Oil Pump Wear and TOD - Related?

[robm]

I pulled the oil pump out of my '93 Loyale the other day, to replace the gaskets and seal. (I have had TOD on start-up in winter, and a persistent oil leak that the main seal did not cure.) The car has 270,000 km on it.

 

I found the pump shaft was severely scored, too badly to make me feel good about reinstalling it. Now waiting for UPS (which does not have either the good reputation or good service in Canada that it does in the US....) to bring one.

 

I noticed that there seems to be 2 outlets for the pump. One goes to the filter and the rest of the engine, the other supplies its own bearing directly. My question is, if TOD is caused by sucking air past the mickey mouse gasket, then wouldn't this bearing see a lot of air too? If so, would that cause the scoring of the shaft?

 

Rob.

[idosubaru]

shaft scoring typically happens when the engine is run low on oil at some point. i've seen it a couple of times.

 

i've seen dozens of TOD soobs with zero scoring on the shaft though, so my guess is that typical TOD doesn't cause shaft scoring. of course if it was severe or not a normal case...then maybe. but my guess is no. air bubbles shouldn't deprive the shaft of enough lubrication to cause damage.

[robm]

It did get prettly low a month or two back. Down to 1.5 liters or so, but it was not low enough to cause the lifters to clatter.

 

But the cambelt did break. Maybe it was the pump that caused that? At first, I thought it was the cam that had seized, but it seems to be OK.

 

Rob.

[idosubaru]

It did get prettly low a month or two back. Down to 1.5 liters or so, but it was not low enough to cause the lifters to clatter.

 

But the cambelt did break. Maybe it was the pump that caused that? At first, I thought it was the cam that had seized, but it seems to be OK.

 

the engine was starved of oil, causing your scoring and belt to break. ironically enough the HLA's will not necessarily clatter before the engine seizes. i was surprised to see it happen myself!

[robm]

Makes sense. The first thing to lose oil pressure is the pump, so it seizes and breaks the cambelt, protecting the rest of the system. Relatively cheap, compared to the damage that could be done to cam, rod and main bearings.

 

I have run it 6000 miles on the new cam belts, so I suspect there was minimal other damage.

 

Reason for running low on oil was a loose drain plug, and not checking the oil level!

[idosubaru]

i'd make sure to change the oil a few times relatively soon afterwards just in case there's metallic particles still coming off of anything. filter should stop it, but i'd at least do the first two or three changes quicker than normal.

 

that's good news, i've seen them seized before. ironically i have the oil pump out of a seized motor in another perfectly running motor now. the engine seized due to oil starvation but the pump was relatively untouched and the belt did not break.

[robm]

I'm on the second oil change now (every 3000) and there have been no shiny bits at any time. The pump shaft would have been more like filings, I would think. Hard to see in the dark oil.

 

Probably took 50,000 miles off the engine, so I won't be too surprised if it doesn't make 400,000 km. Pity.