Oil Pump Replacement

[tonyp444]

Hi everyone,

I have a 1996 325 with twin crusaders. Last season, the oil pressure was reading low on the port engine, but still within spec. I asked my marina to take a look at it and then said they would when we launched this spring.

They said when they launched, the port engine fired up fine and oil pressure was within spec when they first checked it, but then they moved the boat, checked it again, and it was reading zero.

They said they pulled the gauge and put in a manual gauge to make sure it wasn’t a gauge issue, and it was still zero.

They did some further testing this week and said that the oil pump and pickup need to be replaced. Since it is on the bottom of the engine, they said they will need to pull the engine to replace it. They quoted me $10,000. I’d imagine this is mostly labor.

I knew if the oil pump needed to be replaced they would need to pull the engine so I was expecting a big bill, but this was still a shock. Does $10k sound reasonable?

Also, while the engine is pulled, is there any other preventative maintenance we should do in order to make sure we don’t have another huge repair bill in the future?

They said that there wasn’t any blow by, but I’m a bit worried if the oil pump was failing that there could be some excessive engine wear. Would it be worthwhile to get a compression test?

Both engines were replaced in 2021 which was a big selling point for this boat. I was hoping we’d be able to avoid major engine repairs. However, my understanding the previous owner replaced both of the blocks and reused some original engine components so I’m sure the oil pump was original.

Any advice you can provide would be greatly appreciated.

[waybomb]

No. I don't think that's reasonable. At 100 bucks an hour that's about 100 hours.
I have seen bearings fail. I have seen distributor gears fail. I've never seen an oil pump going to zero psi. Just my experience.
Maybe you'll get lucky and find something stuck in the pickup.

[bud37]

Yup generally on a rebuild you always put a new oil pump, they a cheap. Yes, have an engine guy have a look in there.....drifting down then zero is curious.

[Viper]

Ya they better make absolutely sure about the pump before they condemn it. Has anybody recommended an oil analysis to see if anything stands out that might not show up on a compression or leakdown test? It may even reveal the tell tails of a failed pump or drive shaft, or not. Of coarse this only applies if the oil hasn't been changed recently.

I find it interesting that nowhere has it been mentioned that an engine alarm went off, and depending on the model, an electric fuel pump shouldn't work in the absence of oil pressure.

BTW, don't rule out the oil filter, even if it's new. Ran into that more than once; zero pressure, replaced filter, problem gone. Hopefully it's that simple, you never know. Check the simple things first!!

[tonyp444]

Source of the post Ya they better make absolutely sure about the pump before they condemn it. Has anybody recommended an oil analysis to see if anything stands out that might not show up on a compression or leakdown test? It may even reveal the tell tails of a failed pump or drive shaft, or not. Of coarse this only applies if the oil hasn't been changed recently.

I find it interesting that nowhere has it been mentioned that an engine alarm went off, and depending on the model, an electric fuel pump shouldn't work in the absence of oil pressure.

BTW, don't rule out the oil filter, even if it's new. Ran into that more than once; zero pressure, replaced filter, problem gone. Hopefully it's that simple, you never know. Check the simple things first!!

Unfortunately we changed the oil this offseason so the oil test won’t be an option.

That’s interesting about the alarms and fuel pump. In this case, they splashed the boat and started it before I was there, so I’m not sure if an alarm went off or if the fuel pump cut out and killed the engine. I can ask.

And thank you very much for the tip on the filter. I doubt they’ve tried swapping it, and it is a new filter from the recent oil change, so I’m going to make sure we give that a try before going any further.

[Viper]

I've only ever had one oil pump failure in my career, it can happen but that's rare, at least it has been in my experience, it's usually been something else. Also had an instance where the relief valve in a filter assembly somehow caused a no pressure situation. I didn't think it could but I took one apart on an old Chrysler 440, cleaned it and the oil pressure returned so I have to conclude the valve was the cause. That too was a sudden drop in pressure to zero. I also suspected the pump but was determined to check every other possibility before committing to an engine removal which is what they should be doing too. The pump should be the last resort.

I agree $10K seems excessive for this even at the typical door rate up my way at an average of $130/hr CND but I don't know your circumstances. Accessibility is everything.

[bud37]

Maybe this was one of their tests but......Consider asking them to pull the distributor and prime the engine oil pump thru there with a drill to check for pressure without starting the engine, they can check the pump drive mechanism and have a look down in there as gm engine oil pumps are all internal. That is why I suggested talking to a mechanic familiar with building engines etc.

Also.....Even if the pump is found to have failed, the engine internals main and rod bearings, lifters , cam, crank etc will all have to be checked for damage, the engine would have been noisy with no oil pressure on the gage, hopefully there was a small amount that the gage was not accurate enough to register.

[km1125]

Source of the post Maybe this was one of their tests but......Consider asking them to pull the distributor and prime the engine oil pump thru there with a drill to check for pressure without starting the engine, they can check the pump drive mechanism and have a look down in there as gm engine oil pumps are all internal. That is why I suggested talking to a mechanic familiar with building engines etc.

Also.....Even if the pump is found to have failed, the engine internals main and rod bearings, lifters , cam, crank etc will all have to be checked for damage, the engine would have been noisy with no oil pressure on the gage, hopefully there was a small amount that the gage was not accurate enough to register.

^^^^Agree with all of this.

I would not be worried (or even check) compression. The real concern should be the main and rod bearings if the engine was truly running with 0 PSI oil pressure. Definitely pull the distributor and spin the oil pump to do further analysis without starting the engine. I have heard (but personally not experienced) where the oil pickup tube drops off the oil pump, but that would result in an immediate loss of all pressure and not sometimes just reading low.

And, yes, $10K is crazy expensive to pull the engine. Unless they're talking about pulling it, rebuilding it and putting it back in.