Jeep guy supporting wifes’ new GLC 300 coupe
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Junior Member
Joined: Sep 2025
Posts: 22
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From: Maryland
2023 GLC 300 coupe
Jeep guy supporting wifes’ new GLC 300 coupe
Hey,
My wife just purchased a CPO 2023 GLC 300 Coupe with 25k miles; it was a lease return. It is a very pretty car and her perfect shade of blue.
I am 100% a Jeep guy (I have 3: 1951, 1995, and 2013). I diy all my Jeep stuff from replacing the flooring in the 51 to changing the suspension and all the steering in the 2013. My wife is a big German car fan. This is our first Mercedes and her first 4 cylinder. I struggle with everything being a turbo 4 these days, but such is the way until you get to a level that I don’t want to pay for… lol
My first question is about the 10k/1 year oil change. This interval in a turbo engine is way longer than I am comfortable with. She purchased the maintenance plan and the tire/wheel plan. I plan to change the oil every 5k myself and let her take it in for the 10k interval. Her reputation for tire destruction is well known so the tire/wheel plan makes sense.
Anything we should be prepared for on this 2023 model year? Idiosyncrasies?
My wife just purchased a CPO 2023 GLC 300 Coupe with 25k miles; it was a lease return. It is a very pretty car and her perfect shade of blue.
I am 100% a Jeep guy (I have 3: 1951, 1995, and 2013). I diy all my Jeep stuff from replacing the flooring in the 51 to changing the suspension and all the steering in the 2013. My wife is a big German car fan. This is our first Mercedes and her first 4 cylinder. I struggle with everything being a turbo 4 these days, but such is the way until you get to a level that I don’t want to pay for… lol
My first question is about the 10k/1 year oil change. This interval in a turbo engine is way longer than I am comfortable with. She purchased the maintenance plan and the tire/wheel plan. I plan to change the oil every 5k myself and let her take it in for the 10k interval. Her reputation for tire destruction is well known so the tire/wheel plan makes sense.
Anything we should be prepared for on this 2023 model year? Idiosyncrasies?
Thread Starter
Junior Member
Joined: Sep 2025
Posts: 22
Likes: 7
From: Maryland
2023 GLC 300 coupe
Thanks! Great.... My 2013 Jeep Wrangler has always had potential head issues too. At least we have nearly 3 more years of warranty left before we need to decide to extend the warranty or switch cars. She lasts about 3 years and is adamant about buying 2-3 years old CPO low mileage cars. I hope this is not the first time she/we get burned...
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Joined: Feb 2021
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
Welcome. Nice Car!
If you’re a DIYer then don’t wait for 10k for an oil change. I think 5-6k miles is a good place to start, depending on how the car is driven.
You’ll get a range of varying opinions as far as frequency, but as a DIYer this is relatively easy to do and it’s fairly cheap. Not sure you can suck the oil out on that engine. You'll probably need to lift the car.
Don’t obsess on the head gasket issue, just like the 3.6L in the JEEPs that have head gasket issues….
Coincidentally , your post caught my eye because I have a friend who just lost a head gasket on a 2015 JEEP Wagoneer. About 60k mile. Perfect maintenance record. Their daughter has the exact same car. They got them together same day at the same dealership. Her jeep has 180k as she still commutes! No major engine issues whatsoever.
The reality is these manufacturers produce millions of engines, there are inherent weaknesses in designs. They will surface, but will rarely be higher than A FRACTION of a percentage of total production numbers. (LOL not sure about the 3.6L though
)
It can seem like a lottery, and intensified by a few dozen posts online from these types of failures. The reality is, there are ten’s of thousands of people happily driving their cars who never even visit online forums to rave about how great their car is, for every person who comes here with a blown engine story. I’m not saying it doesn’t suck if it happens to you, just pointing out the reality of the numbers and industry.
Enjoy and Happy Motoring
If you’re a DIYer then don’t wait for 10k for an oil change. I think 5-6k miles is a good place to start, depending on how the car is driven.
You’ll get a range of varying opinions as far as frequency, but as a DIYer this is relatively easy to do and it’s fairly cheap. Not sure you can suck the oil out on that engine. You'll probably need to lift the car.
