89 rebuild
Thread Starter
Instructor
Joined: Feb 2011
Posts: 102
Likes: 13
From: Beaufort SC
89 rebuild
Getting ready to pull my motor out for a rebuild. I noticed there is a small water line that comes out of the back of the intake manifold and goes to the heater hose. First, what is the purpose of it an second can I just plug the intake off and not use it. Thanks
Drifting
Joined: Jan 2021
Posts: 1,312
Likes: 383
From: Northern California
Steam vent is right. The front coolant passages on the '89 heads / intake manifold are open to the thermostat and radiator outlet flow. The back water ports on the heads are closed off with the gasket, except for a 1/8" (approx.) hole in the gasket itself that allows pressurized steam and a bit of water to flow through that passage, and it exhausts the steam/water into that 5/16" metal pipe and small hose back to the main heater hose. I think the manifold is configured specifically for those passages on the '89 because I've seen the TPI Camaro/Firebird intake manifolds and they don't use that fitting and steam pipe. They must handle those air pockets differently near the back of the heads.
Preserve your original parts and clean them, because those small 5/16" pipe and fittings are discontinued from GM last time I checked. May find them through a salvage yard though.
Preserve your original parts and clean them, because those small 5/16" pipe and fittings are discontinued from GM last time I checked. May find them through a salvage yard though.
Thread Starter
Instructor
Joined: Feb 2011
Posts: 102
Likes: 13
From: Beaufort SC
Thanks for all the info guys. I have the original metal tubes and am trying to clean them up to reuse. Was thinking about just trying to use some 5/16 brake line but with that flare on the original tubes I don't know how to make it.
Drifting
Joined: Jan 2021
Posts: 1,312
Likes: 383
From: Northern California
Yeah - the flare on one side is just a normal, simple flare toward the intake manifold fitting. But that other one that the hose itself connects to is an internal ridge flare in two places to help lock the hose clamp, and that I don't know how to do either. So I've kept mine and am just cleaning it up from rust, etc... I'm also planning on using some thread sealing compound near the flare fitting and the threads because I've seen those leak if they are dry.
Burning Brakes
Joined: Mar 2012
Posts: 768
Likes: 22
From: California
FL Events Coordinator
St. Jude Donor'13
If you look up a tube beading tool you will find what you need to make the "bead" on the opposite end. Comes in quite handy when needed to prevent lines from slipping off
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
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
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski