2.7L Knocking

Been gonna post this for a while, but too lazy to type.

2010 2.7L, 61k on the clock. I've owned this truck just over a year. I don't think it did this last year, when it was cold. What it does now:

When it is cold out, like near or below freezing, it knocks on the first start of the morning. The sound is not as deep as a rod knock. It last usually for just a minute or so, then nothing until the next cold morning. I've opened the hood and then started the truck and I'm pretty sure the sound is coming from the air injection valve? (not sure what it's called). It is on the passenger side of the engine nearly in the middle. A hose runs from it to the front passenger side of the engine bay to the smog pump.

I tried to get an audio recording but it didn't turn out well. I can get some pics if needed.

So, do you guys think this is no big deal, or the sound of impending $doom?

 

I have a slight knock with my 12' and have had it checked a few times. I've been told it's normal.

 

I'd say you don't have much to worry about. 2.7s can be noisy when cold and from what I've seen most of them are. Probably just the normal piston slap they get, as long as it goes away quickly I wouldn't worry about it.

 

Probably nothing... My2012, 2.7 liter doesn't have any noise like you described, but it only has 26K on the odometer. It could be the emissions air pump.

 

What weight oil are you using?

 

It should be the 0W20 Full Synthetic.

 

My 2006 has done this since I bought it at 18,000 miles, now at 95,000 miles. Only occurs below 25°F or so. It has never gotten any worse or better, and like you said, goes away after about a minute. I use 5W-30 in accordance with the owners manual. Not worried, this engine is noisy, especially when cold.

 

I run 0-20 Synthetic only in mine. I thought somewhere in that manual said you could use up to 5-20 in an emergency, but go back to 0-20 as soon as possible ? Seems like 5-30 is pretty heavy oil if that's a 4 cyl. Maybe I overlooked something.

 

The 2TR was spec'd for 5w30 until CAFE standards required fleetwide mpg goals. It was switched to 0W20 to help meet those standards around 2008 or so, with no changes to the engine. Being a 4 cyl has nothing to do with recommended oil viscosity. My work truck, a 2005 Ford Expedition with 5.4L V8 recommends 5W20, same as my wife's 1.5L 2008 Honda Fit.

 

Thanks, as you said it goes away quickly. And it doesn't have a damned thing to do with oil viscosity, 0-5w-20-whatever or synthetic. That much I am sure of. I think

 

My '15 4-banger does the same thing on cold-starts with 5k on the clock. Just noisy motors, especially on cold start-up. Mine also doe it only for a minute or so.

No worries.

 

Thank you for the information on the oil weight, I had no idea that is why they did it. Now a second question - what is the best oil weight for our engines ? The old recommendations, or the newer ? Thank you.

 

My 2010 does the same thing when it's cold outside. My tought was that it's maybe the valve's lifters that get some slack when its cold and once the engine heats up they are getting back their shape and tight fit and stop knocking. It stopped caring about it now

 

No problem. I dont think either one is necessarily better, I just prefer to use the recommended viscosity from the owner's manual. People could probably argue it to death, but in the end, the statistical data just isnt there to prove one protects your engine better than the other. You're fine sticking with 0W20 synthetic as long as you're following the oil change intervals.

 

They all do it. Nothing to worry about. Its just the warning that it isn't yet ready for drag racing.

 

LOL pretty much

Yes this light knocking sound seems to be common in our 4-cylinders on cold starts, especially when it's really cold. Mine has made the cold start noise since I got it at 40,000 miles, now has 122,000 miles. The noise goes away within the first minute after starting. Generally I drive it gently until it's near full temp, then I drag race. When the engine's fully warm it just purrs, super smooth, runs great. No worries. I switched to synthetic at 120,000 miles and I now care even less about the noise.