Pelayo114

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?

Ganey

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.

Pelayo114

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?

MelWff

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?

Pelayo114

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?

Ganey

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

Duane4238

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.

Pelayo114

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?

billcarson

a partially restricted radiator can cause a lower hose to constrict.i bought gates hoses after returning dayco crap and they claim their hose does not require a spring.

MelWff

When I bought a lower house from NAPA it came with the spring.

Pelayo114

Are springs sold separately?
Do both upper and lower hoses need the springs?

chonkyapple

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

Pelayo114

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?

jerome1979

FYI willcox sell lower hose with spring

Pelayo114

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.

MelWff

Did you test the thermostat like I suggested above?

Pelayo114

Sorry I forgot that one. I'm not that well with the part names. Where exactly is the thermostat located?

MelWff

If you follow the upper radiator hose to the engine you will find a housing held down by 2 bolts. The thermostat is inside. You may want to pick up a Corvette repair manual to help you.

Pelayo114

The housing is it like a half ball shaped thing bolted down on two sides?
Is that the correct one?

Pelayo114

How much is a corvette repair manual? Or where can i find one?