The colder it is the longer my engine knocks when first started. In the summer it knocks for like a second or two when started. But in the winter it is longer. Its really noticable and knocks for like 30 seconds when its 15F outside when I get out of work. The knock will go away after this time and not knock while driving. I run 5W30 Full Syn oil with an AcDelco filter. Here is a recording I just did with my PPC http://port.maineahs.com/knock.wav. This was recorded inside my truck with the PPC on my dashboard, but with the mic in this thing it actually records more than you normally hear of engine running. I just want to know if this is fairly normal and if there is a way to fix it if not. My truck has done it as long as ive owned it. Some of the roar noise is just my cooling fan running since the clutch on it is stuck on.

 

Do you have a lot of mile on it?

I cannot tell from the recording, does it sound like a clatter of a bottom end knock. What does the oils pressure look like at start up and after it stops?

 

35k miles, sounds mid engine about at spark plug level. Oil pressure is 60PSI and stays at that during knock and after knock then eventually goes to a minimum of 35 when fully warmed up which wont happen to much until next summer. Ill be lucky if it gets more than a couple degrees above freezing for the next 4 months.

 

Here is another recording from in the engine bay but once again it gets alot of fan wind noise. http://port.maineahs.com/knock2.wav

 

Sounds like a collapsed lifter or two. After it pumps up the noise seems to go away.

You do not hear it again at all after it stops?

It should not hurt anything.

 

My truck does it too, but only when it is cold out, but i have a K&N oil filter and 10-40 castrol syntec blend in mine. (the expensive stuff) , the oil pressure is excellent while it is doing this, and only lasts for a couple of seconds.my girlfriend has a tracker that does it when it needs an oil change, she has 5-30 in hers which im gonna upgrade a bit next change. as far as the fan noise, ive noticed most all the vortec sixes do this when they start up.even the ones in the chevy cheyenne pickup.

 

Yah im not woried about the fan unless of course I dont hear it then I know the clutch failed the opposite way. Yah it only does it at start not once more after that. Yah my oil is Qstate Horsepower 5W-30 Full Syn, but I have had the same issue with Qstate TorquePower, Mobil 1, and some cheapy syns on Frams back then and AcDelco filters. I ordered some lucas oil synthetic oil stabilerzer stuff that some people say fixes this. Got it on ebay for 3 for the price of like 1.25 bottles atadvanced auto

 

I have this same light knock only mine doesn't completely go away, you can still hear it a little when it's warm. Doesn't seem to affect performance.I just changed my oil with Valvoline Max Life and put a quart of Lucas Oil stabil in and actually didn't notice a difference likeI thought I would. But dam does that stuff take a while to pour in while it's cold. That some sticky Sheit!

 

Well the lucas oil synthetic oil stabilirzer helped some it made the cold start knock less noticable and last less time. It also seems to have eliminated my knock at 1500-1800RPM which was thought to be due to the lack of a timing chain tensioner.