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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Buddy on October 10, 2010, 03:31:20 pm

Title: cant get the rad to flow?
Post by: Buddy on October 10, 2010, 03:31:20 pm

I just put everything back together and started the truck for the firat time in 7 monthhs.Everything works great but i cant get the coolant to flow. also does it matter what hose goes where when hooking up the heater core

Title: Re: cant get the rad to flow?
Post by: Irish_Alley on October 10, 2010, 04:06:37 pm

Quote from: Buddy on October 10, 2010, 03:31:20 pm

also does it matter what hose goes where when hooking up the heater core

Yup they are two different sizes. But it wouldn't effect your flow. Did it flow before? Are you over heating. How do you know You not flowing good or at all

Title: Re: cant get the rad to flow?
Post by: Buddy on October 10, 2010, 05:11:47 pm

i went to check the coolant level and Bam fuild went everywhere. I grab let it run a while again and it doesnt seem to be flowing through my upper rad hose

Title: Re: cant get the rad to flow?
Post by: Irish_Alley on October 10, 2010, 05:23:37 pm

The upper hose is the return. Is the upper hose getting hot? What's your temp gauge reading

Title: Re: cant get the rad to flow?
Post by: Psycho71 on October 10, 2010, 06:29:14 pm

How old is the water pump? How long has it sat? I've seen many SBC water pumps go bad due to the impeller rotting, sometimes completely. As a test, pull the t-stat and run it that way. It should flow then. If not, I'd be going right to the source. The pump.

Title: Re: cant get the rad to flow?
Post by: Irish_Alley on October 10, 2010, 06:47:31 pm

Even then the lower hose could be collapsing

Title: Re: cant get the rad to flow?
Post by: Buddy on October 11, 2010, 07:04:13 am

cant tell by the temp gauge because the dash is not in yet, as far as the water pump. it has sat for a few months maybe 6 months max. I am going to pull the thermostat and replace and re top up the coolant and see what happens.

Title: Re: cant get the rad to flow?
Post by: Irish_Alley on October 11, 2010, 08:33:46 am

How do you know its not flowing

Title: Re: cant get the rad to flow?
Post by: 74chev4x4 on October 11, 2010, 09:06:24 am

yea like psycho said pull the tstat and run it without it should flow fine if not its either the pump or you have a clog in the radiator somewhere.  If you rule all these out I recently had a similar problem and it ended up being that I had a leak in my heater core which wouldn't allow the system to pressurize, just a thought.