For filling up the system you will use 9.5 liters of special Green coolant type. It’s important to provide cooling for Peugeot’s engine with 1.9 liters volume. You may use code of motor D9B(XUD9A) and volume figure of 1.9 or just tell the 1991 year of production to buy liquid. There is no chance 1989 Express engine will work efficiently with bad cooling. There are some conditions in servicing cooling module at Peugeot Express.
It’s obvious that every 170(XN1T) motor needs good service as stated by Peugeot in instruction. To endure car life take only Green antifreeze and pour not more or less than 9.5 liters. Use your 1.9 engine longer in 1988 Express by keeping these rules. So better use Peugeot’s advice for servicing 1994 Express.