I myself am not a fan of engine cleaners. When you dislodge the gunk where is it going to go? I have tore down many engines and I don't want that stuff flowing through the oil passages.

 

If your oil pressure and other gage readings are in the normal range I wouldn't be too concerned. My 2000 Tundra engine never made any loud noises when it was started in sub-zero temperatures. My 2004 sounds like diesel for the first few minutes after starting in the same conditions. The noise is piston slap due to extra piston to cylinder wall clearances to reduce friction in an attempt to boost fuel mileage. Once the aluminum piston warms up and expands a little the noise goes away.

Larry

 

most engines will knock on start up when they are cold. my truck will knock for 3-5 seconds. as soon as the pressure is at full it goes away. i wouldnt worry.

 

Sounds like textbook piston slap. I wouldn't worry about it as long as it goes away when warm, and doesn't get any worse.

 

yeah. my grand mom has a 2004 chrysler town and country 3.8 liter...talk about piston slap when its cold! it lasts for like 8-10 seconds

 

You might be able to help yourself out by using a synthetic 0W-30 oil. Cold oil is very difficult to pump, and the 0W-30's like AMSOIL SSO have an advantage here over 5W-30 and 10W-30 oils. If I lived up north, that's what I would try. I also like the ADBV in the PureOne PL10241 oil filter. If your oil filter has a nitrile ADBV (black), that could be your problem too. They start leaking below freezing, causing dry starts.

Every engine will sound different when starting at frigid temps. These are the only suggestions that I can make that might help. Piston slap is something that is very difficult to conquer though. The physics involved are tough to overcome. If you are worried about it though, you could do a UOA on your next oil change to see if there is any abnormal ring or piston wear.

There is an engine cleaning product that I like and it is safe to use if you follow the directions. It's called Auto-Rx and can be purchased on the internet. There are others that may work, but most are solvent based. There are many opinions about adding solvents to engine oil. I would just prefer to try something that I know is safe, effective, and with no side affects. If you decide to try Auto-Rx, wait until the temps warm up again (springtime). Auto-Rx is very thick when cold, but very thin when hot.

 

Mine does it too, imo sounds like the oil hasn't gotten to the lifters yet and after a half a minute goes away. It's a good sign if it goes away, my dear old Dad had a 65 LTD that you absolutely had to put an additive in it or the lifter noise would never go away. Casite Tune-up if I remember.

 

My 2000 4.7 has always kocked for 4 or 5 seconds in cold weather when it first starts. Pretty bad too. I took it back to the dealer 3 times when I first bought it and they could not find anything wrong they said. This winter, it has definately gotten worse. It knocks on startup more consistantly. It knocked a bit this morning and it was 46 degrees outside. It has never knocked before lower than freezing. I fear that trouble in on the way. It sounds like a lower end knock to me.

Jimmy
757.404.0185

 

MIne used to knock for the 1st 3-4 seconds when cold outside. Now that I'm using 0w-30 Mobil 1, those noises are a thing of the past. Try it. If you don't think this works to rid of the knocking, then you can drain and pour back 5w-30 and won't be out of but $20 or so.

 

Mobil1 and Castrol Syntec also have 0w-30 oils. 0w is best for those cold starts. But, any full synthetic 5w30 shouldn't have an issue at that temp.

Oil drain down is causing your issue. Its normal for every engine.

Common cause is a slowly leaking ADBV in the oil filter. Use a different oil filter.

What oil and filter are you using?

 

Yes, I had the piston slap on initial warm up too. I switched from 5W-30 synthetic to 0W-30 and it seemed to be much quieter.