Engine Oil for the Peugeot 404: What You Need to Know
Is it still possible to buy engine oil for the Peugeot 404 at a gas station?
No, unfortunately, the situation is a bit more complicated these days. Modern engine oils have very low viscosity and are enriched with cleaning additives. Compared to the oils used 30 to 60 years ago, today’s oils must meet entirely different requirements. The positive properties of a modern oil can have a negative impact on the functionality of a classic car engine.
In modern automotive engineering, oil change intervals of 50,000 km are considered quite standard. To ensure a long service life, extreme filtration of the engine oil is required to prevent the formation of sludge deposits. Additionally, the engine oil must be suitable for short-distance driving, which leads to very low-viscosity engine oils.
What about the 404?
As a rule, the oil is not changed based on mileage but according to the season. As part of preventive maintenance, an oil change is performed shortly before the car is put into storage for the winter to prevent harmful substances or deposits from damaging the engine. During the winter break, the vehicles are not driven and remain mostly in the garage even in the summer. The average mileage of a vehicle rarely exceeds 5,000 km. To prevent corrosion on engine components (crankshaft, crankshaft bearings, connecting rod bearings, pistons, cylinders, etc.), it is essential that the oil film remains present throughout the vehicle even during periods of inactivity.
Why should special engine oils be used for Peugeot classic cars?
The engine oil must ensure this oil film. However, only thick-viscosity engine oils without cleaning additives can do this. In the French classic cars HY, Traction Avant, and 2CV (up to the 2CV4), there isn’t even an oil filter. Contaminants settle in the oil pan and are flushed out with every oil change. That’s why these vehicles have very short oil change intervals.
However, modern engine oil dissolves the contaminants, which are then returned to the oil circulation system. It is obvious that this can cause very expensive engine damage. Furthermore, it should be noted that the chemical additives in modern oils are generally not compatible with the engine seals found in classic cars. Oil seals and other rubber seals can no longer perform their sealing function due to chemical corrosion.
Due to the chemical composition of the engine oil, cork gaskets are susceptible to being washed out by regular exposure to chemicals. The cork gasket is therefore unable to absorb the engine oil. The cork gasket shrinks, leading to a leak. This results in engine oil leaking out.
Example of the harmfulness of modern motor oils
Imagine a nice plate of spaghetti. Please drill three small holes, each 2 mm in diameter, in the bottom of the plate. Next, serve the spaghetti and drizzle it with high-quality, cold-pressed olive oil. Here you can see how the oil clings to the pasta. There is almost no olive oil at the bottom of the plate. No oil drips out of the holes either.
Now pour some cola over the pasta. Notice how the cola doesn’t cling to the pasta, but actually washes the lovely olive oil right off it. Everything collects at the bottom of the plate, but only briefly, because it all drips out through the small holes and onto the table.
Dear classic car enthusiast, what you’re doing to the spaghetti with the cola is exactly what you’re doing to your engine when you fill it with modern high-tech synthetic motor oils. As you can see, not all motor oils are created equal. Everything certainly has its use, but you should look closely at where and how each is used!
Stay away from modern oils, and definitely don’t use synthetic oils—not even in modern classics!
Where can I get classic car engine oil?
We offer a genuine, mild-alloy engine oil for classic cars from ELF / Total. The perfect 20W50 engine oil is available under item number 20001. ELF / Total was the original equipment supplier for both Citroën (Total) and Renault (ELF) back in the day!
As an alternative, we also carry a classic engine oil from Castrol with a 20W50 viscosity. You can use these 20W50 engine oils with complete confidence in all Citroën, Renault, and Peugeot engines built after 1945 (Citroën 2CV, ID, DS, HY, Mehari, Dyane, AMI, GS, Renault 4CV, Dauphine, Floride, Caravelle, R4, R5, R16, Peugeot 203, 403, 204, 304, 404, 504). Of course, you won’t go wrong using it in a VW Beetle or Mini either.
For newer classics that first appeared in the 1980s, we recommend the 15W40 engine oil (our item number 20025). So every Citroën CX, BX, Renault R5 Super, and Peugeot 205, 505, 405, etc., will be happy with it. But of course, it’s also perfect for Mercedes W123 models or Golf 1+2, Opel Ascona, Ford Capri…
For sports cars (Renault Alpine, R5 Turbo, Porsche 911…), we recommend ELF’s 10W60 engine oil (item 10196).
We also carry a classic single-grade engine oil with SAE 40 viscosity. This single-grade engine oil is used in pre-war vehicles (Citroën 7CV, Peugeot 202, 402, etc.).
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