Coolant outlet bolt torque and how far over can it go? - ZR-1 Net Registry Forums

1991 Corvette ZR-1 · 11-11-2022

I am having occasional trouble with the coolant tubes weeping on the bottom near the mating surface with the injector housing. I had my top end ported by Pete and also had him get the old seized torx bolts out while he was at it. I replaced those with stainless from Jerry?s, also gaskets as well. Gaskets were installed dry and I did not see anything specifying they be smeared with sealant.

I made sure all surfaces were clean and smooth. Converted the 89 inch pound suggest torque to ft lb and it came out to about 7.5. That seemed way too low when every other bolt on this engine seems to have a higher torque spec. Is this a misprint? I was good for a month, then I noticed traces of coolant on the cam covers.

I figured they are loose so I broke out the torque wrench and no they are still torqued to 7.5 lb ft. I bumped it to 9 lb ft and torqued them again. Fast forward about a year and another torque to 10 lb ft and they are weeping again. So now I am in a bind. I hate the idea of draining all the coolant to redo both outlet tubes. Is there a safe amount over in which I can torque these bolts? I figured the heat cycles are slowly shrinking the gaskets, allowing them to weep coolant.

Lesson learned, from now on any gasket that goes on this vehicle will have a smear of appropriate sealant on both sides before being reassembled.

11-11-2022	#1
1991 Corvette ZR-1 Join Date: Sep 2018 Location: Florida Posts: 304	Coolant outlet bolt torque and how far over can it go? I am having occasional trouble with the coolant tubes weeping on the bottom near the mating surface with the injector housing. I had my top end ported by Pete and also had him get the old seized torx bolts out while he was at it. I replaced those with stainless from Jerry?s, also gaskets as well. Gaskets were installed dry and I did not see anything specifying they be smeared with sealant. I made sure all surfaces were clean and smooth. Converted the 89 inch pound suggest torque to ft lb and it came out to about 7.5. That seemed way too low when every other bolt on this engine seems to have a higher torque spec. Is this a misprint? I was good for a month, then I noticed traces of coolant on the cam covers. I figured they are loose so I broke out the torque wrench and no they are still torqued to 7.5 lb ft. I bumped it to 9 lb ft and torqued them again. Fast forward about a year and another torque to 10 lb ft and they are weeping again. So now I am in a bind. I hate the idea of draining all the coolant to redo both outlet tubes. Is there a safe amount over in which I can torque these bolts? I figured the heat cycles are slowly shrinking the gaskets, allowing them to weep coolant. Lesson learned, from now on any gasket that goes on this vehicle will have a smear of appropriate sealant on both sides before being reassembled.