Don’t obsess on the head gasket issue, just like the 3.6L in the JEEPs that have head gasket issues….
Coincidentally , your post caught my eye because I have a friend who just lost a head gasket on a 2015 JEEP Wagoneer. About 60k mile. Perfect maintenance record. Their daughter has the exact same car. They got them together same day at the same dealership. Her jeep has 180k as she still commutes! No major engine issues whatsoever.
The reality is these manufacturers produce millions of engines, there are inherent weaknesses in designs. They will surface, but will rarely be higher than A FRACTION of a percentage of total production numbers. (LOL not sure about the 3.6L though
)It can seem like a lottery, and intensified by a few dozen posts online from these types of failures. The reality is, there are ten’s of thousands of people happily driving their cars who never even visit online forums to rave about how great their car is, for every person who comes here with a blown engine story. I’m not saying it doesn’t suck if it happens to you, just pointing out the reality of the numbers and industry.
Enjoy and Happy Motoring
Last edited by crconsulting; Sep 23, 2025 at 02:06 PM.
Thread Starter
Junior Member
Joined: Sep 2025
Posts: 22
Likes: 7
From: Maryland
2023 GLC 300 coupe
Welcome. Nice Car!
If you’re a DIYer then don’t wait for 10k for an oil change. I think 5-6k miles is a good place to start, depending on how the car is driven.
You’ll get a range of varying opinions as far as frequency, but as a DIYer this is relatively easy to do and it’s fairly cheap. Not sure you can suck the oil out on that engine. You'll probably need to lift the car.
Don’t obsess on the head gasket issue, just like the 3.6L in the JEEPs that have head gasket issues….
Coincidentally , your post caught my eye because I have a friend who just lost a head gasket on a 2015 JEEP Wagoneer. About 60k mile. Perfect maintenance record. Their daughter has the exact same car. They got them together same day at the same dealership. Her jeep has 180k as she still commutes! No major engine issues whatsoever.
The reality is these manufacturers produce millions of engines, there are inherent weaknesses in designs. They will surface, but will rarely be higher than A FRACTION of a percentage of total production numbers. (LOL not sure about the 3.6L though)
It can seem like a lottery, and intensified by a few dozen posts online from these types of failures. The reality is, there are ten’s of thousands of people happily driving their cars who never even visit online forums to rave about how great their car is, for every person who comes here with a blown engine story. I’m not saying it doesn’t suck if it happens to you, just pointing out the reality of the numbers and industry.
Enjoy and Happy Motoring
If you’re a DIYer then don’t wait for 10k for an oil change. I think 5-6k miles is a good place to start, depending on how the car is driven.
You’ll get a range of varying opinions as far as frequency, but as a DIYer this is relatively easy to do and it’s fairly cheap. Not sure you can suck the oil out on that engine. You'll probably need to lift the car.
Don’t obsess on the head gasket issue, just like the 3.6L in the JEEPs that have head gasket issues….
Coincidentally , your post caught my eye because I have a friend who just lost a head gasket on a 2015 JEEP Wagoneer. About 60k mile. Perfect maintenance record. Their daughter has the exact same car. They got them together same day at the same dealership. Her jeep has 180k as she still commutes! No major engine issues whatsoever.
The reality is these manufacturers produce millions of engines, there are inherent weaknesses in designs. They will surface, but will rarely be higher than A FRACTION of a percentage of total production numbers. (LOL not sure about the 3.6L though
)It can seem like a lottery, and intensified by a few dozen posts online from these types of failures. The reality is, there are ten’s of thousands of people happily driving their cars who never even visit online forums to rave about how great their car is, for every person who comes here with a blown engine story. I’m not saying it doesn’t suck if it happens to you, just pointing out the reality of the numbers and industry.
Enjoy and Happy Motoring
I just need to source the filter, drain plug/copper washer, and figure out the proper viscosity oil. I change all the other vehicles oil that we have, so I have large storage containers for the used oil. Our dump takes used oil too, so I go every other month to empty them.
