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Nasty decelerating noise/grinding after resonator removed

10K views 21 replies 10 participants last post by  TonyGAudiS7 
#1 ·
Car: 2004 v70R GT

Driving to work today I got the rain squeal for the first time had the car about three weeks now. It had the stock exhaust along with the EBD. After work I headed over to a muffler shop and had them take the resonator out and weld in a straight pipe (wish I had a welder at house since I can weld…)

After they were done and I left the shop I was getting a loud noticeable rubbing or grinding noise also kinda sounds like trans gears grinding with no oil doesn’t sound good at all. Happened whenever decelerating or no accel load on drive train. I turned right around and went back to shop and they put it back on lift and we checked it and I couldn't find any rubbing. I even grabbed the exhaust and shook it around and lifted it up and couldn't find anything its got tons of room now??

So I left and listened to it all the way home which was a few miles. It's weird it instantly goes away when I apply a load to drive train with engine. I can two foot car and stop and it doesn't make noise while drive train is loaded. Also it drive fine under acceleration too.

It has me believing it could be a bearing in drive train or a universal in drive shaft?

You guys have any ideas of what it could be. I’m pretty bummed about it I’ve had car less than a month?

I got a warranty with car but it’s not a cpo car. I’m calling stealership tomorrow and make an apt to have it looked at. I hope pulling resonator doesn’t void warranty

Thanks for any help.

-Tim
 
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#3 ·
Maybe the exhaust is a slightly different length now so the motor sits in a slightly different position now that just so happens to make a noise. I'm gonna guess its a little bit shorter, so when the engine isn't under load, the exhaust is able to pull the bottom of the engine back just far enough so its touching something.
 
#4 ·
Well sorry for your trouble, that is a bummer. I have not taken the resonator off yet, but I will soon. Let us know what happens. The only thing I can think of is that maybe the problem was there in the first place and you did not hear it with the resonator attached. Dumping too much fuel causing a chain of backfires? Just an off the wall guess.
 
#5 ·
I can check motor mounts. When I bought car I checked top mount and it seemed alright I couldn't collapse it by hand or by leaning on it. The way the top mount it is i take it the motor torques backwards?

As for exhaust being a different length it could be but I checked the exhaust sitting on a lift with car running in neutral and moved exhaust around and lifted it up, it seemed fine had play didn't seem to be under any load or pushing on any rubber brackets beside just hanging from them.
 
#6 ·
Having it on a lift, where is the noise coming from. Front of the car, rear, middle?
 
#7 ·
No noise on lift no matter what I did too exhaust.

The noise happens when I left off gas and start to coast and decelerate and doesn’t stop till I’m basically stopped. I don’t think its exhaust because when it first started happing I put car in N and revved it and it had no effect on noise.

The car was on a drive on lift and it was pretty low and all they did was drive it on and drive it off so idk how they could off done something but it started as soon as I left. Wonder if they hit something with the sawzall they used to cut out resonator? I didn’t notice anything like that obvious so…
 
#8 ·
When the removed the EBD, did they put the bolts back in with washers?
If not, the heat shield might get pulled down when driving and rub on the prop shaft, then spring back up again when stopped. Not likely, but possible.

As you mentioned, another possibility is that they damaged something with the sawzall or during welding. I would have a closer look at the propshaft on the lift while turning it.
 
#9 ·
The engine is torqued in one direction under load and the opposite direction under deceleration, so it's possible that when you are decelerating, it's causing some part of the exhaust system to touch something. Or it could be a mount.
Definitely a strange one! :confused:
 
#10 ·
Thinking about what phuz mentioned about torque and my EBD bolt theory... When decelerating, the engine would torque forward causing the prop shaft to lift at the front end. If the heat shield is sitting low, it might indeed rub.
Hope it's that simple.
 
#11 ·
the EBD is actually still on car. I drove right there from work and didn't want to ask them to take it off since they would prob charge for washers I prob have laying in a bucket in garage so its still on and heat shields didn't look like they were sagging. I will be removing bracket tomorrow when I get home from work.

I went out and looked at top engine mount bushing and it seemed like in good shape. there was a little crack at bottom of it. i could barely get motor to move with me yanking on it.
 
#12 ·
Very strange that it only happens when you let up and decelerate. It has to have something to do with the movement when the motor is not torqued. If it was a trans or gear issue it should worsen when you step on it or at least stay constant. It is not likely an AWD issue as that would not be engaged when decelerating on good roads. That car made no noise when we test drove it and with under 50k and as babied as it was it surely was not beat on. Then you get a noise after the resonator is out, has to be related.

I think it has something to due with length of the exhaust or the torque on the motor mount and/or trans mount. My trans mount was worn right out around the bolt for the small bushing, it was sitting in metal with no rubber left. If it is pulling that metal to metal, it may be the culprit. You are almost at 50k and the car is 7 years old with the original round engine mount. If it was replaced by dealer it would be square now.

