Jensen Interceptor Buyer's Guide

Jensen Interceptor Buying Tips

This advice is based on our experience of buying, owning and running an Interceptor. It is designed as a guide to help you choose the right car, but it is not intended as an exhaustive evaluation of the car. It assumes some prior knowledge of the models available. Our knowledge particularly relates to the 7.2 litre Mk3, which is the most common.

General

It is difficult to judge an Interceptor based on price alone. When buying an Interceptor a good general guide is to buy on bodywork and assume that some expenditure on mechanicals will be necessary. Resolving poor bodywork can be difficult to quantify. Fixing weak mechanicals is a more known quantity.

Engine

The 6.3 litre Chrysler is generally acknowledged to be the better engine, but was only fitted to Mk 1, Mk2 and early Mk3 cars. The Mk4 used a 5.9 litre Chrysler engine. Aficionados prize early Mk3s for their blend of engine and aesthetics. However either engine is strong, generally reliable, unstressed and simple to maintain. It should be smooth and silent with no knocking on start up. The main weaknesses tend to be:

Manifold gaskets at the cyclinder head: extreme under-bonnet heat tends to warp the contact. New gaskets do not repair the problem. The head needs to be shimmed flat. Approx. £150 per side
Service history: few Interceptors will have a complete service history. In general cars will either have covered high mileages or very low mileages. There are problems associated with either case. Check for regular oil changes and good maintainance - the engines can suffer from lack of use and don't suit a combination of cold starts and short runs. Check for valve and piston wear.
The engine is designed to run at extremely hot temperatures but the dashboard needle should stay in the cool area, even after long runs and traffic jams. Overheating is not a good sign.
The oil pressure should run at a minimum of 60psi at speed or 25psi at idle
Check all wires, pipes and tubes: due to the extreme uner-bonnet heat they can perish quickly, which leads to other problems. This is particularly an issue with electrical wiring.
A full engine rebuild will cost around £2,000 in parts and £3,000 in labour
The SP is rare, certainly desirable but not necessarily ideal as a first-time purchase due to the extra complexity. It is also relatively difficult to keep in tune.
The engine can be tuned and modified easily, although very few have been. A good improvement is a fuel injection conversion, which improves economy and driveability.

Transmission

The Torqueflite gearbox is strong, incredibly smooth and well matched to the lazy engine. A few Interceptors were supplied new with manual gearboxes but this car was made for an automatic.

A full gearbox rebuild will cost £500
The main problems are caused by oil leaks, which are quite normal for the car but if the levels are not monitored can lead to more serious problems due to wear.
The gearbox should change up and down very smoothly, almost imperceptibly. If it is worn the change into top in particular will be clunky.
The rear axle is also prone to leaks. Signs of excessive leaks clearly indicate problems.
The diff seal is particularly problematic because it uses a 'U' seal that is difficult to fit, leading to oil loss that needs monitored

Bodywork

Every Interceptor was built by hand and uses extensive lead loading. Consequently, what appears to be a simple repair can end up being very expensive.

Jensen had high standards so check for consistent panel fit.
However, Mark 1 and Mark 2 Interceptors are considered to be better quality, but all cars are finished to a high standard. Production of the Mark 3 was increased considerably and Jensen workers felt that quality suffered and some components were cheapened.
The sills are prone to rot - behind the stainless steel cover are inner and outer sills; the inner sill is impossible to inspect visually. Poke a screwdriver into the drainage holes at either end - it should not disappear more than 1.5 inches inside. Replacement of both sides costs £2,000.
Check the passenger footwell boxes, particularly along the leading edge
Check for corrosion around the base of the ear screen and around the hatch hinges. This area is very prone to rust and expensive to repair well - even light bubbling can mean removing the glass, which is difficult to refit well.
Check the fit of the windscreen, which is prone to leaks, leading to rot in the surround and in the footwells.
Other areas of rust: rear wheelarches, fuel filler flap and surround, front wheelarches, door bottoms
In certain areas the lead loading can react with the bodywork to cause rust from the inside. Check particularly around the C pillars and where any remedial work has been carried out, for example wheelarches.
The bonnet and wings can suffer from heat crazing caused by the under-bonnet heat
Check the condition of the front and rear bumpers - rechroming can be expensive

Interior

Interceptor interiors tend to be hard-wearing, although those on Mk3s are of lower quality and those with sheepskin inserts also tend to wear quickly. Interior specifications changed constantly and Jensen, like many small companies, tended to mix and match specifications to suit customers or stock availability.

Walnut dashboards are attractive but tend to delaminate and are expensive to repair
Leather seats and interiors are relatively easy to source second-hand but retrims are expensive. Refurbishing a worn interior without replacement will cost around £1,000. A new interior will be £5,000 but this often isn't necessary.
Switchgear and dials are durable, although speedometer cables tend to wear (check for a dull hum)

Other

The GKN alloys fitted to Mk3s are attractive but tend to become porous and slightly misshaped. If this is the case they are very difficult to balance and will have plenty of weights attached. Replacements are now available.
Correct profile tyres cost around £200 each; however, GKN-shod Interceptors can be fitted with slightly different profile tyres at much lower cost.
The twin-pipe exhaust system is large and heavy and in multiple sections that often do not fit together particularly well. Check the fit and condition. A common design fault of the Interceptor is for (very light) exhaust fumes to be drawn into the cabin when the windows are partially open. Fitting marginally longer back pipes cures this problem.

Driving Experience

For most first-time Interceptor drivers the experience is a revelation. It is a long way from the basic, lazy, rolly-polly, big-engined luxo-barge that some expect. A well-sorted Interceptor is smooth, quiet, extremely refined and very easy to drive. The experience is much more modern than most expect and more sophisticated. It is also a very safe and secure car to drive.

A good Interceptor should hold the road firmly with little disruption over uneven surfaces. It will have good grip, take corners flat and precisely (at least at reasonable speeds) and the steering should be light but accurate. An Interceptor is easy to place correctly and control well on the road. Acceleration should be smooth, quiet and with a continuous flow of power from very low revs. If accelerating hard from a standstill the car should move off the line immediately without body movement or unnecessary wheelspin.

Finding One

We strongly recommend joining the friendly and helpful Jensen Owners Club (www.joc.org.uk). It is a good place for advice and a good source of cars to buy, most of which are well-known to club officials. The website also has a good Forum. Jensen Interceptors are all unique and everyone has their own preferred specification. But unless you are very patient, it is likely that you will have to compromise your original Interceptor specification in order to buy a good car. There are plenty out there but, as with any classic, see a few, get a feel for the car and take as much advice as possible. When you find the car you want it's worth investing a few hundred pounds in an inspection.

Our Interceptor gets a lot of use and we have first-hand experience of the problems and pitfalls. We're not technical experts but we're happy to answer questions and offer advice and guidance. Please email jensen@greatescapecars.co.uk or phone 01527 893733 with any questions.