Hi everyone, I’m new here but I’m trying to salvage my ‘05 Volvo S40. The check engine light came on about two months ago, I went to the local auto shop and they told me it was a gas cap issue. I’ve since purchased three gas caps (all Volvo brand) that haven’t cured the check engine light. Another big issue is the car makes a grinding noise when accelerating and it’s scary to pull out into traffic because the grinding makes accelerating harder, once you are at a steady speed it stops. It also rumbles horribly when it’s in park.

I have have an appointment to get it looked at coming up. But does anyone have an idea of what it could be?

 

1. on the check engine light - if the first gas cap didn't cure the code, no reason to think the cap is the cause. The shop read the fault code for an evap system leak (such as a P0457 code but you should have the shop read the code and write it down then clear it to see if it returns ) but there's other causes like a torn or cracked vacuum line going back to the evap cannister. Once you know the exact code, you can google around or check out Youtube for possible causes.

2. As to a grinding noise when accellerating, its tough to say exactly what without hearing it or looking around. Does it sound different turning left or right? is is a deep rumble or a chatter/squeal? Does the noise happen if you quickly rev in neutral? Does it change pitch with roadspeed? Possible causes can be the drive belts (aka serpentine belts), pulleys or components, motor mounts, axle shafts/CV joints (inner or outers make different noises when turning), wheel bearing. you didn't mention if you have an automatic or manual but given it rumbles in park, I'd be thinking along the lines of motor mounts, or possibly an internal engine component.

 

I agree with mt6127 about the gas cap not being the problem - get the actual code, and it'll most likely point you in the right direction. Just a rant, but the federally-mandated evap systems probably cause more pollution due to the manufacturing of all those otherwise unnecessary parts, and the driving around trying to fix the many problems they create). ;-)

I'm betting that the other "big problem" is nothing more than a bad motor mount - the symptoms fit perfectly. Just have someone (who you trust!) cycle the transmission through R-N-D and back and look for how much the engine rocks. With luck, you'll see the movement at one of the easy-to-get-to mounts.