engine knock

[ipod]

I have owned my venza now since the summer of 09. In the last month I have noticed a distinct knock from the engine on acceleration on a cold start. Has any one else noticed this knock. Have about 14K.

[Scott]

V6 or I4?

I have an 09 as well and no knock that I can hear so far

[ipod]

Have a V6. Have taken it in and they said it sounded like a piston slap, which they said is normal for that engine. I'm concerned about dry wear and tear if this continues. It does go away after full warm-up.

[jrohland]

I doubt that is normal. That engine is used in lots of Toyotas, you should be able to find a few folks with that engine and over 14k miles. See if any of those have a knock. Check Avalon and Camry forums. When you can't find others with that "normal" knock, go to a different dealer.

Has the knock been there through multiple gasoline fill-ups and multiple oil changes? I wonder if you got bad gasoline or low viscosity oil on your last fill-up or service.

Also, could this be a loose part in the engine bay? Maybe some Kentuckian failed to fully tighten a bolt.

[nhcycle]

I've owned several Avalons....the '06 sounded like a diesel...... it's a characteristic of that engine. It may be the fuel.... try fueling up with a different brand to see if it goes away FWIW

[brian_fenner]

Have a V6. Have taken it in and they said it sounded like a piston slap, which they said is normal for that engine. I'm concerned about dry wear and tear if this continues. It does go away after full warm-up.

I would take it to another dealer and see if they say the same thing............excessive piston slap is not a good thing, if that is indeed the issue.

Piston slap is nothing new to piston driven internal combustion engines and compressors. It is the secondary (sideways or perpendicular) movement of a piston against the side of a cylinder bore where the primary movement of a piston is intended to be parallel (up and down) to the cylinder bore. All piston driven internal combustion engines and compressors have a certain amount of piston slap.

Excessive piston slap occurs when the clearance between the piston and the cylinder bore is too great. The piston to cylinder bore clearance becomes too great either through wear, mismatched pistons and cylinder bores at manufacturing or, a combination of both. The audible noise associated with excessive piston slap is due to the perpendicular impact of the piston against the wall of the cylinder bore. Audible piston slap is typically loudest when the engine is first started up. The pistons then expand with heat reducing the piston to cylinder bore clearance thus, reducing the perpendicular impact of the piston against the cylinder wall and its resulting noise.

[nhcycle]

Update:

A TSB was released for this specific symptom on June 9, 2010: T-SB-0146-10

[Venza nut]

Piston slap? you better hope not. that's a connecting rod problem. I hope you get it resolved. I traded my venza, '09 fully loaded, and couldn't wait to get rid of it. I had many problems with that car, it only had 15K on it, with that mileage I expect a lot more out of toyota. never the less, I won't be buying another toyota. Good luck to all who still have this car, I hope you fair better than I did.

Venza nut...OUT!

[CharlieB]

I own a 2010 Venza I-4. It was purchased in the summer of 2010. It wasn't until this winter with the very cold
temperatures I noticed a distinct knock under acceleration. I only have 2k miles on the vehicle and I'm concerned
about it. I've never had this condition with any of my other Toyotas. The knock does dissipate only after the engine
reaches 184 degrees F. I monitor engine functions with the Scan Gauge 2. I will see the dealer about this in the
near future.

[tomd37]

Charlie,

My Venza was purchased end of August 2010 and only has 2500 miles on it. Would appreciate hearing back on your problem and its resolution.