What was I thinking? /96 Buick century /Valve Clatter

Went to my local Buick Dealer thinking they would be more experienced in repairing a leaking intake gasket.The black oil like material in the antifreeze has now stopped appearing,but now the tappets/valves are noisy.The shop says they were carefull not to mix up the pushrods.The clatter is noisy enough now that the anti-(predentonation/ping)sensor is causing timing to be retarded to the max(18 or more degrees)the mileage is now down to 12 miles per gallon with no power for hill climbing or passing.The shop says they have done nothing to cause this problem and are at a loss as what to do.

Please help me out,I’m already out $1,200 for the gasket repair and don,t want to be taken to the cleaners again on a complete on a cam/rocker/lifter ream job.

Please post what size engine you have. Knowing Buick design, I opine that you would have hydraulic valve adjusters in this engine. If the oil was sufficiently contaminated with coolant, it is possible the problem may lie with them.

Let us know what the outcome of this situation is.

Thanks for replying,it has 3100 v-6.Before the shop work on it it ran fine with normal 28-30 mpg.I thought doing the gasket would be good preventive maint.The shop said the black fluid floating in the antifreeze was not oil but leftover casting material goop ect…Buick is having an on going problem with this issue of different expansion rates of alum block and intake manifold causing the intake gaskets to leak.Ford and other manufactures don’t seem to have the problems.The dealer couldn’t determind if this engine used roller or stamped rockers.yikes,it the old we will tear it down to find out.Mean while it could cost by his estimate to run up to 1,800.00 for parts and labor.

Are they sure the correct rods are on the correct valves ?

That V6 uses 2 different pushrod lenghts - Intake are 6 in. long and marked orange, the exhaust are 6 3?8 in. long and marked blue.

Were I a gambling man…

Take the car back to the dealer, and tell them to correct the valve tapping issue.
If the valves were not tapping when you brought he engine in, then that means they screwed something up.

It will not take much more than a couple of hours for them to pull the valve covers, and to inspect the pushrods to ensure that they are in the right positions.


First, check the oil to see if you have enough. With the age of the car, you might put something in the oil that claims to free stuck valves or lifters. If the clattering stops, change the oil. You still have to change the oil if it doesn’t stop.

Was the car clattering when you went to pick it up and if so, did you leave the vehicle there? If it’s this bad then the car should not be driven as that clattering is going to beat the cam lobes and lifter faces up.

If the pushrods are not mixed up then that could point to either misadjusted rocker arms, lifter(s) going bad, or oil pressure loss due to the crankshaft bearings being washed out by coolant diluted engine oil.
With the latter, one should assume if oil is getting into the coolant then it’s far more likely that coolant is getting into the engine oil.

Wished I could be of more help. About all I could suggest is running an oil pressure check. That’s easier than valve cover removal and rechecking of the rocker arm adjustment and if the oil press. comes out ok then it’s time to consider improperly adjusted rockers, especially if it sounds like all of them…

Consider adding 2 qounces of “sea foam” sold at most auto parts stores, to the oil and drive 20 miles if noise gone change oil. it is a great cleaner for sticking valves…