Spark plug replacement - 2015 GM Canyon 3.6L

[Wylie6G72]

I'd love to hear you guys' opinion on this quote. Sun Auto in Wylie, TX. They refuse to use my dealership -purchased AC Delco spark plugs.

Meanwhile, the transmission spill, filter & fill is $380 with my supplied GM filter and pan gasket. Eye watering coin for a spark plug swap, IMO. Thoughts?

 

[The Critic]

Book time is 3.2 hours.

Their labor rate appears to be $205/hr - which is an average to below-average rate in 2026.

 

[JayhawkRoy]

Just curious ---- what brand plugs do they propose?

 

[GMBoy]

That is on the high side. They are marking up the plugs 100% and that labor amount is very high and not the average for the DFW area in Texas. They don't even list required intake manifold gaskets and the whole "system diagosis/testing and test drive not included is plain sketchy. My shop would charge $570 for that job including intake gaskets, diagnostics and test drive to verify repair. This would be AC Delco plugs gapped correctly as well. We also clean the throttle body and MAF sensors, reset fuel trims and idle learns as part of the service. My shop is about an hour south of Wylie

 

[Wylie6G72]

Just curious ---- what brand plugs do they propose?

After denying me use of the AC Delcos I planned to provide, I thought he might put it on the estimate, but no. That's a question I'll have to ask later if I move forward with having them do it.

 

[GMBoy]

After denying me use of the AC Delcos I planned to provide, I thought he might put it on the estimate, but no. That's a question I'll have to ask later if I move forward with having them do it.

The part # he lists comes up as a Delco 41-107 spark plug which my commercial price from AZ is $12.32 each. His markup is insane robbery.

 

[GMBoy]

As a shop owner I can shed light on why the shop did not want to use your provided AC Delco plugs....they are responsible for the repairs and with all the counterfeit plugs running around I can see their reason not to. BUT! When a customer comes with dealer provided parts (and has receipt as proof) I will usually make an exception or price match them for me to use my plugs so I can give them the 2 yr parts & labor warranty. My price is still a few bucks less than what they paid so I still get a little profit, the save some money and I am ok with that for loyal customers.

 

[The Critic]

The part # he lists comes up as a Delco 41-107 spark plug which my commercial price from AZ is $12.32 each. His markup is insane robbery.

Not at all - their markup is industry standard.

https://partstech.com/parts-markup-matrix/

 

[grasscutter]

Automotive repair is a major racket. I thank God for my mechanical ability.

 

[PMT133]

It was about a 4 beer job on my 19. That doesn't include yelling at the dealer for selling me the incorrect plugs for my application.

I know the LFX is a little different but that's in line with quotes in the northeast and why I did it myself... where they typically try to bend you over.

 

[dogememe]

5339 spark plug? Looks be a Denso Iridium Power plug. I have nothing against Denso but this is NOT a stock replacement plug, it is a cheaper “performance” plug (competes with NGK’s cheaper Iridium IX I guess) and I would NOT want this in my vehicle.

I would not have approved this repair and would have taken it somewhere else.

 

[D60]

It may seem like a racket but by the time the shop pays payroll, utilities, insurance, an accountant, subscription fees, disposal services, shop supplies like brake cleaner and towels --AND THEN needs to have a good margin left over for profit .....well, it's really not that crazy.

Let's keep in mind the difference between the original quote and GMboy's is ~$283. I don't mean to be flippant about money but in 2026, $283 really ain't that much money.

If you like the shop and know they do good work, it'd be worth that $283. Now, it sounds like OP doesn't know them well and doesn't trust them, so in that case it's a bad deal.

And I agree I'm baffled by claims that a "road test" isn't included in the labor? What is that? A way to later charge you more if they test drive it? I try not to let anything out the door without driving for a few miles after I've worked on it.

 

[GMBoy]

Not at all - their markup is industry standard.

View attachment 340647

Not at all - their markup is industry standard.

View attachment 340647
https://partstech.com/parts-markup-matrix/

I understand that completely - you are right. I don't follow that at my shop for many reasons. I do understand that pays the bills for the bigger shops.

 

[GMBoy]

It may seem like a racket but by the time the shop pays payroll, utilities, insurance, an accountant, subscription fees, disposal services, shop supplies like brake cleaner and towels --AND THEN needs to have a good margin left over for profit .....well, it's really not that crazy.

Let's keep in mind the difference between the original quote and GMboy's is ~$283. I don't mean to be flippant about money but in 2026, $283 really ain't that much money.

If you like the shop and know they do good work, it'd be worth that $283. Now, it sounds like OP doesn't know them well and doesn't trust them, so in that case it's a bad deal.

And I agree I'm baffled by claims that a "road test" isn't included in the labor? What is that? A way to later charge you more if they test drive it? I try not to let anything out the door without driving for a few miles after I've worked on it.

All good points!

 

[GMBoy]

5339 spark plug? Looks be a Denso Iridium Power plug. I have nothing against Denso but this is NOT a stock replacement plug, it is a cheaper “performance” plug (competes with NGK’s cheaper Iridium IX I guess) and I would NOT want this in my vehicle.

I would not have approved this repair and would have taken it somewhere else.

When I checked by AZ numbers it showed AC Delco

 

[dogememe]

When I checked by AZ numbers it showed AC Delco

View attachment 340706

Interesting, but if you Google 5339 spark plug it shows Denso Iridium Power 5339 as a compatible plug for this vehicle?

 

[AdmiralYoda]

I have a 2021 GMC Canyon with the same engine. I'll be doing it myself soon but this isn't a super simple job like many 4-cylinders. A quick run down.

• You have to remove the engine cover, intake tube and PCV hose. Easy.
• For the passenger side there is an insulation cover over the valve cover that blocks access to the coils. You have to disconnect some harnesses clips and various hold down clips and disconnect some sensor harnesses to remove it.
• The intake manifold has to come off. A handful of bolts. Youtube is your friend here. Disconnect a couple sensors and a vacuum line.
• Remove the driver side valve cover insulation cover. Similar process to the drivers side.
• Then its simple. Remove the coils and replace the spark plugs.
• Leave the valve cover insulation and engine covers off! Or not. I hate them.

So there is a fair bit involved. 3.2 hours sounds reasonable to me. A well motivated and caffeinated tech who has done it 100 times can probably do it faster.

 

[drtyler]

Interesting, but if you Google 5339 spark plug it shows Denso Iridium Power 5339 as a compatible plug for this vehicle?

The close ups and description of the AC Delco plug on Rockauto show an iridium tip but a standard ground electrode. Much like the design of the Iridium Power 5339 plug.

 

[QwikKota]

Not terrible if the intake has to come off. I only have experience with the 2.5L "Iron Duke" in these trucks. Much easier.