How do I backflush?
Thread Starter
Melting Slicks
Joined: Nov 2002
Posts: 2,471
Likes: 2
From: 1993 Quasar Blue 'vert Scottsdale AZ
How do I backflush?
I have a '93 LT1 with no hot air. I notice a lot of you recommend backflushing the heater core. What is the procedure for doing this? Thanks.
Thread Starter
Melting Slicks
Joined: Nov 2002
Posts: 2,471
Likes: 2
From: 1993 Quasar Blue 'vert Scottsdale AZ
Re: How do I backflush? (Strick)
I have a 160 thermostat. I thought that might be the problem but even if I let the temp get up to 180, it's still cold air. Searched in tools and couldn't find anything remotely related to flushing.
Advanced
Joined: Nov 2003
Posts: 89
Likes: 0
From: Apollo PA
Re: How do I backflush? (Lichen)
The easiest way to do this is to buy the backflush kit from prestone (avail at just about any auto parts. It comes with a hose connector and an exit tube that snaps into the radiator cap hole. You simply cut the hose coming off the throttle body, insert the hose T connector and put a hose clamp on each end. Be careful to cut the hose where inserting the T wont interfere with the aluminum tubes on back of the a/c compressor and back enough to stay away from the headers. Pop the exit tube into the rad cap and hook up the hose... turn on thehot water and let it run till the water gets clean.
Not much to it really. Stand clear cus it's gonna :U at you some pretty nasty lookin stuff.
Not much to it really. Stand clear cus it's gonna :U at you some pretty nasty lookin stuff.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Re: How do I backflush? (c4power)
Are you sure it needs to be flushed? You could simply take the heater hose loose going into the heater core and take a water hose and force water through it. But first I would heat the engine up, and then feel both hoses to see if they are hot. If they are, then I would start checking the flapper door inside the heater box for operation. There is a clip on the arm which operates this door and it is known to break. If you remove the electrical connector on top of the heater box, and the piece it connects to, (I dont know the name of it) You can look down in there at the door and see if it is opening and closing.
Instructor
Joined: Jan 2003
Posts: 102
Likes: 0
From: Carson City NV
Re: How do I backflush? (honas)
Be very careful to let your hot engine to sit at least 1 hour prior to flushing the system with cold water. If you do this to a hot engine, you run a very real risk of cracking the iron block due to thermal shock.
Also check this recent thread (http://forums.corvetteforum.com/zerothread?id=691348) for some excellent tips from Steel Blue 91 and others on how to refill your coolant system and eliminate trapped air from the system.
Also check this recent thread (http://forums.corvetteforum.com/zerothread?id=691348) for some excellent tips from Steel Blue 91 and others on how to refill your coolant system and eliminate trapped air from the system.
Melting Slicks
Joined: Nov 2003
Posts: 3,375
Likes: 1
From: Northern CA
Re: How do I backflush? (honas)
Be carefull backflushing. Sometimes you can actually cause leaks by washing particles out of the small holes they may actually be plugging. Really!
A bigger concern is overpressuring the system and splitting the heater core open if he hooks the hose directly to the heater to backflush it. :eek:
Backflushing is good, but the water needs a place to go it the heater is completely blocked
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Advanced
Joined: Nov 2003
Posts: 89
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From: Apollo PA
Re: How do I backflush? (c4power)
BTW.. the reason I suggested the kit is that as our other members have stated, connecting the hose directly to the heater can be a gross error. The kit has a knuckle that you put between the T and the hose that incorporates a "pop off" type of arrangement that prohibits you from putting too much pressure to the heater core. For what it's worth, I just went through all of these same gymnastics on my 90 with no heat. I have virtually eliminated water flow as an issue, and have now narrowed it down to the heater door inside the heater box. This is not going to be a fun job so wish me luck... :smash:
