Hi all,
I have VW Bora 1.6 BFQ engine with automatic transmission(model year 2005). 208.000 km.
About 1 years ago, coolant was leaking from thermostat house. So, I changed thermostat house with thermostat and temperature sensor. I bought it as OEM part from VW.
Then thermostat was failed 3 times until now.
In the OEM part, “Mahle Behr” was written beside VW Audi logos.
It failed in 3 months. Then, I changed only thermostat with aftermarket Mahle Behr part. It failed after 7 months. Again I changed it with mahle behr one more time. It's been 3 months. Then it failed agin.
3 failed thermostats in one year...
The coolant is G13 antifreeze %50 mixed with water.
In the morning, I check the all temprature sensors' value. All shows the same. (engine temperature, radiator temprature and outside temprature)
How did I understand thermostat was failed?
I’m following the blocks in group 130 and 131 in engine group in the VCDS.
Check reference: http://www.ross-tech.com/vag-com/m_blocks/130-137.html
Group 130 Map cooling
Block 1: Engine outlet Temperature [°C] --> The real engine temperature
Block 2: Radiator outlet Temperature [°C]
Block 3: Thermostat Duty Cycle [%]
Block 4: Test ON/ Test OFF/
Group 131 Map cooling
Block 1: Temperature Engine outlet [°C] --> The real engine temperature
Block 2: Temperature Engine outlet (specified) [°C] --> ECU tries to keep engine at that temperature. According to engine load, it changes. if load is low or normal, it keeps at 109.5 C or 105 degree. If load is high, then tries to keep at 94.5 or 90 C degree.
Block 3: Radiator outlet Temperature [°C]
Block 4: Thermostat Duty Cycle [%] --> how much thermostat is open. If engine temperature is bigger then specified engine temperature, it opens according to difference.
(I wrote what I undestand from Blocks values. Please correct me if I misinterpreted something.)
-In the first failure, temperature gauge went up in the high way from 90 Celcius degree to 130C. Also, engine was 125 C.
-In the second failure, temperature gauge goes up from 90C to 95C, after awhile down again to 90. I was following from Vagcom, Engine Controller tries to keep the engine at 109.5 C degree. But, the temperature gradually was going up from 109 to 118 C degree although thermostat looked open(duty cycle more than %70, radiator temprature about 50C. the weather was very hot, about 40C ). Then, duty cycle %100 and fans start to run and temperature goes down to 105C. Thermostat is map-controlled thermostat.
-And now, the third failure, gauge is constant at 90C. When I check on the VAGCOM, ECU tries to keep engine at (Group 131,Block 2 value) 94.5 C degree. but, engine temperature is moving between 94,5 and 99 C degree. The season is winter, radiator temperature is between 10 and 20 C degree.
Another problem is that fuel mixture is going lean when temperature is goes up. If the engine temprature is bigger then the specified value for awhile, ecu makes the mixture lean. In VCDS Group 33 Block 1, lambda value is more than 10% , generally 15% or 17%.
What is the problem? Please help me how to detect or solve this problem. Is it thermostat or Cooling temprature Sensor or something else?
Thanks for your kindly help.
Burak
I have VW Bora 1.6 BFQ engine with automatic transmission(model year 2005). 208.000 km.
About 1 years ago, coolant was leaking from thermostat house. So, I changed thermostat house with thermostat and temperature sensor. I bought it as OEM part from VW.
Then thermostat was failed 3 times until now.
In the OEM part, “Mahle Behr” was written beside VW Audi logos.
It failed in 3 months. Then, I changed only thermostat with aftermarket Mahle Behr part. It failed after 7 months. Again I changed it with mahle behr one more time. It's been 3 months. Then it failed agin.
3 failed thermostats in one year...
The coolant is G13 antifreeze %50 mixed with water.
In the morning, I check the all temprature sensors' value. All shows the same. (engine temperature, radiator temprature and outside temprature)
How did I understand thermostat was failed?
I’m following the blocks in group 130 and 131 in engine group in the VCDS.
Check reference: http://www.ross-tech.com/vag-com/m_blocks/130-137.html
Group 130 Map cooling
Block 1: Engine outlet Temperature [°C] --> The real engine temperature
Block 2: Radiator outlet Temperature [°C]
Block 3: Thermostat Duty Cycle [%]
Block 4: Test ON/ Test OFF/
Group 131 Map cooling
Block 1: Temperature Engine outlet [°C] --> The real engine temperature
Block 2: Temperature Engine outlet (specified) [°C] --> ECU tries to keep engine at that temperature. According to engine load, it changes. if load is low or normal, it keeps at 109.5 C or 105 degree. If load is high, then tries to keep at 94.5 or 90 C degree.
Block 3: Radiator outlet Temperature [°C]
Block 4: Thermostat Duty Cycle [%] --> how much thermostat is open. If engine temperature is bigger then specified engine temperature, it opens according to difference.
(I wrote what I undestand from Blocks values. Please correct me if I misinterpreted something.)
-In the first failure, temperature gauge went up in the high way from 90 Celcius degree to 130C. Also, engine was 125 C.
-In the second failure, temperature gauge goes up from 90C to 95C, after awhile down again to 90. I was following from Vagcom, Engine Controller tries to keep the engine at 109.5 C degree. But, the temperature gradually was going up from 109 to 118 C degree although thermostat looked open(duty cycle more than %70, radiator temprature about 50C. the weather was very hot, about 40C ). Then, duty cycle %100 and fans start to run and temperature goes down to 105C. Thermostat is map-controlled thermostat.
-And now, the third failure, gauge is constant at 90C. When I check on the VAGCOM, ECU tries to keep engine at (Group 131,Block 2 value) 94.5 C degree. but, engine temperature is moving between 94,5 and 99 C degree. The season is winter, radiator temperature is between 10 and 20 C degree.
Another problem is that fuel mixture is going lean when temperature is goes up. If the engine temprature is bigger then the specified value for awhile, ecu makes the mixture lean. In VCDS Group 33 Block 1, lambda value is more than 10% , generally 15% or 17%.
What is the problem? Please help me how to detect or solve this problem. Is it thermostat or Cooling temprature Sensor or something else?
Thanks for your kindly help.
Burak