What is the resale value of the 1975 Mercedes Benz SL?

This article will give details of the 1975 Mercedes Benz 450 SL and answer the following questions: what is the resale value of the 1975 Mercedes Benz 450 SL? What are the things to check before buying a used 1975 Mercedes Benz SL?

What is the resale value of the 1975 Mercedes Benz SL?

The resale value of the 1975 Mercedes Benz SL majorly depends on the condition of the car. If the vehicle is in good to fair condition then 4000 to 6000 USD is a fair price for the car. However, if the condition of the can is immaculate with no rust or electrical issues then car collectors can pay up to 50,000 USD for a 450 SL.

The Mercedes Benz 450 SL is a convertible sports car produced by Mercedes Benz Benz from 1971 till the end of 1989. The design was an instant success in the domestic as well as the international market and it also remained unchanged throughout its production life cycle.

The Mercedes Benz SL model series R107 was sold in many different engine choices and they were targeted toward the American market. Mercedes Benz sold more than 200,000 units in the United States alone and the SL was the only two-door roadster model in the Mercedes Benz lineup.

The Mercedes Benz SL 450 was powered by an M117 V8 petrol engine and produced 222 horsepower and 377 Nm of torque. The V8 engine gave the Sl 450 a muscle car image as the overall weight of the car was only 1.5 tons. 

As the Mercedes Benz SL was sold in such a large number in the United States there are plenty of cars available for purchase in the used car market. This is a good as well as a bad thing. The good thing is there are plenty of spare parts and donor cars on the market and if someone wants to restore a 450 SL, they can do it without purchasing spare parts from the Mercedes Benz dealerships.

The Mercedes Benz genuine parts are specially tested and offer a 2-year warranty but the cost is simply too much especially if the part can be bought from a scrapped car for a much cheaper price.

The bad thing is since SL 450 was sold in huge numbers, it is not exactly as popular among the car collectors as the older models with model series W113.

What are the things you should check before buying the 1975 450 SL?

The Mercedes Benz 1975 450 SL was very reliable but today it is more than 40 years old. Therefore, the car should be checked by a trained technician specialising in classic cars. Mercedes Benz has a separate classic car division at some authorised dealerships. Following are some of the things you can check without the need to lift the vehicle.

  • Exterior paint condition

Check the condition of the exterior paint. It is possible to identify if the car was repainted by checking the colour in the engine compartment and the area between the door hinges. 

If the car is repainted it usually means there is some sort of accidental repair work performed on the car. If the current owner cannot provide details of the accidental repair work then simply walk away from the deal. 

Mercedes Benz spare parts cost and labour rates are very high, restoring the car can easily cost more than the value of the car. 

The SL450 did not have many electrical control units or relays but the components are mostly located behind the dashboard or under-vehicle carpets and seats. Since the SL was a roadster there may be some water damage to the components. Lift the floor carpet and check for any dirt or foliage, the floor should be clean if there is no water entry into the vehicle.

Check the operation of the interior equipment, especially the air conditioning unit. Many cases of faulty air conditioning units and heater recirculation pumps were reported in the SL produced between 1974 to 1976. Repair jobs for the faulty air conditioning units are complicated and can need a complete strip-down of the dashboard.

  • Poor engine performance/ abnormal noise

Take the vehicle for a test drive, if there is black smoke coming from the exhaust then it is a sign of incomplete combustion. 1975 450 SL also had a single row timing chain that was known to stretch or just break, which led to vehicles not starting complaints. 

Mercedes Benz did resolve the issue free of cost by replacing the timing chain on the affected models and updating the design to a double row chain in the models produced after 1980. It is possible that not all the models were updated with the new timing chain and there is no way to check it unless there are repair bills from the authorised service centre.

  • Service history

Complete service history will not be possible to check as the vehicle is more than 40 years old now but there should be repair bills that can give some idea of the condition of the car. Mercedes Benz car service intervals are usually 10,000 miles or 1 year. It has been observed that engine oil loses some of its properties with age and hence it is replaced annually even if the mileage is not reached.

  • Visual inspection

Carry out a visual inspection of the engine compartment, there should not be any coolant or engine oil leaks. Take a quick look over the brakes and brake pads, there should be no rust as replacing rusty brake components can be very expensive.

The SL450 had a cast-iron engine block with an aluminium cylinder head, there can be cylinder head gasket leaks that cause the coolant and engine oil to mix. This can cause damage to the coolant system and reduce the engine oil level. The condition of the coolant should be okay and there should be no traces of engine oil in the coolant reservoir.

  • Vapour lock

The SL450 is known for hard cranking and poor engine pick up due to vapour lock. The fuel system in the SL 450 had a low-pressure fuel pump that pumps the fuel from the fuel tank to the CIS mechanical fuel delivery system. The heat from the engine and the catalytic convertor caused the fuel vapour in the fuel injector. This resulted in a drop in fuel pressure and the mixture in the combustion chamber became lean. 

Mercedes Benz rectified the issue in the 1977 SL 450 model by relocating the catalytic convertor and reducing the temperature in the engine compartment.

The only possible solution for the 1975 SL 450 is to run a rich mixture or swap the fuel delivery pump to a pump with higher fuel pressure. Few customers also used heat shielding wraps on the fuel line so that vapour lock is not formed in the fuel injectors.

Other articles about Mercedes Benz you may be interested in

What are the power steering fluids equivalent to the Mercedes Benz power steering fluid?

Which is the most reliable model in the Mercedes Benz C Class?

Which is the most expensive Mercedes Benz Production car?

Conclusion.

The 1975 SL 450 was the only roadster model in the 1970s sold by Mercedes Benz if it was specifically designed to meet the American road and fuel regulations. There are plenty of used SL 450 in the second-hand car market and it is a good choice for a 2 doors, 2 seaters convertible cruiser. However, the SL 500 which was only sold in Europe is the most sought after SL model. The European SL model was never officially launched in the USA but many models were sold in the Grey market. The resale value is very high as the engine produced more power since there were no restrictions on exhaust emissions.

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