
Nothing worked. The gauge goes to the (R) with no a/c and to the (A-L) range with a/c. Even higher if stuck in traffic. I dont know what to do short of ripping the whole thing apart looking for a restriction in the block or intake.
Please does someone have any ideas I can try. I am truly frustrated and at my wits end.
Thanks,
Tsunami
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Background.....truck has done this for ten years. Rebuilt 1000 miles ago..Attempting to fix all these ongoing problems. Gone thru all the above ideas....To the best of my knowledge all are working properly.
Fan clutch....not sure of the proper test for this, but I wouldn't want to try to stop it when engine running. When engine is shut off the fan stops quickly.
Water pump appears to be good. Doesn't leak, impeller still shiny stainless and connected to shaft.Do they make a better one than stock?
New temp send unit.
Cleaned contacts on gauges Verified temp on gauge with the new sending unit at that temp.
With new 160 thermostat engine runs cooler.
Should I use an external transmission cooler? The lines to the radiator don't feel hot. Doesn't seem like that is a problem.
Recently timed.
Any other suggestions....
Fan clutch....not sure of the proper test for this, but I wouldn't want to try to stop it when engine running. When engine is shut off the fan stops quickly.
Water pump appears to be good. Doesn't leak, impeller still shiny stainless and connected to shaft.Do they make a better one than stock?
New temp send unit.
Cleaned contacts on gauges Verified temp on gauge with the new sending unit at that temp.
With new 160 thermostat engine runs cooler.
Should I use an external transmission cooler? The lines to the radiator don't feel hot. Doesn't seem like that is a problem.
Recently timed.
Any other suggestions....
Tuned
Joined: Jul 2002
Posts: 479
Likes: 12
From: Louisiana
proteks, your right about trying to stop the fan, it's just mine was turning so slowly that I thought i'd give it a try.
As far as testing the clutch it should have some resistance with the engine off, should "roar" for no more than 5 min upon start up then quiten out, and when the engine is hot the fan clutch will engage and "roar" and blow like the devil.
Which mine was blowing, but the new one was like night and day. Also the instructions on the new clutch said that if there was oil or grease on the thermostat coil then the clutch was bad. Mine had a thick layer of grease in and on the coil.
I also changed the thermostat with one of those "fail safe" units (195 degrees), but I don't think it was necessary.
Now the gauge is rock steady at the "R" to just touching the "M". It is now above the old temp of between the "N & O", but I read in another thread that after a month the other fellows gauge settled down back to the old reading.
Anyway keep us informed.
As far as testing the clutch it should have some resistance with the engine off, should "roar" for no more than 5 min upon start up then quiten out, and when the engine is hot the fan clutch will engage and "roar" and blow like the devil.
Which mine was blowing, but the new one was like night and day. Also the instructions on the new clutch said that if there was oil or grease on the thermostat coil then the clutch was bad. Mine had a thick layer of grease in and on the coil.
I also changed the thermostat with one of those "fail safe" units (195 degrees), but I don't think it was necessary.
Now the gauge is rock steady at the "R" to just touching the "M". It is now above the old temp of between the "N & O", but I read in another thread that after a month the other fellows gauge settled down back to the old reading.
Anyway keep us informed.
Last edited by byronbgs; Jul 21, 2004 at 07:47 PM.
Posting Guru
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From: Northern California
proteks, I still wouldent rule out that darn water pump. Replaing with a stock one wouldent be a bad idea at this point in the game. Edelbrock does make a really good Water pump for the Ford V8, not sure about the 300 though. You might want to do a web search on high output waterpumps, as I think there are a few different companies making them now.
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I cleaned all the oil and dirt from the coil. Maybe the clutch is bad...doesn't react until the temp of engine is 260
On a cold start should the fan "roar" or is the coil "cold" and allows the fan to slip. When engine is warm coil stops the fan from slipping and spins at the fastest speed.
Correct me if I am wrong...
On a cold start should the fan "roar" or is the coil "cold" and allows the fan to slip. When engine is warm coil stops the fan from slipping and spins at the fastest speed.
Correct me if I am wrong...
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Bought new fan clutch. New feels a little tighter, maybe. Definitely controls temp better. Had A/C on and held temp steady at about 250 degrees in stop and go traffic. Major improvement, but not 100 percent. Went above L sitting and waiting at a drive thru. Turned off A/C and temp lowered to L. Never lowered just sitting at idle before.
Update:
New radiator, new fan clutch, 50/50 mix, 160 thermostat, new sending unit, gauge accuracy tested.
Radiator cap? Appears to hold pressure....I'm not boiling over.
Thermostat position? Should the spring side go in the block or in the bell housing?
Spring side said "Rad" I assumed that side toward the radiator.
Next step I guess...New water pump.
Update:
New radiator, new fan clutch, 50/50 mix, 160 thermostat, new sending unit, gauge accuracy tested.
Radiator cap? Appears to hold pressure....I'm not boiling over.
Thermostat position? Should the spring side go in the block or in the bell housing?
Spring side said "Rad" I assumed that side toward the radiator.
Next step I guess...New water pump.
Tuned
Joined: Jul 2002
Posts: 479
Likes: 12
From: Louisiana
Originally Posted by proteks
I cleaned all the oil and dirt from the coil. Maybe the clutch is bad...doesn't react until the temp of engine is 260
On a cold start should the fan "roar" or is the coil "cold" and allows the fan to slip. When engine is warm coil stops the fan from slipping and spins at the fastest speed.
Correct me if I am wrong...
On a cold start should the fan "roar" or is the coil "cold" and allows the fan to slip. When engine is warm coil stops the fan from slipping and spins at the fastest speed.
Correct me if I am wrong...