Winter Oil

[kraemerf]

Hi, I am a newbie here (in Michigan) with a 2003 GMC D/A CC 4x4...my first diesel.  I spend alot of time in northern Michigan and and northern Ontario where it gets pretty chilly at night.  This week, I am changing my oil and switching to Rotella T 5w40 synthetic for the winter.  Is there a problem going back to dino oil (Rotella 15w40) for spring through fall?  I'm not sure if it's bad to switch from synth to dino, then back again.

 

Last week, with temps in the 20s, I installed my winter cover - grill only.  I noticed that my outside temp guage (in the mirror) read about 9 degrees warmer than the real temp.  I assume it's because the sensor is behind the grill.  Anyone know where it is located on a '03 GMC and where I can relocate it?

 

Thanks in advance.

[maggot]

That is what I am planning on doing myself. I have done some research and I was told by my brand of oil that as long as you use the same brand you are OK. My brand claims the same add. package on both synthetic and DINO oil. Just a different base stock. As long as you change your oil at good interval you should be ok switching back and forth. Try and keep the same brand if you can.

[Diesel to the Max]

maggot, as far as the mirror temp gage, the sensor is located in front of the grill, hence the higher readings when the grill cover is installed.  Although mine appears to read correctly while running down the road, :thumb: but at idle, it does go up.  ??? A few of the people on The Diesel page relocate the sensor behind the lights:

 

See link below:

 

http://forum.62-65-dieselpage.com/ubb....=004840

[kraemerf]

Thanks for the grill cover link.  What does the temp sensor look like?  I don't know exactly know what I am looking for when I look behind the grill...