Hey everyone,

I have a 1987 240 DL with about 145K miles on it. It is a 4-door with a 5-speed manual transmission.

My car started making a screeching sound, from somewhere near the rear of the engine today. The sound only happens when the engine is under a considerable load, and it seems to happen at 2000 rpm or higher. If it is coasting or not having to work hard, the sound does not occur, as far as I can tell. Once I put enough gas into it, the sound starts. It started when I pulled out of a parking lot, accelerating quickly to make it into traffic. Oil pressure is normal, but I am losing considerable power at highway speeds. To me, it sounds like a bearing failing.

So far, I've done a few things to try and narrow down the issue:

The problem happens even when the car is stationary. In this condition, I will get the sound if I gas it quickly enough, and it occurs at about 3000 rpm. This rules out the driveshaft bearing.

The problem happens even when the clutch is disengaged when stationary, so it doesn't seem to be in the rear portion of the clutch or transmission.

Something that may be relevant: I have had a rattling that I took for exhaust system rattle for about 2 days prior to this happening. It appears to have stopped when this new problem started. Another possible relevant issue: I adjusted the clutch yesterday, as the pedal was too low and I was beginning to have trouble getting the clutch to disengage entirely. The adjustment worked fine for clutch functionality.

I fear that the issue is the main bearings at the rear of the engine, though it seems unlikely at 145K in this car.

Any ideas?

Might not be at the rear of the engine. Might be slipping drive belts at the front of the engine.

No, definitely not that. I popped the hood and revved the engine to get the sound to start, and it comes from the rear of the engine compartment. The belts were also replaced about 1500 miles ago, so they are new and I checked to make sure they're not slipping.

Also, as an update: The rattling sound (which I thought was exhaust noise) is still occurring. I am pretty convinced that this is not exhaust noise, as it sounds like it's something rattling inside a housing.

I talked to my father and described the issue, and he seems to believe it is the clutch throwout bearing. The motor mounts are in need of replacement (I already have new ones, but have not yet installed them), so his suggestion that the throwout bearing and possibly the fork arm of the clutch disengagement lever is the cause of the issue when the engine torques and moves some exacerbating the problem (hence the noise) as the issue seems to hold water with me. A bad throwout bearing would also explain the rattling noise.

I'm going to side with your dad. Same thing happened to a Toyota truck I had. Time to get dirty..............

Thanks. Looks like I have my weekend cut out for me. :wacko:

I've never done clutch work on a Volvo, just my old VW Beetle and a friend's Ford Explorer. How involved is it? Is it reasonable to expect to finish it in a few hours, or is it an all-day affair? As for me, I am relatively experienced as a mechanic and have done all my own work in the past 12 years, except for a complete engine rebuild and alignments.

Some V's have concentric clutch slave cylinders, which are just pedantic lunacy IMNSHO. they make life harder than it needs to be. That said, there are also cable and convention hydraulic systems too. It does seem like a throw out bearing. Estimate 4-5 hrs allowance "by the book" and add a few hours to give yourself enough time to do it. I believe even the Manual gearbox is quite heavy-I recommend more research before you start, & you might need a lowering jack/device. Also at least automatics use Torx screws in this area. I'd also recommend that you replace the rear main seal on the motor, and both front & rear seals on the g'box while it's out, and give serious thought to a complete new clutch. It's a lot of hard work to have to do again if you don't do enough this time. Can't help with info on access to the bolts.

Well, here I am again. A friend helped me investigate further before I went and took on a throwout bearing install. We seem to have localized the problem, and here is my next educated guess:

Rear camshaft bearing. It goes along with the bearing noise, and would explain more reasonably why I lose power when it's screeching. I would think a throwout bearing would change sound when the clutch is disengaged, but it doesn't. Also, a camshaft bearing is much simpler to replace, and doesn't require pulling the tranny, putting the car up on jacks, or even getting underneath.

So does anyone have an opinion as to whether this is plausible?

Mine is a simple cable system. I was told the clutch was serviced right before I purchased it. Likely, they didn't replace the throwout bearing (the clutch was way out of adjustment when I got it, too), but the clutch plate should be almost new. As I am moving away from thinking this is a clutch problem, I probably won't need to pull it apart anyway.

