I've been reading about how some of you have been putting 15w-40 in your 4.9, however, I only have 40K miles on my 91 Deville, would this be recomended? .. I think I've got the main bearing thump.

Thanks ... Tony

From what I have heard the 15w-40 will quite the problem assuming it is the main bearing. The EGR system can make a similar sound. So can some misadjusted ignition components.

Is it in Park when you hear the sound?
When do you normally hear it and what kind of driving have you been doing before hand?

These problems can usually be eliminated fairly easy and not that expensive either.

Lately it seems that I hear it more when I am accelerating .. I hear it in park, it's not too loud yet, but I have noticed it get louder over the past 5K miles.

I also have some pinging coming from the engine, generally when going up hill, but lately I have been hearing that happen while driving on a flat road, without much acceleration ... My task for this weekend will be cleaning the egr system out. Any good ideas for that? ... I heard carb cleaner when the car is running ??

Seafoam would be better to use for cleaning carbon out of the EGR plumbing.

Lately it seems that I hear it more when I am accelerating .. I hear it in park, it's not too loud yet, but I have noticed it get louder over the past 5K miles.

I also have some pinging coming from the engine, generally when going up hill, but lately I have been hearing that happen while driving on a flat road, without much acceleration ... My task for this weekend will be cleaning the egr system out. Any good ideas for that? ... I heard carb cleaner when the car is running ??
Clean two EGR tubes inside throttle body under the plates. Use a coat hanger. Do not worry about chunks of carbon falling down.

I am going to change my front main wednesday or thursday this week (unless something comes up) along with a new oil pan. That damn deer better be glad he is dead already.
:horse:
Yeah, I know it is a horse but close enough. The damage total is going to be more then the car cost me. To bad I like the car.

I run 15W-40 in my '92 deVille, have since I did my 2nd oil change at 106k miles. Now I'm at 129k and still use it. It does quiet the main bearing thump down a bit, but the downside is during the super cold winter months, it can be hard to start, if it starts at all. But that's only on those days when it's below -10*

My EGR tubes are clogged too, that makes a different sound...a lighter sound, more like a rattle than a thump.

sounds like most 4.9s have the rattling as well as the thump.
with mine, i notice that the rattling is getting worse than its ever been.
still havent heard the bearing thump yet.
hope all those engine noises dont ruin the engine if they are neglected!

I'm at 201,xxx with my '93 Eldo 4.9 and have ran 10-40 QS for over 100K, switched to Rotela about a year ago when I found out they were taking all the good addatives out of regular oil. I have never had any "thump" or other funky noises.

Mike

'93 Eldo 4.9
"66 Toronado 7.0

Talking about all the good additives being taken out of oil, from what I have been reading this week about the new diesel-type oil formulations (including the new version of Rotella called Triple Protection) is that they have to REDUCE the amount of ZDP (which our cars love) to meet the new EPA guidelines for diesel fuel beginning in January. So it sounds like one of the main reasons people say to use oils like Rotella is now gone/reduced. Its no coincidence that Rotella's literature states that they reformulated due to the EPA changes. I guess I should try to quickly find some gallons of "old" Rotella.

Anybody know anything about this recent development? Well I'm still using a bottle of GM EOS with every oil change. Surely for goodness that will give me enough ZDP? After all, I have a freshly remanufactured engine to look after! Maybe they substituted ZDP with something better...hmm.

I've been reading about how some of you have been putting 15w-40 in your 4.9, however, I only have 40K miles on my 91 Deville, would this be recomended? .. I think I've got the main bearing thump.

Thanks ... Tony


Tony,
Try the Shell Rotella-T 15w40 brand SL rated oil in your 4.9 engine.

I have been using it in all my cars for several years now and love it.

You can usually find it at Wallmart in the Gallon containers.

My 4.1 has 152k and runs real quiet with this oil that was recommended by an Engineer at Cadillac.

Mike