Cold start knock possibly?

[dieselkane]

Hey everyone. i own a 2003 f250 6.0. when i start it cold outside, it almost sounds like it has a knock to it for a while, when it warms up it stops and runs pretty good. is the knock normal on a cold start? i run synthetic 15-40 amsoil in the truck, and i go about 6000 miles on a change, is that to much even with synthetic? thanks

[SuperDutyPSD6L]

my 2006 6.0 does the same when it is cold. Dont worry about it. Plug it in when ot gets below 40 and that will help alot. Knock for a diesel is not bad just dont drive it for at least 5 minutes so it can warm up a little. It is also recomended to go to a lower weight in the colder temps. hope that helps

[dieselkane]

thanks for the reply man. i never plug the truck in, and i always start it at cold temps lately. its always colder than 40 in the mornings here. sometimes below zero.

[SuperDutyPSD6L]

wow below zero is even worse. Yeah always plug it in below 40 for sure below 30. Will help save ur injectors,glow plugs, and is a whole lot easier on ur engine. Just remember to unplug before you start it or u run the risk of shorting out the block heater. Let me know if plugging it in helps it!

[william_04_x]

i started mine once when it was 20 below and the block heater was NOT plugged in...at the time i had a plug in the exhaust manifold where i had pulled my thermocouple...when it started it RATTLED and SHOOK so hard i thought the whole truck was gonna come apart..the damn EM plug shot out right when it started and i heard the exhaust leak...it sounded like crushed ice in a metal blender...I FREAKED!!!

as soon as i started driving i knew what it was..

i went back to where this happened after all the snow melted...that was 4 moths later, and i found that stupid little plug....it was still there...

i have a big ol' hose clamp wrapped around the one i have in now..

6.0's don't like cold oil!!