Buick Verano engine knock on cold start
Asked by Wariat81 Oct 12, 2022 at 09:29 AM about the 2015 Buick Verano Convenience FWD
Question type: Maintenance & Repair
My car has been making a engine knock sound after a cold start. Once it
warms up a bit for a few seconds (up to a minute in the winter), it completely
goes away. It didn't do this when I first bought the car used. The first oil
change I did (40k miles) I used full synthetic oil, and it was shortly after that
when I started noticing it. The oil level has always been fine. The mechanic
could never figure it out, but they never let the engine go full cold either. I've
used full synthetic on all my vehicles for years, never had this issue before.
6 Answers
beatupchevy answered about a year ago
See if a noisy lifter/valve quite oil additive takes care of it just before your next oil change . They may have done that to sell the car .
You need to track down the sound, if it’s top end it could be a bad lifter, if mid engine block it could be piston slap, if bottom end it could be rod bearings. Make certain that you are using the right engine oil weight.
Engine knock is one thing; tappet clicking is another. It could be the lifters aren't getting oil as quickly as needed and that could point to a lubrication problem, like the engine might not have gotten proper oil changes for a LONG time. If it's engine knock, that could be rod bearings experiencing this. At this point you need a mechanic to diagnose this problem and I'd do it now..... And Yes, you might have gotten defrauded in the purcahse of a damaged car.
Check out carcomplaints.com for any recalls on this vehicle. I'm seeing one for excessive oil consumption. Also, I'm seeing the recommended oil is 5W 30 synthetic blend. Not full synthetic. Check your owner's manual to be sure. Hope that helps! Jim
The car had 35k on it when I bought it. Owned by a retired woman. It had service records from the dealership. It showed its oil changes. The manual only states the required viscosity is 5W-30, and doesn't say anything about it being petroleum based, synthetic, or a blend. It did specify Dexos1. These were criteria the oil I used had met. I guess one day I might drop it off the night before so they can hear it from a cold start. Hopefully they can figure it out fast, because he'll only get like 10 seconds to listen to it before it goes away. Thanks for the suggestions.
Going by what you said that they will only get 10 seconds of noise that usually shows up as a lifter making the sound. Then you need to find out why it’s doing that, could be just a weak lifter, could be a bad lobe on the cam, bad anti drawback valve in the oil filter or even a weak oil pump.
