Knocking on Acceleration 09 XC70

Bobleuko · Post by **Bobleuko** » 11 May 2019, 06:24

Hello all,

There is a loud knocking noise coming from my 2009 Volvo XC70 3.2L AWD. The noise only occurs during acceleration. The knocking pauses for a split second when it switches gears. It seems it only knocks when the engine is under load. It occurs in both drive and reverse. It also occurs when the car is in drive/reverse and I give it throttle while applying the brake so it doesn't move. In neutral, the knock is less distinct.

Water pump has been replaced, idler and tensioner pulley replaced, serpentine belt replaced. Mechanic says engine mounts look fine.

Currently running 10w40 synthetic. Knocking becomes louder after car has warmed up. When cruising (not accelerating) the knocking disappears. The car has ~180,000km (112,000 miles).

I have attached a link to a video I took where you can hear the noise, sorry it is not very clear. Please ignore the low fuel light and warning light (unrelated).

Any ideas what this could be?

Thanks in advance

tigerscott · Post by **tigerscott** » 19 Feb 2020, 19:37

Mine is doing that too. Volvo says it is a wrist pin or crank bearing failing and needs a new engine. Another mechanic says he has seen this in another car, the engine eventually blew, while Volvo is telling me the 32 is bullet proof. I am trying to decide the likely hood that a donor engine will have the same problem. What happened with yours?

Richard99 · Post by **Richard99** » 17 Mar 2020, 10:44

Sure it's not a mechanical problem with the AWD system?

Bobleuko · Post by **Bobleuko** » 18 Jun 2020, 11:37

Hey, I believe my mechanic had previously mentioned that it could be a wrist pin. He said that it would likely not be worth repairing due to the cost. I am still driving my XC70 daily, have put another 30,000km (19,000 mi) on it and its still going strong. I do however think that the knock has become more pronounced. I found that running thicker oil helps with knocking a little bit.

I don't think it is a mechanical problem with the AWD system, because the knocking still occurs when the engine is revved in neutral.

Post by **pgill** » 18 Jun 2020, 14:41

Check your thrust rod it is likely broken

If it is broken then the mount under it has likely collapsed

You will need to lift the engine a couple of inches to replace the collapsed mount

https://www.freel2.com/forum/topic32979.html

Good luck

Paul