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Volvo S70 has weird humming/buzzing noise when idling!

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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mikey4040
Posts: 14
Joined: 3 August 2011
Year and Model: 1998 Volvo S70 GLT
Location: MA

Re: Volvo S70 has weird humming/buzzing noise when idling!

Post by mikey4040 »

The Search Is Finally Over!

Found the problem it is a vacuum leak. Right under the thermostat housing a little bit in the back there is a black hose it runs behind the manifold the hose itself split a little a tiny bit and it's causing the noise. I was fishing around the engine with the car running today had a large screwdriver and i was moving all hoses around and when i moved this specific hose the noise changed pitch and then i moved it a little more and then it stopped. Problem is the hose is very hard to get to to properly replace it with a new one without removing the power steering pump and thermostat housing there is just no room for hands. I noticed if i push on the hose either up or down very lightly the noise stops so I'm going to use a tie wrap a long one so i can maneuver it in the tight space and around the split area of the hose and zip it up this will shut up the noise by closing the split and keeping it like that it's a small split. You could probably use some heat resistant silicone that hardens to but I'm going with a wrap tie the other end of the hose is being held on with a wrap tie so i know it will hold up to the engines heat. It did not cause the check engine light to illuminate and no performance was 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 I'll be happy with a patch. Thanks for all the advice i appreciate it. Does anybody even know what the hose i mentioned is? :D
Last edited by mikey4040 on 05 Nov 2011, 17:08, edited 2 times in total.

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rspi
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Year and Model: 850 T-5R Wagon
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Post by rspi »

Dude, I asked you about all of that oil on top of your motor over on Volvo Forums. That is your PCV system tubing. You will have to replace that system ASAP. Treat it like your timing belt is about to break.

To replace the PCV system you will have to remove the intake manifold. You are only the 2nd person I have ever heard of that actually had broken tubing to that oil box under there. Here is a link to a thread for it over on Volvo Forums:
http://volvoforums.com/forum/volvo-850- ... ers-18639/

The PCV system is probably the most neglected system in these cars and can cause damage equal to that of the timing belt failure, especially if it blows your RMS.
'95 855 T-5R M, Panther - 22/28 mpg, 546,000 miles
'95 955 T-5R Yellow Wagon, Lemonade, 180,000 miles
--------------------
Volvo's of past: '87 740 GLE, '79 262C Bertone, '78 264, 960's, '98 S70 GLT, '95 850 T-5R YellowVolvo Repair Videos

mikey4040
Posts: 14
Joined: 3 August 2011
Year and Model: 1998 Volvo S70 GLT
Location: MA

Post by mikey4040 »

I told you on the other forum you probably didn't read it yet that picture is NOT my car. I just used it because it showed the exact area of the noise but again it's NOT my car in the picture mine doesn't have oil like that my engine is pretty clean. Thanks for the advice though.

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rspi
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Joined: 5 November 2011
Year and Model: 850 T-5R Wagon
Location: Cincinnati OH
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Post by rspi »

Good. However, if your PCV system has hoses in that condition you should do the system ASAP.
'95 855 T-5R M, Panther - 22/28 mpg, 546,000 miles
'95 955 T-5R Yellow Wagon, Lemonade, 180,000 miles
--------------------
Volvo's of past: '87 740 GLE, '79 262C Bertone, '78 264, 960's, '98 S70 GLT, '95 850 T-5R YellowVolvo Repair Videos

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