Recently my 07 XC70 w. turbo, develop a symptom; it idle smooth, stepped on gas the engine rev up smoothly, but when drive the speed from 40m/h and higher, if I step on gas the engine(?) or trans(?) or drive axles(?) would vibrated, but if I ease up on gas the car would happily smoothly go along fine up to 70-80m/h no vibrating. Any body have any idea where is vibrate from? I appreciated any advice.

 

Wow, so many moving parts. An 07? So I'm guessing 120K miles? Give or take? The engine mounts esp the front one, that's the one on the passenger side under the crankshaft would be my first guess. Then the other bottom mounts. Then of course the passenger side cv holder needs a quick look see. I had a funny vibration on my S60 AWD with the prior owner trying to save a buck by going to one of those muffler shops. Turned out they installed a universal flexible section which didn't have the same curve as oem and was causing similar vibrations as you describe. Of course oem cost 1000 bucks for just the part, easy fix though. Is their anything stuck on the driveshaft's? All 5 of them? I had a lot of string from someplace get wrapped around the drive shaft once was a bugger to troubleshoot till I looked at the haldex coupling on the final drive. And finally could be a wheel bearing or loose bushing, sometimes with the changing geometry under acceleration these things show up. My comments about Volvo wheel bearings, any model or year. They work just fine,....they rarely ever fully self destruct and then it's a no brainer to find the culprit. I can't tell you how many times marginal bearings sit there annoying the crap out of me. AND guess what, when you change the bearing the vibration goes away. Heck of a way to trouble shoot isn't it? Think balancing your wheels more often, AT LEAST EVERY YEAR!!! Unbalanced wheels can marginally damage the bearings, and I don't care if the vehicle is on a lift or whatever you just can't tell when those wheel bearings are compromised. Totaled bearings no issue,...marginal, you find out when they gets replaced. Did I mention balancing your wheels more often? Good luck, let us know! (And this isn't the complete list.)

 

Thanks Chrisd111, Yeah, I bought the car with 177K, now it's 180K+, I want to check those things you've mention But how do you tell if it was bad?

 

With wheel bearings that haven't totally failed yet and you can't tell how worn they are by inspection or turning them by hand,...you kind of can't tell a perfectly new wheel bearing apart from one that promotes wobble or vibration or play!! This is the point with any wheel bearing but seems all the more so with these Volvos. YOU find out what you have been missing and or the issues go away when you change the bearings. Sorry most people don't want to hear this! As an example the wife's XC70 with 275K miles on it. She had some wheel vibration at speed, 65 mph. Everyone attributed it to tires that hadn't been balanced over time. And again truthfully after having the tires balanced some of the vibration went away. BUT WHEN THE WHEEL BEARINGS WERE REPLACED THE VEHICLE WAS AS SMOOTH AS SILK, AT 100MPH, NO VIBRATION WHATSOEVER. **** the dealer that said the bearings were fine.

The engine mounts are kind of the same idea, they actually can be measured for height, if you can get in there,...but mostly until they fully fail, and they will, you can't tell, ...until you change them and at 180K that front mount should be changed, it's an relatively very easy job, in fact this discussion cost more that actually just changing the front engine mount (the one under the crank pulley) at 150K the front engine mount should be changed and to all those asswipes that say don't fix it unless you can prove its broke,....well go ****e in your hats, the mount should be changed, period.

CV axels, the main drive shaft in an awd, yup you guessed it,...you got vibrations, there on the list to be changed as well. Remember the main awd drive shaft has a very flimsy rubber mount, which is subject to abuse, which holds a bearing, have the thing removed and sent it to Colorado drive shaft to be rebuilt, just because you can.

Replace these common culprits starting with the engine mount first, be systematic with parts that change geometry under acceleration, over time, you will eventually find "the" culprit. This is all covered under maintenance, these parts all wear at different rates , starting at 150K they all should be on a list to be replaced anyways.

And again this idea of waiting for a total failure or the respective part to fully fail, is just the wrong way to think. Replace your shocks before they fail,...everyone knows at 75K shocks are on the list, no arguments. But when it comes to all the other moving parts???? Wait? Why wait. No different than any other vehicle.

You will save in the long run, your Volvo will still be running strong as compared with every other vehicle that will rust apart and not be repairable any longer.

These forums are for people that take some pride in fixing their own vehicles and making them last, you want perfection then buy a new vehicle every five years and let some one else fix them.

Good luck, let us know what happens,...

 

Thanks Chrisd111, the problem was solved, finally the check engine light is on, OBD said Misfire cylinder 1, I replaced the ignition coil, the light is gone, the car now run smooth as new, it speeded from 30 all the way up to 100mph without a hick up, I'm very happy now, with most of needed services done, next is timing belt ( it's still look good, but not know when it was replaced) and right side drive axle leaking grease, then it'll be good for awhile.

 

After replaced ignition coil the car run good for a week, then when I got on the highway steped on the gas it went smootly up to eighty about two minute the engine start hesitated and lose speed, pressed on gas it's start vibrate and slowed down, check engine light blinking, I ease on gas, it rumbling and pick up speed slowly, I park the car and turn the engine off for five minute, start the car and drive home, engine run rough check engine light on and stay. I scan the engine OBD said multiple missfired and all five cylinders missfired. Temperature was dip down teensI didn't drive the car for few days, when I start the engine still not smooth but not as rough as before, try to drive on the hiway I ease up on the gas, the car moving along fine up to seventies. Because I bought the cat had 177K miles,I don't know when the timing belt was last replaced, I order new timing belt waiting for warm weather day to replace it.
OK, the day I'm waiting is here, it will be 60'. After removed timing belt I notice the water pump look new, the tensioner look new, the idler pulley still tight no play, chech the old belt it look almost as good as the new belt, now I noticed the writing on the fuel injection rail faded but readable, TB 164,505, I saw it before but never have a thought about it, now obviously the timing belt was replaced at 164+K miles, only more than 12+K miles before I bought the car. Put every thing back, reset the tensioner to warm setting, tight it up good. I take a short test drive, the car run so sweet ( atleast for now, will do a longer drive tomorrow), If every thing stay Ok from now on; my cnclusion is when they replaced timing belt, the mechanic didn't tight the belt tnsioner tight enough, the belt loosen out slightly off the timing, make the car run rough and mkssfire. Hope it's good till next timing belt change.

 

Well today I took the car out and pushed it hard, it happyly speed up to 100mph, but on the way back the check engine light is on, idle is little rough still, replay #5 ignition coil, take another test drive, all is well and strong, idle is smooth and queter.