After installing new brakes, master cylinder, and brake lines and having radiator flushed and cleaned I finally started my '80 for the first time in probably 6 years and 13 years since it's been on the road. That was a short warm up. Then a week later I replaced the fan clutch and started up again, this time for a good warm up (can't drive it - not registered, power steering not functional). Warmed up and then brought up to 2,000 rpm for about 15 second then up to 3000 for a few seconds, then to idle. Walking around found coolant leaking. Radiator good OK, water pump OK, no reservoir overflow - in fact low. 

|UPDATED|11/7/2016 7:40:19 PM (AZT)|/UPDATED|


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Heater core?

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1973 L-82 4 spd

Looks more like a hose leak to me. Heater cores will normally leak to the inside of the car. What I see is leakage around the clamp....I'd double-check that the clamps are nice & snug before condemning the core itself. 

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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

after the post i realized i should check the car floor.  it's wet.  guess i'm doomed - well, 36 years, 90,000 miles, sitting for 13 years - par for the course.  

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Before you put plates on it and drive it down the road I suggest changing all belts and hoses.Otherwise you will be on the side of the road changing blown out hose.

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Agreed. Rad hoses already replaced along with many vacuum lines. Winter project is to pull power steering control valve and other hydraulics, all of which are leaking (and were practically since the car was new) to rebuild and replace all hoses. This is all just to get the car able to be driven to places to start the real work - engine rebuild, tranny replacement - 700R4, rear end rebuild (it's got a knock) with change to 3.33 gearing. Likely change to headers (thinking Stans Tri-Y), mini high flow cats (we're an emission checking county in PA) out to real dual exhaust so will make sure the new cross member for the tranny has the necessary shape to add a pipe to the passenger side. Lot's of ancillary stuff to go along with all that. 

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I've found it easier to pull the engine and tranny as a unit.

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1973 L-82 4 spd

Even with a bad/loose clamp or even a cracked hose at the clamp can still leak fluid inside to the floor.  might be worthwhile to pull the hoses off and check them, and maybe putting a little pressure into the heater core and see if anything leaks out

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StingrayJim
NCM Lifetime Member #1936

Stingray's '76���������������������������� StingrayJr's '78���������������������������Lil Red '94

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Thanks for the input. It is definitely worth checking and hoping for the best. 

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I decided to change my heater core on my 78 with A/C since I'm putting a new dash in. Everything on removal went fine. Trouble I'm having now is finding the correct core to put back in. Every core I've searched are 2 " thick and the original one is 2 1/2" thick. Other  dimensions are correct. The tubes on the 2" every vendor has are too far apart to pass thru the opening in the heater box it fits in. The tubes on the old one is 3 1/4" apart and new ones are 4 1/2 ". The aluminum housing won't take that much modification. If any has a good vendor for these please post. I'm still searching so I'll let you know if I find one. Not sure if yours had A/C.

So I had a very similar problem to yours back in 2012 - even down to the 2" vs 2 1/2" dimensions.  Here's my thread that documents the problem - I eventually found the correct core on eBay.

|UPDATED|12/1/2016 12:18:03 AM (AZT)|/UPDATED|


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Thanks for the reply Dave. I actually used your past post for info. I figured out my problem was my 78 has a 1977 heater core and ducting as original . 77 and 78 have different cores. Must of been an early production I don't have a VIN on my car. Long story. Corvette Central is close to me so I checked there and the pictures of the 77 matches my core. I should of realized the year because I ran into the 77 parts issue before. ( Brain dead from jet fuel) I'll get my dash while I'm up there and save shipping. Thanks again. Hope to see you in Branson..

It very well may benefit you to pull the core ANYWAY. I pulled one on a 75 with no heat and no leaks. PLUGGED to the max with silt. After a good cleaning and instaltion, no leaks and FABULOS heat. They do not get much use, so the silt just settles in the system.

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Love good advice. You were right on with old one being clogged. Never noticed any drips in the cockpit but indeed had green signs of a future leak. With the dash out sure made it an easy task. Thanks