Amen to the 3.6 issues. I had an oil cooler issue early on so I've already swapped mine out for a newer revision of that part. Hopefully, I dodged that bullet. I don't worry about it and just enjoy it. That is the plan with this car.
I've been around long enough to understand the "forum effect" and not get too caught up in the sky is falling stories. Yes, there are failures, but our percentage amongst owners of what ever car forum we participate in is low. Just like mechanics only see problems so they can't really comment unless nothing ever comes in on a particular model.
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
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MBWorld Fanatic!
Joined: Feb 2021
Posts: 1,419
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
MBWorld Fanatic!
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From: Colorado
G550
Your OM should specify a MB oil specification such as "229.71". Go to https://operatingfluids.mercedes-benz.com/ and select "Engine Oil", scroll down to the "229.xx" sheet, select it, and a list of MB approved oil brands/formulations/viscosities are listed.
I do 5K/12 month (whichever occurs first) on every vehicle I own (doing my '95 Jeep today). It's my money to waste.
I do 5K/12 month (whichever occurs first) on every vehicle I own (doing my '95 Jeep today). It's my money to waste.
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Junior Member
Joined: Sep 2025
Posts: 22
Likes: 7
From: Maryland
2023 GLC 300 coupe
This should help:
https://operatingfluids.mercedes-benz.com
https://operatingfluids.mercedes-benz.com
Your OM should specify a MB oil specification such as "229.71". Go to https://operatingfluids.mercedes-benz.com/ and select "Engine Oil", scroll down to the "229.xx" sheet, select it, and a list of MB approved oil brands/formulations/viscosities are listed.
I do 5K/12 month (whichever occurs first) on every vehicle I own (doing my '95 Jeep today). It's my money to waste.
I do 5K/12 month (whichever occurs first) on every vehicle I own (doing my '95 Jeep today). It's my money to waste.
Don’t expect too much. It is mid restoration now.
Day I brought it home
as it sits now. I’m midway through replacing the floors. I’m a better grinder than welder.
Thread Starter
Junior Member
Joined: Sep 2025
Posts: 22
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From: Maryland
2023 GLC 300 coupe
The car sits at 25k now, so I want to change the oil and set my baseline going forward. It was a lease and maintained by the dealership, so the oil was changed 5k ago at 20. It is almost the perfect time aside from the fact that it was only changed 2 times since new!
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From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
In our C I change the oil at about 6k, sooner for my AMG cars and the GLS. I use LiquidMoly in all of my cars. I use only Wix filters...and, the cost of ownership of each vehicle is quite low....
Now, if you need a Jeep engine...the owner of this joint is a friend of mine..... https://titanengines.com
Now, if you need a Jeep engine...the owner of this joint is a friend of mine..... https://titanengines.com
Thread Starter
Junior Member
Joined: Sep 2025
Posts: 22
Likes: 7
From: Maryland
2023 GLC 300 coupe
In our C I change the oil at about 6k, sooner for my AMG cars and the GLS. I use LiquidMoly in all of my cars. I use only Wix filters...and, the cost of ownership of each vehicle is quite low....
Now, if you need a Jeep engine...the owner of this joint is a friend of mine..... https://titanengines.com
Now, if you need a Jeep engine...the owner of this joint is a friend of mine..... https://titanengines.com
As to needing a Jeep engine, the only one even sounding like that is the 4.0 in the 1995. It has piston slap that is common of the 4.0s from that era. At over 165k miles it is due, but it keeps running and I’ll wait until it lets loose before I worry about replacing the engine. It is an ice cream Jeep if you know what I mean. I appreciate the link to your friend’s company. It is always helpful to have recommendations. I’ll add that to my folder for Jeep vendors.
Last edited by jeep63; Sep 25, 2025 at 10:16 AM.
MBWorld Fanatic!
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From: Colorado
G550
I used LiquidMolly in her Porsche Macan S exclusively, so that is my go to for this car too. Where I still don’t have clarity is the viscosity. I’ve never seen so many different codes to represent oil. I’m used to 0w20 full synthetic, 5w30 semi-synthetic, or 10w20, etc…
As to needing a Jeep engine, the only one even sounding like that is the 4.0 in the 1995. It has piston slap that is common of the 4.0s from that era. At over 165k miles it is due, but it keeps running and I’ll wait until it lets loose before I worry about replacing the engine. It is an ice cream Jeep if you know what I mean. I appreciate the link to your friend’s company. It is always helpful to have recommendations. I’ll add that to my folder for Jeep vendors.
