Car will not reach operating temperature

jbourke367

Well-known member
Joined
Aug 10, 2014
Location
South Shore, MA
TDI
99.5 Golf TDI
Hey guys,
I have a 99.5 Golf TDI. The car will not reach operating temperature when driven. I have just replaced the coolant temperature sensor hoping that this would fix the problem. However, the car still runs cool. I am running about 30% cooler than the normal operating temperature of 190. The car is tuned with the EGR cycle removed. I have also deleted the EGR cooler and EGR valve with a racepipe. I am not sure where I should go from here to troubleshoot this problem. Thanks.
Josh
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
I agree it is likely the t-stat. Don't use a generic one if possible. I learned the hard way with the same problem that went upside down on me. Car was cold, changed t-stat, all was well and then shortly after that my car starts to overheat. Knowing it couldn't be the t-stat because it was new, (sarcasm) it became a very expensive trip to the shop to find out it actually was the "new" t-stat I had just replaced was stuck shut.
Just because the part is brand new, don't forget humans touched it and humans aren't ever perfect, so a new part can die early sometimes. In my 30 plus years of messing with cars I have only seen two bad t-stats, so it hasn't happened to me often, but it has happened more than once. Good luck and keep us posted, will you?
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Yup, the Bentley recommends testing 'em in a pot of boiling water... and that's great advice for brand new ones as well.
 
Top