Engine Will Not Reach Proper Operating Temperature
CO River Rat
Joined: Feb 2004
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From: Lake Havasu City AZ
One other thought: If the hose to the coolant reservoir has a pin-hole leak, the radiator will suck air instead of coolant as it cools down. If this is the case, you'll never get rid if the air lock.
Steve
Steve
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Joined: Oct 2006
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Originally Posted by tonyford
Thank you all for the replies, much appreciated.
The fan clutch is spinning freely with engine off, so it is not siezed up, but an excellent thought that I missed. I am beginning to believe what Dave posted about the water pump not pumping enough warm water through the system. I was out today with the truck and got it up to normal operating temp, as soon as I pulled into the driveway and let the engine idle, the temperature started to drop down towards the Cold mark, and rather quickly I might add. This leads me to believe it is a circulation problem dependent on engine speed. The impeller is turning somewhat at the higher rpm's, but at idle and lower rpm's it is not turning at all and not circulating the hot coolant through the system.
Now the problem I have with my theory, and Dave's, is why isn't the engine overheating at idle if the impeller is not circulating the coolant? Wouldn't it get overly hot from not circulating through the radiator and getting cooled off? Last two days temps here have been between 20 and 30 degrees, not bitter cold and normally the truck would heat up fast in these temperatures. Also why when turning on the heater it cools off even faster at idle?
I am not about to start changing parts indiscrimantly if I am not completely sure if that is the problem.
As for what one post said:
"did you put the proper temperature t-stat in?
#3 the coolant is suppose to be changed every two years. have you flushed the system?
#4 do a compression check to make sure everything is sound"
I kind of ignored any of this. The parts store only had one listing for thermostats for this vehicle and it was the standard temp thermostat.
Coolant is NOT supposed to be changed every two years, yes you can change your coolant every two years if you want to waste money and time doing it. Coolant will last as long as 5 years or more as long as your cooling system is functioning properly. Prestone guarantees 5 years minimum for their coolant. I have known people who NEVER changed their coolant and NEVER had a problem. Whomever says your coolant must be changed every two years must work for one of the coolant manufacturers, lol.
I have no signs of lost compression, engine runs great, no loss of power, and no signs of anti-freeze mixing with the oil.
I still have to think about the water pump theory or still could be as simple as an air lock still in the system. I might just drain the system and start over again, not because the coolant has gone bad, but because it may be the only way to get rid of a bad air lock.
The fan clutch is spinning freely with engine off, so it is not siezed up, but an excellent thought that I missed. I am beginning to believe what Dave posted about the water pump not pumping enough warm water through the system. I was out today with the truck and got it up to normal operating temp, as soon as I pulled into the driveway and let the engine idle, the temperature started to drop down towards the Cold mark, and rather quickly I might add. This leads me to believe it is a circulation problem dependent on engine speed. The impeller is turning somewhat at the higher rpm's, but at idle and lower rpm's it is not turning at all and not circulating the hot coolant through the system.
Now the problem I have with my theory, and Dave's, is why isn't the engine overheating at idle if the impeller is not circulating the coolant? Wouldn't it get overly hot from not circulating through the radiator and getting cooled off? Last two days temps here have been between 20 and 30 degrees, not bitter cold and normally the truck would heat up fast in these temperatures. Also why when turning on the heater it cools off even faster at idle?
I am not about to start changing parts indiscrimantly if I am not completely sure if that is the problem.
As for what one post said:
"did you put the proper temperature t-stat in?
#3 the coolant is suppose to be changed every two years. have you flushed the system?
#4 do a compression check to make sure everything is sound"
I kind of ignored any of this. The parts store only had one listing for thermostats for this vehicle and it was the standard temp thermostat.
Coolant is NOT supposed to be changed every two years, yes you can change your coolant every two years if you want to waste money and time doing it. Coolant will last as long as 5 years or more as long as your cooling system is functioning properly. Prestone guarantees 5 years minimum for their coolant. I have known people who NEVER changed their coolant and NEVER had a problem. Whomever says your coolant must be changed every two years must work for one of the coolant manufacturers, lol.
