68k miles, 05 S60 2.5T
Vibration/rough at idle only. Otherwise the car runs very strong. I have just put in brand new Volvo spark plugs. During the rough idle, it almost sounds like the bassy noise that a diesel garbage truck makes when it stops next to you. Can it be the coils? I believe 2 out of the 5 coils have been replaced by the previous owner from the looks of it when comparing all 5. I have also cleaned the MAF.

 

Unplug the coils one at a time. If a coil is good, you'll notice the difference immediately. If it's bad, there won't be any difference. Replace the "no-difference" coils, if there are any.

HTH,

Lynn B.

 

Thanks, I'm going to give that another try. When I did it the first time, the coils didnt make a big difference when I unplugged them one at a time.

 

From my experence there will be a trouble code/check engine light and it will even tell you which cylinder is not firing. I'd guess idle-up solenoid or carbon buildup. I'm willing to bet they need to clean the carbon out of the engine. I run STP carbon choke cleaner through the engine while its running. I pull the intake hose out a little and stick the spray tube in and blast away while its running and opening the throttle. I'll run 20-40% of a can if its never been done before or not done in some time. I find carbon build up is often the cause of ruff idle. If its never been done, I take it slow and spay a little at a time. If you dislodge a large chunk of the carbon you might stick a valve open and your looking at more issues. Slow and steady is key. Your looking to eat away at the carbon build up not get it all real quick which is where you will mess up your engine.

 

I agree with Neotype33, my car ran rough and would stall...it ended up being the oil seperator/breather box....I would caution using the carbon cleaner, the oil seperator/breather box only cost $70 and will insure your car runs better...if you remove the manifold look at the oil seperator/breather box and see if it is built up with carbon it so, just replace it!

 

Well I only ran a bottle of injector cleaner which might have helped out slightly. I have had this car for only 2 weeks so appearantly, the vibration I'm feeling is normal since these engines are not as smooth as v6 engines according to a Volvo specialist. I'm getting 35mpg on the hwy so I think the engine is running above par. Any thoughts or comments regarding the vibration to being normal for these 5 cyl engines?

 

the vibration is not normal, check your tires and see if they are cupped? that could be a reason that you feel a vibration it's not the engine as this so called Volvo specialist is implying, it could be anything from the ball joints to the tie rods or anything tied into the steering! it is hard to say but it is unlikely that the engine is causing the vibration unless your car is running ruff! keep us posted on anything you find out and good luck

 

Will do. It only happens when its at idle. So I doubt tires are the culprit. I noticed that the cross brace that holds the upper engine mount tilts back and forth fairly easily. But then again its held on by rubber mounts so that might be normal.

 

well since you said it only happens at idle it very well could be that one of your engine mounts is bad...good luck and repost letting us know if you found out the problem!

 

I think you are feeling the vibration of the 5 cylinder...I know at idle it's much rougher than even the 5.3 V-8 in my truck. But it smooths out quickly and runs at 2000 rpm much softer than the V-8.

 

Yup, excatly. As soon as it starts moving, it runs perfect. I think the 5 cylinder odd number makes it rough? I'm getting low 30 mpg.

 

With 68K miles I would check/replace the upper engine mount and the lower transmission torque mount.

Lower:
Volvo Torque Rod (850 C70 S70 V70 S60 XC70 S80 XC90) Hutchinson 30680750 | FCP Euro

Upper:
Volvo Torque Rod Mount - Hutchinson 30680770 | FCP Euro

Very easy to change both of them. One tip is to have someone put it in gear then tighten them to the proper torque.

 

Neotype33 is on the right path
However i would see if you can pull any codes from the ECU first.
If none are present, look at the live data make sure you have good/correct readings from the Engine sensors.

The first question i would ask a customer is , When was it serviced last and by who?
Was everything you paid for actually changed and serviced?
Never go by the service history or the word of you garage;the things i have seen ("technicians" do) to save a £ is unbelievable.
Until someone listens to the bassy noise themselves and can diagnose a problem from it,we might as well guess all day long.

Bad idle is usually 1 misfire - unusual if it pulls well,over idle
2 bad fueling - to much or to little air - leak or blockage in system
3 faulty engine sensor - covered this with a plug in
4 Mechanical wear of a component/ sensor-failing e.g EGR MAF CPS Big ends ??? - would usually give you a fault code. not always, this is why you need to plug it first in and determine if it has any stored codes!
round and round we go!
There are to many scenarios why a motor has a problem.
Never assume, there is always a reason.

 

I just ordered the mount tonight from fcp. I noticed my lower rod was easily moving left to right. I doubt that is normal??
This is not a trick question, do I put the car in drive or reverse when I tighten them? If you think about it, reverse makes more sense as it gets rid of the slop in the correct orientation.

 

problem fixed by 70%, it was the upper mount and lower mount. at 68,000 miles, both upper and lower mounds were not in good shape. maybe it's because the rubber is old since mine is a 2005 model. thanks to all those that help me out.

The reason why say 70% fixed is because there is still a slight vibration but that might just be from the nature of 5 cylinder engine.