You're correct that normal bulbs and "Long Life" bulbs are compatible and they can be interchanged freely.

The big difference is in bulb life, a normal 3157 bulb has a rating of 1,000 hours on the high wattage filament, and 5,000 hours on the low wattage filament.

A Long Life 3157 has ratings of 2,000 hours on the high wattage filament and 10,000 hours on the low wattage filament.

I'm figuring that GM specified the LL bulbs in locations where they are critical like signal lights since you don't want them burning out prematurely.

Thanks for your post!
 

I know this is years later but I was stuck at Walmart looking for my blinker bulb and once again HHR forum saved me a lot of time!

That's what we're here for, glad we could help.

Please Help, This is the Combat Zone :-) My light is out where the stick shift is (automatic) At nite when it's supposed to light up where the P R D 1 2 letters are it is dark- it went out the other day. Can you please tell me what bulb number goes in this
area. Also maybe you can tell me the best way to change it without breaking or shorting
out something. Thank You -- The Combat Zone

If you have the leather boot the bulb is part of the shifter. If not then it's the mood light in the headliner.

Search automatic shifter bulb and the first thread showed that there is a bulb somebody found one in his 2006 shifter.
It is a pain to find and change the bulb and there is no mention of the bulb number, mine burnt out 3 months ago it's on my to do list next spring

I just did a bit of research; the 2006 front turn signal (DRL) is listed as 3157 KX, and the 2011 front turn signal (not DRL) is listed as 3157 K. (Those are clear bulbs, some special edition cars use amber bulbs 5702 KA).

K means Long Life, X means High temp (can stand high temp, not is high temp).

There is a difference between 3157 and 3057, It is my belief that substituting is the reason some 2006 MY cars have melted DRL housings.

3057 12.8/14V 2.10/.48A 32/2CP (26.88/6.72W)

3157 12.8/ 14V 2.10/ .59A 32/3CP(P27/7W)

Try this web site they listed all the bulbs for my 2011 LT

light bulbs | Partsgeek.com

The shift indicator light bulb is a #37 mini push in bulb, for the automatic trans HHR

I made the mistake of just reading the 2nd post in this and assumed the fog lamp numbers listed were interchangeable. Turns out they are not. The correct one to use depends on year and or sub-model. Here is a breakdown on all of the lamps.

• ​High beam headlight and Low beam headlight: H13;​
• Fog light for 2006~2007 Chevy HHR: 9140 ; for 2008~2011 Chevy HHR submodel SS or SS Panel: H11 / H8 / H8LL / H11LL ; for 2008~2011 Chevy HHR submodel LS, LS Panel, LT or LT Panel : 9140
• Front turn signal light ( blinker light)/ Parking light: 3157 / 3157K / 3157-SCK
• Rear turn signal light/Brake Tail light: 3057 / 3057KX / 3157-SCK
• Back-up reverse light: 921 / 921K
• 3rd Brake light / Center high mount stop light: 921
• License plate light / Tag light: 168
• Interior Dome light: 578
• Interior Map light: 2825 / 2825L / W5W
• Glove box Light: 194
• Luggage compartment light: 212-2
• Auto Trans indicartor light: 37
• Front & Rear side marker light: 194