Mediocre heat
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Senior User
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From: Pittsburgh!
Mediocre heat
Alrighty... '97 F250HD, 460 5-speed. Judging by the fuel it burns I should have all kinds of heat!!!
For what it's worth, the temp guage never makes it more than a 1/3 of the way up... my '92 300-6 made all kinds of heat... any Ford I've ever owned made all kinds of heat.
Does this sound like the previous owner snuck a cooler t-stat into it? Heater core problem? Something else?
What would be a reasonable t-stat to run? 195? I won't be towing any mountains across the desert so I'm not too worried about keeping it cool.
Thanks much!
For what it's worth, the temp guage never makes it more than a 1/3 of the way up... my '92 300-6 made all kinds of heat... any Ford I've ever owned made all kinds of heat.
Does this sound like the previous owner snuck a cooler t-stat into it? Heater core problem? Something else?
What would be a reasonable t-stat to run? 195? I won't be towing any mountains across the desert so I'm not too worried about keeping it cool.
Thanks much!
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a colder thermostat has no effect on the operating temp of the the vehicle. all it ever does is determine at what temp the coolant begins to flow through the block at warm-up. the engine's gonna run at the temp it runs at, regardless of the t-stat. i BELIEVE the stock t-stat is 192/195, so go with that.
now, it's interesting that your 300 made so much heat. my 90 300 M5OD ran ice cold even with its dinky lil radiator. my 89 F250 351 ZF 5-spd does pretty much the same. never even reaches the "N" in NORMAL. now, my buddy's 89 302 AOD would get up to about the "O" everytime.
my GUESS is that one of two things is happening here:
1) the gauge isn't THAT accurate. wouldn't surprise me. Fords are somewhat notorious for this. only real remedy would be an aftermarket gauge to let you know what you're TRULY running at.
2) auto trannies may just have a tendency of raising the operating temp of the vehicle. don't know if your 300 was auto or not, but i've noticed that the "operating temp" accordgin to the gauge is a little higher in auto trucks of this era than the manuals.
Mike
now, it's interesting that your 300 made so much heat. my 90 300 M5OD ran ice cold even with its dinky lil radiator. my 89 F250 351 ZF 5-spd does pretty much the same. never even reaches the "N" in NORMAL. now, my buddy's 89 302 AOD would get up to about the "O" everytime.
my GUESS is that one of two things is happening here:
1) the gauge isn't THAT accurate. wouldn't surprise me. Fords are somewhat notorious for this. only real remedy would be an aftermarket gauge to let you know what you're TRULY running at.
2) auto trannies may just have a tendency of raising the operating temp of the vehicle. don't know if your 300 was auto or not, but i've noticed that the "operating temp" accordgin to the gauge is a little higher in auto trucks of this era than the manuals.
Mike
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From: North Dakota
Originally Posted by whiteyfordzx5
a colder thermostat has no effect on the operating temp of the the vehicle. all it ever does is determine at what temp the coolant begins to flow through the block at warm-up. the engine's gonna run at the temp it runs at, regardless of the t-stat. i BELIEVE the stock t-stat is 192/195, so go with that.
Engines were designed to run at the 192 or 195 that the factory thermostat is. You can put down to 180 in and make a *slight* power increase, along with more fuel being used. Anything below 180 accelerates engine wear due to cylinder wash from unburned fuel.
I would start with a new 195 or 192 thermostat, whatever the book says it is supposed to have. Thermostats are cheap, easy, and if you have never replaced it who knows the condition of what's in there now.
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Originally Posted by Steven@nd
The thermostat has EVERYTHING to do with the operating temperature of the vehicle. If you totally remove the thermostat and drive when it is 0 degrees, the engine will never warm up enough to come out of open loop mode.
Mike
Lead Driver
Joined: Feb 2003
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From: Oak Harbor, OH
The thermostat controls the MAXIMUM temp of the engine. It may get a little warmer that rated but not by much. A 195 degree t-stat opens at 195 degrees and closes at like 190. It regulates water flow through the engine to keep it as the rated temperature.
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From: Pittsburgh!
Originally Posted by whiteyfordzx5
a colder thermostat has no effect on the operating temp of the the vehicle. all it ever does is determine at what temp the coolant begins to flow through the block at warm-up. the engine's gonna run at the temp it runs at, regardless of the t-stat. i BELIEVE the stock t-stat is 192/195, so go with that.
now, it's interesting that your 300 made so much heat. my 90 300 M5OD ran ice cold even with its dinky lil radiator. my 89 F250 351 ZF 5-spd does pretty much the same. never even reaches the "N" in NORMAL. now, my buddy's 89 302 AOD would get up to about the "O" everytime.
my GUESS is that one of two things is happening here:
1) the gauge isn't THAT accurate. wouldn't surprise me. Fords are somewhat notorious for this. only real remedy would be an aftermarket gauge to let you know what you're TRULY running at.
