Volvo 850 1996 N/A (Repair Journey) Part 2

[DennisCA]

I would replace all the vacuum lines yes. I've never used silicone hoses so I cannot really say except I know a lot of people use silicone so it must work, still I would get the right size hoses.

I've used rubber vacuum lines instead as they are cheap and I can buy them by the meter. I've also used smaller rubber fuel lines as vacuum hoses, on my 850 in particular.

Hi,

Do you know where to get? I can't find any.

Rubber or silicone? I've bought rubber lines from both Biltema and Motonet.

Example 5 and 3 mm rubber
https://www.motonet.fi/tuote/alipainebe ... ct=45-8105
https://www.motonet.fi/tuote/alipainebe ... ct=45-8102

Silicone hoses can be best bought online
https://www.do88.fi/fi/artiklar/silikon ... index.html

[BeerDeer]

Highway Vibration Issue:

- At speeds between 60–90 km/h, I sometimes hear and feel a vibration, especially after hitting potholes or accelerating suddenly.
- The vibration lessens as I slow down and eventually disappears but can return.
- It doesn’t occur at idle or low speeds.

Question: Could this be caused by the tires, or is it something else?

Additionally, when the car has been parked cold for a day or more, I hear a loud clunk sound when I reverse and then drive forward. This only happens once, and after driving around, the sound doesn’t repeat—even if I stop, reverse, and drive forward again. However, if the car is parked for another day or so, the clunk happens again.

Could these issues be related?

[yanga001]

Highway Vibration Issue:

- At speeds between 60–90 km/h, I sometimes hear and feel a vibration, especially after hitting potholes or accelerating suddenly.
- The vibration lessens as I slow down and eventually disappears but can return.
- It doesn’t occur at idle or low speeds.

Question: Could this be caused by the tires, or is it something else?

Additionally, when the car has been parked cold for a day or more, I hear a loud clunk sound when I reverse and then drive forward. This only happens once, and after driving around, the sound doesn’t repeat—even if I stop, reverse, and drive forward again. However, if the car is parked for another day or so, the clunk happens again.

Could these issues be related?

When were your tires balanced and are all the weights still on them? This could cause intermittent vibrations on your car.

I used to have a loud clunk in the rear delta link when i was driving my v70. It sounded like a big metal clunk that went through the whole car. This happened on both of the 98 V70's i drove so i suspect it was somewhere in the suspension back there.

[BeerDeer]

Highway Vibration Issue:

- At speeds between 60–90 km/h, I sometimes hear and feel a vibration, especially after hitting potholes or accelerating suddenly.
- The vibration lessens as I slow down and eventually disappears but can return.
- It doesn’t occur at idle or low speeds.

Question: Could this be caused by the tires, or is it something else?

Additionally, when the car has been parked cold for a day or more, I hear a loud clunk sound when I reverse and then drive forward. This only happens once, and after driving around, the sound doesn’t repeat—even if I stop, reverse, and drive forward again. However, if the car is parked for another day or so, the clunk happens again.

Could these issues be related?

When were your tires balanced and are all the weights still on them? This could cause intermittent vibrations on your car.

I used to have a loud clunk in the rear delta link when i was driving my v70. It sounded like a big metal clunk that went through the whole car. This happened on both of the 98 V70's i drove so i suspect it was somewhere in the suspension back there.

Hi everyone,

My car recently had the brakes replaced. The left side was always making noise and braking, but I still hear a sound that might be coming from the driveshaft or CV joint. However, most of the vibration is gone, and it's much quieter now, just a tiny bit of noise left. I’m not entirely sure what’s causing it.

Also, I’m still having cold start issues. This morning, it took three attempts to start, and I had to press the accelerator before turning the key, but it started immediately then. It was cranking and cranking with no luck before that. The temperature is -10°C.

