Engine rattle on cold start

westex39 · December 12, 2003

I have a 2003 Trailblazer with the 4200 I-6 engine. When starting, the engine has a slight rattle for about 5 minutes. It's not a knock, it sounds like valve lifter rattle.

Once the engine warms up it's quiet. It has done this since new. Presently have about 1600 miles.

Does anyone have any pictures or schematics showing the overhead cam and lifter setup? I don't know if there are any lifters installed or not. I just assumed there were lifters installed since there areno valve adjustments is recommended.

I checked with the dealers here, none of them have seen the top of the engine and don't know how it is setup. Hard to believe.

Thanks,

Westex

Cool Zr2 · December 13, 2003

If it only has 1600 miles you better have the dealer do any adjusting on the engine. And you say that they have never had the tappet cover off one of those motors scares even me !!! Find a different dealer with a better service department.......or wait to see if for some strange reason it goes away with some more miles.

Even if you rebuild engines for a living, messing with that will risk you voiding your warentee (sp) if they find out.

Also, are you running 5w-30 inn there? If not its a real good idea.

westex39 · December 13, 2003

cool zr2,

I started out with the factory oil, 5W-30 I assume. At 537 miles I changed to 5W-30 Mobil Drive Clean and installed a Wix 51522 filter. Then at 1566 miles I went to Amsoil 5W-30 full synthetic with the Amsoil SDF64 filter. As I said It had made this noise since new. It hasn't gotten any worse.

I had a Dodge pickup with a 318 c.i. that made this noise too. It was roller lifters so they said. Just wish I could find a schematic of the valve operating mechanism.

If it gets worse I take it to the dealer.

thanks for your response.

Westex

ddombos · December 13, 2003

2002 Trailblazer LT:

My wife had this noise since the first winter we had the vehicle (12-2001). It is a really squeaky rattle if you are talking about the same thing that I am talking about. Mine rattles about 3-5 times then pauses for a second and repeats this until engine warms up a bit.

In my case, it seems to only make this noise when it has sat for some time in temperatures below freezing. Hence, it is only observed during the winter months. This condition hasn't gotten any worse since my wife first noticed it. Of course, I flipped when I noticed it and found out that she had known about it and not said anything. At this point I can launch into a tirade about her family being content to let things go to $H!T and not maintain things in proper working order, but I will digress.

To sum up, I've got what appears to be the same symptom. It has not progressed during my ownership of the vehicle (05-01 to present). I think I will have it looked at as my vehicle needs a 50,000 mile service soon. I haven't had the opportunity to bring it in during the winter to have them investigate the noise.