Guys, I'm havig a strange problem. I never used a thermostat on my engine, because down here it gets really hot sometimes, and my car is used more in city trafic, with low speeds.



This is the fact: Ford specifies a 180º thermostat for my engine, and I decided to give it a try. Bought a NOS one, tested it, and works fine, opening at 79º Celsius, that's almost 180ºF.

While running in town, the temperature goes up to 200, and sometimes 220. That scared me. I have a mechanical temp gauge from Summit, and I tested it too, it's working fine. My radiator is the stock one, with a new core (3 row) and a 13 lbs Motorcraft cap. I run new atifreeze, and have no leaks.

I got the thermostat out, and the car runs at 160, 170 all day long, with some rare 190 readings at stop and go trafic.



My question is: Would a lower temp opening thermostat be better than running without one at all? Once the thermostat is open, shouldn't the engine work the same way it does without a thermostat (of course, just never going below the opening temperature)?


Túlio Lazzaroni "FORD", Florianópolis SC Brasil.

'74 Ford Galaxie 500 292 V8

'82 Ford Galaxie Landau 302 V8

'98 Chevrolet S10 4.3 V6

'01 Ford Focus 1.8 Zetec

Fuel efficiency will be better with the engine running warmer.  Engine wear is also less with the warmer running engines.  If the engine is not losing water as a result of boil overs, I wouldn’t be concerned about the engine running 190-200°F.

Lorena, Texas (South of Waco)

The temperature rating of the thermostat controls the MINIMUM operating temperature.The maximum temp is controlled by the cooling capability of the rad,fan,water pump etc.If you change to a 160 stat the maximum temp should come down somewhat but almost certainly it will be higher than 160.You might look into an electric fan and a smaller water pump pulley which would turn the water pump faster.How many blades are on the fan?More blades give better cooling.Is there a fan shroud on yours.Also helps cooling.

  

Yes, I have a fan shroud, the stock one, with the factory 7 blade A/C fan. A 160 stat would be nice, but I'll have to buy it from Summit or on e-Bay, because all I could find here are 180. Now, that it's starting to get cold here, my Galaxie is running between 160 and 170. I have some brand new thermostats, one from Ford/Autolite (NOS), another from Rotunda, and one from MTE Thomson, all 180. The one from Autolite has the biggest flow capacity, as the opening is bigger, and the valve opens more. This one was the one I tested. It also has a small 1/16" hole in it, to allow air bleeding. On my 302 powered Galaxie I use a thermostat, the factory original, but it's 160 degree.

Other thing I noticed was the oil pressure. With the stat on, it goes to around 30 PSI at idle (650 RPM). Without the stat, the pressure goes to 40 PSI at idle. I think that's a result of the difference in temperature altering the oil's viscosity. I'm using 20W50 API SJ oil, from Motorcraft (manufactured here by Texaco), that has a high zinc content.

Túlio Lazzaroni "FORD", Florianópolis SC Brasil.

'74 Ford Galaxie 500 292 V8

'82 Ford Galaxie Landau 302 V8

'98 Chevrolet S10 4.3 V6

'01 Ford Focus 1.8 Zetec

If you're using the stock sender location for the temperature gauge, then your temperature is actually about 10 degrees higher at the thermostat and that will make it about right for a 180 degree thermostat.


Lawrenceville, GA

If you mean the hole at the head, then no. I'm using the hole at the intake, about one inch from the thermostat.

Túlio Lazzaroni "FORD", Florianópolis SC Brasil.

'74 Ford Galaxie 500 292 V8

'82 Ford Galaxie Landau 302 V8

'98 Chevrolet S10 4.3 V6

'01 Ford Focus 1.8 Zetec

You could try the wide mouth type Mr. Gasket #4367 (180), or CASCO's 170 if you live near the equator. More flow should help.

Also, since thermostats are fairly cheap devices (buy several/pick the best), I wouldn't trust one that hasn't been tested thoroughly. Penalty for failure is just too severe.

6 VOLTS/POS. GRD. NW INDIANA

I found one, from Stant, at Summit Racing (431-13476 part). It's a 160 thermostat.

Since without the thermostat my engine works without overheating, even with the A/C on, I just have to pick one that's good on keeping the lower end temperature without interfering with the cooling capability of the 292.

Around here I have a problem, that is quite irritating. I can find dozens of options for thermostats, if the engine in question is a 302 Ford, a Chevy small block, or a 250 Chevy six. Y-Block? Nope, only factory original NOS stuff with 30+ years old, new parts from MTE, that are good, but all 180, or then import a part from the United States. I live in southern Brazil, and by experience, I would say you can compare the clima with Florida. Miami is just like my city, lot's of cars, and lots of heat.

Due to this, I can buy one or two, but the seller must ship the part to me. Summit does, Dennis Carpenter does, etc, but lot's of sellers don't, so I kind of need to buy a part with a good indication.

Túlio Lazzaroni "FORD", Florianópolis SC Brasil.

'74 Ford Galaxie 500 292 V8

'82 Ford Galaxie Landau 302 V8

'98 Chevrolet S10 4.3 V6

'01 Ford Focus 1.8 Zetec

Are there a lot of Mopars over there? They use the same thermostat.


Lawrenceville, GA

The big block Mopar thermostat is 52-54 mm diameter - sizes here are 383/413/426/440 cubic inches. When the guys refer to a "big mouth" thermostat they are talking about the diameter of the moving poppet. Many are manufactured with a 52/54 diameter - but the poppet is only 25/26 mm. The ones with the 38 mm poppet are the ones to find. Mr Gasket brand "high flow" is sold here.

This type is known as a "Robertshaw" type thermostat and they work quite well - have a huge opening. The hole in the poppet support is one of three (about 5 mm dia each) added so that water can pass through when the thermostat is closed. When modified this way  - you can put an orfice in the "bypass" hose (that goes out the front of the intake manifold and directly back to the water pump). When you block or orfice this passage, water can't directly bypass the radiator and reheat. A 3/8 std pipe plug with a 5 mm drilled hole, inserted in the tube will do the job.

 
 Steve Metzger       Tucson, Arizona