I’ve already replaced the battery, spark plugs, rotor cap, and rear seals, and cleaned the camshaft sensor. I’ve read that it could be the coolant sensor or even the vacuum lines (since mine are almost breaking and still original). However, I don’t have any idle issues at the moment, so I’m not sure if that’s the cause. Could it also be a fuel-related issue? I don’t experience any fuel problems while idling or driving, though.

Any thoughts on what might be causing this?

[BeerDeer]

I recently replaced the timing belt and serpentine belt on my vehicle and reassembled everything. However, I noticed an issue with the timing tensioner. My friend pointed out that it was leaking, and when we tensioned the belt, I heard a bang. Despite this, the tensioner became firm and tight. I’ve decided to replace it again and have already ordered a new tensioner for both the serpentine belt and timing belt.

I have a couple of questions:

- Is it possible to remove the timing belt without breaking it?
- Is it normal for the car to shoot up to 2500 RPM every time I start it (cold or warm) before settling to a stable 800 RPM? There are no other apparent issues.

For some additional context, I replaced all the vacuum hose lines today with 5mm hoses and repaired the PCV system. Everything seems tight and well-fitted. I also thoroughly cleaned the IAC (Idle Air Control valve). It makes a noise when I shake it, and the movement is smooth. The throttle body also feels smooth during operation.

I’d appreciate your advice on these points.

[abscate]

That high startup idle is not normal for a P80, unless the SAS system is pumping in extra air into the intake somehow? P2 models do it to provide this to burn off extra cold start fuel

[scot850]

+1 with Abscate here. Not normal to jump that high. Maybe 1500 rpm on a cold start and then returning to 850-900rpm regular idle. I can't think why this would happen, especially as it returns to 'normal'. If it was staying high it may be more obvious and being an NA engine it removes turbo vacuum leaks. I'll have a think on this to see if anything jumps to mind. I'm working on a 98 V70 NA later, maybe it will give me inspiration!

Neil.

[BeerDeer]

That high startup idle is not normal for a P80, unless the SAS system is pumping in extra air into the intake somehow? P2 models do it to provide this to burn off extra cold start fuel

I replaced all hoses today with a 5mm one. Stock ones were like 2mm or 1mm...

[BeerDeer]

+1 with Abscate here. Not normal to jump that high. Maybe 1500 rpm on a cold start and then returning to 850-900rpm regular idle. I can't think why this would happen, especially as it returns to 'normal'. If it was staying high it may be more obvious and being an NA engine it removes turbo vacuum leaks. I'll have a think on this to see if anything jumps to mind. I'm working on a 98 V70 NA later, maybe it will give me inspiration!

Neil.

Its weird indeed. It spikes there and goes to the normal range. Then nothing happens. Stable. No other issues.

Do you know about the tensioner // timing belt?

[scot850]

Yes you can remove the timing belt without breaking it. Is it a new belt on the car, or are you needing to replace it?

If you are just concerned with the hydraulic tensioner, then if it is leaking, I would recommend replacing it.

To re-tension a hydraulic tensioner, I use a bench vice, and open it wide enough to be able to fit the tensioner in. Then crank the jaws of the vice maybe quarter of a turn and let it sit for a minute, then and other 1/4 turn and so on until it is fully compressed. Use a metal nail to act as a pull pin and when the tensioner is compressed fully there should be a hole that lines up on the shaft, and the body of the tensioner so you can fit the nail in to stop it expanding again until it is installed.

Most repair guides will tell you to pull the crank pulley to allow you to remove the timing belt and fir a new one. If you are removing the old one permanently, then just cut it and remove it.

To fit the new one, if you are careful you can remove the small retainer on the bottom of the casing. It is held in with 2? 10mm bolts. Removing that gives just enough room to work the old belt out (if not cut), and work the new one in.

Sorry, working on the V70 did not give me any inspiration other than perhaps when it is cold the throttle cable is sticking. Make sure the spring assembly at the engine end of the cable is not frayed, and lubricate the area with some light oil. Also check the throttle body is not dirty and sticking when cold.

Neil.