4.9 valve chatter

[69Eldo]

Hi

I have a 1992 eldorado with a 4.9 engine. When I start it, the valves rattles for about 1min and then it goes away and its fine.

Any Idea to make it go away?

Thanks

[Otto Skorzeny]

Are you sure it's the valves and not the lifters?

[69Eldo]

im not sure it could be the lifters thanx

[TJ Hopland]

Is it any different if the engine is hot vs. cold?

[Fred Zwicker #23106]

I had a similar problem with my 1955 Pontiac Safari V8 engine after an oil change.  The Quick Lube used 5W30 semi-synthetic and there was plenty of clatter at startup, which stopped after the engine warmed up a bit.  I changed the oil to 10W40 and the problem is solved.  You may want to check your owner's manual to see what is recommended and stay with the exact same weight and type of oil called for.  I am also wondering about using synthetic oil in older engines, as some say that it can leak.  For that reason, I do not use synthetic oil in any of my cars - new or old.

Fred

[TJ Hopland]

I have put synthetic in older and crappy engines and it did not seem to leak or burn any faster than regular did.

[Dave Shepherd]

I would test the engine oil pressure to start with and on an 18 year old engine unless you know it was and is properly maintained, some or all of the lifters could be sludged up and/or bleeding down.

[Fred Zwicker #23106]

TJ Hopeland Quote:  "I have put synthetic in older and crappy engines and it did not seem to leak or burn any faster than regular did."

Regarding leakage of synthetic oil - all I know is what I have heard on several auto forums and from some old timers, but yesterday mentioned this to the Service Manager at a local new car dealership and he said that he had heard this was true and accordingly they do not put synthetic oil in older vehicles unless customer insists.  The manager at our local Quick Lube said the same, so who knows?  I sure don't.

Fred

[Otto Skorzeny]

If TJ's old crappy engine was already leaking oil he may not have been able to tell the difference.

[TJ Hopland]

On the ones that already leaked or burned oil the consumption did not seem to change.  On old engines that were not leaking before changing to synthetic did not seem to make them suddenly leak.  Sure some did eventually start to leak (like 30,000 miles later) but who is to say it was not going to happen anyway?    I had got a good deal on a bunch of synthetic so that is all I ran for a few years.  After that experience I now run at least a blend in the winter in my daily drivers, even if it does not help it just sounds so much less painful on those -0* days.  My local parts store often runs coupons that will get you their store brand of premium full synthetic for the price of the name brand regulars so then I will pick up the full but most of the time in the summer I just stick with the 'family' brand regular stuff.    Maybe a factor is that I for the most part over change my engine oil?  

What happened to '69' and is 4.9?   Perhaps he is lucky enough not to have to work this weekend and is enjoying the long weekend?

[35-709]

FWIW, I used to use 10W-40 Pennzoil in my 1972 Chevy 350 powered pickup.  Since the engine is showing signs of poor treatment by its former owner, I decided to change to 20W-50 Mobil 1 (I'm in Florida) to see what it might do.  I have now traveled 2100 miles since the oil change and it has burned 1/2 quart, excellent for most any engine, amazing for this one.  No leaks.
Geoff N.

[CEC #20099]

CEC
I have a 90 SDV , 4.5 with 166 K miles. Cadillac Requires the use of 5W-30 or 10W-30 oils, nothing heavier or lighter. These engines were designed with close fit pistons, etc , to reduce internal friction. Despite mine being  abused when new (repossesed) , it runs quietly on Pennzoil 10W-30, & never has lifter noise.
5W-30 makes the engine a little noiser. These engines had main bearing noise issues on cold start, when new. It is not a lifter noise.

Please install a good mech oil pressure gauge, & find out if you have oil pressure, on startup. This can be a lifter sludging issue, or a more dangerous oil pressure issue.

Clarence C. #20099