ProPickup Quick Tip
Drilling & Tapping Diesel Intake Manifolds
A little dab of grease on a drill bit can save hours of time when it comes to installing boost gauge and flow meter sensors into a Duramax intake manifold
by Bruce W. Smith
I love utilizing tricks of the trade to speed up installs without jeopardizing the end results.
This is especially true when it comes to installing boost gauge and/or flow meter sensors into the Duramax aluminum intake manifold.
The normal, play-it-very-safe routine to drill and tap the holes for the sensors is to remove the intake so you can do the work on the bench.
This way you can blow out any shavings that may have slipped into the intake whilst you were drilling and tapping.
But getting the intake off takes time (and as all contractor’s know, time is money.)
Removing the intake requires unplugging all the wiring connectors that lay over the manifold, disconnecting the battery leads to the alternator and controller on top of the intake, disconnecting the air intake tube and EGR hose, and then removing the half-dozen or so bolts that attach intake to plenum.
Seasoned shop mechanics like Truck Supply & Outfitter’sDaniel Parker speed up this process by leaving everything in place and using bearing grease to keep the metal shavings from getting inside the intake — and being sucked into the engine.
The process is dirt simple:
- Dab the drill bit into thick axle grease so there’s a dime-sized glob stuck to the tip. Then drill slowly (this keeps the drill bit cooler so the grease stays in place) until the grease blob is covered with metal shavings.
- Then pull the drill bit away from the engine and wipe the glob of metal-shaving-coated grease on a shop rag.
- Re-load the bit with grease and repeat the process again. This might take two or three passes to get through the aluminum manifold.
- Once the bit breaks through, use a small, flat screwdriver (with grease on its blade) to carefully remove any shavings that might remain on the inside of the hole.
- Now, to tap threads, place the tap into a variable-speed drill and dab the tap into the grease. Insert tap into the hole and very slowly let the drill do the turning. Remove the tap once or twice to clean and reload.
These two steps can save you more than an hour in valuable shop labor when it comes to installing sensors for turbo boost and water-methanol injection flow gauges.–Pro