02 ram 4.7 still overheating

My truck is still overheating. I've changed the radiator and it still pegged the gauge but did not boil out. I put the old thermostat in with out the guts and it is a little better. It is not pressuring up the rad or leaking out the exhaust like a cracked head and there is no water in the oil. Do you think the impeller on the water pump is spining?

I hear that brought up a lot but in my 37 years of experience as a tech I've never seen it. Doesn't mean it can't happen, just that odds are against it. I have seen the impeller eaten away from corrosion or cavitation, but that's pretty rare too. I would pull it and look at it as well as the timing cover.

Are you sure the fan clutch is working? Does it overheat at idle/low speeds or highway speeds?

Well. I agree that it is very unlikely, but this truck belongs to my daughters boyfriend and that is what is dad is thinking. I'm doing this for free and money is a real big issue. The rad was full of red crap that I assume was rust. 187 miles on the same coolant is not good. In test driving to check the heating, I found a pinion bearing out so I had to rebuild the rear before we could fix the overheating problem.

The fan is stiff when it is cold and I have not checked after it warms up, but it seems fine. It overheats driving down the road at 30 to 50. It was 23 degrees last night driving at 40mph on an ice slick road and still was overheating. At least with the thermostat out it does not lose any coolant.

I have to ask, did you put a new radiator in or a used one? If it had that much rust in it then the impeller could be a problem as well as build up in the block.

Its a new rad and I flushed out the block with a hose as best I could. I fear the block has some stoppage as well. One thing is that the heater does not work well at all. With the thermostat in, it works a little. With the gutted one, it does not work at all. I think I will try and figure out which lines go to the heater and flush those if I change the pump. Thanks for you help.

Yeah the heater core is probably plugged up as well or there just isn't enough circulation.

I'll let you know what is was. Thanks for the help.

You're welcome. Good luck.

Well just got back from a from a little diagnostics from my friends at a tranny/engine rebuild business and they run the codes (the check engine light has been on for some time, I am told). Fuse to the a/c fan was out and cly #4 and 8 have a misfire. I could tell it had one cly not hitting when I started this ordeal. This truck is a prefect example of neglected maintenance. He put a sniffer in the radiator tank and it turned the blue fluid into a greenish yellow. He said that meant it had some hydro-carbons in the coolant. I never knew they had a test like that. It went to about 236( we had the scanner plugged in) just driving around the block in 20 degree weather. I bet if I pulled the plugs in 4 and 8, I would find signs of coolant in the chamber.

we have a 2001 durango 4.7 and yes it did spin the impeller! It was overheating and I was very doubting it was the water pump. Finally took it apart and sure enough the impeller was PLASTIC and cracked! Dan

I have a 2003 Durango 4.7, same problem, the center of the impeller broke, water pump was only a year old. I'll post pictures tomorrow.

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Well just got back from a from a little diagnostics from my friends at a tranny/engine rebuild business and they run the codes (the check engine light has been on for some time, I am told). Fuse to the a/c fan was out and cly #4 and 8 have a misfire. I could tell it had one cly not hitting when I started this ordeal. This truck is a prefect example of neglected maintenance. He put a sniffer in the radiator tank and it turned the blue fluid into a greenish yellow. He said that meant it had some hydro-carbons in the coolant. I never knew they had a test like that. It went to about 236( we had the scanner plugged in) just driving around the block in 20 degree weather. I bet if I pulled the plugs in 4 and 8, I would find signs of coolant in the chamber.

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If that's the case the engine is probably sludged as well from lack of maintenance. Going to get expensive from here.