1977 Corvette overheating
Thread Starter
Instructor
Joined: Jan 2011
Posts: 221
Likes: 1
From: Sylmar CA
1977 Corvette overheating
I recently rebuilt my 350 engine and transmission and have my vette in running condition. One slight problem. When running it about 15 minutes on the freeway at about 70-80 mph it seems to want to overheat, more or less at about 240-250 degrees, and the gauge shows that its just one small line above overheating. Any thoughts as to why this could be?
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
1) Rad. may be clogged- rad. shop can rod out to fix. 2)There is a small black dam under front bumper to get air to rad. which may be missing. Thermostat could be bad.
Misc. Low water level or lower rad. hose could be collapsing. Wrong temp. sender or seals missing around rad.
Misc. Low water level or lower rad. hose could be collapsing. Wrong temp. sender or seals missing around rad.
Thread Starter
Instructor
Joined: Jan 2011
Posts: 221
Likes: 1
From: Sylmar CA
I barely had my radiator fixed so it can't be that. Hoses are all new. Water level in radiator is fine. How can I tell if its the sender. Or seals or thermostat?
Is there any way to physically be able to tell?
Is there any way to physically be able to tell?
Race Director
Joined: May 2006
Posts: 18,662
Likes: 2,563
Did you install the steel spring in the lower hose when you replaced it? Either check the thermostat in a pot of water with a thermometer or just replace it. Do you have all the seals around the radiator and shroud?
Thread Starter
Instructor
Joined: Jan 2011
Posts: 221
Likes: 1
From: Sylmar CA
The steel spring I thought was in there by mistake so I took it out. Do I need it?
Just to be sure, where is the thermostat exactly? In the front side of the engine?
And I'll double check the seals once I'm home.
What's the shroud?
Just to be sure, where is the thermostat exactly? In the front side of the engine?
And I'll double check the seals once I'm home.
What's the shroud?
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Check for large spring in lower hose which keeps it from collapsing. Check for the small black dam under front bumper or seals missing around rad.
see
http://forums.corvetteforum.com/c3-t...e-success.html
see
http://forums.corvetteforum.com/c3-t...e-success.html
Burning Brakes
Joined: Sep 2009
Posts: 1,124
Likes: 140
From: Western New York
If you're not overheating while driving around town at stop and go, then your thermostat is OK. Although you could be missing some seals around the radiator or maybe even a spoiler under the nose to direct air toward the radiator, the fact that you're only overheating at highway speeds points directly to your lower hose collapsing. It happens when things get warmed up and the hose softens. As the water flows through the hose, the hose collapses and you then experience the rise in temp as the water slows or worse, stops circulating. Spend another $20 and get a good lower hose with the spring in it. Good luck.
Duane
P.S. I wish my '72 could overheat in September. Today's high was around 64 and tomorrow might reach 58. It's all downhill after that, I'm afraid.
Duane
P.S. I wish my '72 could overheat in September. Today's high was around 64 and tomorrow might reach 58. It's all downhill after that, I'm afraid.
Last edited by Duane4238; Sep 29, 2011 at 05:30 PM. Reason: Addition
Thread Starter
Instructor
Joined: Jan 2011
Posts: 221
Likes: 1
From: Sylmar CA
Is there any way that I can get a spring without purchasing a new hose?
When I bought my hose it didn't come with any spring, and the old original spring was already rusted.
The black dam I remember being there, I'll double check once I'm out of class tho.
So my thermostat and gauge appear to be fine? It's just the lower radiator hose that is collapsing due to the missing spring inside?
When I bought my hose it didn't come with any spring, and the old original spring was already rusted.
The black dam I remember being there, I'll double check once I'm out of class tho.
So my thermostat and gauge appear to be fine? It's just the lower radiator hose that is collapsing due to the missing spring inside?
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Intermediate
Joined: Nov 2009
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From: townsville q.l.d.
No and No.
The waterpump, for want of better words, is sucking the coolant
through the bottom hose which can course it to collapse
in an earlier post you said you removed the spring, the spring stops the hose from getting sucked flat= little or no coolant flow.
The top hose gets coolant pushed through it like a garden hose=cant collapse.
Get a new hose,cheaper than a new engine
Thread Starter
Instructor
Joined: Jan 2011
Posts: 221
Likes: 1
From: Sylmar CA
Oh I see, thanks for the help, I appreciate it.
Is that the only reason it could be overheating?
Also (Off Topic) I've noticed that my rear tires are messed up, the rear passenger side burns out yet the driver side rear does not, now I know its posi but i don't know why they're not both spinning, any ideas why?
Is that the only reason it could be overheating?
Also (Off Topic) I've noticed that my rear tires are messed up, the rear passenger side burns out yet the driver side rear does not, now I know its posi but i don't know why they're not both spinning, any ideas why?
Thread Starter
Instructor
Joined: Jan 2011
Posts: 221
Likes: 1
From: Sylmar CA
I let the engine warm up and reved it to 3-3.5k rpm and the hose didnt seem to collapse.
Any other ideas what it might be. In city and street it does run a bit warm and almost borderline overheating, in highway after 20 minutes its also borderline overheating. Any ideas? And how can I post pictures to show what I'm seeing.
Any other ideas what it might be. In city and street it does run a bit warm and almost borderline overheating, in highway after 20 minutes its also borderline overheating. Any ideas? And how can I post pictures to show what I'm seeing.