Thermostat

[Jacks1986Lebaron]

Can a improperly working thermostat cause a car to run like crap, sluggish, poor fuel economy?

Yet, never have the car over-heat???????

I read up on thermostats some, and it seems it should be over-heating if thermostat wasn't working properly!!

[Butch]

If it's stuck open the car will not get up to operating temps, if it's closed it will over heat. If the eng. runs too cold the puter will run richer thinking the eng. just started.

[Jacks1986Lebaron]

......ohhhh.......good grief!!!

I just talked to Dad and he was changing the thermostat!!!

[Butch]

No biggie, it's cheap enough.

[88 DODGE]

I just changed the thermostat on my Aries, it was stuck closed. The job was 5 minutes and cost 8 bucks while also fixing the overheating problem.

[dc8flyer]

Here is a tip when replacing the thermostat:

Thermostat Modification
An additional improvement can be made to the system by drilling a small (1/8" or smaller) hole in the thermostat plate (the area around the valve seat). When installing the modified thermostat, rotate it so that this hole is as high as possible. This does two things. Firstly, the thermostat can never completely stop the flow of coolant, which reduces the thermal shock to the head that occurs when the thermostat opens (see above). Secondly, if air and gasses do rise in the head and collect behind the thermostat, they can escape into the radiator (and out the overflow tank) through this hole even if the thermostat doesn't open.

http://minimopar.knizefamily.net/index.html

I made this modification myself. Along with replacing the thermostat, the engine runs cooler and warms at a much slower and even rate. I also replaced the thermostat with a 180 degree range vs. the original 195 degree range. That allows the thermostat to open at a lower temp also reducing the thermal shock to the engine.

Now, if I could just find a coolant temperature sensor with a lower range to engage the radiator fan sooner, I would be very happy.

[Jacks1986Lebaron]

Thanks for the tip!!!

[Hemi-Dude]

Here is a tip when replacing the thermostat:

Thermostat Modification
An additional improvement can be made to the system by drilling a small (1/8" or smaller) hole in the thermostat plate (the area around the valve seat). When installing the modified thermostat, rotate it so that this hole is as high as possible. This does two things. Firstly, the thermostat can never completely stop the flow of coolant, which reduces the thermal shock to the head that occurs when the thermostat opens (see above). Secondly, if air and gasses do rise in the head and collect behind the thermostat, they can escape into the radiator (and out the overflow tank) through this hole even if the thermostat doesn't open.

I made this modification myself. Along with replacing the thermostat, the engine runs cooler and warms at a much slower and even rate.
I also replaced the thermostat with a 180 degree range vs. the original 195 degree range. That allows the thermostat to open at a lower temp also reducing the thermal shock to the engine.

Now, if I could just find a coolant temperature sensor with a lower range to engage the radiator fan sooner, I would be very happy.

A 180 degree thermostat is a BAD IDEA, especially on a fuel injected engine. The coolant temperature NEEDS to be 195 degrees or higher for proper system operation.
As for finding a coolant temperature sensor with a lower range, not smart either. The radiator fan does not need to come on sooner than the pre-set 212 degrees set by the engine controller.
As I live in Arizona and commute to California on a regular bases, I have no problem with the engine running at 220 to 240 degrees as long as I have the proper mixture of good, clean coolant and a properly working 16 lb radiator cap. You don't have to be AFRAID of heat as long as it is under control.

[dc8flyer]

Here is a tip when replacing the thermostat:

Thermostat Modification
An additional improvement can be made to the system by drilling a small (1/8" or smaller) hole in the thermostat plate (the area around the valve seat). When installing the modified thermostat, rotate it so that this hole is as high as possible. This does two things. Firstly, the thermostat can never completely stop the flow of coolant, which reduces the thermal shock to the head that occurs when the thermostat opens (see above). Secondly, if air and gasses do rise in the head and collect behind the thermostat, they can escape into the radiator (and out the overflow tank) through this hole even if the thermostat doesn't open.

I made this modification myself. Along with replacing the thermostat, the engine runs cooler and warms at a much slower and even rate.
I also replaced the thermostat with a 180 degree range vs. the original 195 degree range. That allows the thermostat to open at a lower temp also reducing the thermal shock to the engine.

Now, if I could just find a coolant temperature sensor with a lower range to engage the radiator fan sooner, I would be very happy.

A 180 degree thermostat is a BAD IDEA, especially on a fuel injected engine. The coolant temperature NEEDS to be 195 degrees or higher for proper system operation.
As for finding a coolant temperature sensor with a lower range, not smart either. The radiator fan does not need to come on sooner than the pre-set 212 degrees set by the engine controller.
As I live in Arizona and commute to California on a regular bases, I have no problem with the engine running at 220 to 240 degrees as long as I have the proper mixture of good, clean coolant and a properly working 16 lb radiator cap. You don't have to be AFRAID of heat as long as it is under control.

I'll try posting my response to your concerns again.

No one is "afraid" of heat and as far as smart goes, well, I think I would have phrased my opinion differently.

Your concern about a 180 vs 195 degree thermostat is unfounded. You seem concerned about the coolant temperature being 195 degrees or higher for proper operation yet a 180 thermostat doesn't prohibit the system from doing that. Perhaps you think the thermostate operates like the one in your house, I don't know. The 180 thermostate simply allows coolant to flow sooner to reduce thermal shock to the head. This manages the rate to normal operating temps better than a 195 thermostat.

You say your car runs normally between 220 to 240 degrees yet your radiator fan comes on at 212. So your fan runs continuosly? Sounds like something is wrong here.. It doesn't sound like your "proper mixture of good, clean coolant and a properly working 16 lb radiator cap" is working too well.

I don't have the exact nubers as to when the radiator fan comes on, but when my car is moving and there is proper air flow over the radiator, the engine runs cool and there is no need for the fan. It is when sitting still that the engine will start to get hot, at or above the upper normal operating range. Thus the fan comes on to return the coolant to the normal range. It is in these instances, sitting still, that I would prefer a sensor that turns on the fan before the coolant starts to exceed the normal range. There isn't anything un-smart about this.

If your fan comes on at 212 and your normal operating range is 220-240, I think I would have your system checked. There isn't any reason your fan should be running continously as you seem to indicate.

[89ARIES]

I am scared to death about overheating my car again and would rather have a 180 degree thermostat. I just replaced my headgasket because for years the car never ran as cool as it should. Fortunately,
the damage was minimal. I am of the opinion that it is better for the engine to start cooling sooner than later.