Hello All,


I haven't been on in a while due to my 2001 S40 running great with all the help from all of you in the past. I've come across a situation recently that I just cant figure out. So acceleration is fine up until I hit highway speeds. Anywhere from 60-75 MPH on the highway, the car shakes. Very noticeable during acceleration and keeping steady uphill as well. I've read multiple items online and it can be a anything from electrical to tires. I've replaced both ignition coils, and all spark plugs. Seems like the vibration isn't as harsh, but still there. I'll be getting my tires balanced tomorrow morning as well. Besides the engine mounts, what other items could cause shaking during acceleration between 60-75 mph? Also, every day it's different. Some days it's 65-70, some days it's 60-70. I hope the balance of tires fixes it. Crossing fingers!


Thanks again for being the best Volvo forum around!


Chris

 

Check the lower control arm bushings and the CV joints. Even if the CV joint boots aren't leaking, the joints can wear.

 

If they are the CV joints wouldn't there be issues turning such as clicking noises? Also would it only shake during highway speeds or all the way through the acceleration range and not just 60-75 mph? Thanks again for the additional information!

 

Clicking is one symptom of a bad CV joint. They can also get loose from wear. I believe the passenger side has an intermediate shaft with a bearing in the middle that can get loose too.

 

I've had that issue. More specifically, mine would vibrate on acceleration beginning at about 45mph and up. As soon as I eased off the gas the vibration would go away. No trace of any vibrations on braking (either hard or soft).


I got tires rebalanced first, I had previously done an alignment check so didn't do that. I then replaced the passenger side CV joint and vibration is gone. I did not buy new, instead, just bought one from the local junkyard and slammed it in. All good. At higher mileage, the replacement of the passenger side CV joint seems to be pretty common. The drivers side last longer. I had no clicking - I'm thinking that clicking only happens when the outer bearing fails not the one half way down the shaft.


I would be inclined to go with a used Volvo CV joint instead of getting a cheap new one. Read too many stories of those vibrating again after 20,000 miles.

 

Thank you so much for the additional information. The Dealership is going to check and stated they'll replace for 175 at the most, along with me purchasing my own part. I've read about vibration too with aftermarket parts, however, is there a specific aftermarket one they're talking about? I use Rock Auto and would like to purchase an aftermarket one since it's cheaper, however, don't need the vibration after 20k miles either. Also, should I purchase both driver and passenger side parts and have them install at the same time? Wouldn't want to put a new one in and then the other side have issues within a month either.

 

I can't speak to brand differences but if it's convenient and the price is right, give it a go.


I would not bother to replace the other side. You will not need an alignment or anything after replacing the passenger side so no real savings in doing both anyway.


Good luck. BTW $175USD seems a bit high given that all that is involved is:
1) loosening axle nut while car is on ground
2) popping wheel off
3) removing intermediate bearing bracket (2 bolts)
4) taking axle bolt off and turning wheel to make room for axle removal
5) pulling axle out of hub
6) prying axle out of transmission
putting new axle in, etc.


What's their hourly rate?

 

Thank you all. Apologies for the delay. I believe their rate is $120 an hour? I only paid 140 for the labor so it was a little bit over 1 hours time for them. They did say the part I purchased was a really nice one. Especially for aftermarket. So..another issue arose. The fan works great when I first start the car. Then when I take my kid to school, and drop him off, when I get back in the car to start it, no fan blowing air. After driving for a bit, it'll kick on. Would this be more of the fuses causing issues, or the fan itself? While the fan is not blowing, when I change the fan settings from low to high, i can hear a click towards the higher range, I believe between 3-4. Does that mean the fan is going out since it's trying to engage it? Also, how easy is this to replace?

Again, thank you all for your help. It's been greatly appreciated since I've had my 2001 S40 since Oct 2000. I know it's an older car, however, it's been the first car I purchased and want to keep it maintained for as long as I can, especially since the MPG is awesome and I drive 120+ miles daily for work.

 

The fan issue is normally the blower motor resistor. The usual symptoms are the fan works on high setting but not on the lower settings. It's located behind the glove box, inside the ducting between the blower motor itself and the cabin air filter. If you are handy with soldering you can remove the transistor and replace it with one bought online since Radio Shack is pretty much no longer to be found.

Anyway, the blower motor resistor as purchased from Volvo. The heat sink part is inside the ducting and the black plastic part is outside and holds the whole unit in place:


The 2N3055 NPN transistor separated from the heat sink and electrical hookup:

 

Thanks for the information! I'm handy with soldering, however, no solder or soldering gun in hand at this time. May just purchase a whole new resistor, then get a soldering gun and mess around with the old one at a later time. Also, I've read both the resistor and the fan are connected? Is this correct that I can pull both out at the same time? Also, should I change out the filters more since it's next to the resistor, which is housed in the duct? Thanks again Hudini for the information!

 

No the resistor is separate from the fan motor. The fan motor is in the right front corner up under the glove box. Now it should have an extra wiring harness attached between the original hookups because of a safety recall with the defroster. My 2001 has it.

The blower motor resistor is more toward the middle of the ducting. The cabin filter is just to the left of the resistor. If you have not replaced the filter then by all means do it. When my resistor first conked out years ago I found my cabin filter completely clogged with junk. I thought maybe the lack of airflow may have contributed to the death of the resistor.

To replace the resistor you first remove the glove box and the fiber kick panel below it. At this point you can easily see the resistor. However, there is a metal bar blocking the way. You loosen the metal bar at each end then gently move it enough to access the Phillips head screws holding the resistor. Disconnect the electrical connector, remove the 2 screws, and pull it free. Replacement is opposite of removal.

Working bent over the door sill is not fun. Bring knee pads or maybe an old pillow to protect your knees. My ribs are always sore whenever I have to do stuff like this.

 

Hey Guys. Me again. And you are right, knee pads or an old pillow does help a lot. Kind of weird after looking around behind the glove box that they couldn't place it horizontal instead of vertical. Anyways...the resistor is replaced, still no air blowing. I know the ECC still works because while driving down the highway I can move the temp to hot or cold and the air coming in during high speeds is what I set it too. Also, the way I can change it from blowing to feet, to just vents, etc. Any ideas? FYI, I checked the fuses in both the engine compartment and in the driver side foot well, made sure they were still good. HAHA. If it's not the resistor, time to change out the blower motor? Would that be the cause? Again, thanks for all the help you guys!

**Addition** The old resistor was dirty, but nothing I can see was actually coming loose. Will clean it up to have as a spare.

 

So it doesn't work on any setting? Check that you have the recall wiring harness between the original harness from the car and the original harness to the fan. There should be an extra harness with a bulge in the middle. The bulge contains the fix that the recall addressed which is the fan not working at times which may allow the defroster not to work when it's most needed.

You can also disconnect the fan harness and test for 12v from the car with a multimeter. I tested the fan itself by removing it and hooking up 12v and a ground.