'91 L98 coolant back-flush
Thread Starter
Burning Brakes
Joined: Apr 2002
Posts: 1,012
Likes: 0
From: In the land of a Horse with no name
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06-'07
'91 L98 coolant back-flush
I just replaced the heater core in my '91 (L98 motor) and want to backflush the system Before I reconnect the heater core. Currently the 2 heater hoses are connected to each other, bypassing the new core. How do I do this? Any info would be appreciated. Thanks. Bedroker
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
I would just drain the coolant and refill, warm the engine to operating temperature, drain, and repeat until the drained water looks reasonably clean. Some run the engine with the drain petcock open and a hose keeping the system full, but this method never opens the thermostat.
If you want to go beyond this, you could bring the radiator to a radiator shop for cleaning.
If you want to go beyond this, you could bring the radiator to a radiator shop for cleaning.
Heel & Toe
Joined: Nov 2011
Posts: 15
Likes: 0
From: Fayetteville GA
Coolant back-flush
I bought one of those Peak flush kits that connect in the heater hose but not sure which one. Then I plan to remove the top radiator hose at the engine end to allow coolant to escape as clean water is run in. These kits have worked real well on other cars that I own and very inexpensive.
Racer
Joined: May 2006
Posts: 426
Likes: 16
From: Concord CA
I use the Flush Tee also (Prestone kit, but you can buy the Tee in bulk). Works well. I have my Tee connected to the hose coming from the Throttle Body to the Heater Core. Just follow the instructions.
I also use it to help bleed air out but cracking the cap a little and letting air out until coolant start to come out.
I also use it to help bleed air out but cracking the cap a little and letting air out until coolant start to come out.
Heel & Toe
Joined: Nov 2011
Posts: 15
Likes: 0
From: Fayetteville GA
A little different
I don't know, things might be a little different on the C5 vette. Both my heater hoses go to casting that contains the water pump (I think) and the thermostat (I think). I'll still need to disconnect the hose to the top of the radiator so there is someplace for the water to come out.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
In California it's illegal to dump antifreeze into the gutter, so no DIY flushing in your driveway is allowed. Where I live anything that goes into the gutter goes directly into the Pacific Ocean.
You CAN dump it down the sink drain, though. They assume it will be so diluted that it won't be a problem for the sewage treatment plant.
There are shops with equipment that flush the cooling system with hot water to keep the thermostat open. It's kind of specialized equipment, so you need to look around to find a place that can do this.
You CAN dump it down the sink drain, though. They assume it will be so diluted that it won't be a problem for the sewage treatment plant.
There are shops with equipment that flush the cooling system with hot water to keep the thermostat open. It's kind of specialized equipment, so you need to look around to find a place that can do this.
Heel & Toe
Joined: Nov 2011
Posts: 15
Likes: 0
From: Fayetteville GA
I guess if you want to be more environmentally friendly you could first drain ALL the coolant in the system for proper disposal and then use the fresh water flush. There would still be a very small percentage that would go down the gutter into the water system. The EPA should probably encourage the antifreeze manufactures to produce a product that is more environmentally friendly.
Racer
Joined: May 2006
Posts: 426
Likes: 16
From: Concord CA
You could drain the Coolant and dispose of it at a Waste Disposal location, Which is what I do.
I also fill run and drain one more time before (which i also dispose of) I run the Back flush with water. Not completely Green, but its the best I can do.
We have a Household Waste center, which is also where I recycle oil, filter and other items, Maybe you can find one in your area. Be Green and Recycle !
http://www.co.contra-costa.ca.us/dep...ions/v5951.htm
Also Amsoil markets a "Biodegradable Antifreeze", could be other's
http://synthetic-motor-oil-air-filte...antifreeze.htm
BC
I also fill run and drain one more time before (which i also dispose of) I run the Back flush with water. Not completely Green, but its the best I can do.
We have a Household Waste center, which is also where I recycle oil, filter and other items, Maybe you can find one in your area. Be Green and Recycle !
http://www.co.contra-costa.ca.us/dep...ions/v5951.htm
Also Amsoil markets a "Biodegradable Antifreeze", could be other's
http://synthetic-motor-oil-air-filte...antifreeze.htm
BC
Last edited by bczee; Nov 16, 2011 at 11:21 AM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
