: 4.9 oil pump in 4.5

09-28-10, 07:21 PM
I have a spare 4.9 oil pump on the shelf that I'm about to throw away. However, it occured to me that I might be able to use it in my own.

The 4.9 oil pump had benefits over it's predecessor including increased flow and pressure as well as reduced load.

I've had multiple pans off on various 4.9's and 4.5's, but for the life of me, I can't remember if the baffles are different. Does anyone know if the oil pans changed/if the 4.9's pump and pickup tube will fit in the 4.5's oil pan?

09-29-10, 02:22 AM

No specifics on the baffles but if that dude says it fits then I'd be confident enough to try. I would bet that a 4.5 pan would fit a 4.9 if necessary.

09-29-10, 02:55 PM
Compare on rockauto.com and see if the part number is the same.

09-29-10, 03:25 PM
Well you wouldnt want the part # to be same since the 4.9 pump is an upgraded design and the oil pan is a junkyard part. One thing I did notice while looking up the pump for my car is this:

"If screen assy. touches baffles in oil pan - oil pan must be replaced w/O.E. No. 3532055; Incl. screen"

^ Thats for a 90 seville. The 91 seville oil pump listing doesnt say that and the pump looks quite different.

09-29-10, 06:26 PM
"If screen assy. touches baffles in oil pan - oil pan must be replaced w/O.E. No. 3532055; Incl. screen"

^ Thats for a 90 seville.

That's interesting.

Then I'm gonna assume that the 4.9 got a revised oil pan to fit the new pump. I don't have an extra pan laying around and I'm not going to buy one, junkyard or new, in order to replace a pump that already works fine.

The stock oil pump has been fine for 175k so it's still adequate. If I could have just thrown the updated pump in without any other changes, I might have done it.

11-18-14, 12:01 PM
I know this is an old posting but thought I would give it a try just in case...........do you still have the oil pump and would you be interested in selling it?

12-17-14, 12:31 AM
Shaagger and others, with the 4.9 pump discontinued(M182) you can use the M132 pump with the recommended size intermediate shaft, no issues with it's installation on my 92 with the 4.9 style pump and oil pan baffle.

12-20-14, 11:42 PM
thanks, good to know. Fortunately just last week I found a GM NOS pump on craigslsit, of all places!! LOL
It made a significant improvement in the engine oil pressure and greatly reduced and or completely eliminated the main bearing mallet knock.
The mallet knock is now greatly reduced at idle and eliminated completely above off idle!! I am one happy Cadillac owner again!!