Hi my truck sounds like a deisel truck when i start it , till it warms up then it sounds fine. Its a normal 5.3. v8 engine runs a regular gas. I was told it has rod knock which g.m.. vehicles have a history of having, what is that ? and how much to fix?
thanks
2007-10-29 04:22:35 · 6 answers · asked by Anonymous in Cars & Transportation ➔ Car Makes ➔ Chevrolet
Yep, it is a common problem. I have a '97 5.7L and it does that more during the winter/colder temperatures.
The oil is thicker and harder to pump when cold, causing the knocking condition. You could try running a lighter oil during the winter to help this.
Fixable, yeah, if the motor is torn down and rebuilt. Just live with it... I have 183K mi on my truck, it knocks a little first startup during the winter. I have some pretty cold winters so I have installed a block heater in place of one of the freeze plugs. I get near instant warm air, and it also helps with the knock.
2007-10-29 06:37:19 · answer #1 · answered by boogie_4wheel 7 · 0⤊ 0⤋
350(5.7) Chev engines do this, I have a 350 in a customized van and it makes this knocking noise when I first start it up in the morning and sometimes in the day if it has been setting for a while! The problem with some 350 is that the oil pump doesn't get the oil to the rods and mains as soon as it should and this is what causes the knock! To fix this problem you would need to drop the oil pan and replace the rod and main bearings and while you were at it change the oil pump too! You could for now get 20-50 Lucas Oil and that will help the knock until you can replace the bearings!
2007-10-30 09:44:03 · answer #2 · answered by book writer 6 · 0⤊ 0⤋
I think you're hearing what is known as piston slap. This happens for a couple of minutes when starting a cold motor until the pistons heat up and close up the clearance between the skirt and the cylinders. GM motors have been doing this for quite some time and it's irritating as it started when they stopped fitting pistons to cylinders years ago. It actually doesn't hurt anything mechanically. To fix it, you have to either overhaul the motor with new pistons being installed or install another motor. If you have a rod knock, that is much more of a serious issue. This is a crankshaft bearing problem or a rod that is malformed. This should be fixed as if a rod throws, you will have no motor left at all.
2007-10-29 14:15:58 · answer #3 · answered by Deano 7 · 1⤊ 0⤋
This is a common thing. I had a brand new 350 from the factory put in my pickup. when I first start it up, it knocks. After changing the oil that is lighter weight, it does not knock anymore. so, try putting a lighter weight oil in the engine. You should notice the difference. A good oil to use is Mobile 5w30. That is what I use and no more knocking.
2007-11-01 23:36:44 · answer #4 · answered by inflamedzero2002 2 · 0⤊ 0⤋
i've had Chevy's my entire life and never had one with rod knock, so it most definately is not a common problem, maybe its just valve clatter untill the oil reaches the valve train. Run sone 5 w30 in it in the colder months, that might help. Put in some STP, thats another good thing to keep an engine well lubricated at startup.
2007-10-29 13:53:13 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Lighter oil or a better oil pump may help
Also, get your mechanic to check the autochoke is working properly.
2007-11-02 04:14:13 · answer #6 · answered by oldersox 5 · 0⤊ 0⤋