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The Cars => 1966 Shelby GT350/GT350H => Topic started by: deathsled on May 06, 2024, 04:03:49 PM

Title: 195 degree thermostat?
Post by: deathsled on May 06, 2024, 04:03:49 PM
I seem to have a small coolant leak.  Could be around the thermostat housing.  While at it I am looking to replace the thermostat and I saw a recommendation of 195 to fix any potential overheating problems.  Thoughts?
Title: Re: 195 degree thermostat?
Post by: Bob Gaines on May 06, 2024, 04:16:02 PM
Quote from: deathsled on May 06, 2024, 04:03:49 PMI seem to have a small coolant leak.  Could be around the thermostat housing.  While at it I am looking to replace the thermostat and I saw a recommendation of 195 to fix any potential overheating problems.  Thoughts?
This is my go to thermostat. It is a 180 degree high flow design .Used successfully on many cars for decades by me and many others .https://www.summitracing.com/parts/mrg-4364
Title: Re: 195 degree thermostat?
Post by: FL SAAC on May 06, 2024, 04:18:38 PM

I recall a study years back when I was looking at the thermostat temp thing with the Mustang and I recall that wear increased when engine temperature was kept below 180F (another reason to avoid the 160 stats) and performance was reduced when you got above 190, hence the 180 being the "sweet spot", a perfect balance of low wear rates and performance.

Best wishes and keep kool out there !
Title: Re: 195 degree thermostat?
Post by: Bob Gaines on May 06, 2024, 04:28:00 PM
There is a Ford large diameter thermostat that was used up to and including 1966 production and a smaller thermostat that started being used starting in 1967 production. You need to be certain which thermostat housing you have.Maybe post a picture or check the casting numbers . The summit part I posted a link to is for the smaller thermostat. 
Title: Re: 195 degree thermostat?
Post by: deathsled on May 06, 2024, 04:46:33 PM
Engine is a late 80s 302 that came out of a Mustang drag car.  So a five liter Fox body type 302 thermostat is what I will need.
Title: Re: 195 degree thermostat?
Post by: KR500 on May 06, 2024, 04:48:59 PM
195 deg. is the OE thermostat spec. and they work just fine if there are no other issues with the cooling system, engine, exhaust and ignition system. Using a 180 T stat I find makes very little difference if you are chasing an over heating issue. A high flow may help some, but maybe not as to high of a flow ( as in no T stat,the coolant flows to fast through the radiator to get a good heat transfer and could actually be worse). Fixing the root cause of the over heating is the cure not using a band aid lower temp T stat.
Title: Re: 195 degree thermostat?
Post by: Bob Gaines on May 06, 2024, 05:45:51 PM
Quote from: deathsled on May 06, 2024, 04:46:33 PMEngine is a late 80s 302 that came out of a Mustang drag car.  So a five liter Fox body type 302 thermostat is what I will need.
The one I posted a link to is the small thermostat which will work in the housing that you have. Getting to the root cause of a overheating problem and fixing that is always good but sometimes it is a trick in figuring that out. Somethings things like overbored engine or engine block with scale in the water passages can be difficult to fix short of tearing apart the entire engine. If the inexpensive thermostat fixes the symptoms then some people are satisfied with that rather then finding the root cause. The debate goes on as to what degree to use. To each their own. I know what has worked for me after listening to all of the debate. Use your best judgement on what to do. 
Title: Re: 195 degree thermostat?
Post by: deathsled on May 06, 2024, 06:08:22 PM
I think the only reason it's overheating is because antifreeze has been leaking out. Still a new thermostat is no doubt due and I got a radiator cap as well. Will see. Taly ho!