I have no signs of lost compression, engine runs great, no loss of power, and no signs of anti-freeze mixing with the oil.
I still have to think about the water pump theory or still could be as simple as an air lock still in the system. I might just drain the system and start over again, not because the coolant has gone bad, but because it may be the only way to get rid of a bad air lock.
Thanks,
Gene
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Joined: Oct 2006
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To me, I think that you're trying to make the problem more difficult than it is. If it blows hot air, then the coolant is getting hot, if its REALLY hot air, and the gauge says cold, then its the sending unit. In some models, I think the sending unit, and the temp sensor used for the ECU is the same.
That being said...What brand thermostat did you use? From the description (that you got it off the shelf from the book), it seems like you have a stant. They are GARBAGE, complete and utter JUNK. I replaced a really old OEM one on my cousins GMC (Garage Man's Companion) with a STANT, and it did the same thing after a week (over cooled), more specifically, it was really cold at an idle, and driving it warmed up, but always just blew luke warm air. I replaced it with another stant, and same thing after a week. We went and got one from NAPA, and it still works great to this day. The point is...dont use STANT. And it sounds to me like you have a thermostat problem. I had a similar problem in my 4.0 Ranger, it was 97 degrees out one day, and I drove about 10 miles, and the needle hadnt come off C yet. Over cooling thermostat. Imagine if that had been in the winter!
Let me know how you make out
That being said...What brand thermostat did you use? From the description (that you got it off the shelf from the book), it seems like you have a stant. They are GARBAGE, complete and utter JUNK. I replaced a really old OEM one on my cousins GMC (Garage Man's Companion) with a STANT, and it did the same thing after a week (over cooled), more specifically, it was really cold at an idle, and driving it warmed up, but always just blew luke warm air. I replaced it with another stant, and same thing after a week. We went and got one from NAPA, and it still works great to this day. The point is...dont use STANT. And it sounds to me like you have a thermostat problem. I had a similar problem in my 4.0 Ranger, it was 97 degrees out one day, and I drove about 10 miles, and the needle hadnt come off C yet. Over cooling thermostat. Imagine if that had been in the winter!
Let me know how you make out
New User
Joined: Apr 2015
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First off, THANK YOU for all the insight within this thread! Well it's April of 2015... Hold all y'all are alive and well.. My 99' E150 5.4L with rear heat (ProAirllc) is doing roughly the same thing. Should I move this to the van section or does anyone want to hear about this issue? TIA DD!
Thread Starter
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Elder User
Joined: Nov 2003
Posts: 544
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Wow this thread is nearly 10 years old.
I dumped the Ford Ranger about a month after my last post and bought a Ford Escape.
The Ford Escape was a great vehicle and lasted me quite awhile until the transmission went.
Now I am a Subaru fanboy. Love my Forester and my wife now has an Impreza 5-Door Hatchback.
Why Ford stopped selling Rangers in the USA is beyond me. They were great little trucks back in the 80's and 90's.
I dumped the Ford Ranger about a month after my last post and bought a Ford Escape.
The Ford Escape was a great vehicle and lasted me quite awhile until the transmission went.
Now I am a Subaru fanboy. Love my Forester and my wife now has an Impreza 5-Door Hatchback.
Why Ford stopped selling Rangers in the USA is beyond me. They were great little trucks back in the 80's and 90's.
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Joe Kucinski
Junior User
Joined: Mar 2004
Posts: 88
Likes: 0
From: South Austin
Wow this thread is nearly 10 years old.
I dumped the Ford Ranger about a month after my last post and bought a Ford Escape.
The Ford Escape was a great vehicle and lasted me quite awhile until the transmission went.
Now I am a Subaru fanboy. Love my Forester and my wife now has an Impreza 5-Door Hatchback.
Why Ford stopped selling Rangers in the USA is beyond me. They were great little trucks back in the 80's and 90's.
