No heat and running warm

Long story short. 2003 Ram 1500 Quad Cab with a 4.7
Fall of 2009, no heat, temp guage in normal range. Replaced heater core. Heat returned.
Summer 2010, Coolant tank on top od Rad leaking, temp guage normal range. Tank changed. The very next day, red check guage light, temp guage almost maxed out. Luckily, a block away from dealer. Rad clogged.
Rad changed.
Winter 2010, takes for ever for temp guage to start climbing after start, little to no heat when very cold outside temps, temp guage levels out about 1/8" before half way mark. Thermostat changed, some heat returned, still takes awhile for temp guage to climb, now levels out at the half way mark. Pretty much stays there at highway and city stop and go driving. Shut off truck for a few minutes to run an errand, and temo guage is at 3/4 mark after restart, Returns to half after driving resumes. No overheating or hot coolant smells inside or outside of truck. Suspect dealership did a poor or no flush when core and rad were changed. Do I need to try a core back flush, in conjunction with a complete system flush? If so, which hose should be the inlet hose to the core? They both feel the same temp to me. Is it the one with the "T', or the straight one to the water pump?
Sorry, not so short after all. Any ideas? Thanks in advance.

Are you losing coolant anywhere? The 4.7s are notorious for overheating problems and warping heads. Have you checked the fan clutch? But I would try to flush out the whole system.

Coolant level has not dropped. What should I look for when checking the fan clutch. I forgot to add, that at random times, the engine will sputter after getting on the gas after a slow yield or complete stop. It may do it once every two weeks or go a month with out doing it. Not sure if it's related.

Just make sure the clutch isnt always engaged, but you would notice a big whooshing noise if it were doing that, but it could explain why it took so long for the motor to heat up.

Sounds to me like you might have air trapped in your cooling system, for that you need to burp it. You will need to park the truck somewhere so that the filler neck is sitting higher than the engine, rather it be on a ramp or on a hill of dirt. then, take the radiator cap off and crank the engine...let it run so that the thermostat can cycle a couple times...top off with coolant and put the radiator cap back on.

Gonna second air in the system, and welcome to the site bud.

Sounds almost like a stuck thermostat. But that's my .02cents. Welcome to the Forum

AWE Daniel said:

Just make sure the clutch isnt always engaged, but you would notice a big whooshing noise if it were doing that, but it could explain why it took so long for the motor to heat up.

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Will check, but sounds pretty quiet at start up.

adamwilkes14 said:

Sounds to me like you might have air trapped in your cooling system, for that you need to burp it. You will need to park the truck somewhere so that the filler neck is sitting higher than the engine, rather it be on a ramp or on a hill of dirt. then, take the radiator cap off and crank the engine...let it run so that the thermostat can cycle a couple times...top off with coolant and put the radiator cap back on.

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Sounds logical. My driveway is inclined just right for the task. I also noticed I have a plug I can remove where the upper hose connects to engine. Would that worlk as well?

KGBIGCOUNTRY said:

Gonna second air in the system, and welcome to the site bud.

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Thanks. That's two. I hope that's all it is.

Bigtman07 said:

Sounds almost like a stuck thermostat. But that's my .02cents. Welcome to the Forum

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Stat was changed about a month ago, Thanks for the welcomes and advice folks. I appreciate it a ton.

Best way to do it is like adam said just to remove the rad cap... it will take awhile though do to the colder temps and can cause a mess so just be prepaired.

KGBIGCOUNTRY said:

Best way to do it is like adam said just to remove the rad cap... it will take awhile though do to the colder temps and can cause a mess so just be prepaired.

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Will do. Thanks again.

I will give you a little hint to avoid air bubbles in your cooling system when doing a flush refill. Instead of adding water/coolant to the radiator itself, add it through the intake with the truck inclined...then do your tstat and bolt the tstat housing back on....and top it off...

^To clarify he means the housing for the coolant not the air intake lol.

KGBIGCOUNTRY said:

^To clarify he means the housing for the coolant not the air intake lol.

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HAHA, yeah...on the other hand, if you add coolant to your air intake, I have a sign for you...LOL

adamwilkes14 said:

HAHA, yeah...on the other hand, if you add coolant to your air intake, I have a sign for you...LOL

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Ya never know... I normaly reread anything I post far as checking or fixing something so it will be black and white on what to do. I work on stuff for a living and you would be suprised what ya will see jacked up because a word was mis understood.

KGBIGCOUNTRY said:

Ya never know... I normaly reread anything I post far as checking or fixing something so it will be black and white on what to do. I work on stuff for a living and you would be suprised what ya will see jacked up because a word was mis understood.

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I do not doubt that one bit...

Luckly its a 4.7 so its a toss up on what would go first... either the head gaskets or the piston cracking, or the connecting rod breaking taking out the block... decesions decesions lol.

Did as advised. Ran engine on incline with cap off for over an hour. No help. Not even a burp. Fluid level came up in the tank a little, but never pushed anything out.

adamwilkes14 said:

I will give you a little hint to avoid air bubbles in your cooling system when doing a flush refill. Instead of adding water/coolant to the radiator itself, add it through the intake with the truck inclined...then do your tstat and bolt the tstat housing back on....and top it off...

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That would be kind of hard to do. My Stat is on the bottom.

Sounds like you have had one or more thermostat failures and air trapped in the system.

Do you know what type of Tstat they put in the truck? Most of the good ones have a fail safe to when they fail they just stick open.