Update:

I now have audio files of the sound. I'm not convinced it's the camshaft bearing, as i don't know if a bearing like that would make a sound so shrill as this. My other theory is that it has something to do with the exhaust, as the EGR system is right around there as well. It reminds me of a plastic grocery bag getting air sucked across it, or someone blowing across a blade of grass.

I have attached the audio files in this post.

stationary-1.wav is what it sounds like when the engine is revved.

1-2-1-2-3.wav is a recording of me leaving the parking lot from work, going from 1st to 2nd gear, stopping at a light, then going 1st to 2nd to 3rd gear.

2-3.wav is a recording of me going from 2nd to 3rd gear.

I'm going to try and get a hold of a stethoscope to see if I can pinpoint where it's coming from. Any ideas would be appreciated.

You can use a 2 foot piece of 1 inch tubing(section of garden hose works) to pin point the sound.

Sounds like possibly you have a vac leak that is oscillating the rip/tear/puncture area as you increase vacuum.

Never heard anything like that

Good luck, and let us know!!!!!!

There are vacuum lines in the dash, but I doubt they provide enough 'suck' to make a big noise, but a damaged carbon cannister infront of left F wheel may make nasty noises. Particularly on higher vacuums. It doesn't sound like a major bearing, might be very bad seal but you'd expect an oil leak.... more like vacuum or bearing/brushes in the alternator-perhaps something rubber rubbing on something. The pre-heat hose from the manifold might have some clues. Check ALL hoses for stiffness, cracks and blockages. It doesn't sound like a belt either. Maybe foreign matter rubbing on flywheel/similar. How good are your engine mounts? Could it be a bad power steering box-wiggle the wheel to check? Water pump is not impossible either-any leaks????

No, no leaks. Oil pressure is good, no leaks there either. Engine mounts need replacement - i already have them - just haven't done it.

So....

I've come full circle and am pretty convinced that it's the throwout bearing, or possibly the pilot bearing. I'm still primarily thinking throwout bearing. I've let a couple of mechanically adept friends listen to the noises, and one of them is certain the rattling is the throwout bearing. Driving it tonight, I've found that the rattling and the screeching are mutually exclusive, they never happen at the same time. This leads me to believe that both noises are caused by the same issue, and that since both come from the bell housing area - the problem is the throwout bearing. The problem is also worsening, both the rattling and the screeching. The rattling is louder and more pronounced, and parts of it coincide with shifting and release of the clutch. The screeching is happening more frequently, with less load on the engine than before. Unless there's something that points to another problem, i'll be replacing the throwout bearing, pilot bearing, and other clutch parts (depending on their condition) tomorrow, along with the motor mounts and possibly the transmission mount.

Whew. I'm already tired just thinking about it.

EDIT: Talked to another friend who is a Volvo guy, and he immediately knew the sound, and verified for me that it indeed is the throwout bearing. He said he knows the sound well, and that he has had the same issue with a manual transmission 240 in the past. I'm quite confident that this is the problem now, and this friend offered to help me do the work. We're going to be going at it in the morning.

Thanks to everyone who has offered help. I'll let everyone know how it goes.

Sounds like something very similar to a noise I discovered after replacing my head. Check the torque on all the bolts holding the camshaft in place, and make sure they are not too tight.

I found that with these nuts over tightened the car would screech at revs above 3000. It was louder than yours sounds, but this could be your problem, and very simple to rectify. Why it would start up all of a sudden though is strange if it is this problem.

I think your dad's analysis is spot on.

<HERESY mode on> I have an '88 Nissan Exa Targa, & they are 'known' for breaking the throwout yoke-makes a real nasty knock 'til fixed, I promise you. Then there's the 5 hours min to replace the water pump (CA18 na motor). Obscene to build such difficult/expensive to maintain crap! Good thing it's for sale soon as it's fixed....... I guess I'll have to find a fool to buy it, but there's no shortage of them, less with some cash, but still, no shortage. <Heresy off>. Wonder if its happed to you????