2025 GLC 300 – High RPM at Startup (Even When Warm)
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Joined: Nov 2025
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2025 GLC 300 – High RPM at Startup (Even When Warm)
I’ve got a 2025 GLC 300 (Petrol), and I’ve noticed it consistently revs quite high right after startup—around 1,400 RPM — and it stays like that (noisy too) for 2 minutes. This happens whether the engine is cold or warm, and regardless of outside temperature.
I haven’t seen this behavior in previous models I've owned, so I’m wondering if it’s a normal part of the newer engine management system or if I should push for a deeper look at the dealer.
Anyone experiencing the same?
I haven’t seen this behavior in previous models I've owned, so I’m wondering if it’s a normal part of the newer engine management system or if I should push for a deeper look at the dealer.
Anyone experiencing the same?
Member
Joined: Dec 2016
Posts: 84
Likes: 10
2025 GLC 300
This happens with my GLC and all the loaners I've driven. I have searched for an authoritative answer as to why but haven't found a good answer. I do seem to have more boost available from the mild hybrid though if I wait for the high idle to drop than instantly driving away.
Thread Starter
Newbie
Joined: Nov 2025
Posts: 2
Likes: 0
This happens with my GLC and all the loaners I've driven. I have searched for an authoritative answer as to why but haven't found a good answer. I do seem to have more boost available from the mild hybrid though if I wait for the high idle to drop than instantly driving away.
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Joined: Oct 2012
Posts: 583
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2026 GLC300 4Matic (X254)
My 2025 does it too. All my other cars did it only for 20-30 seconds. This one does it for like 2 minutes (if you let it). Nice thing is, waiting my normal 15 seconds or so and putting it in Reverse causes no lurching or clunking. Probably just a cold start emissions thing.
