Project 2: Thermostat & Housing Replacement
Applicable Years: C1, C2, C3
Skill level: 1 Wrench
Tools required: sockets, ratchet, razor scraper, screwdriver
Time required: 1 hour
Parts source: Paragon Reproductions
The thermostat housing on my '67 big-block was looking a bit shoddy, and the old warhorse has a tendency to run hot in summer traffic, so I thought it would be a good idea to replace the stock thermostat with a 160-degree unit when I put a new housing on the engine. This is an easy project that will help your engine to run cooler and make the engine look nicer-especially if you're doing some additional cleanup and detailing while you're at it, as I did.
Drain enough coolant from...
Drain enough coolant from the radiator so that the level is lower than the thermostat, then use a ratchet and 9/16-inch socket to remove the two bolts that hold the housing onto the intake manifold.
Lift the housing off, use...
Lift the housing off, use a screwdriver to loosen the clamps, and pull the hoses off it. You can also lift the thermostat out of the manifold at this time.
The new parts with the old...
The new parts with the old ones above them. Only one gasket is required and will be used, although there are two in the picture.
Here's the old thermostat...
Here's the old thermostat housing. If you have nothing else to do with an afternoon, you can use a Dremel and a wire brush to clean off all the crud and corrosion; or, you can simply replace it as we're doing here.
Use a razor scraper to clean...
Use a razor scraper to clean off any gasket material, loose rust, or other debris on the manifold, as this stuff will impair a water-tight seal for the housing.
Here's the manifold after...
Here's the manifold after cleaning it up a bit. It's also a good idea to retrieve any debris that may have fallen into the opening, as this can clog the thermostat and you really don't want any of this garbage circulating through your radiator, water pump, or the rest of your cooling system.
Rust never sleeps, so this...
Rust never sleeps, so this is a good time to paint over any exposed metal on the manifold before you put the housing back on. I cut down an empty spring water bottle, sprayed some "Chevy orange" into it, and used a small disposable brush for such touch-ups. Nitrile gloves are also a good idea to keep paint off your hands.
It doesn't make too much sense...
It doesn't make too much sense to use rusty bolts to secure a nice new housing, now does it? I decided that stainless bolts and washers were the best way to go, in keeping with the rest of the stainless I used on the manifold in another project.
This is a final look at the...
This is a final look at the old and new pieces as a reminder of why I'm replacing this housing. The old part is perfectly serviceable, however, and can be cleaned up (this would make a good indoor winter weekend project) or can be sold to someone looking for a bargain on eBay.
The gasket has a peel-off...
The gasket has a peel-off backing so it will adhere to the housing and stay in place without any sealant. Permatex will be used for the other side, however.
Permatex is smeared around...
Permatex is smeared around the edge of the housing to ensure a water-tight seal when it mates with the manifold. All that remains to be done is to insert the new thermostat, put the housing on the manifold, bolt it down, and reattach the hoses.
Voila! Quite a difference,...
Voila! Quite a difference, no? It not only looks better, it should run cooler now as well, so what's not to love?