Help - 79 overheated this evening
Thread Starter
Intermediate
Joined: Apr 2016
Posts: 46
Likes: 2
From: Lakeland FL
Help - 79 overheated this evening
I pulled into the driveway and was pouring radiator fluid out of the overflow. I saw no fluid links in the cooling system.
I figure its the water pump or the fan clutch. With the engine off, should I be able to turn the fan both directions? My fan spins freely both ways. I'm figuring this is not cool. The neighbor mechanic says it's the fan clutch. The front spring in the clutch appears to be bad? The front piece on the clutch is apparently out too far indicating the clutch spring is broken?
Does this sound correct? I'm hoping to replace the fan clutch first thing tomorrow morning.
I figure its the water pump or the fan clutch. With the engine off, should I be able to turn the fan both directions? My fan spins freely both ways. I'm figuring this is not cool. The neighbor mechanic says it's the fan clutch. The front spring in the clutch appears to be bad? The front piece on the clutch is apparently out too far indicating the clutch spring is broken?
Does this sound correct? I'm hoping to replace the fan clutch first thing tomorrow morning.
Thread Starter
Intermediate
Joined: Apr 2016
Posts: 46
Likes: 2
From: Lakeland FL
I"m reading the fan should turn freely either direction when the engine is off and cold. More then 3 free spins can indicate the clutch is bad?
My clutch does spin freely, has no play and does not spin more then one free rotation by hand.
I called the PO and he stated the clutch and water pump were new less then 20,000 miles ago. He guessed a thermostat as the car was sitting and used only infrequently recently and the thermostat may have failed due to the sitting.
I just bought a new thermostat
Thoughts?
Thanks
Last edited by 596; May 7, 2016 at 09:51 AM.
Burning Brakes
Joined: Apr 2013
Posts: 1,194
Likes: 109
From: Las Vegas NV
Maybe he got a cheap fan clutch. Get a good name brand fan clutch and make sure the system has been bled properly. There is not much to the cooling system of a '79 C3, but the relatively low filling spout on the radiator makes bleeding a bit trickier than it should be.
Some recommend drilling small holes in the thermostat to aid with that. I like to fill the system from the thermostat housing and hose and quickly reconnect it all when it is full.
Some recommend drilling small holes in the thermostat to aid with that. I like to fill the system from the thermostat housing and hose and quickly reconnect it all when it is full.
Le Mans Master
Joined: Aug 2006
Posts: 7,427
Likes: 1,560
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
There are several things to check before you blindly start changing parts.
Pull the thermostat and put it in a pot of boiling water and see if it opens, if not get a 'fail safe' replacement.
How old are the hoses? The bottom hose can collapse and restrict the flow.
Here's a link to 'How a clutch fan works'.
http://www.haydenauto.com/featured%2...s/content.aspx
Is your shroud in place and do you have the spoiler (air dam) under the front of your Corvette?
With your car at operating temperature and the cap OFF do you see water flowing?
Is your radiator original and has it ever been cleaned?
Another link:
http://www.camaros.org/pdf/corv_cooling2.pdf
Pull the thermostat and put it in a pot of boiling water and see if it opens, if not get a 'fail safe' replacement.
How old are the hoses? The bottom hose can collapse and restrict the flow.
Here's a link to 'How a clutch fan works'.
http://www.haydenauto.com/featured%2...s/content.aspx
Is your shroud in place and do you have the spoiler (air dam) under the front of your Corvette?
With your car at operating temperature and the cap OFF do you see water flowing?
Is your radiator original and has it ever been cleaned?
Another link:
http://www.camaros.org/pdf/corv_cooling2.pdf
Thread Starter
Intermediate
Joined: Apr 2016
Posts: 46
Likes: 2
From: Lakeland FL
There are several things to check before you blindly start changing parts.
Pull the thermostat and put it in a pot of boiling water and see if it opens, if not get a 'fail safe' replacement.
How old are the hoses? The bottom hose can collapse and restrict the flow.
Here's a link to 'How a clutch fan works'.
http://www.haydenauto.com/featured%2...s/content.aspx
Is your shroud in place and do you have the spoiler (air dam) under the front of your Corvette?Yes and Yes
With your car at operating temperature and the cap OFF do you see water flowing? I'll try this
Is your radiator original and has it ever been cleaned?The radiator was replaced at the resto 20k miles ago
Another link:
http://www.camaros.org/pdf/corv_cooling2.pdf
Pull the thermostat and put it in a pot of boiling water and see if it opens, if not get a 'fail safe' replacement.
How old are the hoses? The bottom hose can collapse and restrict the flow.
Here's a link to 'How a clutch fan works'.
http://www.haydenauto.com/featured%2...s/content.aspx
Is your shroud in place and do you have the spoiler (air dam) under the front of your Corvette?Yes and Yes
With your car at operating temperature and the cap OFF do you see water flowing? I'll try this
Is your radiator original and has it ever been cleaned?The radiator was replaced at the resto 20k miles ago
Another link:
http://www.camaros.org/pdf/corv_cooling2.pdf
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
I have never had any luck with the 'fail safe' thermostats. The ones I have used just stick open the first time they are used. Buy a good quality thermostat, maintain your cooling system properly, and forget the gadgets.
Thread Starter
Intermediate
Joined: Apr 2016
Posts: 46
Likes: 2
From: Lakeland FL
Installed a good quality thermostat with a good quality gasket. The old gasket looked rather worn and rotten. It basically disintegrated when i removed the old thermostat. I'll guess the old thermostat was in here quite some time. I've run the car twice for 20 minutes in the garage and the temp never went much higher then 130 or so.
The radiator hoses appear fine. The lower hose appears brand new with the tag still bright and new. The upper hose is good.
I'll keep my fingers crossed as I head the 3 mile trip to work Monday morning.
The radiator hoses appear fine. The lower hose appears brand new with the tag still bright and new. The upper hose is good.
I'll keep my fingers crossed as I head the 3 mile trip to work Monday morning.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
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