I would take in like you are planning and let them look at it. Mounts are cheap and easy, you can even go with stock replacements from tasca if you are worried about vibration. If it is exhaust length go back to muffler shop and have it redone. Which shop did you go to btw? It is just too much of a coincidence that this happened when you were leaving the shop.
 
#13 ·
I'm thinking it has to do with exhaust length and motor torquing. It has to be because car was driving fine before. Maybe exhuast is a tad shorter or longer and a mount besides top one is bad and motor is rotating more than normal and causing it to rub something.

You say a newer mount is square and does not fill entire opening in mount? if so the top mount on my car is a new one than. I couldn’t see the lower ones. if car doesn’t go in shop tmw i will jack it up and check the other mounts if you can even see them.

Man I hope if car goes in shop it won’t be in for long... I do not want to drive cobra if we are getting another snow storm plus that car hasn't seen winter in 5 yrs


I went to the meineke in Elsmere on Kirkwood hwy next to the VA hospital. I wish I had a damn welder I would have done it myself. All the more reason to get a little single phase mig now
 
#14 ·
Yeah go buy one and you can do mine. Lol.

I thought the upper engine mount was the round style as it looked just like mine. The trans mount has a larger and smaller bushing. The smaller of the two was stripped all the way out. The trans mount is very easy to see just behind the motor. You should replace both engine and trans mount at the same time.

http://www.ipdusa.com/Volvo-S60-P2/...per-Engine-Stabilizer-Mount/p-74-392-761-235/

http://www.ipdusa.com/Volvo-S60-P2/...rethane-Transmission-Mount/p-74-392-761-3330/

IPD shows the stock square mounts and then the old circular mount with their poly bushing. I thought the mount on yours looked like the round one. The round bushing in the round mount will have some light showing around the bolt through the center. They get brittle and shatter when you take them out. However I could not rock or move mine when I bought the car. You have to get it out before you can really tell. I would have to look at it to be sure, but I swear it was the old round style when we had the hood up.
 
#17 ·
Why? No one else has had to go that far.
I agree that the muffler shop may have gone a little nuts.
Sounds like it just needs a better look and a tweak.
( :cool: BUY THE WELDER! :rolleyes: ;) )

You might also take a shot at having someone
else drive and spock it out from the back seat.
Could help you isolate the source.
 
#18 ·
Well had the car up on jack stands and was checking over every inch of exhaust and didn't really find anything...

The only thing I did notice was around the bearing where driveshaft splits the heat shields were damn close to driveshaft and also if I shook the exhaust side to side it could make it hit pretty easy against the shielding. So I loosened some of the shielding that was closest to shaft and bend and pushed it out of the way as much as I could than tightened it back. Also took out the EBD and replaced bolts back making sure that shielding was tight and out of way of shaft.

I checked the bushings and they all seemed pretty good. The only that looked kind of worn was the lower tranny mount but it didn’t look too bad. I will probably replace that one and the top with the ipd poly units.

So after doing that took it down and went for a drive and it stopped making noise…???? I don’t know how but its quite now and beats the hell outa me.

A couple of things I noticed when under car I noticed the pass front axel is going. The boot lost its seal and shot grease all over the place. Some good news the angle gear housing is dry as a bone actually besides the grease the under of car is pretty damn clean. The exhaust bracket that holds the converter at end of down pipe looks like hell and almost rusted off won’t be surprised if that breaks.
 
#20 ·
Well had the car up on jack stands and was checking over every inch of exhaust and didn't really find anything...

The only thing I did notice was around the bearing where driveshaft splits the heat shields were damn close to driveshaft and also if I shook the exhaust side to side it could make it hit pretty easy against the shielding. So I loosened some of the shielding that was closest to shaft and bend and pushed it out of the way as much as I could than tightened it back. Also took out the EBD and replaced bolts back making sure that shielding was tight and out of way of shaft.

I checked the bushings and they all seemed pretty good. The only that looked kind of worn was the lower tranny mount but it didn't look too bad. I will probably replace that one and the top with the ipd poly units.

So after doing that took it down and went for a drive and it stopped making noise…???? I don't know how but its quite now and beats the hell outa me.

A couple of things I noticed when under car I noticed the pass front axel is going. The boot lost its seal and shot grease all over the place. Some good news the angle gear housing is dry as a bone actually besides the grease the under of car is pretty damn clean. The exhaust bracket that holds the converter at end of down pipe looks like hell and almost rusted off won't be surprised if that breaks.
I bet the heat shield around the propshaft was rubbing during deceleration. That propshaft moves up and down slightly as the engine torques. :)
 
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