How to test oil pump?
Thread Starter
Melting Slicks
Joined: Sep 2002
Posts: 2,783
Likes: 2
From: Engineers do it better.
How to test oil pump?
I have the pan out right now and want to make sure the pump is working fine. How do I test a pump? Car's got 55k mi on the motor.
I don't wanna change it for the sake of changing it...
I don't wanna change it for the sake of changing it...
Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,377
From: At my Bar drinking and wrenching in Lafayette Colorado
Amir -
It's not often that a pump goes bad, unless it's had metal go through it (like a cam going bad...). If you've had metal go through the engine, change the pump.
There are a couple things you can do to check the pump out. The first is with the pan on the engine, you can use an oil pump prime tool along with a mechanical pressure gauge in the oil passage and spin the pump. You should easily be able to obtain 40psi or more on a drill motor with a good pump. Since you have the pan off the engine, you can't do a "wet pressure test", but you can pull the bottom plate off the pump and inspect it. If the pump is bad, you'll have wear and scoring of the bottom plate, the surfaces of the gears, and you'll see wear on the gear teeth themselves. If you have any observable wear of the pump, replace it.
It's not often that a pump goes bad, unless it's had metal go through it (like a cam going bad...). If you've had metal go through the engine, change the pump.
There are a couple things you can do to check the pump out. The first is with the pan on the engine, you can use an oil pump prime tool along with a mechanical pressure gauge in the oil passage and spin the pump. You should easily be able to obtain 40psi or more on a drill motor with a good pump. Since you have the pan off the engine, you can't do a "wet pressure test", but you can pull the bottom plate off the pump and inspect it. If the pump is bad, you'll have wear and scoring of the bottom plate, the surfaces of the gears, and you'll see wear on the gear teeth themselves. If you have any observable wear of the pump, replace it.
Burning Brakes
Joined: Jul 2005
Posts: 787
Likes: 0
Oil pumps almost never go bad.....they get the oil before anything else.
That said, it's cheap insurance to buy a new one.
I'll disagree about just abstractly going to the high volume pump......I wouldn't run one unless I wa going to run a motor atpretty high RPMs and then ONLY WITH A LARGE CAPACITY OIL PAN.
That said, it's cheap insurance to buy a new one.
I'll disagree about just abstractly going to the high volume pump......I wouldn't run one unless I wa going to run a motor atpretty high RPMs and then ONLY WITH A LARGE CAPACITY OIL PAN.
Melting Slicks
Joined: Feb 2003
Posts: 3,053
Likes: 4
St. Jude Donor '03,'11
Originally Posted by evil herbavore
I'll disagree about just abstractly going to the high volume pump......I wouldn't run one unless I wa going to run a motor atpretty high RPMs and then ONLY WITH A LARGE CAPACITY OIL PAN.
Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,377
From: At my Bar drinking and wrenching in Lafayette Colorado
Turtle -
We avoid using the high volume pumps on small block Chevys because they tend to pump too much oil up into the top end of the engine. This results in excessive oil consumption down the valve guides with no real benefit to the lower end. A nice pump with good balance between reasonable volume and good pressure is the stock Z-28 pump.
We avoid using the high volume pumps on small block Chevys because they tend to pump too much oil up into the top end of the engine. This results in excessive oil consumption down the valve guides with no real benefit to the lower end. A nice pump with good balance between reasonable volume and good pressure is the stock Z-28 pump.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Lars - You don't even need a pressure gauge. I have a 1/3 HP drill and it immediately overloads the drill.
If it wasn't pumping the drill would lot get such a heavy load.
If it wasn't pumping the drill would lot get such a heavy load.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Thread Starter
Melting Slicks
Joined: Sep 2002
Posts: 2,783
Likes: 2
From: Engineers do it better.
I took the pump off tonight. I have not taken the plate off to see the wear on the gears yet. Do that tomorrow... But I did notice the plastic sleeve had split along the middle. What is the function of this sleeve?
BTW, I have the motor apart because of my wiped cam recently. If there is any wear on the pump, I will be getting the Z-28 pump.
BTW, I have the motor apart because of my wiped cam recently. If there is any wear on the pump, I will be getting the Z-28 pump.
Cruising
Joined: Dec 2005
Posts: 11
Likes: 0
From: Mineville Nova Scotia
As you said the cam is wiped out, just about where all that metal went? You can bet the block and everything else in the engine has been contaminated, Filters can only do so much. Maybe it is time to look at a overhaul?
Thread Starter
Melting Slicks
Joined: Sep 2002
Posts: 2,783
Likes: 2
From: Engineers do it better.
Originally Posted by b71vette
Cheap insurance: new melling z28 pump/new pump shaft with steel collar (not the fiber like OEM).