lexixel

I think they probably were under-inflated. I remember they were 2.9 bar hot and I lowered them to 2.5. Now they're 2.7.

I don't have a gauge to check for pressure. I thought I live quite close to the gas station, so I only added 0.2 bar to the recommended value. Maybe 2.7 is better; even at 2.9 they seemed to be fine.

Bgw70

I usually go 2.5 bar (36psi) on cold tires

Tires will usually increase about .3bar (4psi) from cold to hot.
Ambient temp makes a difference too.

Sounds like you are good to go IMO.

Harold57

It sounds like it is time to invest in a pressure gauge. It could save you having to replace some expensive tires!

lexixel

Some updates (i think there's still some problem)

So I've driven it for another ~4000 km. I still find some weird noise but I'm not sure where it comes from.

I think the helicopter noise is from the front tyres (Bridgestone Potenza Re50a rft). It becomes unnoticeable at speed.

There is also a whining noise:

1. I checked the pressure the other day and inflated more (2.9 bar hot), and this noise got worse (60~80 kph and 100~120 kph). I lowered to 2.7 and it got back to the original interval (70~90kph, mostly 70~85).

2. I think maybe around 115 kph there is also a whine, not as obvious.

3. The other day at start up before running, I heard a very faint whine. Opened the hood, it seemed to originare from the front of the engine. Maybe water pump? The car is supposed to have a new pump (I have the paid invoice for the job). After driving there was no sound. So maybe dew on the serpentine belt? I'll drop some water on the belt and see.

4. I jacked up the front wheels. Still no play (like when I checked last time ~4000 km before). The left side still spins freely. The right side doesn't, but I think it may be the brake, because this time I put the car in neutral and first jacked up the right side. I think I'll touch the centre of the wheels after a drive and see if there's temperature difference.

5. No pulling or excessive vibration. The ride is a bit harsh.

So I'm starting to think maybe the wheels are fine. Could it be the steering pump? I'm confused. A friend rode with me and confirmed it comes from the front. The noise is low and not noticeable with the window open or music on.

Harold57

Regarding the whine, it depends on what kind of whine it is as to what that could be. I'd start with the belts though and with those, I'd start with the one that is accessible. You can also use a long screwdriver to help locate noises in some cases. Place the screwdriver tip down on something stable (not a belt or pulley!) near where the noise is coming from and place your ear up against the other end of the screwdriver (the end of the handle) and you can use that as a crude stethoscope. (Finding a whine with a screwdriver may be a challenge though.)

4. If the right side tire doesn't spin freely, it is likely only one of two things: a wheel bearing or the brake not releasing fully. I'd bet on the latter.

There is a spring that pushes the pads back to the resting position. If the spring is missing, bad or if there is crud (rust or otherwise) in the travel path of the pad or spring, then the pad will not return to the resting (non-engaged) position. I'd start there.

lexixel

Hi, I've got some updates:

Still this problem, still haven't found out the source of the whine, though I have a candidate now.

So now this whine is most audible between 75 and 90 kph on the clock, loudest at ~84. It's quiet at 0-40, 50-75, 90-110, and >115. It can be heard at 40-50 and 110-115 if it's very quiet (no other cars around) and the road is very smooth. Today I put the car to N at 50 kph and revved the engine; I couldn't really hear the engine but there seemed to be this whine mixed with road noise. I also passed by a couple of stone-paved crosswalks today, and the whine is very similar to the road noise generated there. I also moved my head around as much as I could; it seems that the noise is the loudest on the driver side close to the dashboard.

I find it hard to believe it could be tyre noise, because at 84 kph it's quite loud and very intrusive (not if the top is down, though). I tried to shake all the wheels again this week; there was no play, but the passenger side front wheel makes some noise when I change the direction of rotation (it was rolling fine this time).

So my primary candidate is the PF wheel bearing, with the front RFT as the backup. The problem is that these tyres are still almost new (I've done 8k km on them; the PO may have done more, but the threads almost haven't changed and are very deep).

It has been whining like this for at least 7k km (when I first noticed, because it's not audible if I play any music), maybe even since before I got the car.

The low-volume whine from the front of the engine I think is normal; I drove some new cars during the summer and it's no different. This is probably just the sound of the belt when cold.

Anyone has any ideas? Maybe a test I can do?

Bgw70

How about out a video a so we can hear the noise?

Lesly1

Even though there's no wheel play when moving up & down, you could have a dry wheel bearing.

Chris.......From OZ.

ShawnOk

iTrader: (1)

Just to make sure, it's not an alternator whine, right? I used to have an abandoned '97 JDM Honda (Acura) Integra in the Caribbean that had alternator whine. I guess, you could test by popping the hood, staying in park, and increasing the RPMs. To test the steering pump, pop the hood, keep the car in park and turn the wheel from side to side. Ask someone to listen for the whine. Please report back.

Coleroad

A mechanics stethoscope is a great tool for under hood noise diagnosis. They are not expensive either. Here is mine

BCT

I just bought an SC, and the power steering fluid is black. If your fluid has not been replaced, it is possible the pump will whine. Even if it is not whining, the fluid should be replaced regularly. It seems that most people do not replace power steering fluid for some reason.

lexixel

Thanks for all the replies.

I've changed the power steering fluid completely. I've also tried to rev the engine when parked. I don't hear much. I used a long screwdriver and posed it against the thermostat housing and the cam covers; seems normal there, too.

I think the car doesn't whine without moving.

I thought of a test: by simply rotation the front tyres to the rear I could know whether it's wheel / tyre or bearing / suspension. Right now, however, I don't have a lift or another hydraulic jack. Should I go to a tyre shop and ask them to do a rotation, maybe check the balance, too?

I'll try to record the noise, but I have only my phone and I guess it'll remove the noise from the recording.

I think it may be a back bearing, but hope it's just the balance.

lexixel

Hi, so I've made a couple of clips

This one is the rolling noise taken at 80, 120, and 50 kph. The noise I'm talking about is hardly discernible; the second take seems to have captured it the best.


This one is the engine sound / noise at cold and after warming up. The camera actually captures a noise I haven't paid much attention to before. It could be the fan, the steering pump, or the water pump.

lexixel

Another update:

After much aggravation, this evening I spent over an hour and checked the timing belt + water pump. Now I can confirm that the mechanic the PO paid indeed had changed the belt and pump (because I never saw the parts replaced), so it's probably not the water pump.

I have found, however, that the serpentine belt tensioner pulley doesn't spin freely. It has no play at the moment. I think the faint whistle / whining noise may be from this pulley. This noise is actually most discernible at about half a metre / two feet away from the grill. It could just be intake noise, though. In fact, the noise from the engine bay is not noticeable unless I open the hood and listen very closely. I revved the engine and heard nothing.

The noise from the wheels is different: my phone was really picking it up clearly, but it was very annoying at around 80 kph.

Lesly1

Did you try Coleroad's idea.? It's inexpensive & will come in handy for the future as well. In the Old days we used a long screwdriver to pinpoint tappet & other noises.

Chris......From OZ.