My son will be getting out of the hospital soon, don't think he'll be riding his Harley soon. He has a 99 1500 ram pickup with the 5.9 gas motor. Has been over heating. He replaced the thermostat, didn't help. He's convinced the water pump is next. I've never seen a water pump fail for any reason besides weeping and bad bearing. Not cause over heating. What else is a likely reason for the over heat problem?

I had my 2001 1500 dodge ram sport do that once and the soft plugs were bad on it but not leaking any anti freeze and it had me looking and changing things out tell I found that out. mine would only start overheating when it sat and not while driving. that's what I had maybe the same for you but maybe not

Edited July 10, 201411 yr by fossum99

So many things it can be, i have seen the impeller broke off on a water pump andcthe vanes completly gone. They are also well known for cracked heads. Can also be head gasket. Best thing to do is put a pressure tester on the system and see if you are getting cylinder pressure in. Also can do a vapor test on the cooling system

I agree with Mopartechnician my 99 Durango started doing that and I got the thermostat,  water pump, and radiator changed before I found the head gasket on the driver side was bad... 

How did you find out which side was bad?

Fan Clutch maybe?? I had that go in my 1500 gasser years ago.  And, if one head gasket  is bad the other can't be too far behind...

Didn't really find the side till I tore it apart but I did have excessive pressure in the radiator along with exhaust gasses

Fan clutch is possible. How about the face of the radiator is it packed with mud, bugs, etc. You'll have to remove the radiator to clean it good from both sides. How about the core tube are they all plugged up with corrosion blooms from old corrosive coolant?

 

Water pump rare to fail but typically you would see the pump weeping water. As for the pump vane being gone or broke would be cause from corrosive coolant eating them.

 

So when was the last coolant system flush and fill last done?

Maintenance history is unknown. He has owned it for about 6 months. It's not here at my location, so I cannot comment on the specifics. He has a friend (mechanic) who is going to attempt a diagnosis. I'll let you know what he comes up with.

Head gaskets are possible but always trouble shoot in order.  Inspecting the radiator should be early.  Might want to check the thermostat because even a new one can be NG. 

Cleaning & flush is probably a good idea at this point so you know what you've got.  There's instructions here for the clutch fan test.  It's often hard to see water pump weep because of belts & it's under tension.     

History unknown... 

Starting & running the engine with the cap off will often show bubbles in the coolant (head gasket problem) as would testing with a pressure tester.  Also possible PO put stop leak in & sold the truck...  

5.9 V8...  is 360 small block LA engine.   (273 bored to 318 bored to 340 bored to 360)   I wouldn't be surprised if a head gasket has worn out...  not a lot of sealing surface in those decks.