1999 Lesabre. 3.8

Knocking On Startup -
This just started happening one day when the outside temperature was like 10 ° F

When the engine is cold, often there will be a knocking sound like a pushrod or valve.
The sound is almost identical to the noise an ignition spark makes. It quickly disappears, sometimes it goes on for a couple minutes and other time only a few seconds.
It keeps rhythm with engine speed.

No change in oil condition yet it is time for the 3000 change.
Check Engine light works but does not come on while driving.
No evident signs of an intake failure [I even pulled the TB and the stovepipe area looks good.]
No akward exhaust colors or fumes.

Oil pressure is about normal, a little over 40 PSI like always.

So I might guess that it could possibly be one of the hydraulic lifters leaking?

What else should I ckeck? If I DO have to pull the lifters, would that require removing the entire intake system? Is there any type of additive or oil I could use to unstick a lifter if that IS a problem?

Green Coolant

Would the standard green coolant be a safe replacement for the dexcool? If not, then what to use?

My car'* original motor died within 15 miles of buying the car! I put in a JY engine, and it made racket since the first day I started it. I cried to the JY and they gave me another. 2 years later, the noise on startup is still there, and the 2'nd replacement eng. is still in the garage. No spun bearings, or rods through the block yet, and she'* still running strong just a bit noisy.

Sorry, no suggestions.

Try a bottle of Lucas in the oil and see if that helps. Lucas helps to protect the engine on startup. You may also consider going to a heavier oil, like a 10W-40. Or even running a bottle of seafoam in the oil before you drain it to help break down the sludge buildup. Green coolant is NOT safe to mix with Dexcool. It will turn into a gel and cause all sorts of problems. Either fully flush out the Dexcool, or use the universal yellow coolant.

I know they are not compatible but if I replaced the orange totally with the green, would the cooling properties be the same for these engines?
BTW I have never had any overheating problems, and I change the 'stat for summer/winter 180 195

You need to make sure you flush ALL the dexcool out if you decide to put green in. I personally use the universal yellow stuff. That way if I am in a bind and need coolant, I can put either dexcool or green in. The universal has the same properties as the green, but wont congel with the dexcool.

Knocking noises on startup are disconcerting, but are not always something horrible. Especially if the noise goes away in a short while. Really big problem noises like bad main or rod bearings make noises that do not go away.

Drain the Dex and refill with "mixes with any type or color" coolant according to the instructions in Techinfo http://www.bonnevilleclub.com/forum/...=article&k=100

If you really really want to use old green phosphated coolant, (I can't imagine why you would) you better be absolutely sure you have removed all of the Dex from the cooling system first. Green and Dex will cause big sludge. This includes the heater core, engine block, and radiator.

Thanks for the replies
Well I don't insist on the green, I can go with the mix w/any color.

I just do not want the orange stuff in there.