2000 jimmy knocking noise

01-09-2011, 05:56 PM
my lifters are knocking is there any thing i can put in to free them up. more when it cold, no oil in radtor, would 5w -30 help.

01-09-2011, 07:53 PM
Coolant in the oil is a very common cause of lifter noise. Do you have to add coolant? Is there a coolant leak that you can't seem to locate? Look at the underside of the oil fill cap, is there a chocolate milk shake colored goo in it? If the answer is yes to any or all of these, the problem could be a leakng lower intake manifold gasket. A cooling system pressure test will tell if there is a leak. If the leak is internal, coolant can leak into the crankcase and thin the oil causing lifter noise, especially when the engine is cold.

You should be using 5W30 oil all the time.

12-27-2011, 08:23 AM
if you are not having issues with coolant leaking into your oil, the first thing to look at is your oil pressure gauge. is it below about 20 pounds? if so, you may have a loose oil pump or some other internal oil leak. that is probably the worse case scenario, because it may mean that the rest of your engine is being starved of its life blood, oil. if the oil pressure is fine, and your gauge moves correctly (pressure goes up when you rev the engine) there is an old mechanics trick that was taught to me by my uncle ( GM maintenance repairman and race car engine builder). add 1 PINT of dextron II automatic transmission oil to the crankcase at the time of a fresh oil change. and drive as usual. if this will not cure it in one oil change, you will need mechanical repairs. ATF has a LOT of detergents in it, which should open up sludged oil galleys if anything besides actual hands on will do it. i have done this in the past, and it has worked a couple of times. there has never been any engine damage from doing this as far as we could tell (no, i never did a complete tear down on an engine), but my uncle had. if there was a problem, he would not have recommended it. now, i will say that was on older flat tappet (hydraulic) cars. i am not certain it would work with roller lifters in today's vehicles. but the operating principals are the same. si i do not see why it would not.

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