CARCARETOOL VEHICLE GUIDE

Opel Diplomat

Opel Diplomat — sedan, 2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8. Explore engine specifications, fuel economy, dimensions, tire sizes, seating, maintenance and tire-pressure guidance.

Engine2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8

Transmission2-speed Powerglide automatic

About the Opel Diplomat

Opel Diplomat is a sedan in the full-size luxury car class. The available vehicle data lists 2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8 as an engine configuration, paired with 2-speed Powerglide automatic and a FR layout layout. Public source material describes the model in the context of its design, market positioning and vehicle history.

This Opel Diplomat guide focuses on the details drivers commonly want to know, including engine information for 2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8 and 2-speed Powerglide automatic transmission information. Exact specifications should be matched to the relevant model year and market.

Opel Diplomat specifications at a glance

Use this table for the model-level essentials. Exact figures may vary by year, trim, engine and market.

Make	Opel
Model	Diplomat
Model years	Not specified
Body style	sedan
Vehicle class	Full-size luxury car
Manufacturer	Opel
Production	1964–1977
Market / country	FI, GB, NL, UA

Engine, transmission and performance

Engine information for the Opel Diplomat includes 2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8.. Transmission information includes 2-speed Powerglide automatic.. The listed drivetrain/layout is FR layout.

Engine	2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8
Transmission	2-speed Powerglide automatic
Drivetrain / layout	FR layout

Dimensions, weight and practicality

Dimensions and capacity figures are presented as published source data when available.

Wheelbase	2845 mm (112 in)
Length	4948 mm (195 in)
Width	1902 mm (74.9 in)
Height	1445 mm (56.9 in)
Kerb / curb weight	1380 –

Opel Diplomat other specifications

Image	Opel Diplomat A V8 Coupé 1965-1967 frontleft 2008-07-17 U.jpg
Caption	The 2-door Opel Diplomat Coupé was very rare
Name	Opel Diplomat

Opel Diplomat generations and model years

Where a source covers multiple generations, CarCareTool selects the generation(s) that best match this catalog model instead of mixing unrelated variants.

Generation / scope	Years	Engine	Transmission	Drivetrain
Opel Diplomat	1964–1977	Not specified	Not specified	FR layout
Diplomat A	1964–1968	2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8	2-speed Powerglide automatic	Not specified
Diplomat B	1969–1977	2.8 L ''CIH'' I6; 5.4 L ''54S'' V8	4-speed manual; 3-speed automatic (I6); 3-speed TH-400 Turbo-Hydramatic automatic (V8)	Not specified

TIRE PRESSURE

Recommended tire pressure for Opel Diplomat

Check the vehicle placard or owner’s manual for the manufacturer’s cold inflation pressure. CarCareTool estimates are clearly labelled when an exact verified value is unavailable.

Normal load32 PSI front30 PSI rear

Fully loaded34 PSI front33 PSI rear

Load condition	Front	Rear	Status
Normal	32 PSI	30 PSI	Estimate
Fully loaded	34 PSI	33 PSI	Estimate

Calculate how much air to add

Frequently asked questions about Opel Diplomat

These FAQs are generated automatically for this specific vehicle from the specifications, features and ownership data available in CarCareTool. Questions are selected by relevance so the page focuses on details that can actually be answered for this model.

What engine does the Opel Diplomat have?

The available source data lists the Opel Diplomat engine as 2.6 L ''OHV'' I6; 2.8 L ''CIH'' I6; 4.6 L ''Chevrolet'' V8; 5.4 L ''Chevrolet'' V8. Engine availability can differ by model year and market.

What tire pressure should I use for the Opel Diplomat?

For the correct setting, use the cold inflation pressure on the vehicle placard or in the owner’s manual. When CarCareTool does not have a verified configuration-specific value, its starting estimate is 32 PSI front and 30 PSI rear for normal load. This is an estimate, not an OEM recommendation.

What is the best engine oil for the Opel Diplomat?

There is no single best engine oil for every Opel Diplomat configuration. Use the viscosity grade and manufacturer approval specified for the exact engine in the owner’s manual.

What body style is the Opel Diplomat?

The Opel Diplomat is classified as a sedan.

What are the dimensions of the Opel Diplomat?

The available source data lists length 4948 mm (195 in), width 1902 mm (74.9 in), height 1445 mm (56.9 in), and wheelbase 2845 mm (112 in).

What transmission does the Opel Diplomat have?

The available source data lists 2-speed Powerglide automatic transmission options for the Opel Diplomat.

Is the Opel Diplomat FWD, RWD or AWD?

The listed drivetrain/layout for the Opel Diplomat is FR layout.

Who makes the Opel Diplomat?

The manufacturer listed for the Opel Diplomat is Opel.

When was the Opel Diplomat produced?

The available source data describes production as 1964–1977.

How much does the Opel Diplomat weigh?

The available source data lists a kerb/curb weight of 1380 –. Actual weight can vary with engine, trim and equipment.

What class of car is the Opel Diplomat?

The Opel Diplomat is listed in the Full-size luxury car class.

Which markets or countries sold the Opel Diplomat?

The CarCareTool catalog currently associates the Opel Diplomat with FI, GB, NL, UA. Market availability and specifications can differ.

What came after the Opel Diplomat?

The available vehicle data lists Opel Senator as a successor where applicable.

What replaced the Opel Diplomat?

The available vehicle data lists Opel Senator as the successor where applicable.

How often should I check the tire pressure on the Opel Diplomat?

Check the tires regularly and before long trips, with the tires cold. Use the vehicle placard or owner’s manual as the source of the manufacturer’s recommended pressure.

Should I use the tire sidewall pressure for the Opel Diplomat?

No. The maximum pressure printed on the tire sidewall is not automatically the vehicle’s recommended setting. Use the vehicle placard or owner’s manual for the correct cold inflation pressure.

Does the recommended tire pressure change when the Opel Diplomat is fully loaded?

It can. Many vehicles specify a different cold pressure for heavier loads. Check the vehicle placard or owner’s manual for the exact loading condition.

Can the Opel Diplomat have different tire pressures front and rear?

Yes. Some vehicles specify different front and rear pressures because axle loads and vehicle configurations differ. Follow the exact vehicle recommendation where available.

Why can mileage differ from the published figure for the Opel Diplomat?

Published fuel economy is measured under a defined test method. Real-world mileage can vary with traffic, speed, temperature, tire pressure, payload, maintenance and driving style.

Data sources and verification are available in the page editor; exact specifications can vary by year, market, trim and engine.

Opel Diplomat images

Vehicle images are shown from the stored source image records when available.