I dumped the Ford Ranger about a month after my last post and bought a Ford Escape.
The Ford Escape was a great vehicle and lasted me quite awhile until the transmission went.
Now I am a Subaru fanboy. Love my Forester and my wife now has an Impreza 5-Door Hatchback.
Why Ford stopped selling Rangers in the USA is beyond me. They were great little trucks back in the 80's and 90's.
New User
Joined: Sep 2003
Posts: 2
Likes: 0
You should get a infra red thermometer check actual temps before and after thermostat,upper lower rad hoses,front and back of motor and at heater case inlet and outlet hoses.This will eliminate a guage failure ,verify a open thermostat,will help diagnose coolant circulation or lack of circulation.The 4 cyl rangers had a problem with a missing restrictor ,or it would rust out causing the coolant to circulate to fast , running to cold.A flatwasher installed in heater hose inlet will fix that.The 4.0L huge problem with thermostats .the impeller on the water pump will dissipate and low,no circulation .Uneven coolant temps ,erratic is an indication of this ,the only other way is to remove water pump and inspect.If you are familiar with normal coolant flow rate then you can pull the outlet hose from pump and that can show pump operation.If you use a tester or scanner when a code is generated that doesn't mean to replace a part ,it sends you to a diagnostic procedure to do some tests to find the problem.A code 21 doesn't mean replace the ECT ,you wasting your time and money.I am a retired ford senior master diesel and gas tech,34 years experience ,I have seen most every problem there is.
Last edited by yaknart33; Apr 8, 2015 at 11:40 PM. Reason: left out a word
New User
Joined: Jan 2019
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Hello
I have a 98 fird ranger 3.0 with a cluch fan will not reach running temp new rad new hoses and thero stat its a 195 ran for hour and water temp only got to 110 degrees witch also is causeing cool or no heat the truck is missing the fan strouds. But un sure if that can cause it no leaks pressured the system and it holds any ideas im stumped
Moderator
Joined: Jan 2004
Posts: 13,851
Likes: 111
From: SW Va
Welcome to FTE.
I see you don't have any replies yet, so I'll see if I can get things started.
We don't know if you had heat before the work, so you may have more than one problem.
Maybe the heater core is blocked, so has it been putting out heat Before the thermostat was replaced? If so, then you might have a faulty new thermostat.
If the heat was wimpy before the work you might now have a faulty dash gauge temp sensor, or a faulty new thermostat that's sticking open.
So after say 15 min engine run time check/feel the upper radiator hose, if it's cold or barely warm to the touch after 15 min idle time from a cold start, the new thermostat is likely stuck open.
If the upper radiator hose too hot to hold, the thermostat is likely ok & maybe you have a faulty temp sensor, or a heater blend door control problem that it's not moving, so all the air will come through the heater core, so feel the engine bay heater hoses to see if they & the upper radiator hose is hot, if not, it's another clue that the new thermostat is faulty/stuck open, or if the upper radiator hose is hot, but the heater hoses aren't, the heater core is blocked. If the heater hoses are hot then it suggests the heater core is ok & maybe you have a console heat control problem, maybe a vacuum leak to the controls, or maybe a blend door operation problem. The blend door is a common wimpy, or no cabin heat problem.
I suppose if you didn't get a good refill & cooling system burp you could have a large air bubble in the heater core that wouldn't conduct heat to it, but you'd likely hear some grumbling sounds from the engine or heater core as the coolant would boil & grumble with air in it, as it would cause a pressure drop below the boiling point.
If you think the system didn't burp well after refilling, turn the cabin heater temp control to Max temp/heat, park front end up hill, the steeper the better, or elevate the front end, the higher the better, so the radiator is the high point in the cooling system.
