I have a 99 Dodge Ram 1500 with the 5.2L. Last month I replaced the heater core and everything was running fine with the truck. The other day on the way home from work the upper radiator hose blew off the radiator. I was able to pull over reattach it, top of the radiator and make it home. I have replaced the thermostat, thermostat housing, upper hose and the radiator cap. Last night I raised the front of the truck and took the radiator cap off and let the truck warm up, to get the air out of the system. After about 45 mins I put the cap on and took it for a ride no issues
This morning when I was letting the truck warm up the upper radiator hose got hot like normal but there was a lot of pressure in the hose. It feels like it is going to blow off again. Any clues to what could be going on?
Thank for your help
This sounds strange, my first suggestion would be a bad radiator cap but you changed that. The next step would be to put a radiator pressure tester on the radiator and run the engine to see how high the pressure gets in the radiator.
The radiator cap should blow off at about 13 to 15 pounds of pressure and the coolant should go into the overflow bottle. If the pressure goes over these cap values then you may have a bad cap ( which can be tested with an adapter with the radiator pressure tester). If the pressure goes over that and it keeps climbing you could or may have a blown head gasket, cracked head or block, broken head bolt, clogged radiator which is not likely but would need to be looked at if no problem is found.
Check also the clutch fan for proper operation. If the clutch fan is bad the fan won't turn fast enough raising the pressure of the radiator with higher temperatures.
Try these few suggestions and get back to me with your results. We can diagnosis the problem further if needed.
I do not have a pressure tester for the radiator but I will see if auto zone has a loner. My other question is how hard should the upper rad hose be? When it is cold I can squeeze the hose completely no problem but once it’s warm I cannot. Is this normal or is that a sign of too much pressure. With the cap off and the engine warm the fluid will go up and down when I rev up the engine so I would assume the radiator is not clogged. There is no white smoke or antifreeze in the oil but I am going to do a head gasket test this weekend. For the last 2 days I have drove the truck back and forth to work with no issues so I don’t know if I am just over thinking it or not.
One last thing this all started after i replaced the Heater Core about 2 weeks ago, do you think maybe it was just an air in the system problem that caused the hose to blow?
Last edited by AronA (2/1/2019 5:27 PM)
The hose being hard when the engine is hot is normal. If the truck is running normal now with no issues then it sounds like you are good to go.
As of the air in the system causing the problem I think it was just coincidence that it happened when it did.
Just drive normal and monitor the cooling system, if everything is running the way it was for a few days then you should be in good shape and consider everything normal.