Several weeks ago I had to have a new water pump installed on my 96 Dodge Pickup. All has been fine until cold weather arrived and I noticed my heater was not putting out the amount of heat it used to. After checking a few things under the hood this is what I have discovered that has me puzzled – the bottom radiator hose does not get hot. The hoses do not pressurize nor does the whole system. You can take the cap off any time with out any pressure being on the system. This is a new cap also and I also had a new thermastat installed. I guess my question is do I have a problem with my radiator not pressurizing and the bottom hose being cold and soft. The top hose gets hot but is soft due to no pressure. What’s going on here? bcarll
The lower hose is much colder because the cooled water goes into the engine through it. I don’t believe you will ever burn yourself on that hose. It may get hotter if the engine is working a little, but you can’t be under the truck when it is moving. The water in the radiator has to be right up to the cap to make it pressurize. The coolant recovery cap if it is the metal one that goes right on the radiator is designed that way. The system should pressurize if you start it cold with the cap on and check it hot. Keep some coolant in the reservoir too. That will insure that the radiator is full enough to pressurize. Then if it doesn’t hold pressure, you can start looking for the leak.