Strange noises from the timing belt area Volvo S70 98 Base

luckykolo · Post by **luckykolo** » 02 Jan 2023, 20:23

Strange noise from timing belt area when engine cold. It starts around 1 min. This was recorded when the ambient temp was around 65 F. When it's cold outside, the noise is really loud. I tried to pinpoint the noise with the statoscope, but I did not hear it close to any pulleys (including the crankshaft pulley). It almost sounds like coming from deep inside the engine. I will record it with temp around 45F in the future. Noise disappears after a few minutes, although it's replaced by another type of noise, the chirping type: check out this link: . I guess it's coming from the harmonic balancer/crankshaft pulley area. It's not as loud, just a rhythmic chirping sound. Again I tried to pinpoint it with a stetoscope, and I could not pinpoint it to any particular pulley. Based on the phone recording, I would guess it's a crankshaft pulley. What do you think? The timing belt was changed in 8/2019 around 140 000 miles. Now it's around 162 000.

Post by **scot850** » 03 Jan 2023, 13:28

It is hard to say even with the video and sound.

I can only suggest removing the timing belt and checking the tensioner and idler pulleys to see if they have noisy bearings. The crank pulley does had a harmonic balancer built in but no bearing as such. As you already look like you have the serpentine belt off we can eliminate those option and as a -98 car it has the pneumatic tensioner so unlikely that.

Also it is a non-turbo so no oil cooler thermostat in that area. The only other thing would be the oil pump possibly?

Noises as you know can travel so it can be hard to pin down.

Neil.

luckykolo · Post by **luckykolo** » 03 Jan 2023, 17:41

The problem with that is that since noise is intermittent, most likely, it will only show up under the load. And taking off the timing belt is an awful lot of job. All pulleys were OE quality. The water pump was by Gates, but I have excellent access to it with the stethoscope, and it sounds good. The harmonic balancer is working without the load since it does not have the serpentine belt on... You are saying that the crankshaft does not have any type of bearings, right? This was the only pulley I had a hard time getting directly with the stethoscope - I tried the shield underneath the crankshaft pulley and the aluminum oil pan close to the shield to no avail. I could not even hear the chirping noise, which was most likely in this area. As far as the deep rubbing noise, I will inspect the engine mounts and other parts once it gets cold. The noise lasts longer with a temperature drop... I also wonder if it could possibly be PCV vacuum system? I tried opening the oil cap - no difference in noise. PCV system was done a few years back, and when the car is warm, the glove on the oil cap is deflating, which according to some guys, means the system works. Nevertheless, I noticed some oil residue on the top of the PCV black box, which is weird since I don't remember spilling oil.
There is one more thing; I have a code P0442 which is Evaporative Emission System Leak Detected (small leak) - it's been there for the last year or so... The noises are a recent thing...
Anyway, if anyone ever heard such a noise, please let me know...

Post by **scot850** » 03 Jan 2023, 22:32

I don't see it being the PCV system or the Evap leak as most of the items are not in that area.

As to the oil leaks, check the sealing ring on the oil filler is not leaking. They need to be replaced with a good quality part every 2-3 years or so. If there is evidence of oil around the oil filler cap then this is likely the source of the oil leak. The PCV pipes do run across the area above the oil separator tank so oil could run down any of those. If you have negative pressure on the glove test then I think the PCV system is ok.

The oil pump is mounted right behind the crank pulley.

P0442 is probably a leaking pipe in the Evap system. On your car it is probably under the LH front fender where the carbon can is and the pipes tend to fail.

Neil.

luckykolo · Post by **luckykolo** » 03 Jan 2023, 23:49

Is it possible that the oil pump could make such a noise? Is there some type of bearing in it?

Maestrours · Post by **Maestrours** » 04 Jan 2023, 01:04

Hi, are you sure that the noise comes from the timing belt's pulleys? it might be the alternator, or steering pump as well?

Post by **kallekula** » 04 Jan 2023, 01:46

Hard to say from just a video. Since this is an interference type of engine I would remove the timing belt to be able to inspect all involved components. Don’t think it’s the harmonic balancer or the oil pump, but who knows. Stranger things has happened.

Post by **scot850** » 04 Jan 2023, 09:56

Maestours, if you look at the first video carefully you can see there is no serpentine belt fitted so none of the accessories are causing this particular issue. It is a good point to make though.

Neil.

luckykolo · Post by **luckykolo** » 04 Jan 2023, 12:17

yep, serpentine belt is off. BTW I have the car connected via jumping cables to another vehicle's battery, so I don't have to worry about battery dying out. It might help someone in the future. The problem is that the noise when engine is cold goes away after 5 min or so. I will try on Thursday evening to run it again - it should be around 45F. It might give me more time to poke around with stethoscope.

Post by **scot850** » 04 Jan 2023, 14:23

If it was a turbo then I would say it was the engine oil cooler thermostat, but you don't have one.

Sorry but I am out of ideas other then checking the individual pulleys on the timing belt system.

I re-read your notes above. Normally we only recommend Aisin or OE Volvo water pumps as other brands tend to fail and take out engines. Now I don't know who supplies or makes the pumps for Gates.

Neil.