Coolant Temp Sensor

Rudolf Diesel

Veteran Member
Joined
Jan 25, 2001
Location
Western Pennsylvania
TDI
2006 Jetta
My car is having a start problem when the ambient temp is 30-40°F. The car hesitates and really smokes. It seems that the glow plugs aren't staying on long enough. Here is the catch. When temperatures fall to 10-15°f the car starts great. Could it be my coolant temp sensor? No CEL at the moment. Car is a 1998 TDI jetta with 121k.

Thanks Jeff
 

20ValveT

Veteran Member
Joined
Oct 4, 2002
Location
Canada
If you have a multi-metre you can test the coolant sensor to see if it is operating properly. Make sure to test the tothe connection to the sensor as well, I belive it should read 5 volts. I'm not sure on the sensor itself, I think its 5-7 ohms I'd have to look at the manual to be sure and then as the car warms up it should decrease. Email Gofaster he would be better able to solve this problem.
 

tdi_lamb

Well-known member
Joined
May 24, 2002
Location
Oshawa, Ontario
TDI
99' A3 Black Jetta TDI
Your symtoms are consistant with my starting problems this past fall. A $15 cdn temp sensor fixed it. It's not a hard job, but expect to leak some coolant when you pull the sensor out. Be sure to get the right coolant from the dealer.

tdi_lamb 1999 A3 Jetta TDI
 
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