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BigBob, Service Manager/Service Manager
Category: GM
Satisfied Customers: 4838
Experience:  Shop Manager with 25 years experience
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1999 silverado, how do I replace the hose connectors to the

Customer Question

1999 silverado, how do I replace the hose connectors to the heater core that are located in the engine comparment?
Submitted: 7 years ago.
Category: GM
Expert:  BigBob replied 7 years ago.

J 43181 Quick Connect Connector Removal Tool. You can get these quick connect removal tools at most local auto parts stores. graphic

let me know if I can help further.

Good luck,


Customer: replied 7 years ago.
The answer was helpful for understanding only, as there are no auto parts stores in my area that carry a removal tool that will help. After replacement I am still having problems. I filled the radiator and checked flow through the heater core and engine but i still have overheating problems and the heater hasn't worked since the core connector broke. I am left with two issues. My service manual indicates that once the engine is up to temp the fan should be difficult to rotate, which isn't the case, indicating a faulty fan clutch. It also suggests that pinching the upper radiator hose and releasing it should produce a noticable surge, which isn't present, indicating a faulty water pump. I am at a loss. The connector that I was able to procure has a 1/2 inch male pipe which I have adapted to fit the 5/8 ID hose on what i believe is the heater core inlet. A standard garden hose hooked to the heater core outlet, as best as I can ascertain, produces good flow from the inlet hose. The same set up on the engine also produces good flow, yet i still have a problem with overheating and the heater hasn't worked since the core connector failed. What on earth could be causing this problem?
Expert:  BigBob replied 7 years ago.
So with the heater core hooked up and the engine running at operating temperature are both hoses going to the heater very hot? When the engine is at operating teperature are both radiator hoses hot? When does it overheat at idle, highway speeds or both?

Customer: replied 7 years ago.
I also removed the thermostat in an attempt to eliminate it as a possible problem. Everything put back together and allow the truck to idle to operating temperature, neither the hoses on the radiator or to the heater core got hot. Last evening I drove around my neighborhood thinking moving would help but it didn't. Same symptoms, overheating and the heater blows cool air.
Expert:  BigBob replied 7 years ago.
What size motor do you have?

Customer: replied 7 years ago.
I've got a 99 sliverado extended cab with the 5.3 liter.
Expert:  BigBob replied 7 years ago.
It sounds like the radiator is plugged up. When running the vehicle check the temp at the radiator when it starts to get hot, if theradiator is still cool it is probably plugged up. Since the heater core was plugged up this is a good possibility