SEC 04 · Wrenching guides
Twenty-five step-by-step WRX and STI jobs from the shop floor — from spark plugs and fluid services up to head gaskets, wheel bearings, and boost control. Written for people doing the work themselves. Tools listed, no steps skipped.
Doing EJ25 head gaskets right: engine-out method, MLS gaskets, resurfacing, and the torque sequence that keeps them sealed.
Read the procedure →The 105k service on any EJ-powered WRX/STI: belt, pump, tensioner, idlers, and getting all the cam marks lined up without panic.
Read the procedure →Sluggish spool, weird idle, fuel trims out of range — before blaming the tune, pressure-test the intake tract.
Read the procedure →Dropping the 5-speed out of a GD WRX for a clutch, flywheel resurface, and the throwout/pilot bearings everyone forgets.
Read the procedure →Changing plugs on a flat-four means working blind between the heads and frame rails. The tricks that make it a two-hour job instead of a bloody-knuckle afternoon.
Read the procedure →The classic EJ oil leak: valve cover gaskets weep onto the exhaust and smoke. Doing both sides with tube seals ends it for a decade.
Read the procedure →The classic Stage 2 enabler: swapping the restrictive stock downpipe for a catted 3-inch, without rounding the studs that fight back.
Read the procedure →A dyno tune is only as good as the car you bring. The mechanical checklist that stops you from paying for a diagnosis session instead of a tune.
Read the procedure →That speed-dependent hum that changes with lane position is a wheel bearing. Pressing a new one into a GD rear knuckle without wrecking the new bearing.
Read the procedure →Clunks over bumps and vague turn-in are usually control arm bushings and ball joints on a 20-year-old chassis. Doing the whole arm at once.
Read the procedure →Swapping struts for coilovers on a GD/VA, setting preload and ride height correctly, and what to tell the alignment shop.
Read the procedure →Two-year-old brake fluid is brown and boils early. A full flush with correct bleed order, by hand or with a cheap pressure bleeder.
Read the procedure →Plastic end-tank radiators die at 15 years, usually on the hottest day. Replacing radiator, hoses, thermostat, and cap in one go, plus the Subaru burping ritual.
Read the procedure →Supporting mod for bigger power: a modern high-flow pump in the stock hanger. Access is under the rear seat, and cleanliness is everything.
Read the procedure →Swapping injectors for E85 or big power on top-feed rails, with the O-ring discipline that prevents fuel leaks over hot headers.
Read the procedure →The best dollar-per-smile mod on a WRX: short throw shifter plus front and rear shifter bushings turns the sloppy 5MT feel into a rifle bolt.
Read the procedure →Clicking on full-lock turns means an outer CV joint is dying. When a boot kit saves the axle and when a quality replacement axle is the smarter play.
Read the procedure →The health check before buying, boosting, or diagnosing an EJ. Reading the numbers that reveal ringland damage before it becomes a rod through the block.
Read the procedure →Cam timing codes (P0011/P0021) on higher-mileage EJs are usually clogged banjo bolt filters in the AVCS oil feed, not dead sensors. The 30-dollar fix.
Read the procedure →The most neglected fluids on any WRX. Fresh GL-5 in the 5MT/6MT and rear diff transforms cold shifting and protects the R160/R180.
Read the procedure →Cloudy GD headlights are UV-burned clearcoat, not dirt. Sanding, polishing, and sealing them properly - the spray-and-pray kits fail in a month because they skip the seal.
Read the procedure →Northeast WRXs dissolve from the bottom up: rear arches, rocker seams, and subframes. The annual oil-film treatment that keeps a GD alive in New Jersey.
Read the procedure →The stock GD turbo inlet is an accordion straw. Replacing it with a hard silicone inlet - the deepest-buried bolt-on on the car - plus why intakes need tunes.
Read the procedure →A clutch pedal that sticks low, engages on the floor, or feels inconsistent is usually hydraulics, not the clutch. Testing and bleeding the master and slave.
Read the procedure →Overboost spikes, lazy boost, or boost falling on its face - understanding the GD's wastegate, restrictor pilot, and boost control solenoid turns mystery into diagnosis.
Read the procedure →