Best Oil Pump for a 5.7 Hemi
TL;DR: The 5.7 Hemi runs a crank-driven gerotor oil pump bolted to the front of the block behind the timing cover, and on this engine the pump is not just a lubrication device - it is the hydraulic power supply for the lifters, the cam phaser and, on equipped engines, the cylinder-deactivation solenoids. That makes an original-equipment or OE-supplier pump the default correct answer for a stock or mildly modified engine, because those systems were calibrated around the factory pump's flow and relief behaviour. A high-volume pump earns its place on a built engine with looser bearing clearances, added oil-fed hardware or sustained high rpm, and it does very little anywhere else. Whatever you fit, replace the pickup tube seal, prime the pump before start-up, and torque every fastener in the factory sequence to the value in the service manual.
How the 5.7 Hemi oiling system is laid out
The 5.7 Hemi is a pushrod, overhead-valve V8 - two valves per cylinder, hydraulic lifters riding on a single in-block camshaft. It does not use overhead cams, lash adjusters or cam followers, and that matters here because the valvetrain is fed directly by the oil the pump is producing.
The pump itself is a gerotor design driven off the crankshaft snout, mounted to the front face of the block and covered by the timing cover. There is no driveshaft, no distributor gear and no separate pump drive to fail - it turns whenever the crank turns, at crank speed. Oil is drawn through a pickup tube from the pan, pushed through the filter, and distributed to the main bearings, rod bearings, lifters and heads. An integral pressure relief valve dumps excess flow back once system pressure exceeds the pump's design limit, which is why fitting a bigger pump does not automatically produce proportionally more pressure everywhere.
Three consumers make Hemi oil supply more consequential than on an older pushrod V8:
- The hydraulic lifters. They need clean oil at pressure to pump up and hold their adjustment. Aerated, contaminated or low-pressure oil is a direct path to noise and eventually to lobe and lifter damage.
- The cam phaser. Engines built with variable cam timing use oil as the working fluid to rotate the camshaft relative to the crankshaft. Pressure and cleanliness govern how quickly and accurately the phaser responds.
- The cylinder-deactivation solenoids. On engines equipped with the factory displacement-on-demand system, oil pressure routed through solenoids in the lifter valley collapses specific lifters to deactivate cylinders. Marginal oil supply here produces symptoms that look nothing like an oiling problem.
Pumps live in the oil pumps and pickups collection, and everything else specific to this engine is grouped under 5.7 Hemi parts.
The tiers, and which one is worth your money
| Tier | What you are actually buying | Best fit | Real risk |
|---|---|---|---|
| Original equipment (dealer) | The exact pump the engine was built with, with the factory relief calibration the phaser and deactivation system were tuned around | A stock engine you intend to keep, or one that has already had an oiling failure | Highest cost, and part numbers changed during the production run |
| OE-supplier / OE-equivalent | The same manufacturers that supply the assembly line, boxed under their own brand | The default recommendation for most owners - factory behaviour without the dealer counter | You still have to confirm the number covers your exact year and application |
| Reputable aftermarket standard-volume | An independently engineered gerotor set from a manufacturer with a real warranty | Higher-mileage engines where the rest of the engine sets the ownership horizon | Rotor-to-housing clearance control varies far more between manufacturers than within any one of them |
| High-volume / high-pressure | Taller rotors, a stiffer relief spring, or both | Built engines with loosened bearing clearances, oil-fed turbos or sustained high rpm | More parasitic drag, faster pan aeration, and no usable benefit on a stock engine |
| Unbranded bargain | An unmarked housing with unknown rotor tolerance and unknown relief calibration | Nothing that also feeds a phaser and hydraulic lifters | Pressure that drifts out of range and takes the valvetrain with it |
The honest summary: on a stock or lightly modified 5.7, the factory pump specification is not a compromise you need to fix. It was sized for an engine whose valvetrain and cam phasing depend on predictable pressure. Buy the OE-supplier tier and spend the difference on oil and filters.
When a high-volume pump is actually the right call
A high-volume pump moves more oil per revolution. That is useful only if the engine can consume it usefully, and counterproductive if it cannot. Reasons that genuinely justify one:
- Increased bearing clearance. A built short block assembled with looser main and rod clearances leaks more oil at every journal, and flow has to keep up.
- Added oil-fed hardware. A turbocharger, an oil cooler circuit or a remote filter setup adds both consumption and restriction.
- Sustained high rpm. An engine that lives near its limit for extended periods has less time per revolution to fill the bearings.
- A windage and drainback package being addressed as a whole. Extra volume without a pan and pickup that can supply it just moves the shortage upstream.
Reasons that do not justify one: a slightly low pressure reading on a worn engine, a lifter tick you have not diagnosed, or a general belief that more is better. Extra volume takes crankshaft power to produce, works the relief valve harder, and can whip more air into the oil in a stock pan. If pressure is low on a high-mileage engine the pump is often not the cause - worn bearing clearances, diluted or overheated oil, a loaded pickup screen or a sticking relief valve all present the same way on the gauge.
