i have a 91 DeVille with 4.9 i guess they told me that i need to change the rod bearings are out, are these easy to change , what do i need to do,, i've been working on engine for awhile but never this deep, i'm pretty sure i can tackle it, at work i was going to look it up in ALL DATA, but also wanted your guys input on the difficulty and steps to take on changing the rodbearings...

Thnaks in advance,

RMS

Are you having the classic 4.9L Main Bearing Thump? Do a search for thump and take a look, it might be "normal".

If it is the thump, then they make a special bearing for that.

Blaze

Yeah, if it's the "main bearing thump", it is common and said to be nothing more than an annoyance. 15/40 Rotella oil is also said to be a big help. Do some homework before you do a lot of work.

If the knock disappears when you losen a little bit the serp belt with a braker - that's the main bearing knock which is harmless.

If it is the thump, then they make a special bearing for that.

Blaze

does anyone have the part number for this bearing?

Your Cadillac Dealer should know exactly what you need for there was only one bearing to replace the ones that knocked. However, you must make sure your car has that problem before they do it or it will cause more problems.

Blaze

Main bearing thump at cold start-up is "normal" for the 4.9

Rod bearing noise is something quite harmful. Be sure you recognize the difference between the two.

Main bearing thump will go away, or at least become less pronounced as the engine approaches normal operating temperature. The main bearing noise will not likely return until the next cold morning start.

Rod bearing noise does not go away but gets increasingly louder as the engine approaches normal operating temperature as the bearings actually begin to separate due to added heat. Quite frankly, the fix is normally not worth it unless the car is otherwise pristine.