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Discussion Starter #1
My Commander has just began overheating when driving below 50 mph, not up to the danger zone, but about 3/4 on gauge. If I drift or idle, the gague comes back to normal. Also, the heat will blow cold when this happens. No warning codes though. Sounds textbook thermostat? I'm considering going ahead and replacing it myself. Thoughts?
 

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My Commander has just began overheating when driving below 50 mph, not up to the danger zone, but about 3/4 on gauge. If I drift or idle, the gague comes back to normal. Also, the heat will blow cold when this happens. No warning codes though. Sounds textbook thermostat? I'm considering going ahead and replacing it myself. Thoughts?
Don't drive under fifty.:stickpoke:
 

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Sounds more like coolant level is low in the engine block. If you have a small leak, the cooling system will draw air through the leak instead of siphoning fluid back from the overflow tank.

Just checking the fluid level at the overflow tank is NOT good enough, you have to remove the pressure cap on the radiator and check inside the pressurized part of the cooling system, to make sure the coolant level is at its proper level. Make sure you only remove the pressure cap when the engine is cold, remove it while its hot and you'll likely burn yourself badly when scolding fluid burst out under pressure.

If Coolant level is too low, there often won't be enough fluid to circulate it through the heater core. And the engine temp will start to climb, BUT NOT overheat if the only problem is low coolant level.

If it was a thermostat problem, the coolant circuit for the heater core is on the engine side of the thermostat, regardless of what the thermostat does, the heater core should reflect the same temp as the engine. So if temps for the engine start to climb, then the temp in the heater core should climb with it.

Your seeing the opposite, as engine temp climbs, the heater core gets cooler, sound more like low fluid level, and you notice the conditions where water pump isn't spinning fast enough to circulate the low fluid level completely through the engine, it just splashes it around.
 

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Thoughts? You want thoughts from me? Well, wow.....I don't know where to begin.

Thermostsat......maybe. But I wouldnt think that would overheat the engine
and lose cabin heat. But the dealer will want about $140 to replace your
thermostat....so don't let the dealer do it.

Flush the radiator from the back side of the engine. Point the hose into the
radiator from inside the engine bay. Push out anything that may have been
stuck in there.

Ready more more thoughts? Did you ever think about the earth losing mass
and shifting orbit?
 

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Discussion Starter #5
Thanks for the responses. Yep coolant is low, hopefully that will fix the problem. Still recommended to do 50/50 coolant/H2O?
 

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Thanks for the responses. Yep coolant is low, hopefully that will fix the problem. Still recommended to do 50/50 coolant/H2O?
50/50 with the Proper Anti-Freeze and water as pure as practically possible.

i.e.

Zerex G-05 or the Dealer HOAT anti-freeze, and distilled water from the Grocery Store.

Keep an eye on how fast the coolant level drops, you may have a leak that is so slow, its easy to live with, or may have recently developed a leak that will need attention and repair soon.

Also keep in mind, pressure caps are cheap and they rarely last the life of the vehicle, just a weak pressure cap can cause coolant level to drop by letting it boil off.

Finally, 2006 means the vehicle is likely 5 years old or more, give or take a couple of months. The change interval for the coolant is 100k miles or 5 years and for anti-freeze, its more a time thing then mileage, you likely need a full coolant change.
 

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Discussion Starter #7
How about the Prestone 50/50 prediluted? Says it can be used with any make/model. That's all I could get my hands on right now. Yes, it is exactly 5 years now. If I top it off with the Prestone, knowing that i'm going to get a full coolant change within the week, think that's ok?
 

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How about the Prestone 50/50 prediluted? Says it can be used with any make/model. That's all I could get my hands on right now. Yes, it is exactly 5 years now. If I top it off with the Prestone, knowing that i'm going to get a full coolant change within the week, think that's ok?
I would NEVER mix GM DexCool with any other anti-freeze and definitely would NOT use it in a vehicle NOT designed for DexCool.

Read the last post of this thread.
http://www.jeepcommander.com/forums/showthread.php?t=15106&page=2

Yes, Prestone is dying DexCool a different color and selling it as an universal anti-freeze. They are getting sued left and right, but they still do NOT change the label on the bottle, I guess they are making enough money off the scam to keep doing it.

If you can't find Zerex G-05 or Dealer HOAT anti-freeze, remember FORD switched to the same anti-freeze as Chrysler, even getting a bottle of HOAT from the Ford dealer would be better. Finally, if your really in a Jam, I'd use the original formula Green (IAT) anti-freeze before I would use the Prestone Garbage. HOAT is designed to be tolerant of the Green IAT, to avoid the problems Dexcool ran into. I don't recommend mixing anti-freezes, but I do recommend mixing the Grean IAT with HOAT over mixing anything with Dexcool and/or adding Dexcool or Prestones derivative to your cooling system.

Sometimes the generic anti-freezes are the old green formula, they will have "silicates" and "phosphates" in the ingredient list, that is what they use for anti-corrosion protection. HOAT has a small amount of this as part of its corrossion protection package.
 
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