Heater core flush questions
Thread Starter
Race Director
Joined: Dec 2007
Posts: 10,064
Likes: 77
From: Elgin, IL
Heater core flush questions
Here is my problem. I have no heat in my 96 LT4. I have searched and found several posts about flushing the core and fixing the problem. I have checked all the normal other things such as fluid levels, vacuum doors, the engine temp is fine, etc. and figure that the core is clogged. My question is, how much coolant will come out if I just take off the hoses to the core in order to flush it back and forth with a garden hose? I will also be cleaning out the pressure valve in the line to make sure it is working properly. I would like to try it out before flushing the whole system in case I need to actually replace the core. Any info would help or if anyone has any pictures of when they did it that would be great too.
Thanks
Thanks
Le Mans Master
Joined: Aug 1999
Posts: 7,338
Likes: 137
From: WilkesBarre PA
Mine was just blocked. I had very poor heat or it would be there for a second then none. I was changing my optispark, and already had the coolant drained when I blew compressed air through to core and it cleared it. I tried blowing through with me blowing in the hose and couldn't get anything through. I have to refill tonight to check it all out.
Your prolly better to just drain all the coolant then flush the core, then start fresh with new coolant. A fun messy job lol.
Your prolly better to just drain all the coolant then flush the core, then start fresh with new coolant. A fun messy job lol.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
You need to disconnect both lines to the heater and run a garden hose thru it both ways several times. The debris will come out with the water. Don’t try to over pressurize it but just have a good flow.
It would be wise to also do the whole system since you are going to loose a good deal of the coolant anyway. And especially if it was clogged you want to get rid of as much of that old coolant as you can. I would also drop the lower radiator hose and flush the radiator best as possible.
Besides how long has it been since it was flushed? Over 2 years your due.
It would be wise to also do the whole system since you are going to loose a good deal of the coolant anyway. And especially if it was clogged you want to get rid of as much of that old coolant as you can. I would also drop the lower radiator hose and flush the radiator best as possible.
Besides how long has it been since it was flushed? Over 2 years your due.
Last edited by pcolt94; Oct 20, 2009 at 09:26 AM.
Team Owner
Joined: Sep 2003
Posts: 20,170
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
When the winter comes along so do all the heater core related posts.
I fixed the control valve in the water line to the heater core to remain open permanently. This prevents heater core rot by continuously circulating the water. No problems with the A/C
Still have a new core on the shelf.
I fixed the control valve in the water line to the heater core to remain open permanently. This prevents heater core rot by continuously circulating the water. No problems with the A/C
Still have a new core on the shelf.
Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
If I had the original heater core out, I would just replace it. That would be the best time to do it as it will leak eventually. Plus, the plastic tubes can crack when you remove and install the heater hoses with it being so old. I think the new ones are metal.
Race Director
Joined: Sep 2000
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From: The Top of Utah
RACE ON!!!
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Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
That would really suck you put the original back in, then you crack it when you put the heater hose back on.
Burning Brakes
Joined: Oct 2009
Posts: 773
Likes: 2
From: Minneapolis MN
Here is my problem. I have no heat in my 96 LT4. I have searched and found several posts about flushing the core and fixing the problem. I have checked all the normal other things such as fluid levels, vacuum doors, the engine temp is fine, etc. and figure that the core is clogged. My question is, how much coolant will come out if I just take off the hoses to the core in order to flush it back and forth with a garden hose? I will also be cleaning out the pressure valve in the line to make sure it is working properly. I would like to try it out before flushing the whole system in case I need to actually replace the core. Any info would help or if anyone has any pictures of when they did it that would be great too.
Thanks
Thanks
Seen too many problems at my shop with Dexcool.Also GM had a lawsuit over it.It damaged gaskets causing them to leak during warranty period.I can give you the TSB(technician service bulletin) if you like.Dexcool sucks,trust me.I cannot say enough about how bad this stuff is for gaskets,seals,radiators,heatercores etc.Never seen the same problems with green coolant!I will bet my Corvette green is better for everything in your car,just drain & fill it every year or so.If anyone tells you different they are WRONG!
