I want to replace the oil pump on my L98 . I don't like the 15lbs. or less I see when it gets over 200. Has anyone done this?? What manufacturer is best and would a high volume pump be a good idea? Seems to be pretty straightforward job on this car, with removal of pan and slight movement of crank..correct? Any tips or suggestions??
Thanks!

 

How many miles are on this car? It isnt' very hard to pull the oilpan off.

 

It has almost 100K, is my daily driver and runs absolutely perfect in all aspects except "hot" oil pressure.

 

Have you tried moving up to the next weight oil? If you are running 5W-30 now, you may want to consider 10W-30. :)

 

That's what I did. I was running 5w-30 Mobil 1 and for some reason, my pressure is lower than what I'm used to seeing, so I went two steps up to 15w-50 and now it's much higher! I should probably have only gone to 10w-30 or 10w-40 whichever is the next Mobil 1 weight... but with a hot Texas summer just ahead, I figured 15w-50 would be okay.

 

I am using 20/50 , has anybody tried replacing the pump and noticed a difference?

 

Aye chiuaua.... you're already up there on the oil weight I see. Might be something more than the pump. :( I wish I could say for sure. I've got 166k on my original pump and the engine still pulls 60psi at cold idle w/5W-30 in it. 54psi at hot idle.

If you do replace the pump you may want to go with a high pressure pump, and not a high volume pump. From what I've seen the high volume pumps do not give the oil enough time to cool before returning into the engine.

 

If you suspect the pump, just get a Melling std. volume pump. Your stock pump may just have a weak spring or the clearances are not right. This is the same pump we use on stroker motors. The problem with a high volume pump is it can feed the top of the motor too much, and the oil can not drain back fast enough. This would leave the bottom end with little, oil possibly causing pre-mature bearing failure.

We offer the Melling pump for $25.

Also try testing the oil pressure with a good mechanical gauge, it's possible you do have 20lbs at idle, but your gauge/sending unit is a touch off.
Terry

 

You may as well replace the rear main seal while you have the pump down. Its just another couple bolts and you have the rear cap off giving you access to the seal. The trick when using the two piece RMS is to leave one end down below the block about a 1/16 of an inch one one side and up about 1/16th of an inch on the cap on the other side. Put a light coat of sealent on both ends and bolt the cap back up. Tighten to 12 Ft Pounds, wack the crank forward then backward with a babbit (lead) hammer (or a piece of wood and a hammer) Then tighten the cap to spec. I think its 80 pounds.

Here is what I wrote for someone else about the pan:

WHat you need to do is remove the starter (its a little tight but you can push the cooler lines to the side and sneek it down, two bolts, one nut on the rear, and one large and one small nut on the selenoid) and oil filter. Then remove the 18 nuts and bolts for the pan...and out it comes. Its pretty simple, nothing else is in the way. When you put the new gasket in, put some RTV on it and stick it on the "Block". (if you are using a one piece) if you are using cork and rubber put the cork part of the gasket up first with RTV then the two rubber seals up with RTV. Then put RTV on the pan and slid it in (front up first) Make sure you clean all contact points for the gaskets (block and pan)with break cleaner, that way you get a good seal. All nuts and bolts should be wire wheeled before replacing, makes for a easier and better job....DON"T FORGET TO REPLACE THE OIL

 

Let me re define my answer a bit...I changed the oil weight because of the low press. I encountered late last summer when I got the car. I haven't had it in a high temp. situation this year yet, but I consider the 20/50w to be just a "band-aid" for this problem. I would like to respond to the mechanical problem. I am aware of the problems with the high volume pump at high RPMS but this is litterally my daily driver and I save my "crazy driving" for my other hot rods, this car is as babied as a non-garaged daily driver could be. Terry if I order from you, can I get gasket and whatever else I need as well?
Again ..has anybody had this problem and "fixed" it with a pump replacement?
Thanks alot for all the responces!

 

Jon, 86+ is a one peice seal. He would have to pull the tranny.

 

I wonder why you couldn't use a 2 piece? Curious

 

I'm not familiar with the 2-piece design, so I can't really say for sure. The 1-peice (I should of taken a picture when I had it out) is inside of a metal housing that is held on with 4 bolts to the rear of the block. You remove the housing and there is a gasket between the upper 1/2 of this housing and the block. Theseal is inside of this thing. You press the seal out of the housing, and press a new one into it.

 

Yes we have the oil pan gaskets also.
Terry

 

On the two-piece, you remove the rear cap, slide the old half out from around the crank then slide the new seal half back around the crank. Place the other half of the seal into the cap and bolt it up. Sounds like an easier method then having to remove the tranny. Must be one more of GM’s masterful engineering accomplishments.

 

:D

 

TPiS...I cannot get your website to work! Can you tell me a phone# or way reach you?

 

TTT

 

I believe the cam bearings help the oil pressure,maybe
to much clearance at this point. Somebody tell me i'm wrong!
Matt

 

Does anyone know how to get in touch with TPiS ?