Jaguar

Jaguar service tips by model

1974-1981 XJ6 and 1982-1987 XJ6 Series III

These cars are generally held to be some of the prettiest sedans ever designed. However, they do have some problems.

The XJ6 was the standard model. In some years and makets Jaguar offered an XJ6L with more floor space for rear seat passengers. A premium Vanden Plas version was also offered on later cars. The Vanden Plas was set apart by special color combinations, full leather interior (the base XJ6 had leather seat faces and vinyl elsewhere), center console in the rear, and plush overlay carpets. The XJ6 and Vanden Plas were mechanically identical.

A 12-cylinder version of this car was sold outside the United States as the Daimler Double Six. The XJ12 model was also sold here some years in small quantity. Maintenance costs are considerably higher on the 12 cylinder models.

Here are some things to check on your car, or on a car you’re looking at buying:

• Gas tanks rust out and they are becoming hard to find.
• Undercarriage rust in general is a problem on these older cars.
• There was a manufacturing problem with the engine blocks on the 1984-1987 6-cylinder cars that caused the rear main seal to leak oil.
• Engine removal and overhaul is needed to repair this properly.
• Front ends have numerous grease fittings, and ball joints and upper control arm bushings can be worn out by 50,000 miles.
• The inboard disc brakes on these cars are very time consuming to replace.

Robison Service has complete repair facilities for these cars. In addition to mechanical service we offer restoration of interior woodwork and leather.

1988-1992 XJ6 and Vanden Plas – the XJ40 models

These cars were a radical departure from the traditional Jaguar. They had a much greater level of electronic gadgetry, much of which has become problematic. They are much more modern and sophisticated in design than the Series II cars they replaced, but they were also the most problematic vehicle Jaguar produced in modern times. Here is a brief summary of problem areas on these cars:

• Exterior door handles become tight and break. Regular lubrication and adjustment can prevent this
• Headlamp switch modules fail and replacements are costly.
• On the 1988 and 1989 cars the electroluminescent dash modules fail and replacements currently cost over $1,000.
• Crankshaft position sensors on early cars were a frequent cause of no start complaints
• The batteries in these cars were too small, leading to no-crank situations. The batteries in these cars will go dead if left sitting more than 2 weeks, even in a car with no battery drain issues.
• Front wheel bearings were too weak, being susceptible to damage hitting potholes here in New England
• The self leveling suspension fitted to these cars was problematic. Most cars have by now been retrofitted with conventional coil springs and shocks in the rear.
• The hydraulic system used for the brake boost was problematic and costly to repair

1993 and 1994 XJ6 modelsThese cars shared the chassis of the first XJ40 cars but Ford’s influence (Ford bought Jaguar in 1990) was beginning to appear in the form of sharply increased quality.

The 1993 and 1994 cars are head and shoulders above previous XJ40 models in terms of production quality.

1997 and newer 8-cylinder cars – XJ8, XJ8 Vanden Plas, XJR,
XK8, S-Type V8, V8 cam chain tensioners:

The tensioners for the cam-to-cam timing chains come apart. The plastic face that touches the chain comes off and the metal base of the tensioner rides on the chain. The car will perform fine until one day the chain will snag on the broken tensioner it will derail, and the valves will bend.

In addition, when the tensioner fails the pieces may tangle in the guides for the main timing chain.

We suggest taking the cam covers off your engine to inspect the tensioners. Inspection takes a few hours, and it may save you thousands in engine repairs. If your tensioners are bad we suggest fitting the latest style.

Replacement of the tensioners with new style parts is an 8-hour job. Replacement of the main chain and guide rails is a much bigger job, generally 20+ hours of additional work. Repair of bent valves is a 40+ hour job. So it’s clearly to your benefit to change the tensioners before they come apart and damage the valves or the main timing chains.

Nickasil damage in 1997-2000 v8 engines:

The early v8 engines used a process called Nickasil to make the cylinder bores. Nickasil is essentially a glass (silica) liner in the aluminum bores. It’s very hard and the pistons can run on it for hundreds of thousands of miles without any significant wear.

However, if the engine is allowed to overheat the Nickasil can sustain damage and fail. If this happens your engine will wear out within a few thousand miles, losing compression and becoming hard to start.

There are three cures if this problem happens to you:

1. Install a used engine from a newer car. Engines are available for $4-5,000 from salvage yards. Installation takes 2-3 days labor.

2. Install a brand new Jaguar short block. This is the best option from a quality and durability standpoint but cost is high — over $10,000 in most cases. The new block uses cast iron liners and will not be subject to the same failures.

3. Repair your engine by installing liners in your block. We are starting to do this now for Jaguar after doing it for many years in Ferrari and Rolls Royce motors. Our iron liners will not fail like Nickasil and cost is lower than buying a new block through Jaguar. This is the preferred repair in our shop.

Overheating problems:

The water pumps in Jaguar v8 engines have plastic impellers. These impellers can come apart, causing the engine to overheat because the water pump no longer does anything. This can be a tricky problem to diagnose because there is nothing visible from the outside. You have to remove the water pump to see what’s wrong. A new pump is the cure, and you have to make sure you flush all chunks of the old pump out of the block to keep the new pump from suffering the same fate.

Another problem we are seeing on 1997-1999 cars is deterioration of the hoses. In some cases the snap fittings that hold the small hoses in place break, allowing the hose to come loose and spray coolant. We suggest fitting all new hoses if this happens to you.