C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
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Old Apr 12, 2016 | 05:01 PM
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While restoring the engine compartment of my 68'(52,000 miles) I used those tower clamps. While driving down the freeway the temp began to rise, rapidly !. I was coasting down the off ramp, the gauge was reading 250 deg.

Upon close inspection, the heater core hose had come off. Not sure if I forgot to tighten that one or didn't' get it tight enough.

I replaced the hoses again, new tower clamps and made sure all have been tightened. The first time running the engine, I had a leak above the lower radiator hose connect.

Oil is clean and clear exhaust.

Repositioned the lower hose. Leak reduced to a drip.

Started engine, exhaust is white steam. Oil still clean, no sign of contamination.

Pulled the pump, the inspection plate gasket looked suspect. I think this is where the leak is. Any one have any thoughts on the engine and where I can find this inspection plate gasket?
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Old Apr 12, 2016 | 05:06 PM
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Normally the pump leaks at the weep hole on the bottom...
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Old Apr 12, 2016 | 05:46 PM
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Steam out the exhaust means coolant finding it's way into the combustion chamber. The first thing I'd suspect is a blown head gasket. It only gets uglier from there, like a cracked head.

What inspection cover / pump? Fuel pump, water pump, oil?

Last edited by SH-60B; Apr 12, 2016 at 05:48 PM.
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Old Apr 13, 2016 | 01:02 PM
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Originally Posted by patrick68
While restoring the engine compartment of my 68'(52,000 miles) I used those tower clamps. While driving down the freeway the temp began to rise, rapidly !. I was coasting down the off ramp, the gauge was reading 250 deg.

Upon close inspection, the heater core hose had come off. Not sure if I forgot to tighten that one or didn't' get it tight enough.

I replaced the hoses again, new tower clamps and made sure all have been tightened. The first time running the engine, I had a leak above the lower radiator hose connect.

Oil is clean and clear exhaust.

Repositioned the lower hose. Leak reduced to a drip.

Started engine, exhaust is white steam. Oil still clean, no sign of contamination.

Pulled the pump, the inspection plate gasket looked suspect. I think this is where the leak is. Any one have any thoughts on the engine and where I can find this inspection plate gasket?
Definitely a head gasket at least!
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Old Apr 13, 2016 | 01:10 PM
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Originally Posted by SH-60B
Steam out the exhaust means coolant finding it's way into the combustion chamber. The first thing I'd suspect is a blown head gasket. It only gets uglier from there, like a cracked head.

What inspection cover / pump? Fuel pump, water pump, oil?
Water pump. I can always make a gasket. If you are having the pump rebuilt they can access the pump shaft and seal by removing this plate.

I'll pull all the plugs. I hate tower clamps. Biggest POS ever.
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Old Apr 13, 2016 | 01:12 PM
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the back water pump gasket should be available at most auto parts stores
http://www.autozone.com/cooling-heat...?checkfit=true

you need to do a compression test
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Old Apr 13, 2016 | 01:54 PM
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Originally Posted by SH-60B
Steam out the exhaust means coolant finding it's way into the combustion chamber. The first thing I'd suspect is a blown head gasket. It only gets uglier from there, like a cracked head.

What inspection cover / pump? Fuel pump, water pump, oil?
ditto. first indication is over pressurizing the cooling system and blowing off hoses. put a pressure guage on the radiator cap and run the engine. if it runs up past 15 psi quickly you've got a problem...
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