1998 Volvo S70 Repair Question
1998 Volvo S70 GLT has weird humming/buzzing noise when idling ****Videos of problem noise****
Link to thread-
Links to videos-
It sounds like a vacuum leak. Have you checked for that
No i have not checked for a vacuum leak. I could check that out tomorrow and see if i see any vacuum hoses around that area.
Check hoses, intake, throttle body plate... It sounds like a rubber hose to me, however. If you know how, use carb cleaner to check for the leaks.
If you do have a vacuum leak it could be an internal vacuum leak. Remove the oil dipstick and see if the noise goes away. If it does then you need to replace the oil trap box. Keep us posted please.
I tried to pull the dipstick out already as well as removing the oil cap. If you click on the forum link you can see the other advice forum posted and the things i already did and tried. Thanks for replies....
Ok then I believe your noise is coming from the piston cooling valve. Remove the serpentine belt and timing belt cover and run engine with timing belt cover off. The piston cooling valve is under the water pump area. It is a 17mm bolt I believe. If you do here the buzzing the noise from that area then replace the valve. Good luck to you and let us know what happens. To replace it you will need to remove the timing belt and water pump so see if you can get just the water pump gasket or if you need to do the whole water pump as well?
Found problem it is a vacuum leak like Jacobandnickolas mentioned. Right under the thermostat housing there a black hose it runs behind the manifold it split a little causing the noise. i was fishing around with a screwdriver moving all hoses around the engine and when i moved that the noise stop. Problem is the hose is very hard to get to without removing the power steering pump and thermostat housing. I noticed if i push on the hose slightly the noise stops so I'm going to use a tie wrap a long one so i can maneuver it in there and around the hose and this will shut up the noise. It did not cause the check engine light to illuminate and no performance lost so this should do the trick. To replace the hose with a new one will be a PITA to get in there without removing things. Thanks for all the advice i appreciate it.
Good job and thanks for keeping us posted to the fix.
I thought that is what it sounded like. Glad it's fixed. Let us know if you have questions in the future.