any ideas?

[Mars Barz]

I was wondering if anyone ever had this problem before.
Up here in Minnesota it gets pretty cold out. Any time its below 20 degrees and I use a low octane fuel (87), when I start up the Tahoe the engine ticks bad until it warms up then it purrs as always. But if I use a high octane fuel (92) it can be 30 below zero and no knock occurs. Whats up with that? Any input would be greatly appreciated.

 

[79powerwagon]

Are you serious? Did you just move to the cold north? That ticking is your oil system struggling to take that frozen oil and get it moving around where it needs to be. Even my new cars do that for a moment or two... all cars do.

I found a BIG help is to run a good synthetic oil (I use 5W-30) and it greatly reduces this.

EDIT: Sorry! The smilies didn't work! I wan't scolding you!

 

[DJTricky]

i have the same issue, where in MN are you?

 

[Mars Barz]

Im in St.Paul
yeah its more annoying than anything.
Ive lived in MN for 26 yrs.
Just wondering if its something I should be worried about or not. Its a 99 Tahoe with 130,000mi

 

[Donnyballgame]

Nope, she is good and loose now. Should be good for another 100k.

 

[peterey2]

probly just the oil. when it gets cold it gets very thick, puts strain on the oil pump and it cant get oil up into the top of the motor.

 

[bowhunter22]

Its called piston slap.

When you go from below freezing to normal operating temp. the pistons will expand about .015" of an inch if not more. So untill a little heat gets into them they're rattling around in the cylinder.

But if you drive it hard when it is cold like that you will dammage the pistons.

 

[DJTricky]

is about 35-55mph driving it hard?

 

[79powerwagon]

is about 35-55mph driving it hard?

No, that's not what he means. No heavy acceleration, no hard hill climbs... basically drive it like an old man until it warms up...

 

[DJTricky]

ok no problem there then, i was thinking he ment rpms and such.