Description

Subaru IMPREZA 2008 Service Manual – Factory Specs, Not Guesswork

You’ve got a 2008 Subaru Impreza on the lift. The customer says the check engine light is on, and the transmission feels off. You pull out a generic manual and start guessing torque values? That’s how you snap a bolt in the bell housing and double a simple job. I’ve been turning wrenches for 28 years, and I’ve seen more head gasket failures caused by bad specs than by bad parts. The Subaru IMPREZA 2008 Service Manual is the only document that tells you exactly what Fuji Heavy Industries intended. 3860 pages of step-by-step procedures, not a single page of fluff. This is what you need on the bench.

Engine and Electrical: Where This Manual Earns Its Keep

Open to the SPECIFICATIONS section. Under ENGINE and ELECTRICAL you’ll find the exact data for the EJ25 and any variant that rolled off the line in 2008. Compression ratios, firing order, ignition timing – all spelled out with the factory tolerances. I’ve had guys come in with aftermarket printouts that list the valve clearance 0.002 inches off. That’s enough to cause a misfire code. This manual gives you the number straight from the assembly line. Page 73? It lists the charge pressure for the turbo models if you’re working on a WRX. No interpretation needed.

Transmission Work – Don’t Guess the Specs

The TRANSMISSION chapter covers both the 5-speed manual and the 4-speed automatic (plus the 5-speed automatic if equipped). Fluid capacities, line pressures, clutch pack clearance – everything. You’ll find the torque converter end play specs on the page after the removal procedure. I’ve had apprentices skip those pages and over-tighten the valve body bolts. That’s a $600 mistake. This manual tells you the inch-pound values for each bolt. Use it.

Why Factory Specs Beat Aftermarket Reprints

Aftermarket manuals copy from each other and introduce errors. Subaru’s own SERVICE MANUAL includes the latest TSB updates and corrections printed as of 2008. The PRECAUTION chapter covers ABS, VDC, airbag disposal, and even the correct way to remove coolant hoses without damaging the fittings. That’s information you won’t find in a third-party book. If you’re serious about doing the job right, you use the OEM document. Automotive Industry Overview shows that OEM documentation reduces warranty claims by 40% in dealerships. That’s real money.

3860 Pages: What’s Actually Inside

Breakdown: GENERAL INFORMATION (foreword, how to use, specifications, precautions, identification, recommended materials, pre-delivery inspection, periodic maintenance). Then the major systems – Engine, Transmission, Electrical, Steering, Suspension, Brakes, Body, Heating & AC, and Diagnostics. Every section includes the exact OEM torque specifications, wiring diagrams, and diagnostic flow charts. No guesswork – just factory steps. The PRE-DELIVERY INSPECTION section alone has 38 checkpoints, including TPMS initialization and immobilizer setup. Use that for any PDI job.

Who Should Buy This Manual

DIY owners who plan to keep their Impreza for another 100,000 miles. Home garage enthusiasts who’ve already done an oil change and want to move to timing belts and head gaskets. Professional mechanics who need a reliable reference without crawling under a dusty shelf. If you’ve got a scan tool and a torque wrench, you can follow these procedures. But you need the right numbers. The manual also covers the VTEC-like variable valve timing system used on some 2008 models – it’s all in there.

FAQ

Is this manual for the 2008 Subaru Impreza only?

Yes. Covers 2008MY GE and GH chassis. Not for 2007 or 2009.

Does it include wiring diagrams?

Absolutely. The ELECTRICAL section contains full system schematics for the engine management, ABS, SRS airbags, audio, and body control. Each diagram is accompanied by connector pinouts and color codes. If you’re chasing a parasitic draw or a no-start, this is your map. The manual even includes the test mode connector location for the ECM – saves you half an hour hunting under the dash.

What about torque specs?

All fasteners are listed in the SPECIFICATION and ENGINE sections. Head bolts, main bearing caps, transmission case bolts – inch‑pound and foot‑pound values. Page references are in the index.

Can I use this for a 2007 Impreza?

Not recommended. 2008 had several running changes. The wiring and some torque values differ.

You’re paying for one thing – accuracy. This manual gives you that. Access the Factory Manual now and stop relying on forum posts and ambiguous reprints. Your Impreza deserves the original spec.

Related Manuals:
SUBARU IMPREZA 1993 Service Manual – Section: Electrical Section
Subaru Impreza Service Manual
SUBARU Impreza 1994 Service Manual – Section: Engine Section

External reference: Automotive Industry Overview