{"product_id":"innova-3612-compression-tester","title":"Innova 3612 Compression Tester — 0–300 PSI Dual-Scale Gauge, 14mm Adapter, Release Valve | Air-Cooled VW \u0026 Porsche Engine Health Check (3612)","description":"\u003ch2\u003e\u003cb\u003eInnova 3612 Compression Tester\u003c\/b\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cb\u003eShort answer:\u003c\/b\u003e The test to run when an engine still idles rough after a by-the-book tune-up. Screw the 14 mm adapter into each plug hole, crank the engine, and read each cylinder on the 0–300 psi gauge. Even, healthy numbers mean the problem is fuel or ignition. One low cylinder means a valve, ring or head gasket problem, and a squirt of oil tells you which.\u003c\/p\u003e\n\u003cp\u003eOur \u003ca href=\"\/pages\/vw-tune-up-spec-lookup#compression\"\u003eVW Tune-Up Spec Lookup\u003c\/a\u003e gives the factory compression figures where VW published them, and the procedure to get a reading you can trust.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eVehicle \u0026amp; Engine Fitment\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eAir-cooled VW Type 1, 2, 3 and 4:\u003c\/b\u003e 14 mm spark plug threads.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePorsche 356, 912, 911 and 914:\u003c\/b\u003e 14 mm spark plug threads.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAlso fits:\u003c\/b\u003e 12 mm and 18 mm plug threads with the included adapters.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eKey Features \u0026amp; Benefits\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003e2½\" dual-scale gauge:\u003c\/b\u003e 0–300 psi and 0–2,100 kPa, so a reading matches either manual.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSide release valve:\u003c\/b\u003e holds the reading until you've written it down, then resets without disconnecting the hose.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003e15\" fuel-rated hose with brass fittings:\u003c\/b\u003e reaches the plug holes behind the cylinder tin.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eThree adapters:\u003c\/b\u003e 12 mm, 14 mm and 18 mm.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eTechnical Specifications\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003ePart Number:\u003c\/b\u003e Innova 3612\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eGauge:\u003c\/b\u003e 2½\" dial, 0–300 psi \/ 0–2,100 kPa\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eHose:\u003c\/b\u003e 15\", with side release valve\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAdapters:\u003c\/b\u003e 12 mm, 14 mm, 18 mm\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eFrequently Asked Questions\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eHow do I test an air-cooled VW?\u003c\/b\u003e Engine warm, all four plugs out, throttle held wide open, coil wire disconnected so it won't start. Crank each cylinder for the same number of strokes and write the reading down.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eWhat's a good reading?\u003c\/b\u003e VW's manual gives 114–142 psi new and 100 psi minimum for the B and early AE 1600, and 107–135 psi new and 85 psi minimum for later AE, AH and AK engines, with no more than 28 psi between cylinders. The \u003ca href=\"\/pages\/vw-tune-up-spec-lookup#compression\"\u003espec lookup\u003c\/a\u003e shows the figure for your engine.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eOne cylinder is low. Now what?\u003c\/b\u003e Squirt about a teaspoon of engine oil into that cylinder and test it again. If the number comes up, the rings are worn. If it doesn't, it's a valve or the head seal. A tight valve is the first thing to check: adjust the valves and test again.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eInstallation\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cb\u003eTech Note:\u003c\/b\u003e Pull the coil wire from the distributor cap and ground it before cranking, so the engine can't start and the coil isn't sparking into the open air.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cb\u003eExplore Related Categories\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eDoing the full tune-up? Start at the \u003ca href=\"\/pages\/vw-tune-up-spec-lookup\"\u003eVW Tune-Up Spec Lookup\u003c\/a\u003e, then browse \u003ca href=\"\/collections\/tools\"\u003eTools\u003c\/a\u003e and our \u003ca href=\"\/collections\/engine\"\u003eengine parts\u003c\/a\u003e.\u003c\/p\u003e","brand":"Innova","offers":[{"title":"Default Title","offer_id":66877313548403,"sku":"3612","price":49.95,"currency_code":"USD","in_stock":true}],"url":"https:\/\/www.washburnsmetal.com\/products\/innova-3612-compression-tester","provider":"Washburn's Metal","version":"1.0","type":"link"}