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1967 Nova SS
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Discussion Starter · #1 ·
Not on my Nova, but it is on my truck. 1994 GMC OEM 350 121,000 miles. This past summer the radiator tank busted (stupid plastic side tank crap) and truck ran hot (210/220) before I noticed it. Replaced radiator and no further issue until I went to check anti-freeze level this winter. Radiator low but truck had not shown high temp. Re-filled and checked it again week or so later, Little low again.

No leaks in heater core, no leaks around or in any hoses, nothing in oil pan. No noticeable white smoke out tailpipe and nothing noted in smell of exhaust (although my sniffer not too good). Truck cranks and runs good. Slight miss noticed when idling at red-light. Not sure what's going on unless it's a head gaskets, but not sure.

Checked compression and plugs. Cylinders 1, 3, 5, 7 all at 150 to 155. Cylinders 2, 4, and 6 at 130 to 145. Cylinder 8 at 155.

First two pictures below is plug # 2 cylinder. Next two are # 6 cylinder. Plugs in # 4 and # 8 looked OK.

Feedback appreciated

Hand Fluid Liquid Finger Drinkware
Hand Liquid Drinkware Fluid Finger



Gas Wood Bumper Cylinder Metal
Liquid Fluid Wood Drinkware Gas
 

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Good advice above. I've had surprisingly good luck in the past with Bars leak, but I'd guess you burned the head gasket, likely in a couple spots, and any fix would be temporary. I'd guess the coolant was low enough to not be in that critical head gasket area, but not so low that the temp sender was uncovered. I'd probably do both head gaskets, since you're in there anyway.
 

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1967 Nova SS
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Discussion Starter · #5 ·
Appreciate the responses. I am going to do one more test with a "Combustion leak detection kit". Local Harbor Freight had one and basically it's a solution that changed color if exhaust gases are detected in the coolant system.

Shane - thanks for suggestion on internet search.

Dean - I'll do both sides for sure and have heads tested as well.
 

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I use the Lisle 75500 combustion leak detector, sadly I can pretty much assure you the head gasket(s) are smoked, I do a lot of them for the same thing that happened to yours. When I quote for the new radiator I include the head gasket replacement with the job....almost always ends up needing them. At least the customer has a worst case scenario price.
 

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I'm almost convinced your right. It is what it is.

I looked at the Lisle unit but no one locally had one. Maybe the HF knock off will work.
Fortunately, the '94 TBI motor is pretty much like any other SBC.. Should be an easy fix.
 

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You could also run a thinner head gasket, maybe even knock .010 in off the heads and get a bit more compression, depending on how far down the piston is in the hole. Change the water pump, belts, hoses, timing chain, and anything else that's convenient while it's apart. I actually like when stuff like this happens. It's an opportunity to make things better, stronger, faster than before. As long as I don't screw anything up in the process. For me, not screwing things up is the hard part.
 
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