LM2 3.0 Automatic cool fill and Coolant air removal process

[Bubba10417]

Hi guys. I have a 21 AT4 with the 3.0 LM2 motor. I’ve had it a year with just over 30,000 miles and since new I rarely experience a slight coolant smell coming from the engine bay after it’s parked. I’ve read that some say it was the smell after regen and others say they’ve eventually found coolant leaks in different areas. I’m trying to monitor it as much as I can but it definitely smells like coolant. It was a bit low when taking it in yesterday to the dealer so I figured they’d top it off an I would monitor it a few times a week. When reading up on it I also read about the automatic coolant fill and air removal process in the 3.0 supplement. 
 

Is it necessary to run the automatic coolant fill and air removal process every time even a 1/2 inch of coolant is added?  My dealer didn’t even top off the tanks so I’m not happy so when I go back in  I surely do not trust them to do that. 
 

should I do it on my own? 
 

will it hurt anything by doing it if it wasn’t needed or if done too often? 
 

thanks for any help. I’m trying to learn as much about this vehicle as possible. 

[Bubba10417]

I do see that it says to do that if it is empty but is it needed for top off? 

[redwngr]

You do not need to do the procedure if just doing a top-up.

If the coolant level is low enough that air may have entered the cooling system it should be done to remove air.

It won't hurt it to do the procedure during top-up. 

 

Regen should not have a coolant smell.

On a new truck, the first few regens may be burning off oil/grease/overspray from the outside of the exhaust.

 

Some LM2's have been had issues with exhaust leaks, but that is a different smell than either coolant or grease/oil burn-off.

 

I'd recommend doing coolant level checks/top-ups on a cold engine. (and of course parked on a consistent slope, preferably flat)

Coolant expands when warmed, so then the question becomes  'how warm was it when checked"?  

 

If it's being checked at as part of an oil change service or when getting fuel -- observing the coolant tanks confirms they still have coolant, but it doesn't give an accurate indication of level.

If you chasing a small/slow leak -- then doing an 'accurate' check more frequently is important.