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1976 sedan deville 500 engine noise

Started by bostongeorge, September 15, 2017, 01:28:42 PM

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bostongeorge

OK guys my car has a 130000 miles on it about it with a 100 on it and I have been driving it I keep the old change very regularly thing is it's developed a lifter or a valve tap in the top of the engine I know it's not bottom I do No engines well enough to know that but this is the thing I had an oldsmobile 455 rocket with the same noise and  poured kerosene and water in the carburettor while it was running now I'm not saying I'm about to run out and do that but there's got to be a chemical a Lucas something to free it up or something the noise is breaking my heart and I can't really afford to open it up and just go exploring is anybody have any pointers I could probably record the noise
Charles Letson

V63

Check for fuel contamination by the fuel pump into the crank case. I had a 77 do that and enough fuel was getting in the crankcase to cause lifter noise. Changing oil would solve it...for a while. Then the ticking returned. Fuel pump replace resolved the issues.

Verify correct and clean oil level.


Jeff Rosansky CLC #28373

I had lifter noise issues in my 472 that drove me crazy so I have been down this road before. There are too many possibilities to list here. Here is my suggestion--

You need to determine your oil pressure statis. Pull the oil pressure switch and hook up a cheapie oil pressure gauge (I got 1 from HF). See what your pressure is at various rpm and report back.
Jeff
Jeff Rosansky
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille


Scot Minesinger

Thanks for the video.  You do not write the history, but presuming that the heads have never been removed and the timing chain is original.  Sounds like it could be exhaust manifold leak - check that out if you have not already.  Also, make sure your exhaust heat riser is open when warmed up.  Make sure no vacuum leaks as well.

I had the same thing, opened her up and attached pic is where the valve stem wore through the rocker arm.  Had to replace intake valve and rocker arm.  The parts were under $100 (including head gasket) and the machine shop charged $75.  My labor if sent out probably $1,500.  A valve job was completed about 10k miles before, so only dealt with the one head.  Tried all the detergent oils and non-sense that never works for me ever to no avail. 

If all those things are OK, you will likely have to open her up.  Probably needs a valve job, as that is the weak point of these engines - bottom of engine is probably fine.  If you remove the heads yourself and bring them to a machine shop with the high quality parts from MTS (or similar), then the price of the work will be way less.  While your at it probably should replace timing chain and rear engine main seal - then you are into - might as well remove engine and clean it - might as well....

I hope you are able to cure it quickly and easily without opening her up,

Scot
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty