Cooling System Problems
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Cooling System Problems
2015 Ram 1500 5.7 with 170,000 miles. I have fluctuating temps, no radiator pressure and truck runs hotter than it did before my maintenance (used to be steady at 201 deg)
I did a coolant drain/fill, new thermostat, new rad hoses, new cap. Bled system by removing plug above stat along with the "special funnel"....think air is out...not sure. Lower hose was cold for a day...again replaced stat with a 203 degree standt; now lower hose is fairly warm. Noticed that thermostat doesn't open until about 212 degrees...don't understand. Also, when truck is at operating temp, system has no pressure...carefully removed cap....no pressure. Why? Truck temps fluctuate from 199 to 208 degrees, which sounds like an air bubble?. I can't find any external leaks. Could an OEM waterpump cause my trouble?? Also when looking into the radiator, engine hot, I cannot see any moving coolant.
I am at my wits end here...Sorry for the long post....Any ideas?
I did a coolant drain/fill, new thermostat, new rad hoses, new cap. Bled system by removing plug above stat along with the "special funnel"....think air is out...not sure. Lower hose was cold for a day...again replaced stat with a 203 degree standt; now lower hose is fairly warm. Noticed that thermostat doesn't open until about 212 degrees...don't understand. Also, when truck is at operating temp, system has no pressure...carefully removed cap....no pressure. Why? Truck temps fluctuate from 199 to 208 degrees, which sounds like an air bubble?. I can't find any external leaks. Could an OEM waterpump cause my trouble?? Also when looking into the radiator, engine hot, I cannot see any moving coolant.
I am at my wits end here...Sorry for the long post....Any ideas?
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From: Clayton MI
If it isn't building pressure, there is a leak somewhere...... I would expect to see coolant dripping somewhere though. If the system is getting pressurized, then yeah, temps are going to be unstable.
You will only really see coolant moving in the radiator when the thermostat is open...
You will only really see coolant moving in the radiator when the thermostat is open...
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Cooling System Problems
Thanks for reply Hey You.
Could air bubbles cause temp fluctuations?
The truck was at operating temp when I looked in the radiator....I was surprised to see no coolant movement....
Is a high mileage OEM water pump a possible culprit?
Could air bubbles cause temp fluctuations?
The truck was at operating temp when I looked in the radiator....I was surprised to see no coolant movement....
Is a high mileage OEM water pump a possible culprit?
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From: Clayton MI
Air bubbles can indeed cause some truly interesting cooling system behavior. 
It is possible the pump vanes are simply worn down... in which case, it won't be real enthusiastic about moving coolant. Some will move simply by convection, but, I really don't think that is enough to keep your engine from burning up. With a 170K on the pump, replacing it sure wouldn't hurt.
It is possible the pump vanes are simply worn down... in which case, it won't be real enthusiastic about moving coolant. Some will move simply by convection, but, I really don't think that is enough to keep your engine from burning up. With a 170K on the pump, replacing it sure wouldn't hurt.
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Cooling System Problems
Thanks Hey You!
That's the direction I was leaning...Just didn't want to throw parts at it. I think I will do a pressure test in case there is a leak I can't see; but 170,000 miles on a waterpump is a long time....
That's the direction I was leaning...Just didn't want to throw parts at it. I think I will do a pressure test in case there is a leak I can't see; but 170,000 miles on a waterpump is a long time....