Project Y2K Gets an Aluminum Makeover with Moroso

Although some C5 Corvettes are now nearly old enough to drive themselves, with proper maintenance and a little elbow grease, they can still look nearly as good as they did when they left Bowling Green. Unfortunately, some components, especially those made of plastic and subjected to extreme temperature changes in the engine bay, just don’t age well no matter how well they’re cared for.

Project Y2k, our 2000 Corvette project car, corners better and accelerates harder today than it did fourteen years ago, but time has not been as kind to some of Y2k’s plastic underhood components. Dirty, cracked, and generally worn-out-looking, these aging pieces can make even the cleanest engine bay look cheap and tired.

Thankfully, Moroso offers some beautifully-made aluminum solutions for these ugly underhood problems. We’re installing Moroso’s aluminum coolant expansion tank, fuse box cover, brake booster cover, and an air-oil separator. Our blue-collar supercar is finally going to look as good as it drives.

Functional and beautiful. We’re installing the Moroso coolant expansion tank, brake booster cover, fuse box cover, and air-oil separator.


Moroso Part Numbers

  • PN 63787 Coolant Expansion Tank Corvette 1997-2004
  • PN 74240 Brake Booster Cover, Fits: Corvette 1997-’08 & Cadillac XLR 2004-’08
  • PN 74241 Fuse Box Cover, Fits: Corvette 1997-2004
  • PN 85474 Air-Oil Separator Universal Fit 3/8″ 90° inlet & outlet fittings, 36″ of 3/8″ rubber hose

More aluminum!

For our first underhood upgrade, we decided to tackle the frumpy black plastic fuse box cover. The Moroso aluminum fuse box cover sits on top of the stock cover and gives it a much more finished, serious look. Moroso’s Thor Schroeder likes the big, TIG-welded aluminum fuse box because it “covers up that big expanse of plastic in the engine compartment and is a great way to finish up the look of the engine compartment.”     

The stock fuse box is pretty dingy. The fuse box cover is held on with a captive thumbscrew, which we'll need to temporarily remove to put the new cover on.

Left - Use a pair of zip-ties through the slots on each side of the tower to release the hold-down screw. Right - The hold-down screw is no longer captive! Don't forget to remove the zip-ties...

Replace the stock cover and slide the Moroso cover over it. Screw it down and you’re finished.

Coolant Expansion Tank

Often, the ugliest part of any engine bay is the coolant expansion or overflow tank. Not only is it a big ugly plastic blob, it will inevitably begin to crack and leak after several years. Installing Moroso’s big, bold aluminum coolant tank is one of the most immediately noticeable things an owner can do to improve the way a Corvette looks with its hood open.

Not only does the aluminum replacement tank look like something you’d find on a race car, it will keep looking good for years. Modified Corvettes, especially those with a turbo or supercharger, can produce enough underhood heat to melt or crack the stock plastic tank, making this an essential upgrade if one wishes to avoid a big mess and possibly a very expensive meltdown. As Schroeder at Moroso put it, “Our aluminum coolant tank gives you a piece of mind on the track and street creed in the pits when the hood is open.”

Start by siphoning as much coolant as possible from the stock coolant tank. After draining the coolant, remove the hose clamps from the two hoses leading to the underside of the coolant tank, and the single hose up top. Then, remove the two top mounting bolts.

Left - Don't forget about the one bolt underneath. Right - With everything disconnected, remove the stock coolant tank.

With the Moroso coolant tank in the right general position, you'll need to tilt it a bit in order to reattach the coolant hoses. Replace the two top and one underside mounting bolts and the job is done.

Refill the tank to 2″ below the top of the filler neck, and replace the cap. Finished!

Boosting the Booster’s Appeal

The Moroso brake booster cover attaches to the stock brake booster with hook-and-loop fasteners, and has a sighting cutout in the side so the brake fluid level can be checked quickly without tools.

Left - Apply four adhesive hook-and-loop dots to the reservoir glue-side down, and then place the other four dots on top of them, glue-side up. Center - The reservoir cap has to come off to slip the cover in place. Right - Slide the cover over the reservoir and press it firmly onto the dots. Replace the cap and you're finished!

Schroeder says, ‘The cover itself comes in an aluminum finish that can be polished, chromed, powdercoated or painted for a custom look.’


Breathing Cleaner with the Air-Oil Separator

The assembled air/oil separator with drain valve and elbow on the bottom.

The Moroso Air-Oil Separator dramatically reduces the amount of engine oil being introduced into the intake air by the stock PCV system. PCV systems route pressurized crankcase gases, also called ‘blowby’, directly into the intake between the air filter and the throttle body.

Under normal conditions, for ‘normal’ cars like your mother-in-law’s Camry, this system works just fine. But for those who want to get the most out of their engine, pumping atomized crankcase oil into the intake is less than ideal. At worst, an excessive amount of oil in the combustion chamber can foul plugs and cause serious power loss or detonation.

The top half of the separator. PCV gases flow in through one side of this baffle, down into the collector, and then back up and out the other side into the intake.

At best, when the PCV system is working properly and only a small amount of oil is being burned, basic scientific reasoning tells us that any oil being introduced into the intake must also be displacing clean air, reducing the amount of oxygen the engine can use to burn gasoline and create horsepower.

In addition, Schroeder noted that, “Oil deposits [can] form in the intake tract, including the valves themselves, and [lower] the efficiency of the intercooler in intercooler-equipped vehicles.”

In fact, when we pulled the PCV hose on Project Y2K, it was so swollen and soaked with oil that it slipped off the valve without any effort at all. All that oil going into the combustion chamber can’t be doing much good.

Inside the air/oil separator. The lower half collects the gunk that would otherwise be in your intake.

The air-oil separator traps and stores this gunk before it is drawn back into the engine. Moroso’s large-body air-oil separators like ours have a drain on the bottom to allow for easy, no-mess disposal of the collected oil.

We mounted the air-oil separator on the subframe next to the passenger-side headlight, in the extreme front-right corner of the engine bay. This location will allow us easy access to the drain elbow on the underside of the separator.

Installing the Air-Oil separator

We mounted the separator at the front of the engine bay, next to the passenger-side headlight. This location allows straightforward hose routing and easy access to the drain on the underside of the separator.

We tapped into the factory PCV system right at the check valve, which can be seen here just above the nitrous solenoids.


The stock PCV connection was so swollen and soaked with oil that it slipped off without any effort.


Right - The new hoses routed from the PCV valve to the separator, and from the separator back into the fitting on the intake manifold. Left - The air/oil separator mounted and connected.

The finished installation routes the hose along the intake tube, down to the separator, then back along the passenger fender and across to the engine.


Same great engine, now with less cheap-looking plastic.

In keeping with our affordable supercar theme, these parts deliver impressive bang-for-the-buck, totally transforming the underhood appearance of Project Y2k without being prohibitively expensive. We like to remind our readers of the ways in which Project Y2K outperforms a stock C6 – better handling, more power – and now we can confidently say that it looks better, too. 

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