BX2200 overheats

upgw · Jun 24, 2004

Well, it's a mechanical device that opens and closes, I see no reason why it couldn't get 'stuck' in the middle between the two states, even though I've never personally witnessed that failure mode. Oh well, don't want to hijack the thread over this! ;-)

- Patrick

Bird · Jun 24, 2004

( I had a ’69 Dodge Charger with a flex fan which required a lot of power to turn. When out on the highway the temp gauge would indicate just below HOT. )

This is the first time I've heard of one of those in many years. I assume you're talking about the same thing I put on my '68 Roadrunner when the fan clutch went bad. A new fan clutch was expensive, so I put on a green fiberglass fan with sharply curved blades and as the RPM increased, the blades tended to flatten out. I never had any problem with overheating, and the only time the gauge would rise a little higher than normal was during extended periods of running in excess of 100 mph.

Junkman · Jun 24, 2004

( ................ the only time the gauge would rise a little higher than normal was during extended periods of running in excess of 100 mph. )

Were you the chaser or the chase E??????? /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Bird · Jun 24, 2004

( Were you the chaser or the chase E??????? )

Actually, neither. /forums/images/graemlins/wink.gif /forums/images/graemlins/grin.gif It was in a place where there was not another human or vehicle in sight, for an amazingly long length of time, other than my wife, who was with me.

SCB · Jun 24, 2004

Junkman,

I have seen two different thermostats stuck in the middle. One in a Jeep Comanchee pickup and another in a toyota celica. It can happen.

joe_tiac · Jun 24, 2004

It's been raining all week here. 'probably be next week before I get to test overheating again. Meanwhile I'll check out the belt and do a better cleaning to the radiator.

Thanks all, Joe

Junkman · Jun 24, 2004

( Junkman,

I have seen two different thermostats stuck in the middle. One in a Jeep Comanchee pickup and another in a toyota celica. It can happen. )

That is considered "stuck open".... open is open..... closed is closed..... If the thermostat is in the middle position when removed, as you describe, then, when you put it into boiling water, it will continue to open. It will not close at all. When you remove a thermostat, it should always be closed. It needs heat to open. My point is that I have never seen a thermostat that was partially open and wouldn't open the rest of the way when put into boiling water. I have never seen a thermostat that was closed and when immersed in boiling water that would only open a small amount. They either opened fully, or they didn't open at all. If they don't open, they are referred to as "stuck closed". These are the characteristics of thermostats. Manufacturers have for years been trying to create a thermostat that when it failed, would always fail in the open position, but have not been able to do this successfully in a wet system. The only thermostat that I know of that will fail in the open position continually is in the Corvair. That thermostat operates at ambient air temperatures and when it fails, the bellows will fall open.

BIGUN · Jun 24, 2004

Bird,

Actually mine was the type with steel spokes and thin stainless steel blades riveted to the spokes. Those blades had a lot of pitch to them and it roared loudly when revved up. The idea was for the blades to flatten out at high RPM, but the way it roared and made the less than perfect belt slip it seems to me it used more power than a clutch type fan. This fan was installed before I bought the car used, possibly as an attempt to fix the overheating problem caused by the belt which was also on the car when I bought it. /forums/images/graemlins/smile.gif

Junkman · Jun 24, 2004

Those metal fan blades were originally designed for cars that did towing of trailers or were in a constant service such as a police car. If my memory is correct the trade name was "Flex Blade". A conventional fan blade turns continually at all engine speeds, but doesn't do a good job of cooling at lower engine speeds. At highway speed, it wastes gas. The fan clutch was designed to disengage when the engine got to the higher revolutions of highway speed. This was so the engine would conserve fuel. The highway speed was considered enough to keep the engine cool. The center of the clutch was manufactured from an aluminum casting with fins on it, and had a viscous liquid sealed inside of it. As the fluid in the fan clutch gets hot, it gets thicker making the fan turn faster. The fan clutch is located in the radiator air stream and reacts to the ambient temperature. When the engine is cold, the fan doesn't spin much at all. I used to demonstrate this by grabbing the fan blade when the engine was at an idle and holding it. (back then I took chances that I now consider foolish) As the fan clutch gets hotter, the fan does more cooling. At highway speed, the incoming air would cool the liquid and the clutch disengaged. They are commonly known as a thermostatically controlled viscous fan clutch. When the viscous liquid leaked out, then there was no fan action at all, hence the over heat problem. These clutches have been in use since the early 1960's and I believe that they are still being used. I used to replace them regularly in my shop because they were / are prone to failure with time / mileage. If it failed and you didn't replace it, because it was winter and the engine didn't exhibit signs of overheating, the fan clutch would come apart and take out the radiator. They are also quite expensive for some models.

SCB · Jun 24, 2004

( My point is that I have never seen a thermostat that was partially open and wouldn't open the rest of the way when put into boiling water. ) 

The thermostats that I referred to were partially open and would not open further when heated to boiling. After soaking in radiator super flush and cleaning with a wire brush they did open when heated. We are probably spending way too much time on this, but it can and has happened.