Where Can I get a 180 stat that will open when it is suppose to. I have a edelbrock waterpump, becool radiator and csi fan controller. Usually I set the Fan to come on at 205. If I set it to come on any lower it runs all the time. Just for kicks today I set the fan to come on at 200. I let the car warm up and the fan kicked on. The strange thing is the fan was blowing cold. The top hose felt like the thermostat was open, so I wonder if it is not fully opening until 200 or more. After that test I set the fan to come on at 215. Then I again felt the air from the fan, It was hot.

15 degrees difference between tests.
first test fan was blowing Cold. Id say just above ambient temp 40 degrees
second test fan blew hot

Whats Up?
Thanks

 

what temp do u have the fans to turn OFF at?

 

That all depends on what the various parts are actually measuring.

The fan switch is screwed into the head, so it's really measuring head casting temp, more than coolant temp. The thermostat is in the intake manifold, so it's measuring coolant temp at that point. It's very easy for there to be that much temp difference between those 2 points.

 

The Csi turns off at the same temp it turns on at. For this reason I have it in the intake manifold by the thermostat. I think that it would cycle to fast if it was in a head.

When The second test was done ( fan on at 215) the stock gauge would climb to 220 when the CSI turned on the fan. Then stock gauge would drop quickly. The CSI would drop slow. I do not notice this when the CSI is set to 205.

 

...and beyond what RB clarified, the rating temperature of a thermostat is the temperature at which it begins to open. A given thermostat may not be fully open until almost 15-20 degrees beyond the rating temperature, or right about where you are suspecting it is operating.

Another thing to consider is the innacuracy of the factory dash instruments. They aren't made by Fluke, so there is probably some "tolerance" in the system. The only really reliable dash instruments are the speedometer and voltmeter, and even the speedometer is suspect in some installations depending on the speedo drive gear and differential combination installed.

If you suspect a sticky or improperly opening thermostat, test it in water in a saucepan on the stove top. Use a good thermometer to monitor water temperature and watch the valve as the water temperature rises and falls. You'll be lucky if you find one that opens fully within ten degrees of the rated opening temperature.

And as RB pointed out, you need to compare apples to apples, not head temperature to intake temperature. AS a guideline, I have a 180°F thermostat in my TA, and the car consistently runs between 200-205°F on hot summer days regardless of AC use, engine load, and how it is used (just cruising, or chewing up rice).

 

200-205 where is the sender? maybe I will try putting the sender in the head, I was just afraid it would cycle to fast.
I dont suspect a sticky thermostat. Last thermostat worked the same way.

 

Thought of another thing.

I think its Hypertech that makes a fan swith that turns on at 200 off at 185. I have been reading the boards and some people are using a 180 stat with the Hypertech sender. How could this be. I would think the fan would never turn off because the stat would be mostly shut.

Sorry if I seem to go overboard on this one Just want to keep those aluminum heads around 200 Degrees. The Hottest it has ever got was 225 not at an idle but flying down the road

 

I have an Autometer water temp gauge in the drivers side cyl. head. When I get on the highway I sometimes see the gauge spike 220* or more, but the laptop scanner never goes past 180* where the stat is set to open.

I've been told it hot spots circulating after the stat opens. It makes sense, all the hot coolant has to go thru that head to get to the radiator right after the stat opens up. I'm gonna move my sender to the intake.

 

The stat should be within 5-10 degrees of its rated temperature for where it opens. Most of the time they are fairly close. Its possible you asked for a 180 and got a 195. The only way to check that is to check the thermostat itself, the temp rating is stamped into the middle of the bottom side of the thermostat.

I used to sell parts and misboxes are not all that uncommon.

 

The cooling system on a car is often misunderstood because people try to oversimplify it in their minds. In reality there are many complex dynamic factors involved in the prediction of what the system will do. Several points were already brought up: one being that the thermostat opening temperature is not precise, it can vary up or down from it's rated temp just because of factory tolerances. Also, as already pointed out the thermostat doesn't reach fully open until the actual temp has risen quite a bit more. Just because your thermostat begins to open at a given temperature doesn't mean that your engine coolant temperature will never get hotter than that temperature. If you have a 180 degree stat in your car, is it possible for your coolant temp to reach 230 degrees under certain conditions? Certainly. Under heavy acceleration on a hot day the coolant temperature will easily rise well over the temperature of the thermostat rated opening point. When the heavy acceleration ceases, the thermal system will gradually return to a more steady state condition closer to the rated temperature of the stat.

Another factor is at what temperature the cooling fans turn on and off. Just because the cooling fans turn on at a given temp it doesn't immediately imply that the engine temp will never rise above that point. The coolant has to travel some distance from the hot engine to the cold radiator, and it is quite possible for the coolant to get much hotter while in the engine than the fan turn on point at the radiator. Also, just because the cooling fans are on doesn't mean that all the coolant in the radiator is instantly cooled to that point. It doesn't happen instantly, it's a gradual process and it depends tremendously on the temperature of the coolant as it reaches the radiator, what air flow is passing through the radiator, and the temperature of the incoming air. Again, it's a dynamic system and there are a lot of variables involved. Is the car stationary? Is it moving? Is it a hot summer day and the fans are pulling air at 95 degrees, or is it a cold Minnesota morning and the incoming air is a frigid -35?

Thermostat rating and coolant fan turn on point are not absolute limits to engine temperature. They are factors which help control engine temperature, certainly, but they do not have absolute control themselves.