Description

Infiniti G20 1991 Service Manual – Real OEM Data, Not a Reprint

You’ve wasted enough Saturday afternoons fighting aftermarket manuals that list three different torque specs for the same bolt. Or worse – none at all. I’ve seen DIYers snap head bolts because some PDF said “tighten to 60 ft-lbs” when the factory calls for 22 ft-lbs plus a 90-degree turn. That is why you need the Infiniti G20 1991 Service Manual – the actual manual Nissan issued to its dealers, not a scanned reprint scrambled by OCR. 1054 pages of factory-approved procedures, wiring diagrams that actually match the car, and torque values you can trust. No guesswork, just the data that built these cars.

Infiniti G20 1991 Service Manual: Real OEM Data

This manual was printed in 1991 by Nissan Motor Co., Ltd. The foreword on page 2 states: “All information in this manual is based on the latest product information at the time of publication.” That means every procedure in sections like Engine Mechanical (EM), Fuel & Emission Control (EF & EC), and Brake System (BR) was written by the engineers who designed the car. If you see a torque spec in the GI section (page 3 covers tightening torque of standard bolts), that is the number the assembly line used. Aftermarket publishers don’t have access to those records – they photocopy, guess, or omit.

Torque Specs from the Factory – GI Section

Page 3 of the manual lists the tightening torque of standard bolts. But that is just the start. Every critical fastener in the EM chapter has its own table. The General Information (GI) section also includes how to read wiring diagrams (GI-7) and follow flow charts in trouble diagnoses (GI-11). You get the actual Nissan diagnostic logic, not some generic “check voltage here” advice. For a 1991 G20, the factory torque for the cylinder head bolts is 22 ft-lbs initial plus 90 degrees – confirmed in the EM section. I’ve seen three different aftermarket manuals print three different numbers. This one has the right one.

What’s Inside the 7 Key Sections You’ll Use Most

The Quick Reference Index lists 16 sections. Seven of them are what any serious job will hit: Engine Mechanical (EM), Engine Lubrication & Cooling (LC), Clutch (CL), Manual Transaxle (MT), Automatic Transaxle (AT), Front Axle & Suspension (FA), and Brake System (BR). Each section starts with an inspection procedure, then disassembly, then reassembly with torque values. The Electrical System (EL) section alone is thicker than most aftermarket manuals. If you’re swapping a water pump, the LC section gives you the coolant capacity (6.3 quarts), the belt tension specs, and the bolt tightening sequence. That kind of detail keeps you from pulling the radiator when you don’t need to.

Read the Wiring Diagrams Correctly

The GI section has a dedicated page (GI-7) on how to read the wiring diagrams. Most DIYers skip it and end up chasing shorts. The Heater & Air Conditioner (HA) section uses those diagrams to show you the blower motor circuit, the A/C compressor relay, and the thermistor. Every wire color is listed – Nissan used a specific code. The manual tells you how to interpret splices, connectors, and ground points. If you’ve ever had an electrical gremlin on a 1990s Infiniti, you know the aftermarket diagrams are often wrong. This manual is the source.

OEM vs Aftermarket: Why This Manual Wins

Aftermarket manuals like Chilton or Haynes are written by freelance writers who disassemble a car once and take notes. They miss steps, merge different model years, and often omit safety warnings. The Infiniti G20 1991 Service Manual includes a full PRECAUTIONS section (page GI-2) that covers battery disconnect, fuel system depressurization, and jacking points. The LIFTING POINTS AND TOW TRUCK TOWING (GI-21) shows exactly where to place the lift arms. That matters on a unit-body car with pinch welds. I’ve seen a floor jack crush a rocker panel because someone used the “generic” location from an aftermarket guide. This manual has the factory drawings.

If you need the next model year, check the INFINITI G20 1992 Service Manual. For a deeper dive into identification numbers, the Infiniti G20 1993 Service Manual – Section: Identification Information has the VIN decoding charts. And if you’re working on a later Nissan product, the Infiniti FX35, FX50 2009 Service Manual – OEM Factory Specs follows the same engineering approach. For background on how manufacturers structure service documentation, see this Automotive Industry Overview and Automotive Industry Overview.

Frequently Asked Questions

Does this manual cover the automatic transmission transaxle?

Yes, section AT covers the automatic transaxle.

What is the page count and publication year?

1054 pages, published in 1991 by Nissan Motor Co., Ltd.

Is this the same manual the dealer used in 1991?

Exact same. This is the official service manual issued to Infiniti dealerships. The foreword and safety notice are identical. Aftermarket reprints often crop out pages or rescan at low DPI, but this is a true factory PDF with all 1054 pages intact.

How are torque specifications listed – metric or imperial?

All torque specs are given in both Newton-meters and foot-pounds. The GI section includes a tightening torque table for standard bolts. For critical fasteners like head bolts, the exact values are listed in the EM chapter. You’ll also find fluid capacities in quarts and liters. Nissan provided both because techs work in both systems. If you rely on a manual that only gives Nm and you’re using a foot-pound wrench, you’ll convert wrong. This manual gives you both numbers.

Safe? I’ve been turning wrenches since before the G20 hit the streets. When I see a DIYer or a shop tech fighting a P10 because they used a generic manual, I tell them to get the factory source. The Infiniti G20 1991 Service Manual is that source. 1054 pages, OEM wiring, real torque values. Stop burning time on bad information. Access the Factory Manual.