Milk the lower radiator hose about a dozen times to chase any entrapped air bubbles toward the radiator. This works to purge air past the thermostat air bleed valve & back to the top of the radiator. If the new thermostat wasn't a Motorcraft, or a design like it with the air bleed valve, you'll have to wait until the thermostat opens for the air to pass the thermostat & get to the top of the radiator, so this step will have some but not full effect
Make sure the coolant recovery tank is topped up & that the radiator cap is functioning, as it'll burp air out of the system as it cools & automatically top up the coolant from the recovery tank. SO, if you'll mark the tank & check it after it cools down, you can see if the recovery tank level dropped when the system burped.
Top up the recovery tank with a 50/50 mix of distilled water & the specified Undiluted coolant.
Start the engine & let it fully warm up so the thermostat is fully open, the temp gauge peaks & drops back, or the upper radiator hose is too hot to hold. Then increase engine rpm to say 1500-2000 for 30 seconds or so, to chase any air back to the top of the radiator, then shut the engine off & let it completely cool & check the recovery tank mark & if it dropped you know it burped, so top it up.
If it drained the recovery tank you know you had a Large air bubble, so top up the recovery tank & radiator & repeat with the front end elevated, until it stops burping & the system should be purged of air.
A bunch of preliminary trouble shooting thoughts for consideration, let us know what you find.
I see you don't have any replies yet, so I'll see if I can get things started.
We don't know if you had heat before the work, so you may have more than one problem.
Maybe the heater core is blocked, so has it been putting out heat Before the thermostat was replaced? If so, then you might have a faulty new thermostat.
If the heat was wimpy before the work you might now have a faulty dash gauge temp sensor, or a faulty new thermostat that's sticking open.
So after say 15 min engine run time check/feel the upper radiator hose, if it's cold or barely warm to the touch after 15 min idle time from a cold start, the new thermostat is likely stuck open.
If the upper radiator hose too hot to hold, the thermostat is likely ok & maybe you have a faulty temp sensor, or a heater blend door control problem that it's not moving, so all the air will come through the heater core, so feel the engine bay heater hoses to see if they & the upper radiator hose is hot, if not, it's another clue that the new thermostat is faulty/stuck open, or if the upper radiator hose is hot, but the heater hoses aren't, the heater core is blocked. If the heater hoses are hot then it suggests the heater core is ok & maybe you have a console heat control problem, maybe a vacuum leak to the controls, or maybe a blend door operation problem. The blend door is a common wimpy, or no cabin heat problem.
I suppose if you didn't get a good refill & cooling system burp you could have a large air bubble in the heater core that wouldn't conduct heat to it, but you'd likely hear some grumbling sounds from the engine or heater core as the coolant would boil & grumble with air in it, as it would cause a pressure drop below the boiling point.
If you think the system didn't burp well after refilling, turn the cabin heater temp control to Max temp/heat, park front end up hill, the steeper the better, or elevate the front end, the higher the better, so the radiator is the high point in the cooling system.
Milk the lower radiator hose about a dozen times to chase any entrapped air bubbles toward the radiator. This works to purge air past the thermostat air bleed valve & back to the top of the radiator. If the new thermostat wasn't a Motorcraft, or a design like it with the air bleed valve, you'll have to wait until the thermostat opens for the air to pass the thermostat & get to the top of the radiator, so this step will have some but not full effect
Make sure the coolant recovery tank is topped up & that the radiator cap is functioning, as it'll burp air out of the system as it cools & automatically top up the coolant from the recovery tank. SO, if you'll mark the tank & check it after it cools down, you can see if the recovery tank level dropped when the system burped.
Top up the recovery tank with a 50/50 mix of distilled water & the specified Undiluted coolant.
Start the engine & let it fully warm up so the thermostat is fully open, the temp gauge peaks & drops back, or the upper radiator hose is too hot to hold. Then increase engine rpm to say 1500-2000 for 30 seconds or so, to chase any air back to the top of the radiator, then shut the engine off & let it completely cool & check the recovery tank mark & if it dropped you know it burped, so top it up.
If it drained the recovery tank you know you had a Large air bubble, so top up the recovery tank & radiator & repeat with the front end elevated, until it stops burping & the system should be purged of air.
A bunch of preliminary trouble shooting thoughts for consideration, let us know what you find.