International Harvester 3688

The International Harvester 3688 is a tractor produced by International Harvester. It is equipped with a 436 ci 7.1 L engine. The listed engine power is 113.72 hp 84.8 kW. Transmission: 16 forward and 8 reverse. Operating weight: 11300 to 13200 pounds.

Engine Power

113.72 hp 84.8 kW

Fuel & Capacities

50 gal 189.2 L

Transmission

16 forward and 8 reverse

Operating Weight

13200 lbs 5987 kg

Overview

	1981 - 1985 30 SeriesRow-Crop tractor 30 Series Row-Crop tractor

Production
Manufacturer	International Harvester
Row-Crop tractor
Built in Rock Island, Illinois, USA
Total built	2,572
Original price was $45,000 in 1981

Variants
3688 Hi-Clear	high-clearance model

International Harvester 3688 Engine
International Harvester 7.1L 6-cyl diesel
Engine details ...

International Harvester 3688 Transmission
16-speed partial power shift
Transmission details ...

International Harvester 3688 Power
Drawbar (claimed)	100.2 hp 74.7 kW
PTO (claimed)	113 hp 84.3 kW
Drawbar (tested)	99.21 hp 74.0 kW
PTO (tested)	113.72 hp 84.8 kW
Performance test details ...

Mechanical
Two- or four-wheel drive
Final drives	bull gear
Differential lock	rear
Power steering
Hydraulic wet disc brakes
Cab standard with heat and air-conditioning. Optional burgundy or western finish interiors.

Capacity
Fuel	50 gal 189.2 L
Hydraulic system	22.5 gal 85.2 L

Hydraulics
Type	closed center
Capacity	22.5 gal 85.2 L
Valves	2 to 4
Pump flow	18 gpm 68.1 lpm
Total flow	27 gpm 102.2 lpm
Steering flow	12 gpm 45.4 lpm

Tractor hitch
Rear Type	II
Control	draft sensing

Power Take-off (PTO)
Rear PTO	independent
Rear PTO Type	540/1000 (1.375)
Engine RPM	540@2100
	1000@2100

Dimensions & Tires
Wheelbase	105 inches 266 cm
Weight	11300 to 13200 pounds
Front tire	11L-15
Rear tire	18.4-34
Full dimensions and tires ...

Electrical
Ground	negative
Battery volts	12

References

Buyer's Guide 1982 published by International Harvester
International 30 Series Tractors published by International Harvester
Operator's Manual 3088, 3288, 3488-Hydro and 3688 Tractors (1258513C1) published in 1981
Tractors 90 & 110 HP published in 1981, by International Harvester
3288 and 3688 Product Guide published in 1981, by International Harvester

Engine

Engine Detail — 436 ci / 7.1 L Diesel

Manufacturer	International Harvester D436
Fuel Type	Diesel
Configuration	6-cylinder, liquid-cooled
Displacement	436 ci 7.1 L
Bore/Stroke	4.30x5.00 inches 109 x 127 mm
Air cleaner	dual dry elmement
Compression	16:1
Rated RPM	2400
Idle RPM	900-2400
Starter volts	12
Coolant capacity	26 qts 24.6 L
Oil capacity	14 qts 13.2 L

Transmission

Transmission — 16 forward and 8 reverse partial power shift

Type	partial power shift
Gears	16 forward and 8 reverse
Clutch	355.6mm cerametallic disc
Oil capacity	90 qts 85.2 L
Left lever selects gear, right lever selects high, low, or reverse range. Tractor may be shifted on the move without the clutch between gear pairs (1-2, 3-4, etc). Synchronized shifting, using the clutch, between gear pairs (2 to 3, 4 to 5, etc). The transmission is four-gear with the powershift provided by an electric solenoid actuated Torque Amplifier.
With 18.4-34R1 rear tires.

Dimensions

International Harvester 3688 Tires
Ag front	11L-15
Ag rear	18.4-34

Dimensions
Wheelbase	105 inches 266 cm
Length	184 inches 467 cm
Width	102 inches*Width at minimum tread. 259 cm
Height (cab)	112 inches 284 cm
Shipping weight	11300 lbs 5125 kg
Operating weight	13200 lbs 5987 kg
Ground clearance	13 inches 33 cm
Rear axle	3.25 by 104 inches 82 by 2641 mm
Rear axle	3.25 by 118 inches 82 by 2997 mm
Front tread	60 to 84 inches 152 to 213 cm
Rear tread	66 to 128.5 inches 167 to 326 cm

Tests

Nebraska Tractor Test 1440
Diesel 16-speed 2WD May 26, 1982 - June 7, 1962 Link: Nebraska Tractor Test 1440 file
PTO performance
Power at rated engine speed	113.72 hp 84.8 kW
Fuel use	7.5 gal/hour 28.4 l/hour
Power at rated PTO speed	112.48 hp 83.9 kW
Fuel use	7.1 gal/hour 26.9 l/hour
Drawbar performance
Max power	99.21 hp 74.0 kW
Fuel use	7.5 gal/hour 28.4 l/hour
Max pull	12250 lbs 5556 kg

Photos

International Harvester 3688 with two-wheel drive.

International Harvester 3688 with four-wheel drive.

Recommended Implements & Sizing Guide

Engineering recommendations for International Harvester 3688 based on its 113.72 HP power envelope and ASAE agricultural standards.

Implement & Operation	Recommended Size	Workload Rating	Engineering Notes
Moldboard PlowPrimary Tillage	4 to 5 Bottom (16-18")4 - 5 铧 (40-45 cm)	Heavy Duty	Heavy primary tillage; semi-mounted hitch recommended.
Rotary Cutter / MowerMowing & Clearing	10 to 12 ft Flex-Wing3.0 - 3.6 m 折叠双翼	Heavy Duty	Wide swath pasture and crop residue shredding.
Rotary TillerSeedbed Prep	90 to 120 in Heavy Duty230 - 300 cm 重型旋耕机	Commercial / Field Scale	Deep intensive seedbed preparation for commercial row crops.
Disc HarrowSecondary Tillage	10 to 14 ft Tandem / Offset3.0 - 4.2 m 重型交错耙	Heavy Duty	Aggressive residue cutting in corn/cotton stubble.
Hay BalerHay & Forage	5x6 Round Baler or 3x3 Mid Square1.5x1.8 m 大圆捆或中型方捆机	Heavy Duty	High density baling; requires minimum 85 PTO HP.

Sizing & Soil Condition NoteActual implement sizing varies depending on local soil conditions (heavy clay vs sandy loam), field slope, and operating speed. Heavy tillage implements may require front ballast weights and wheel weights.

Fluids, Capacities & Working Autonomy

Standard fluid requirements, service intervals, and continuous runtime estimates for International Harvester 3688.

Estimated Continuous Field Runtime: 8.5 hrs

Approximately 8.5 hours of continuous field operation at ~75% rated power on a full tank (50 gal / 189.3 L).

Estimated 75% Load Fuel Burn~5.9 gal/hr (22.4 L/hr)

Engine Crankcase Oil

SAE 15W-40 (Heavy Duty Diesel)

Standard Spec: API CK-4 / CJ-4 Heavy Duty

Service Interval: 150 – 250 Hours

Transmission & Hydraulic System

UTTO (Universal Tractor Transmission Oil)

Standard Spec: ISO VG 46 / 68 (Wet Brake & Trans Compatible)

Service Interval: 600 – 1000 Hours

Engine Cooling System

50/50 Ethylene Glycol Pre-mix

Standard Spec: ASTM D6210 / Heavy-Duty OAT Antifreeze

Service Interval: 2 Years / 1500 Hours