79 Spider. Has thermostat orientation changed

Keep it on topic, it will make it easier to find what you need.
Post Reply
barnesjtsl
Posts: 203
Joined: Fri Apr 03, 2009 2:13 pm
Your car is a: 1979 Spider
Location: Hillsboro, OR

79 Spider. Has thermostat orientation changed

Post by barnesjtsl »

I have purchased a new thermostat. Not OEM. It looks like the orientation has changed? I put it in with the two openings that you can blow through freely pointing toward the water pump and the tee at the top of the engine. When I run the car with this orientation the thermostat never opens. I took it out and boiled it and it opens fine. When I took it out what looks like the charging cylinder (the part that gets hot and opens the thermostat) is pointed toward the lower hose to the radiator? In this position the thermostat will never open.

What am I missing here? Is the correct orientation now the free flowing openings upper engine to lower radiator hose? I'm stumped.

jb
User avatar
azruss
Posts: 3659
Joined: Sun May 30, 2010 12:24 pm
Your car is a: 80 Fiat 2000 FI

Re: 79 Spider. Has thermostat orientation changed

Post by azruss »

It sounds like the orientation is ok. The valve closes off the lower radiator hose only. You can trap air in the lower radiator hose and will not allow it to heat up. A couple of ways fix this. first is to allow it to get hot, shut the engine down until it gets cooler and repeat the process until enough heat works its way to the thermostat for it to open. 2nd is to fill the bottom radiator hose and radiator to the thermostat level before assembly to minimize the amount of air in the lower hose. Last is to drill a small hole (1/8-3/16") in the valve to allow that air to work is way through the hose and into the top of the radiator. The entire system must be air free for it to work properly.
barnesjtsl
Posts: 203
Joined: Fri Apr 03, 2009 2:13 pm
Your car is a: 1979 Spider
Location: Hillsboro, OR

Re: 79 Spider. Has thermostat orientation changed

Post by barnesjtsl »

Thanks, azruss

I have delt with the trapped air issue many times. I drive it up on ramps in my sloped driveway and do the final fill(s) from the flush connection on the heater hose at the back of the engine. I also have a 1/4" pipe thread plug in the "T" at the top front of the engine that the thermotstat hose connects to and flows to the top of the radiator. I open that and make sure the hoses are full as well. I also have a 1/32" hole drilled.

I have the two openings that flow through freely connected to the waterpump and the hose that flows to the "T" at the top front of the engine as they are supposed to be, but the charging cylinder that gets hot and opens the thermostat is pointing toward the lower radiator hose. Oriented this way the thermostat will never open, yet I have it installed correctly regarding the flow through hose connections.

According to my manual the charging cylinder is supposed to be pointed at the waterpump as part of the continuous flow through, yet the one that I have (I actually have two of them) has the charging cylinder pointed toward the lower radiator hose when oriented correctly via the flow through connections.

jb
Post Reply