2) auto trannies may just have a tendency of raising the operating temp of the vehicle. don't know if your 300 was auto or not, but i've noticed that the "operating temp" accordgin to the gauge is a little higher in auto trucks of this era than the manuals.
Mike
now, it's interesting that your 300 made so much heat. my 90 300 M5OD ran ice cold even with its dinky lil radiator. my 89 F250 351 ZF 5-spd does pretty much the same. never even reaches the "N" in NORMAL. now, my buddy's 89 302 AOD would get up to about the "O" everytime.
my GUESS is that one of two things is happening here:
1) the gauge isn't THAT accurate. wouldn't surprise me. Fords are somewhat notorious for this. only real remedy would be an aftermarket gauge to let you know what you're TRULY running at.
2) auto trannies may just have a tendency of raising the operating temp of the vehicle. don't know if your 300 was auto or not, but i've noticed that the "operating temp" accordgin to the gauge is a little higher in auto trucks of this era than the manuals.
Mike
I appreciate your response.
I really think the t-stat does matter. If it opens every time the engine hits 180 degrees, the engine won't get any hotter than that... provided the cooling system can keep up. I'll agree though that a 180 degree t-stat won't keep a motor from running much hotter than that, or even overheating, if the cooling system is inadequate.
I wish Ford guages were more accurate... I was really going on the temp of the "heat" blowing out of the vents... pretty luke warm... and just meant to give the guage as a reference point. (My 2003 Mercury Marauder has a really cool looking oil pressure guage... that reads 60psi all the time. The stock sending unit is just an on/off switch, 6 psi = ok! Grrr... so, like I say, I really wish Ford guages meant more!)
I'll bet you're right regarding auto trannies because they pump fluid through the same cooling fins, but these are both 5 speeds.
Thanks for the 192/195 idea... if I've got a 180 in there now (who knows) that'd be a big difference.
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From: Pittsburgh!
Thanks for the other answers... seems like the t-stat is where I should start?
Guess I'll need a gasket with that!
Guess I'll need a gasket with that!
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Post Fiend
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From: Lakewood, Ohio
and use some power blaster on the bols before you try to remove them.
have you checked blend door?
did you try reversing hoses on heater core?
did it used to heat better or is truck new to you?
have you checked blend door?
did you try reversing hoses on heater core?
did it used to heat better or is truck new to you?
Thread Starter
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From: Pittsburgh!
Originally Posted by quicklook2
and use some power blaster on the bols before you try to remove them.
have you checked blend door?
did you try reversing hoses on heater core?
did it used to heat better or is truck new to you?
have you checked blend door?
did you try reversing hoses on heater core?
did it used to heat better or is truck new to you?
Fresh ideas. Thank you! The truck is new to me so I don't know its history.
Reversing hoses? Hmmm... I'll put that on my menu.
Haven't checked the blend door... any ideas on an easy way to do that?
I think I'll throw a "Polish thermostat" in front of radiator (aka cardboard!) and see if that gets the truck to run warmer and gets me more heat too. If that's the case I'll go the t-stat route.
Post Fiend
Joined: Mar 2002
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From: Bonita Springs FL
I am not telling you not to change the thermostat, but I'm telling you that it's not the cause of your heating problems, either. 
If you remove the thermostat in a truck, it will run at about 140. Plenty hot enough to heat up the cab. I would guess that your problem is either a clogged heater core or a vacuum leak under the dash. AKA - the blend door.
If it hasn't been done in the last year, flush the cooling system out and change the thermostat. Autozone has everything you need to do this.
If you remove the thermostat in a truck, it will run at about 140. Plenty hot enough to heat up the cab. I would guess that your problem is either a clogged heater core or a vacuum leak under the dash. AKA - the blend door.
If it hasn't been done in the last year, flush the cooling system out and change the thermostat. Autozone has everything you need to do this.
Cargo Master
Joined: Sep 2004
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if the tstat is dead and stuck open, your truck will not run optimally, you will not get much heat, and your truck will really burn up the fuel. I had the exact same problem with an old Datsun pickup years ago. A new tstat fixed all those problems.
Postmaster
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From: West Mansfield, Ohio
But he will get pretty good heat. I agree with the fuel, but not the "not getting enough heat." That big block with no thermostat should pump out enough heat to make it toasty in the cab. Like Andy said, 140 degrees is well enough. I would agree with a smaller truck though. When the thermostat was dead in my Ranger, I had little to no heat, and only got 15 MPG. Little engines dont produce as much heat.
Cargo Master
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Not necessarily. I've seen this discussed in the 67-72 forums numerous times. It's always lack of heat that gets fixed with a new tstat.
Plus, a tstat is $5 and easy to replace. If that doesn't fix it then he hasn't really wasted a whole lot of time and money.
Plus, a tstat is $5 and easy to replace. If that doesn't fix it then he hasn't really wasted a whole lot of time and money.
Last edited by qman; Nov 28, 2005 at 05:57 PM.