1997 STS oil pump

[mudweiser]

Doing a head gasket on a 1997 STS N* 4.6L. Pulled the normal parts and claeaned everything up. Loking at this oil pump, i'm wondering how, or if it's necessary to prime the oil pump? I did hit the cam, crank and all with assembly lube but i'm wondering how to prime this pump.

Also, if i don't have to prime the pump, what makes this oil system superior to all other oil pumps that need a prime?

[BodybyFisher]

I would disconnect the coil pack power and crank the engine over a few 10 second cycles. Holding the key longer than 10 seconds can overheat battery cables, that is why I gave it a 10 second limit.

[mudweiser]

Sounds good. Thank you very much.

[Ranger]

The Northstar oil pump is above the oil level. If it's lost it's prime you'll have to overfill it by 8 quarts and start the engine. Once it has primed you can drain off the additional 8 quarts.

[BodybyFisher]

What Ranger says is true, we have had a few members lose the prime on their oil pump, I recall the guru saying to do the trick that Ranger describes.

I don't know if you have a prime problem yet on your rebuild, if you have NO oil pressure you would do Rangers trick.

By doing what I explained, IF you have your prime, you will begin to pump oil around the engine, bearings, lifters, etc, getting ready for your initial start up.

[KHE]

Take the pump apart and pack the cavity between the impeller and the mating surface of the housing with petroelum jelly. Reassemble the pump and torque the fasteners to the proper specification. That is the procedure in the shop manual.

[BodybyFisher]

Take the pump apart and pack the cavity between the impeller and the mating surface of the housing with petroelum jelly. Reassemble the pump and torque the fasteners to the proper specification. That is the procedure in the shop manual.

I missed that the pump was out, and thought he had installed it already, good catch Kevin

[mudweiser]

Ya, i had removed the pump. I don't think i had to, but it was removed. No, it's already installed and the timing cover is on, balancer is on. I can crank the motor over while it's still on the stand with 12v. Is it possible it will prime w/o removing and packing the pump?

[BodybyFisher]

Ya, i had removed the pump. I don't think i had to, but it was removed. No, it's already installed and the timing cover is on, balancer is on. I can crank the motor over while it's still on the stand with 12v. Is it possible it will prime w/o removing and packing the pump?

That is something that KHE will have to answer.

I know that some pumps can lose their prime and when that happens the crankcase can be over filled to solve the problem, lets wait to see what KHE says

[KHE]

Technically, the pump loses it's prime every time the engine is shut down. Since you have all the timing chains installed, etc. it would be a PITA to tear it down to access the pump...

Once the engine is installed, the ignition control module needs to be unplugged and the engine cranked for 30 seconds per the shop manual. Then the ICM is plugged in and the engine can be started. This is supposed to get oil up into the passages. If you get the STOP ENGINE LOW OIL PRESSURE, then overfill the crankcase by 8 quarts to force the pump to prime and then drain the extra 8 quarts.

Did you torque the balancer to the factory spec? There is an initial torque value plus 120 degrees. The 120 degrees is easy enough to do by putting a paint dot on the bolt next to one of the spokes on the balancer and then tighten the bolt to the next balancer spoke.

[BodybyFisher]

Thanks Kevin, I was dreaming about this last night, thinking that I messed up and caused 'mud' to button it up before packing the pump, whew!

[mudweiser]

KHE - Bodybyfisher,

Thanks guys you made my day. If it wasn't 9AM, i'd crack a cold one. The motor is still on the stand, i had to order the front lower motor mount so i figured i might as well wait to drop it on the frame until the mount arrives.

I bought a torque angle tool for the heads so i just used that on the balancer. I did see in the book about the 120 degree and i think that method would have been easier then trying to hold the balancer and keep the degree tool in place. The second try everything stayed in place.

Now, if i recall the motor calls for 7.5qts of oil. You say to overfill it by 8 qts? Meaning if it does not prime with the 7.5 add another 8 qts? Just wanted to be sure.

[KHE]

KHE - Bodybyfisher,

Thanks guys you made my day. If it wasn't 9AM, i'd crack a cold one. The motor is still on the stand, i had to order the front lower motor mount so i figured i might as well wait to drop it on the frame until the mount arrives.

I bought a torque angle tool for the heads so i just used that on the balancer. I did see in the book about the 120 degree and i think that method would have been easier then trying to hold the balancer and keep the degree tool in place. The second try everything stayed in place.

Now, if i recall the motor calls for 7.5qts of oil. You say to overfill it by 8 qts? Meaning if it does not prime with the 7.5 add another 8 qts? Just wanted to be sure.

It's noon somewhere...LOL.

I don't remember if you pulled the engine through the top or dropped it out through the bottom. If you pulled it from the top, start putting the engine back in as the front mount typically needs to be removed to get the engine to line up.

After you disable the ignition control module as outlined in the manual so the engine does not start, crank the engine for 30 seconds, then plug in the ICM.

If it doesn't prime with 7.5 quarts (it might take a couple of seconds like it does when changine the oil), then immediately stop the engine and add an additional 8 quarts. Start the engine and when the low oil pressure light and warning message go away, shut 'er down and drain the excess 8 quarts out.

Did you use a pint of GM Engine Oil Supplement (EOS) in with the initial oil fill?

[Ranger]

Did you use a pint of GM Engine Oil Supplement (EOS) in with the initial oil fill?

I don't think that stuff is available any longer.

[KHE]

Did you use a pint of GM Engine Oil Supplement (EOS) in with the initial oil fill?

I don't think that stuff is available any longer.

It is still available. It was discontinued for a brief time and then re-intorduced under a new part no. and almost triple the price... I bought some at the local Chevy dealer back in the spring.

[mudweiser]

I dropped the subframe to pull the motor, thats why i ended up waiting for the front motor mount. I debated about pulling the motor from the top but decided to just drop the subframe.

I didn't add any oil Supplement. Should i? What does it really do? I don't polan on having this oil in the motor very long. Everything was coated very well with assembly lube.

[KHE]

If I remember correctly, you had coolant mixed in with the oil. The EOS has a very high concentration of ZDP (The anti-wear additive that is in motor oil). The extra ZDP will help to heal any areas that may have scuffed due to the coolant in the oil.