Curing L98 Tuned Port Intake Leaks - Stop The Seep

Difficulty Index: Experienced - Special Tools Needed

The Tuned Port intake was a vast change from the previous induction systems offered for Corvette. It relied on a simple premise: Increasing the runner length would increase torque.

The L98 Tuned Port took this theory to the limit. With long runners on each side of the plenum that curve around to direct airflow into the main intake housing, the Tuned Port is one of the most recognizable intakes ever made. It worked quite well, too.

Unfortunately, GM was still sending coolant through the intake manifold, so the biggest problem is that the gaskets are showing their age with coolant leaks. Usually, leaks can be seen in the pockets between the head and intake on the rear passenger side of the engine. There are a few more wires or lines running to the intake than there are with a typical carbureted setup in the earlier generations. But with just a bit more information, swapping out the gaskets can be done the same way as any of the sans-electronic small-block predecessors.

With the car timed and tuned, it was ready for another decade and a half of trusty service. Now we can drive it without any coolant leaks, smells, or stains on the driveway. Right. Like it will spend that much time in the driveway!

The first step is to remove...        read full caption The first step is to remove the plenum from the runners. This includes the throttle body as well. At this point, it can be removed as one unit. You can also drain the coolant from the engine and unhook the battery cables.	Next, remove the distributor....        read full caption Next, remove the distributor. We suggest marking the plug wires before removing them, and mark the rotor's location inside the distributor so you can get the proper timing when you reinstall the distributor.	You won't need to remove them...        read full caption You won't need to remove them at this time, but disconnect the fuel lines to the injector rails (don't forget to relieve the fuel pressure first) and remove the bolts holding the rails in position. You'll have to wiggle the injector rails to remove the tubes from the intake.
Remove the runners.	The intake runners have 40...        read full caption The intake runners have 40 Torx-head bolts holding them from the outside and inside. If the runners don't budge, make sure all of the bolts are removed or you'll be shopping for another set of runners and/or intake.