Replacement Engine Install Checklist: What to Replace, Clean and Check

A remanufactured engine leaves the plant measured and tested. Whether it lasts is mostly decided in your shop. AERA, the engine builders' association, says so plainly in its "Suggested Installation Procedures and Instructions": lugging, overheating, a rich mixture, poor lubrication, dirt and coolant seepage are under the installer's control, not the rebuilder's. It even recommends that whoever installs the engine hold an ASE or ADS certification first.

This checklist follows that guidance.

Check the crate first for freight damage and for dirt inside the intake ports. Then confirm every oil gallery plug and freeze plug is in and sealed.

Next, put the new engine beside the old one and compare the bellhousing bolt pattern, the crankshaft snout and the flexplate flange. Casting numbers help. A long block that "should" fit and doesn't costs a day.

Leave the temperature labels on the block and heads alone; heat tabs record whether the engine ever ran hot, and a missing one makes an overheating claim hard to review.

AERA recommends new or remanufactured parts for everything the old engine could have contaminated or worn out:

• oil cooler, where fitted, or its lines flushed if you can't replace it;
• water pump, thermostat and radiator pressure cap;
• all filters: oil, air, fuel, crankcase ventilation;
• the harmonic balancer if its outer ring is set in rubber, because old rubber lets the ring slip and throws off timing;
• motor mounts that have collapsed or torn;
• head bolts, wherever your manufacturer specifies new ones. Many modern engines use torque-to-yield bolts that stretch on the first use.

Clean everything you move over from the old engine, starting with the intake manifold, because carbon and debris left in it go straight into the new cylinders.

AERA's guide calls for recoring or replacing the radiator and flow-testing it, and for at least a 35°F temperature difference between radiator inlet and outlet on a running engine. That is the check that catches a radiator that looks fine and can't shed heat. An engine that overheats on its first long pull was usually doomed by the cooling system it was bolted to.

• Fill with the oil grade and quantity your manufacturer specifies, and write it on the invoice.
• Prime the oil system before the engine fires, so the bearings and cam never turn dry.
• Fill and bleed the cooling system completely; trapped air makes hot spots.
• A little hydraulic lifter noise on the first cold start can be normal while the lifters fill. Persistent ticking is a different conversation; [here's how to sort it out](/blog/lifter-tick-after-engine-replacement).
• Where the valve lash is adjustable, check it again at 500 miles.

Compare this with a transmission install, where the big item is the cooler flush. For an engine it's the radiator: the step most often skipped, and the one that fails a new engine in its first week.

• Warranty policy and Peak Powertrain Protection: /warranty
• Pre-authorization before removing the unit: /blog/pre-authorization-before-removing-unit
• Flush the transmission cooler before install: /blog/flush-transmission-cooler-before-install
• Transmission slip and shudder after replacement: /blog/transmission-slip-and-shudder-after-replacement
• Overheating after engine or transmission replacement: /blog/overheating-after-engine-or-transmission-replacement
• Lifter tick after engine replacement: /blog/lifter-tick-after-engine-replacement