Knocking noise

cass3958 · Post by **cass3958** » 24 Dec 2017, 04:26

I have just heard an annoying noise start up on my 04 XC90 T5 auto. Start the engine no noise. Drive off and there is a slight knocking noise which appears to be coming from the front but only when the car is cold and under drive. Lift off and the noise goes away. coast downhill or put it in to neutral and no noise. Back in drive and there it is again. Once the car is warm the noise goes away. I have just had a new cam belt fitted 4 months ago, the car has just passed its UK MOT (roadworthiness test) this month and two years ago I had a new gearbox fitted to the car. There are none of the old gearbox fault symptoms and the noise definitely sounds like two parts hitting each other causing a tick noise which is consistent with road speed not engine speed. Typical that is is now Christmas eve and with the holidays I am not going to be able to get this in to a garage until the new year but any thoughts I would appreciate.

Post by **oragex** » 24 Dec 2017, 08:06

Hello

Is the noise a constant knock (think ticking watch), or irregular knock?

I'd first check the engine oil level just to be sure.

Were any repairs done recently, apart the timing belt? And the timing belt kit, is it a known brand that was installed? Did they also replace the water pump?

cass3958 · Post by **cass3958** » 24 Dec 2017, 16:42

Knocking is constant like a clock but only until the car is warm then goes away.
Water pump was done with the timing belt which I believe was OEM but no other repairs have been done other than I serviced the car and changed the oil and filter so I know the oil levels are good.

Post by **oragex** » 24 Dec 2017, 18:15

A constant ticking may be a little more important to figure out. You don't mention mileage, but I suppose this was the first timing belt. If this is true, one thing already comes to mind: the mechanics who know these cars don't touch the water pump with the first timing belt. This sounds counter-intuitive, but even the main Volvo dealer won't replace it unless the customer really insists. Sometimes the car is handled by a less knowledgeable mechanic who may not set the belt properly and, more importantly, may use low quality aftermarket parts. This is critical particularly when it comes to the water pump, but also to the belt tensioner. For my peace of mind, I would have the car inspected by a reputed mechanic that knows these cars. There may also be other forums that may be more active on the XC90, such as this one located in UK, http://volvoforums.org.uk/ with great members as well. They can have a list of good garages on their forum. Good luck!

cass3958 · Post by **cass3958** » 25 Dec 2017, 10:57

Thanks for the info. The milage is just under 95k and yes it was the first cambelt. The cam belt broke one cold morning just as I tried starting the car but did not damage any valves. I was very lucky. As soon as I turned the key I knew what had happened and the car was lifted to my garage for repair. What it did do was snap off a lug on the water pump as the cambelt let loose so I know that was replaced with new. Parts were sourced from the local Volvo Indy so had to be good reputable parts. I don't think this is engine related but I might be wrong. The noise is only when moving, in gear under load not coasting. Is not affected by applying the brakes. It seems to be speed related but goes away as the engine warms up. It does not matter if you are in Auto or geartronic manual the noise is still there and does not matter which gear you are in. I have yet to get underneath and have a look which will entail taking the bottom cover off. My thoughts are possibly exhaust manifold blowing or gearbox or drive shaft related but do not know what. I might have to borrow a mates two poster lift, let the car get cold then start it up and run it with the wheels in the air to find out where the noise is coming from.

arfstrom · Post by **arfstrom** » 26 Dec 2017, 18:03

Are you sure its not the ethanol? I have recently figured out, I can not use any ethanol. on my car, (XC90 05 FWD, 2.5T) I will get some engine knocking noise as I am trying to pass a car, or just speeding up to normal speed. once it starts to knock you let go of the accelerator, and then gently throttle up again. but if you stomp on it, it will have a slight hesitation, and it will kick in the turbo. I did run to the local auto store, (orielly) and bought some injector cleaner. It seemed like it cleared it up. but... ultimately I think the problem is the octane/ethanol.

Post by **mrbrian200** » 26 Dec 2017, 18:48

1. At 95k have the spark plugs ever been changed? If not, they're overdue. Also, new ignition coil packs are recommended at about this mileage as well.
-or-
2. Oil flows easier through a partially restricted passage once it's warmed up. However, If that were the case there's not enough information to venture a guess as to where.

cass3958 · Post by **cass3958** » 28 Dec 2017, 04:55

Thanks for the replies.
Plugs have been changed but not the coil packs as they are performing well and do not see the need to replace something which is not broken. Understand the oil flow when warm but this is not as far as I can assertain coming from the engine in that way.
In the UK fuel has not changed that much and Ethonol is not the problem as once warm it will accelerate whilst over taking with no noise. You are refering to a thing called pinking and this is not the noise I have.
Thanks for your assistance I am just going to have to get the car on a lift when called and chase the noise down. I will let you know what I find when I can get it done.

DOND52 · Post by **DOND52** » 08 Jan 2018, 13:09

I had a 2004 XC90 T6 and that's what happen to mine just before the transmission broke. Ends up to be a loud clanking sound in very cold weather. Than once it warms up it goes away. Ended up as a Volvo recall and got a new transmission, but that was at 49,000 miles. I'm guessing you got the 5 speed with the T5.

Oly850 · Post by **Oly850** » 21 Feb 2018, 21:29

Do you gave an update on this issue? If it's a high tinny knock it may be a stuck lifter that goes away when warm, if the knock is a low clunk-clunk it's more likley a low end thing like a rod, but at 95k I wouldn't believe it unless the oil was changed infrequently?