As to needing a Jeep engine, the only one even sounding like that is the 4.0 in the 1995. It has piston slap that is common of the 4.0s from that era. At over 165k miles it is due, but it keeps running and I’ll wait until it lets loose before I worry about replacing the engine. It is an ice cream Jeep if you know what I mean. I appreciate the link to your friend’s company. It is always helpful to have recommendations. I’ll add that to my folder for Jeep vendors.
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From: DFW
SL63
One of my regrets is that I didn’t get my Mom the jeep that she wanted.
Then she could have collected the duckies to line up along the dashboard shelf.
What is the ducky thing anyway?
I never have understood it.
Tourist attractions like Branson Missouri used to run charter cruises with amphibious all terrain modifications of the GMC CCKW and designated it the DUKW.
That is the closest I can come to a connection between the two.
At any rate, welcome to MBWorld.
Then she could have collected the duckies to line up along the dashboard shelf.
What is the ducky thing anyway?
I never have understood it.
Tourist attractions like Branson Missouri used to run charter cruises with amphibious all terrain modifications of the GMC CCKW and designated it the DUKW.
That is the closest I can come to a connection between the two.
At any rate, welcome to MBWorld.
Super Member
Joined: Dec 2015
Posts: 606
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From: Suburban Maryland
2023 E 450 Sedan. 2018 GLC 300. 2013 E 350 Coupe (retired)
Not sure if that year glc has the potential problem with oil leaking into the wiring from the magnetic cam position sensors. My wife's 2018 has been problem free. I hate the run flat ride, but the wife feels more secure with that tire. I used to have a six cylinder Sahara which got a lot of off road use when I lived in New Mexico. Great vehicle.
Super Member
Joined: Dec 2015
Posts: 606
Likes: 239
From: Suburban Maryland
2023 E 450 Sedan. 2018 GLC 300. 2013 E 350 Coupe (retired)
Not sure if that year glc has the potential problem with oil leaking into the wiring from the magnetic cam position sensors. My wife's 2018 has been problem free. I hate the run flat ride, but the wife feels more secure with that tire. I used to have a six cylinder Sahara which got a lot of off road use when I lived in New Mexico. Great vehicle.
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Junior Member
Joined: Sep 2025
Posts: 22
Likes: 7
From: Maryland
2023 GLC 300 coupe
My '95 4L is only at 70K miles, and the engine still purrs. Aside from replacing the RMS earlier this year, upgrading the plug cables and installing motor mounts that don't snap the bolts, I've done nothing to it except change the oil every 12 months (far more frequent than every 5K), and have used Mobil1 since day 1. Inasmuch as I use it for plowing snow, the drive train has been completely rebuilt, and I'm on my 4th clutch. But it's still the best $17K I ever spent.
One of my regrets is that I didn’t get my Mom the jeep that she wanted.
Then she could have collected the duckies to line up along the dashboard shelf.
What is the ducky thing anyway?
I never have understood it.
Tourist attractions like Branson Missouri used to run charter cruises with amphibious all terrain modifications of the GMC CCKW and designated it the DUKW.
That is the closest I can come to a connection between the two.
At any rate, welcome to MBWorld.
Then she could have collected the duckies to line up along the dashboard shelf.
What is the ducky thing anyway?
I never have understood it.
Tourist attractions like Branson Missouri used to run charter cruises with amphibious all terrain modifications of the GMC CCKW and designated it the DUKW.
That is the closest I can come to a connection between the two.
At any rate, welcome to MBWorld.
Not sure if that year glc has the potential problem with oil leaking into the wiring from the magnetic cam position sensors. My wife's 2018 has been problem free. I hate the run flat ride, but the wife feels more secure with that tire. I used to have a six cylinder Sahara which got a lot of off road use when I lived in New Mexico. Great vehicle.