Symptoms that point at the pump - and the things that imitate it
| What you observe | Sometimes the pump | More often something else |
|---|---|---|
| Low pressure hot at idle, normal cold | Worn rotor clearance on a very high-mileage pump | Worn bearing clearances, fuel-diluted or overheated oil, wrong viscosity |
| Pressure that drops suddenly and stays down | A failed pickup tube seal drawing air, or a stuck relief valve | Debris blocking the pickup screen |
| Valvetrain noise on cold start that clears as it warms | Rarely the pump | Lifter bleed-down, drainback, a filter without a working anti-drainback valve |
| Cam phasing faults or rough deactivation transitions | Pressure below what the solenoids need | Sludge in the solenoid screens, overdue oil changes, wrong oil specification |
| Metallic debris in the pan | Pump damage secondary to a failure elsewhere | Bearing or lifter failure that also killed the pump |
The pattern worth internalising: on this engine family, oil pressure complaints are more often a consequence than a cause. Confirm the reading with a mechanical gauge before condemning a pump on a dash indication or a scan tool value alone, because the sending unit and its wiring are themselves a common false positive.
What to buy alongside the pump
Replacing the pump means the timing cover comes off, so the parts behind it are effectively free labour. Plan on:
- The pickup tube seal or O-ring. This is the single most important companion part. A pump that draws air past a hardened seal will never make pressure no matter how good the pump is.
- The timing cover gasket and front crankshaft seal. Both are consumables, both are behind the same cover, and both are miserable to revisit. Check the gaskets and seals collection for the set that matches your application.
- Timing chain and tensioner, if the mileage warrants it. The chain is right there. Weigh its condition against the labour you have already invested - see timing chains, gears and tensioners.
- Lifters, if the pan told you a story. If you found debris, replacing the pump without addressing the valvetrain is a short-term fix. Parts live under valves and valvetrain.
- Oil and a quality filter. Use the viscosity and specification the manufacturer calls for, not a heavier oil chosen to mask a gauge reading. Consumables are in oil, coolant and additives.
Two install points decide whether the job holds. First, prime the pump - pack the rotors with assembly lube or clean oil before the cover goes on, so it can draw prime on the first crank instead of spinning dry while it tries. Second, torque everything in the factory sequence to the value in the service manual; the pump-to-block and cover fasteners are small, and both over- and under-torquing them causes leaks or distortion.
Orders over $70 ship free. If you are not certain which pump matches your vehicle, send the year, model and VIN details to sales@coretransmissionparts.com before ordering rather than after.
Frequently Asked Questions
Is a high-volume oil pump better on a stock 5.7 Hemi? No. The factory pump was sized around a valvetrain, cam phaser and deactivation system that expect a specific pressure and flow behaviour. On a stock engine a high-volume pump adds parasitic drag and works the relief valve harder without delivering anything the engine can use. Save it for a built short block with loosened clearances or added oil-fed hardware.
How long does a 5.7 Hemi oil pump last? There is no published replacement interval - it is a wear item driven far more by oil condition than by mileage. Engines given the correct oil specification on a sensible interval routinely go their whole service life on the original pump. Engines run long on dirty oil wear the rotors and load the pickup screen much sooner. Follow the maintenance schedule in your owner's manual rather than a number from a forum.
Can low oil pressure on a Hemi cause lifter failure? Yes, and it is one of the more expensive ways to find out. The lifters are hydraulic and depend on clean oil at pressure to hold their adjustment. Chronically low or aerated oil supply lets them bleed down and hammer, which damages both the lifter face and the cam lobe it rides on.
Do I have to pull the engine to replace the oil pump? Not usually - the pump sits on the front of the block behind the timing cover, so it is accessed from the front of the engine. It is still a substantial job because of everything that has to come off to reach the cover, and shop labour typically lands in the several-hour range depending on the vehicle and what else is being done at the same time. Confirm the procedure for your specific model in the service manual.
Will a new oil pump fix my Hemi tick? Only if you have confirmed the pump is the cause. A tick that appears on cold start and clears as pressure builds usually points at lifter bleed-down or drainback. A tick that grows with mileage and comes with metal in the oil is a valvetrain problem the pump did not create. Diagnose with a mechanical pressure gauge before you buy anything.
Are all Gen III Hemi oil pumps the same part? No. The Gen III family ran a long production life across displacements and applications with running changes along the way, including differences tied to cam phasing and cylinder deactivation. Confirm the current part number against the manufacturer catalogue for your exact year and application before ordering.
Sources
Written from general Chrysler Gen III Hemi service practice for crank-driven gerotor oiling systems, standard hydraulic-lifter and oil-actuated cam-phasing operating principles, and routine oil pump replacement procedure - pickup tube sealing, pump priming, timing cover resealing and fastener torque in the factory sequence. The high-volume pump discussion reflects standard engine-building practice on bearing clearance and flow demand rather than dyno or flow-bench data for any specific product. No part numbers, pressure specifications, torque values or service intervals are quoted here; confirm all of those against the manufacturer catalogue and the factory service manual for your exact vehicle before ordering or installing.