Northstar Engines and System Technical Discussion Discussion, 1996 4.6 L. Rebuild, what should be replaced. in Cadillac Engine Discussion; 1996 4.6 L. Rebuild, what should be replaced.
Tearing into my 96 4.6L that I purchased as a replacement for ...
Nothing on this spare engine, it was purchased out of the vehicle.
Its currently partially disassembled on the engine stand.
Top end is down to the block, front is down to expose the chains, oil pump is off, flywheel is off, oil filter adapter is off, lower section (oil pan) has been removed.
Very interesting engine design.
My 99 still has the engine with the documented problems (past postings).
Better to be safe than sorry - since it is an older engine (96), the front and rear oil seal should be replaced, rings are probably worn and stuck with carbon and sludge I would replace them. Rod bearings can notbe reused if the connecting rod nuts are loosened at all - they will spin! Main bearings can be reused unless damage is noticed or excess wear is measered (platic gage). The half case seals - if they have never been replaced should be. This will require a new oil manifold plate that has the gasket enbeded in it. This plate requires a new oil pickup tube it is not compatable with the old tube. Us must use a new tube with new plate
Inspect the timing chain tenstioner pads and guides for excess wear - rather deep groves are normal but if they are really deep or there is more wear than the two groves lines then someone has run this engine too long with coolant in the oil or with a low oil level for you to get away with out replacing all bearings and rings.
The oil pump will be fine. But before firing up the engine, over fill the oil - put in 10 -12 quarts to assure the oil pump gets primed and the air gets out - do not fall to do this no oil pressure is a common problem at start ups of overhualed N*engines, after a few minutes drain the oil down to the proper level.
It's a 96 engine! Overhual it! Do the job right the first time and you will have a 300,000 mile engine do it half way or on the cheap and you will be doing it over. For a few hundred extra bucks you can be sure of what you got go cheap and you will always wonder how much longer it will last.
Do you know it was run with coolant in the oil (milkshake) ?
If so I wouldn't bother with that engine. The cost of rebuilding a N* is substantial, but that decision is up to you.
They usually run a long time with leaking head gaskets before the get coolant in the oil. N*'s do NOT get coolant in the oil until the gaskets a totally gone. "Milkshake" is not a common result of head gaskets leaking but shows up after long term use with leaking gaskets.
Was there any oil in the pan when you got it? How did it look?
Have you priced the additional cost of rebuilding this engine over just replacing head gaskets? (usually $700-900 including timesert kit)
The engine came with at least 3 qts or more of light colored milkshake in the engine.
One can only assume the engine was run that way.
I have always wondered how long it takes for the milkshake to seperate back into coolant and water.
Any guesses on that one ?
I am pricing rebuilding the engine compared to the cost of a questional rebuilt one that can be purchased.
Remember that my 99 DeVille has a so called rebuilt longblock, purchased from ebay. With around 11K miles it is already overheating and pressurizing the cooling system. PO's cost was well over 4K including the install.
If I rebuild it, at least I will know the quality of the job.
If you know the price for any of the parts needed and a supplier please post them.
Have been trying to sell the 99 DeVille in the Denver area for 2500 indicating that it needs a headgasket, not a single call.