Rattling noise at certain RPM

[volvo-driver :(]

Hey all,

I was recently given a '85 Volvo360 GL and have noticed a rattling noise when the engine is between 1800-2100 RPM. Or maybe the rattling comes from 1800 onwards but after 2100 the engine blocks the rattling noise, I dunno :banghead:.

I've checked the basics, has anybody else ever had this problem or have a solution?

Thanks in advance. If you need specs let me know.

[EK 2.0]

Describe if you can...Where is the rattling coming from??...and is it constant with the RPM or comes and goes...And what have you checked??

[africano]

yeah there are a lot of things that could cause this rattling

motor mounts
driveshaft
wheel balance
etc

see if you can figure out what's causing it
good luck

[volvo-driver :(]

It is constant with the RPM, once it hits approx 1800 it starts. It sounds like when you hit two marbles together and i'd say about 5 times a seconds. Once the engine hits about 2100 it either stops, or the engine noise is too high and muffles it.

I've checked stuff like the oil, petrol type, and a friend checked the filters and he said they're OK

[DonJuan]

"It sounds like when you hit two marbles together and i'd say about 5 times a seconds." If what your describing is pinging (AKA premature detonation) then it may be an easy fix. It could just be carbon build up in the cylinder. Is your volvo a turbo? Cuz most cars with turbos are biased to premium gas. Also if you car doesn't have many km's on it then it probably isn't build up and is sumthing else, like valve-piston contact, which is VERY bad!!! best thing to do is fill up with premium and run a good fuel system cleaner and injector cleaner setup. If that doesn't work take it into a shop Immedieatley before sumthin breaks.

[GTS Jeff]

^^^ a better way to describe detonation rather than "hitting 2 marbles together" is "rattling an pop can with BBs inside it"

[hjr]

a problem i had with my car was that it was the heat sheild on the exhaust and firewall were loose and it would rattle like that at certain RPM's. Check that out.

[ninspeed]

check all your exaust mounts (espically the ones that are metal on metal)... when i rebuilt rice cakes i forgot to hook up one of the exaust brakets that goes on the motor and it would rattle pretty bad...

[volvo-driver :(]

Ok all, thanks for the responses

I've researched carbon build symptoms and I think this could be the problem, will tell if it fixes it.