2003 Volvo XC70 Grinding sound on start up

Post by **GBS** » 24 Aug 2015, 15:39

Hey all, so I've been experiencing this for a while now and since my car hasn't had any repairs I'm starting to become bored having a fully working car

)

Anyways, my XC70 has this strange grinding sound after starting. I'm not sure how to explain it and sometimes there is no sound, other times its quite strong, it sounds almost like a diesel running and last for maybe a second or two. It also happens after ignition and my initial thought was something with starter when is winding down.

I've already replaced the starter and that didn't change anything, I replaced it when removing alternator so it was an easy job at the time. My next suspect is maybe the flywheel or perhaps transmission? I wish I could make a audio clip of it but since its somewhat random I haven't been able to. Any thoughts appreciated.

difflock54 · Post by **difflock54** » 24 Aug 2015, 18:49

I was going to suggest maybe a dry shaft affecting the starter unit bendix spring causing the starter drive sprocket to remain engaged with the flywheel for too long after engine fires up but I note that you have changed starters as well so unlikely that both units were in need of grease ???

Post by **GBS** » 25 Aug 2015, 08:05

thanks for the quick reply, that's what I was wondering too, like something is too slow to retract but eventually does. So I have no idea what goes on inside the flywheel beyond the starter, would looking into that require some serious dismantling of the transmission side? I might try to do a few starts to see if I can get this on tape or at least a location for the sound.

difflock54 · Post by **difflock54** » 25 Aug 2015, 20:07

Disconnect your battery, unplug the starter motor wiring and unbolt the starter motor unit to enable you to remove the starter unit from the vehicle for inspection.
Check the bendix spring and mechanism for free movement and apply some grease to the shaft if it appears too dry and the retraction movement seems restricted.
Then simply replace the unit and test to see if any improvement is noticeable.
You may need to confirm your radio security code after reconnecting the battery?
Make sure you have the code available should it be needed.
With a torch you may be able to visually assess the condition of the flywheel teeth whilst the starter is out which might confirm if the tips of the teeth have been damaged through slow or delayed bendix sprocket disengagement.
Minor signs are probably not likely to be an issue provided the problem is resolved relatively promptly.