36couper

My 65 coupe (396/425) has been sitting for 3 years. I am getting it put together now and I am nearing the end of completion. Just need to install carpet and seats now.
I took it for a short spin this afternoon (less than 1 mile). By the time I pulled into my driveway the temp gauge was nearing 240. I quickly shut it off and let it cool down.
I noticed the top rad hose is empty (I squeezed it a number of times). I had the over flow cap off and on trying this.
I believe the thermostat is stuck or the is possibly and air block.

If it's the thermostat is there a way to get it to release without having to empty the rad and remove the housing?
If it's an air blockage, what's the best way to get it to burp?


Thanks

babbah

To answer both of your questions IMO you will have to remove the TStat housing.
It is possible that your coolant level is low as well so I would verify that first before doing anything.
And finally check your fan belt to insure it's tight on the water pump pulley.

36couper

Thanks. Looks like I will be busy tomorrow morning.
Yes, coolant level is good and fan belt is tight.

babbah

Hopefully it's just the thermostat. You can test it on a stove with boiling water to make sure it opens. It's probably a 180 degree.

36couper

Great suggestion. The only problem is our kitchen is under renovation and the new stove isn't installed yet.

babbah

Well if you can't test it then install a new one, This way there is no guessing about the old one.
The only thing left after that is the water pump.

Nowhere Man

no out door grill?

Bluestripe67

After sitting for three years I would look carefully at all the rubber items under the hood. Maybe buy new belt/s. You don't need to breakdown caused by old deteriorated parts. Dennis

36couper

I forgot about the BBQ!
I'm going to replace the thermostat this morning.
I failed to mention, everything on this car is new........from front to back. It was being built for a guy who wanted it to match NCRS specs even though it's an undocumented car. I just want to drive it this summer and not chasing down awards.

wraplock

I test every new thermostat in a pot of water on the stove prior to installation. I've had several bad ones. I also like to fill the coolant in the block by filling through the thermostat hole in the manifold, then install the gasket, thermostat and housing. This seems to do a better job of avoiding air pockets.

Don

babbah

JFYI -,I have had 2 Mr Gasket thermostats fail very quickly. Not good.

36couper

To close the loop on this thread, I installed a new thermostat yesterday. It took about 10-15mins.
I let it idle for 20 minutes and never got above 185 degrees. Let's see how it cools this summer in the hot humid weather!

36couper

I took the coupe for another ride around the block after I installed the new thermostat.
By the time I got home after about 5 minutes, the temp was back to 220 degrees.
I opened the hood and reved the motor a bit I could hear the fan belt slipping.
The alternator adjustment was at it's tightest level.
Today I'm going to get a shorter belt but the distance between the alternator and the valve cover is only about one inch. I'll try a belt 1/2" or 3"4" shorter. Hopefully that will clear up the temperature problem.

Westlotorn

Charge your battery with a battery charger, then try your test drive again.
Your battery may just be low after sitting so long and putting a large load on the alternator.

desertpilgrim

I seem to recall a Tech. Svc. Bulletin about filling the 396 - backwards into the top radiator hose when it's loose from the thermostat housing? Maybe someone else can find it - I'll look tonight.

MelWff

I'm going to assume your engine fan uses a clutch. On a completely cold engine that is not running, try to spin the fan blades by hand as hard as possible. If the fan spins more than a revolution or so there is a good chance the clutch has failed. I also assume you have the fan shroud in place and all the foam seals are installed.

36couper

I'll try spinning the fan tonight. Although it doesn't mean much with reproduction parts, virtually everything on my car is new. Virtually every nut and bolt, body off, new frame etc. The shroud is new and in the right position with the foam seals installed
The fan belt that is on it is 56.20" I order a slightly shorter one from NAPA today.
The fan belt squealing when I revved the engine was my first thought of getting a shorter belt. It was on the furthest point on the bracket and there isn't much room between the alternator and the valve cover.
Of course NAPA has a no return policy on fan belts. It's a risk I'm going to assume

babbah

Why are you buying a shorter belt? Just replace the one that it calls for and that should do it.

ejboyd5

After all the other new stuff you have alluded to it would appear that a fan belt is hardly worth talking about.

36couper

The fan belt is too long. The alternator is at the furthest point on the bracket and the belt is clearly not making good contact with the pulley. Hence, the squealing when i rev the engine