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Discussion Starter #1 (Edited)
So my '68 Goat runs hot when sitting at idle in gear, and today I pulled the radiator cap to find I'm about 6" down on coolant! I realize I have a small leak at the thermostat housing, so plan to pop that off, replace the gasket and "while I'm in there" improve the thermostat, although I have no reason to think there is anything wrong with it.

There are SO MANY thermostat options out there though! I would feel bad replacing it with a $5 Auto Zone unit, so any recommendations on a good quality (160 Deg) Thermostat?

Also any thoughts on gaskets? I see the usual $1.50 paper gasket, but for a mere $20 more I can get one with a built in O-Ring, and possibly diamond studded! :)

Assuming I do not want to use gasket sealer.... (?)

I'm not saying this will fix my idle heating problem, but its a start!

Thanks!
 

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I thought my goat was running a bit hot, so I replaced my 160 degree thermostat with a 180 and I drilled a eighth inch hole in the base as recommended.
The 180 actually runs cooler because it slowed the water flow down enough to let it get cooled in the radiator longer. I too, had a small leak in the gasket
after doing this, so I used permatex and now it's tight. You don't need trick gaskets.
You can trim along the edge of the housing with a razor knife to get rid of the overhanging gasket and permatex after everything is clamped down for a clean look.
I have another post here about using Water Wetter. Several have said it works in reducing temperature a bit. Just poured it in mine so I can't say just yet, but for $10 on Amazon, I thought it worth a try.
 

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Discussion Starter #3
Thanks Ralph, I guess in the back of my mind I figured that these inexpensive parts worked for a lot of engines, for a lot of years, but you know how it is- you want the best for your kid, even if it doubles the price to over $10! I’ll go with the 180 degree inexpensive version, stock paper gasket and gasket seal as well. I’d not heard about the 1/8” hole though - just on the base to allow some extra flow when the stat is closed? Thanks!
 

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I was down at Butler Performance a couple of years ago and asked one of the guys what thermostat they recommended....He said they put a 160 degree thermostat in every Pontiac engine they build,....let me tell you they have some unbelievable awesome high dollar tops in the world Pontiac engines......

So I took that recommendation and use a 160. I drill 2 or 3 1/8 holes in the flange. A paper $1 gasket is ok unless you are having a leak problem, usually the original intakes can get pretty rough even after clean up. I have had some still leak with the papaws gasket, but those upgraded gaskets are good, I have gotten some from Ames before that were very good.

Whichever gasket I like K&W Coppercoat gasket sealer with the gasket,.the copper fills in the imperfections in the metal and makes a great seal.

My 461 runs at 180 degrees in the summer, idling forever in hot traffic 195....
 

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Discussion Starter #5
I was down at Butler Performance a couple of years ago and asked one of the guys what thermostat they recommended....He said they put a 160 degree thermostat in every Pontiac engine they build,....let me tell you they have some unbelievable awesome high dollar tops in the world Pontiac engines......

So I took that recommendation and use a 160. I drill 2 or 3 1/8 holes in the flange. A paper $1 gasket is ok unless you are having a leak problem, usually the original intakes can get pretty rough even after clean up. I have had some still leak with the papaws gasket, but those upgraded gaskets are good, I have gotten some from Ames before that were very good.

Whichever gasket I like K&W Coppercoat gasket sealer with the gasket,.the copper fills in the imperfections in the metal and makes a great seal.

My 461 runs at 180 degrees in the summer, idling forever in hot traffic 195....
Thanks Lemans Guy - no electric fan? Do you have a clutch or flex fan? Water Wetter? Oversized radiator? So many questions......
 

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My 66 Lemans originally had AC, I ripped that out.....But AC cars had extra cooling features (that are even better without the condenser dumping all that heat in the engine compartment)

First they had 4 core radiators, and seven bladed fans I kept both those features. But I had US Radiator build me a coppper 4 core radiator with extra large down tubes. That thing looks like original, but cools way better than even the original 4 core. ( Now it does not have the stamped “Harrison” on the top. Like the original if you need that for originality, I don’t care about that.

I use a thermostatic centrifigal clutch, heavy duty. The RPM clutch has a flat plate on the front, the thermostatic has a little circular spring, make sure that you use the one with the spring, the cooling difference is very noticeable. Also make sure your fan clutch is fresh, they lose the silicone fluid slowly, and add temperature gradually, you will notice it mostly at idle. Feel the fan blades......car off please! And see if they feel greasy or oily, it is usually the leaking silicone. Change the clutch.

I use a Flow Cooler water pump with very tight tolerance on the inside plates, an 11 Bolt Water pump as well. Make sure the fan is half way into the shroud, if not you will lose a lot of cooling, and your shroud and rubber surrounds seal it as it should, it does not have to be air tight, just properly blocked.

Make sure you timing is right, retarded idle timing will make the exhaust run hot and therefore the engine. You need about 20 to 24 generally at idle with 10 from vac advance.

Make sure your rubber shrouds are in place in the fender wells, Ames sells them, I think they are $11 each, they will make you run hot if not there because it effects proper air flow through the engine compartment, the radiator needs that suck thru as designed by the engineers..

Some guys rip those out or they deteriorate, put them back you need them.

Of course good hoses clear passages and a new fresh Radiator cap so your pressure is at 16 lbs.....it all matters and it all works together:nerd::nerd::nerd:
 

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Yes a bit of flow a bit of air to rise and not have a bubble. Also make sure your system is at capacity, and not short of the proper capacity of coolant.
 

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I don’t use water wetter, but all those Redline Products are excellent, so in certain cases it may be needed

I use 50/50 mix......
 
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