Heater Core Flush - 96LT1
Thread Starter
Pro
Joined: May 2003
Posts: 503
Likes: 16
From: Virginia Beach VA
Heater Core Flush - 96LT1
..I recently had my radiator flushed/coolant replaced/new thermostat. This helped bring the running temps back to 'normal'.
Now I'm having an issue with the heater. It seems to putting out very little heat, mild at best. I took it back to the shop that did the radiator service and they said it either needs a heater core flush ($150) or the heater core needs replacing (Big bucks).
I don't have the classic heater replacement signs....wetness, film on windows, smell, etc.
I brought the car home. I think i can do the heater core flush myself.
Can those of you who have done this give me an idea how how to do it? I hate to think I need to drain the radiator completely after just putting in new coolant. Is there a easier way? I have the FSM.
Any pics?
Thanks!
Also, I've heard of some using CLR in the system to flush the heater core. Any expereince with that and how did you do it?
Now I'm having an issue with the heater. It seems to putting out very little heat, mild at best. I took it back to the shop that did the radiator service and they said it either needs a heater core flush ($150) or the heater core needs replacing (Big bucks).
I don't have the classic heater replacement signs....wetness, film on windows, smell, etc.
I brought the car home. I think i can do the heater core flush myself.
Can those of you who have done this give me an idea how how to do it? I hate to think I need to drain the radiator completely after just putting in new coolant. Is there a easier way? I have the FSM.
Any pics?
Thanks!
Also, I've heard of some using CLR in the system to flush the heater core. Any expereince with that and how did you do it?
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I flush my core almost every year and is real easy to do. I don’t think my vette got TLC in its early days so it tends to clog up every year or two. So I try to do it every year or 18 months or so. Just so happens I will be doing mine this week since I can tell it's not blowing hot but only warm.
The two hoses to the heater need to be disconnected. One hose goes to the bottom of the surge tank (curved hose), and the other that comes out from the core goes to a plastic fitting about 1 foot from the firewall. After the hoses are off just run a garden hose thru it on low pressure. Just a gental flow is good. Flush both ways until it runs clear. You will see the junk come out initially. Position the hose so the water runs away from any electrical connectors or wiring.
Back in 03 I had to flush mine 10 times both ways before it ran clear. You don’t need a $150 flush and I never used any additives. Just do it every year before it clogs.
The two hoses to the heater need to be disconnected. One hose goes to the bottom of the surge tank (curved hose), and the other that comes out from the core goes to a plastic fitting about 1 foot from the firewall. After the hoses are off just run a garden hose thru it on low pressure. Just a gental flow is good. Flush both ways until it runs clear. You will see the junk come out initially. Position the hose so the water runs away from any electrical connectors or wiring.
Back in 03 I had to flush mine 10 times both ways before it ran clear. You don’t need a $150 flush and I never used any additives. Just do it every year before it clogs.
Thread Starter
Pro
Joined: May 2003
Posts: 503
Likes: 16
From: Virginia Beach VA
I flush my core almost every year and is real easy to do. I don’t think my vette got TLC in its early days so it tends to clog up every year or two. So I try to do it every year or 18 months or so. Just so happens I will be doing mine this week since I can tell it's not blowing hot but only warm.
The two hoses to the heater need to be disconnected. One hose goes to the bottom of the surge tank (curved hose), and the other that comes out from the core goes to a plastic fitting about 1 foot from the firewall. After the hoses are off just run a garden hose thru it on low pressure. Just a gental flow is good. Flush both ways until it runs clear. You will see the junk come out initially. Position the hose so the water runs away from any electrical connectors or wiring.
Back in 03 I had to flush mine 10 times both ways before it ran clear. You don’t need a $150 flush and I never used any additives. Just do it every year before it clogs.
The two hoses to the heater need to be disconnected. One hose goes to the bottom of the surge tank (curved hose), and the other that comes out from the core goes to a plastic fitting about 1 foot from the firewall. After the hoses are off just run a garden hose thru it on low pressure. Just a gental flow is good. Flush both ways until it runs clear. You will see the junk come out initially. Position the hose so the water runs away from any electrical connectors or wiring.
Back in 03 I had to flush mine 10 times both ways before it ran clear. You don’t need a $150 flush and I never used any additives. Just do it every year before it clogs.
Nice play-by-play.....I'm going to tackle it this Saturday.
Thread Starter
Pro
Joined: May 2003
Posts: 503
Likes: 16
From: Virginia Beach VA
The two hoses to the heater need to be disconnected. One hose goes to the bottom of the surge tank (curved hose), and the other that comes out from the core goes to a plastic fitting about 1 foot from the firewall. After the hoses are off just run a garden hose thru it on low pressure.
The temps driving around town are running 198-200. Before I was seeing 210-215.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
What do you do when you pull the hose from the bottom of thr surge tank? Do you have to worry about coolant pouring out? Did you have to move the tank? I just took a look at mine and the tank is in the way. Plus it looks like I need special pliers to get those clamps off.
Obviously if the system is full coolant going to go everywhere. I usually do it when I have the system empty and replacing the coolant and doing the radiator flush also.
Channel lock pliers will release the hose clamps. I have some of the special hose clamp pliers but don’t care for them much. No need to move the tank.
I know you just had your coolant replaced which is unfortunate. You may not have to drain it to do the heater but only lower the level that way you will not lose as much. Then just do the job and refill normally.
When there is junk in the block things may clog quicker. Going 2 years is too long for me. I do it much sooner, once a year if I remember. You can't change the coolant too much. Doing it yourself is only $10-20 of coolant per year. A small price to keeping everything in good shape and working well.
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