Over the last few days here in MN, the weather has cooled down considerably. Since then, my truck has developed a knock after a cold start. When I start the truck, the engine is quiet. It idles smooth and makes no noise. As soon as I put the truck in gear and slightly accelerate, the engine knocks bad. Sounds like it is going to fly apart. It will do this for the 1st 5 minutes of driving. If I start the truck and let it idle for 15 plus minutes, the noise is less prevalent. Anyone else run across this.

I do have the cam phase tick after the truck warms up. Been fightting with the dealer to convince then that the cam phase tick is not right. I don't think this is the same issue.


MJS

 

I assume that no one else is experiencing this?

 

Back in 99 I know at my dealer we would replace the 5.4 2V engines with a cold start knock. If I remember correctly they all do it but only the people who came in the shop to complain got their motors swapped for a new one.

 

I have a bit of a knock, until the truck warms up. I have only noticed it during the cold weather mostly.....
I am not sure what could be causing it. I plan to change the oil this weekend, maybe this might help. For some reason I remember noticing it after the last oil change and the colder weather.... strange!
Any ideas?

-f2f-

 

You need to provide a more detailed description of the noise. These trucks have aluminum block engines. The aluminum has a greater rate of thermal expansion/contraction than steel. When my truck is cold, it sounds like a diesel before it warms up. The noise is not real loud and it does not "knock". It is a loud click or soft tapping, very similar to the sound a fully warmed deisel motor makes. Most people wouldn't even notice it. Because the block is aluminum, it warms up very quickly, <5 minutes. But I live in MD, you are in MN. It gets just a tad colder up their. YMMV.

 

Definately more than just a tick. When I start the truck up, it is quiet. As soon as I put it in gear, it starts to knock. Accelerate slowly and you can really hear it. Looks like it is time for ANOTHER trip to the dealer.

MJS

 

Uh FYI Tyson, NO F150 engine has an aluminum block. They all have cast iron blocks and aluminum heads....big difference.

 

mjs, may I ask what brand and weight oil and what brand filter you are using?And do you do your own oil changes are have them done?
Thanks.
Chris

 

I think chrisadams is on the right track. Anti drainback filter and good brand/correct weight oil......

 

Motorcraft 5w20 semi-synthetic with a motorcraft filter. I always do my own work.

The temp has been fluctuating here somewhat. Yesterday afternoon it was 43 degrees outside. No engine knock when I started it up after work. This morning it was 25 degrees and it knocked on startup.

MJS

 

Try holding the gas pedal all the way to the floor during the first couple cranks. Then take you foot off and start it. Holding the pedal down will prevent it starting, and give the oil a chance to reach the top of the engine.
That will let you test and see if it's oil related. The cam phaser is oil 'powered'. If it still knocks after you pump the oil up that would indicate a physical problem.

Good luck with it,
Chris

 

I am pretty sure I have the same thing. Like most all of them, I can hear the valves and injectors ticking for about 10-15 seconds upon initial startup, but once that goes away and it's idling smooth, if it's real cold outside, it sounds like it's having spark knock when you start driving it. It goes away after you drive it for a minute or two. It also goes away gradually, it just doesnt stop, it gets better until it goes away. It is also only on accel at first and as it gets better it takes heavier accel to cause it. However, just like many other little probs like this, unless it has tripped a check engine light, then the stealership usually just says they don't see it or it's normal or that it's related to something I've done. I have a slight miss under load when in overdrive, but the dealership says my drop in K&N filter is causing it, so of course I put the motorcraft one back in, and of course just like I knew, it still does it and it is actually worse with the stock filter. I am very picky when it comes to my cars and I love my truck, but these little things drive me crazy. I am just trying to realize that these things are mass produced and have some small quirks, but for the most part even with the little annoyances, it isn't going to break, so I should just forget about it and enjoy it. Then later on if something really tears up because of it, I will just drive straight through the service department, grab the service manager by the throat, show him the paper he gave me stating nothing was wrong and make them fix it.

 

This is the SAME thing mine does.... and it is driving me crasy too.

I am going to take mine in, but after turkey day probably.

Anyone else have any ideas on what causes this?

 

You won't get any cam phaser noise when cold, since VCT is disabled until the engine reaches operating temperature.

 

What is VCT