JohFisch91

2007 Volvo S40 Experiencing Power Loss, Reduced Fuel Economy, and Unusual Engine Sounds: Potential Knocking Combustion Issue

Hey everyone, I've got a 2007 Volvo S40 with a gasoline engine that's just ticked over 178,881 KM. Recently, it's been doing some odd things - the check engine light flashed on, it feels like it's lost serious power, and jerks when I step on the gas. My fuel economy's gone down the drain too, and there's this strange noise coming from the engine that I've never heard before. It's kinda got me thinking it might be an issue with Knocking combustion in at least one cylinder. I'm not too keen on heading back to my last mechanic after a not-so-great experience, so I'm looking to gain some wisdom from you all first. Anyone had to deal with similar issues? What was your experience with your mechanic like? Thanks in advance!

(Translated from German)

4 comment(s)

Hey there! Your issue sounds a lot like my old 2010 Volvo S60 had. Had the exact same symptoms - power loss, weird noises, jerking motion, the whole shebang. Turns out, the issue lay with deposits in the combustion chamber. These deposits can seriously affect performance. It screws with the air/fuel mixture which in turn influences combustion. It might well cause knocking in the cylinders, like you suspected. In my case, the garage had to go in and manually clean that out. Quite a bit of work since they had to dismantle and then reassemble the engine components. Wasn't a walk in the park, I'll tell you that much. But once it was sorted, had no issues with the power or knocking. It was like getting my old, rock-solid Volvo back. So my advice, get thee to a trusted mechanic stat. This isn't something you want to wait out. Good luck!

(Translated from German)

Hey, thanks for the intel! It's funny how these ghosts from the machine just pop up, huh? Sounds like this could potentially be what's up with my S40 too. The part about manually cleaning out the combustion chamber sounds like quite the maintenance chore though. If you don't mind, do you remember what it cost you to get that sorted? And have you encountered any additional issues since then? Just trying to get my head around the overall picture. Thanks again!

(Translated from German)

Hey, no worries at all! Love to help a fellow Volvo owner out. I totally agree with you - car issues are indeed like gremlins popping up when you least expect them. Quite the mystery, all right. When it comes to the total 'damage', I remember shelling out a solid 425€ for the mischief - and that was to get those pesky deposits out of the combustion chamber. Not your cheap day out, but hey, it did sort the problem like a charm. Since then, no major problems! Especially, the knocking combustion in at least one cylinder, well, it's been as smooth as a baby's bottom. I haven't faced any of those terrible symptoms since getting it serviced. Overall, I'd say it was worth the cost considering I got my trusty machine back in order. I'd suggest you brace yourself for a small hit to the wallet but I guarantee you it's worth it. Keep us posted!

(Translated from German)

Hello, you're a lifesaver! Your insights are a beacon of hope for my ole Volvo and me. The cost gave me a mild heart attack, I won't lie, but putting my wheels back on track is priceless for sure. It's mostly about trust, right? And if spending that amount gets me rid of those gremlins, as you rightly put it, then it's worth every penny. I'm headed to a legit mechanic as fast as my limping S40 can take me. Thanks for all the guidance! Will surely return with updates (and hopefully a smoother ride). Until then, peace out my friend!

(Translated from German)

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