it runs like a champ...i came across a small deal for this all black beauty (no warranty) and couldnt really pass it up..

the 2nd day of having it, i get a check engine light...so i take it up to autozone to see what the deal is with why this light is on..

they give me the code of PO128
meaning:

a.)Coolant temp is always low (which i noticed the temperature never sits in the middle of the thermometer its always in between Cold and warm? i didnt think that was a bad thing)

b.)Thermostat Defective

c.)ECT (Engine Coolant Temperature) sensor could be defective

and at the bottom of the little read out that they print out for you it says:

the PCM determined that the input from the coolant temperature sensor indicates a temperature value that is below the thermostat regulating temperature.

i was just wonder if anyone has had this problem...if so what to do

and after doing some research i learned about the dex-cool coolant, which by the way isnt in my car...whoever had it before me or the dealership replaced it with the regular green coolant..

any and all help would be awesome!!!

 

The t-stat is cheap and relatively easy to replace. I'd start there. If that doesn't cure the problem, then the next thing would be the ECT. If your temp gauge in the dash is reading low (i.e. not straight up), then I'm betting that the t-stat is at fault.

 

I would argee with Swart. The puter gets its information from a different sensor tehn teh dash gauge does. You got two different sensors telling you your temp is too low.

Thermostat is like $10 or so, plus new coolant, and aa gallon of distilled water.

Get the factory rated thermostat.

The puter adjusts the air/fuel mixture based on engine temp and other things. If your running too cold, you will never get good gas mileage.

 

T-stat first but make sure there isn't an air pocket in the system by the ECT cause that could cause the computer read a different temp than the coolant actually is.

 

what is an air pocket?

 

it sounds like the previous owner had the hypertech power programmer on it. and the 160 thermostat installed on the truck and returned the ECU to stock programming but left the 160 thermostat in which would throw the check engine light.

 

Mine did the same thing when I first got it (you probably read my thread). I replaced the Temp sensor first and it went away for 3 weeks, then came back on. I replaced the thermostat and all was well after that.

As far as the air pocket, park your blazer on an incline so the Radiator fill cap is higher then the rest of the motor, take off the cap and run the engine up to temp and fill up the coolant if it drops any. Make sure to run the heater to clean any air out of it as well.

Couldn't hurt to replace your radiator cap as well.

 

I agree with everything they are telling you. I had to change my Radiator fill cap.