I'm going to be replacing my opti, waterpump and coil in the next few days.

The car has 97k miles on it.

I've been leaking oil from the front cover somewhere, so if I decide to replace, I will have to pull the timing cover and that means replacing the oil pan gasket (in most cases).

If I'm going to replace the oil pan gasket, I'll be using one of the rubber one piece deals, so that means that I'll have the pan out of there, giving me easy access to the oil pump.

Since I'll have access to the pump, it makes sense to service it, right?

What's the normal problem that causes oil pump failure? Does it just wear out, or does the spring wear out or what?

Oil pressure at idle with the engine at full normal operating temp is between 20 and 30 psi (I'd say 25 average), and it gets as high as 50 or 60 or so at WOT.

Would it be ok to purchase a Melling standard volume pump, and use the GM white spring to increase the pressure?

Can I just replace the spring in my stock 97k mile pump and give it a new lease on life?

Or should I just go with a Melling standard volume pump and be done with it?

What's the better approach here? The car is very mildly modded (info in sig), and I'm not planning a cam or anything in this engine.

I'm building (or will be) an engine that will be swapped into the car at a later time.

 

It's a judgement call, but if I had the pan off, IMO I would replace the oil pump and throw in the stiffer spring. The gears in the pump wear over time.

 

I'm currently in the same boat.


It's DEFINITELY a good idea to replace the oil pump while you're in there. It's too cheap not to.


My advice:

-Go to Autozone and pick up the 3/4", standard-volume Melling oil pump. Part number is M-155, and should be $45 I believe.

-Get the high-volume oil pump shaft. Part number is IS-55E, and costs $4.69. This has a *metal coupling* instead of the crappy nylon sleeve that is used on the stock piece. Why use nylon on such an important piece?

-Get the white spring (GM 3848911?), but while the spring is out, go ahead and tack-weld the oil pump pickup tube to the housing (after you've taken your measurements).


My Autozone didnt carry the pickup tube or screen so I'll be getting one at the dealer along with the white spring. I believe the screen has to be welded to the pickup tube. The GM p/n is 12550042, but I'm not sure if that includes the screen and tube, or what. I guess I'll find out shortly...



That's what I'm doing, and it makes sense if you have the means to do so. Perhaps someone else has a better idea.

 

Sorry, I didnt see that you were building up a new motor. If that's going to be happening anytime soon, then you'll just have to weigh the options...

 

12550042 is the pickup tube/screen. 3848911 is also correct for the spring.

The pump is just good insurance-why not?

 

Thanks for the info.

But curious, why the high volume pump shaft? Why not just standard volume with the high pressure spring?

 

As I said, the HV pump shaft uses a METAL coupler/sleeve where it connects to the oilpump itself -- instead of a using a cheap piece of nylon/plastic like what you get with the factory standard-volume pump shaft. Nylon can break -- a metal sleeve most-likely will not.

This does not have any effect on the pump or its output -- just the durability of the driveshaft. At $4.69, it shouldn't break the piggy bank either. Cheap insurance...

 

When I had mine tore down I went ahead and replaced the Oil pump, oil pump pickup, driveshaft, and the mounting stud with the Canton pieces. I think it was around 100 bucks give or take.

-Nate

 

I haven't heard it called a "high-volume oil pump shaft", but it doesn't really matter. It's just a better unit. This is a comparison.

 

I didn't take any liberties in naming the piece -- that's just what it was called on Autozone's computer. It's actually the shaft for the high-volume oil pump that Melling makes for our cars. They've got a separate part number for the standard-volume oil pump shaft, which should be the same as factory (with the nylon coupler).


BTW -- is there anything that you DONT have on your website? Good grief. If I would have known you had it up there, I would have just posted the link...