I am planning to change spark plugs on 2011 Chevy HHR LT. She just hit 75k and I think it would be a good idea to do this service before hitting 100k. The manual is asking for the following:

Spark Plug Gap 0.040 in (1.01 mm) ACDelco 41-103 Professional Iridium Spark Plug

Amazon (https://www.amazon.com/ACDelco-41-10...ct_top?ie=UTF8) sells them mighty cheap right now, 2.50$ each with rebate. However, the website says the following:

Notes: DO NOT CHANGE GAP, Original Equipment, Gap .043

Any advice on this contradicting information about the spark plug gap?

Thanks.

 

DO NOT TOUCH THE GAP. GET ONLY 41-103.

41-103 comes gapped correctly and can be damaged trying to change. Other cheap plugs may have a different spec, plugs are different. Somebody may have fat fingers. Trust the box, not the internet typing skills.

Change them when you want to; but, the "book" says 100,000 miles. I have seen them last much longer.

From the Service Manual:

 

Here's a set of plugs and an air filter, send him a pm and an offer!

https://www.chevyhhr.net/forums/clas...8-parts-57574/

 

Engine valve cover is pretty dirty on my car. What would be the best way to clean it up before installing new plugs. I assume general cleaning with degreaser, brush, and pressurized water would be okay for engine bay with air filter still installed.

I would really dislike to clean the engine bay and leave all that dirt under the airbox.


(not my car)

 

Vacuum cleaner or shop air. Before you remove the plugs.

 

If you have neither you can get a can of that computer cleaner compressed air in walmart or anywhere else. It worked great for me both when replacing the solenoids as well as spark plugs. As for the plugs, I actually replaced all four a few months ago with those exact plugs and my HHR has been completely smooth since; I neither checked nor adjusted the gap. Mind you, the plugs I pulled out were the OEM plugs after 170K or so miles, so the AC delco Iridium are built to last; you might save some money for now and just wait a couple more years depending on your mileage. Also, I used this https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 because I was lacking a proper spark plug socket and it worked wonders. I would recommend purchasing it. Also, make sure you have a torque wrench with low end calibration; the spark plugs should be at 10 or 15 pounds I cant remember right now. I had never changed a plug in my life and the whole process took me about 45 minutes and that was with being slow and careful. Good luck!

 

I just came across this thread (https://www.chevyhhr.net/forums/prob...k-plugs-20198/) and it gives a few good reasons to change them way before 100k. A few members also stated to use anti-seize on threads when installing new ones.

 

Anti seize is a preference. I preferred not to as the plugs have a coating that prevents seizing already from the factory, at least as far as I read. They dont come from the factory with anti seize, and my factory plugs came out with little trouble after 170K miles on them. No stripping or breaking, and the metal doesn't get hot enough to "weld" together as some might suggest.

 

Anti seize compounds are typically composed of metallic,
electrically conductive ingredients. If anti seize compounds come in
contact with the core nose of the plugs, it can lead to a misfire condition.
Anti seize compounds can also have a torque multiplying effect when
installing plugs. This can lead to thread distortion and thread galling
resulting in cylinder head damage.

 

I've discovered that the older threads are more likely to have bad advice. The vehicles were nearly new, not many people had experience with them. Now more time has passed, we understand the vehicle better. Call it a learning curve.

With regard to antiseize, you ignore the manufacturers recommendations at your own risk.

15 lbs ft as donbrew quoted above. And that's not very tight, barely more than hand tight for me. But after heat cycles, they're pretty darn tight.