HELP! Coolant flush problem!

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Jan 18, 2011 | 12:51 PM

zumzero

Thread Starter

2nd Gear

Joined: Jan 2011

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HELP! Coolant flush problem!

Hello! and thanks for looking. I just purchased a 95 Corvette, ran great, no problems, though the coolant looked brownish nasty... so i did a little research and decided to flush the system my self, i took off the knock sensors, ran low pressure water through for 20 minutes or so, cleaned out all the lines and overflow tank, pieced it all back together, i put coolant in the waterpump/block through the thermostat housing to try to eliminate as much air as i could. and now it over heats, digital says 220-225 before ill turn it off, and analog gauge says 245ish. i replaced the sensor for the analog gauge as well...says the same thing, i looked over my lines again and again... i only found one burp valve.. (Bleed screw) on top of the thermostat housing...and it still over heats?!

by the way: before i flushed the system it ran at 185-192 range never higher.

any ideas before i take it to the shop??

Jan 18, 2011 | 01:15 PM

aminnich

Le Mans Master

Joined: Jan 2006

Posts: 6,564

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From: Woodstock Georgia

Wrap a rag around the bleeder screw (there is only one on a 95) and bleed the air out when it is hot enough that the t/stat is open. Just be sure you don't have coolant running down on the opti.

Jan 18, 2011 | 01:19 PM

zumzero

Thread Starter

2nd Gear

Joined: Jan 2011

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did that, and fixing to do it again. lol

Jan 18, 2011 | 01:27 PM

PDQUIK95

Burning Brakes

Joined: Nov 2006

Posts: 1,102

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From: Portsmouth Virginia 396LT4 435RWHP/400RWTQ Best so far 11.26 @ 123mph

If I had to guess,I would say 1) You probably still have air in the system which normally requires a few heat cycles to remove it all or 2)you have installed the thermostat backwards if the temp is actually that high. The vent screw on the housing is the only place designed to burp the system. The remaining air will eventually work its way to the bleed screw at the top. You normally wont get it all out the 1st time.Just bleed it a couple of more times after driving it.
Rick

Jan 18, 2011 | 05:53 PM

jrzvette

Safety Car

Joined: Sep 2002

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From: The reason time exists is so everything doesn't happen at once

The LT1 has a reverse flow cooling system. Someone unfamiliar with it can easily install the thermostat backwards.

Jan 18, 2011 | 07:32 PM

tblt44

Drifting

Joined: Aug 2009

Posts: 1,615

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From: Tampa Fl

bleeder screw,even when you think it's bled bleed it agian as the engine warms.I had the same problem didn't get all the air out.

Jan 19, 2011 | 02:49 AM

enventr

Safety Car

Joined: Aug 2006

Posts: 4,147

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From: Port St. Lucie West Florida

Quote:

Originally Posted by jrzvette

The LT1 has a reverse flow cooling system. Someone unfamiliar with it can easily install the thermostat backwards.

you also might have gotten the wrong stat, reverse flow is the key

Jan 19, 2011 | 11:25 AM

anciano

Burning Brakes

Joined: Aug 2010

Posts: 951

Likes: 3

From: Placerville CA

For some reason people got mad when I have said this in the past (you can be sure someone will squeal in outrage this time, too) but I have had better luck "burping" the system at the surge tank. If you race the engine a little while looking into the surge tank filler hole you may see some bubbles coming out. I did, and that solved my problem even after bleeding several times at the "proper" location where all I got was coolant.

But, as others have said, it could also be the thermostat.