HILLMAN IMP SLUDGE IN THE OIL

Q I have a 1974 Hillman Imp which has suffered from a flickering oil pressure gauge. When this first occurred, I carried out an oil and filter change and during this discovered that the oil filter housing had a build-up of creamy sludge. As the oil filter housing connects to the cam cover, I also removed this and cleaned out the cover and the flame trap, as well as the connecting pipe. Once I had completed this and with the fresh oil in the engine, the oil pressure gauge remained steady and I had no further problems for a while. However, the gauge has once again begun to flicker, and upon checking the cam cover I have found that the creamy sludge has reappeared. I have not needed to top the cooling system up and so I am convinced that this is not a head gasket problem, and is likely the result of the short journeys I undertake. Are there any easy steps to stop the reoccurrence of this problem? Keith Kirby

A As you have mentioned, I would expect the problem to be related to a number of short journeys, which do not allow the engine to reach a sufficient temperature to steam off the condensation which occurs within it. This then allows the moisture to emulsify with the oil and creates the creamy sludge that has resulted.

There are a number of possible actions you can take to help minimise the problem, and the first would be to check the thermostat – the standard Imp thermostat should be 88°C, but a summer stat was often fitted opening at 71°C which would make it run cooler. There are other options which involve insulating the top of the engine to lessen the effects of the cool air causing condensation, but due to the problems that this engine did have with overheating, this may not be advisable. It will of course depend on the usage of your Hillman, but ensuring that the engine is always run up to temperature once started may be the best course of action.