180 thermostat...why hotter????

fastsc92

Registered User
I installed a 180 deg thermostat and now the engine gets hot way to too. I had a 195 in there to begin with and the temp stayed below normal all the time. Now....the temp goes in between normal and Hot. How come? The temp was way up there and the fan never kicked on. Before the fan used to kick on when it hit "normal" I cut wire #14 and it cooled right down, but i dont like the idea of keeping the fan on all the time (dont want to burn it out), and if the high speed ever kicks on at the same time...i might short out the wiring. help me!! Also...when does the high speed fan go on???
 
Hello. I believe your condition can be explained by the fact that the 180* thermo tricks the car into believing it has never warmed up. Therefore, the computer stays in 'open loop' mode and uses saved settings, rather than input from the actual ECT. The previous thermostat allowed it to run just warm enough to enter closed loop operation. I believe you can adjust the settings of the eec with special software to account for this.

Also, cutting the 14 wire on the fan has been found detremental for the following: The fan has multiple wire coils for high and low speed- therefore when high is switched and low cant go off, the fan fights itself. When the car exceeds a certain speed, it is believed the fan actually interferes with proper air flow when on, therefore it shuts off entirely.

If you were running cool previously, I would simply reinsert the 195 * thermostat. Technically, if a car runs cool enough, internal engine components could actually experience more wear.
 
A 180 degree thermostat will not cause the PCM to stay in open loop. From my understanding the time period (for the o2 sensors to warm up) from open loop to closed loop is based on time rather then coolant temp.
 
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Sounds like you have air in your system! Did you bleed the system.......meaning letting all of the trapped air out.

Cheers,
Calvin
 
Lol I didn't even consider air. Basically, watch to see if your coolant goes down over the next few drives. These systems should let trapped air out by themselves, assuming the overflow hose is not clogged.. check it. If the coolant goes down, air is escaping. Mine behaved similarly when I changed my radiator.. and was fine after the air escaped. Took about 4 days.
 
"Also, cutting the 14 wire on the fan has been found detremental for the following: The fan has multiple wire coils for high and low speed- therefore when high is switched and low cant go off, the fan fights itself. When the car exceeds a certain speed, it is believed the fan actually interferes with proper air flow when on, therefore it shuts off entirely."

I don't know where you can say that cutting the 14 wire has been found to be detrimental. That has not been established at all. If you read Les Borda's post from yesterday he simply cautions that you should watch how your temp gauge responds to the use of turning on and off the cut wire. Yes, you should reconnect the 14 wire (via switch) if you are in danger of the high fan being called for (228 degrees). In all other situations, the only down side is a little more wear and tear on the fan itself. Again, the fan does not go off when the car exceeds a certain speed. If the temp is over 222 or if the 14 wire is cut the low speed fan will run regardless of car speed. I don't believe that the fan interferes with air flow at speed. Until recently ALL cars had fans that ran all the time of the fan belts.
 
I agree with the others about trapped air being the reason for quick temp changes. Loosen the coolant bleeder to let the air out. It usually takes several attempts to get all the air out.

Put a switch on the number 14 wire so you can close the circut when and if the high speed fan is needed. I have mine wired with dual controllers to control low and high speed fan settings.

If for any reason you want more heat in the engine, just raise the fan settings and it will warm to that level.

David
 
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