MC

In my 80SC, I am experiencing some rise in my oil temp gauge. The first year I had the car, the needle never moved "out of the box". It stayed right below the line. At first I thought I was low on oil, but the dipstick still reads above the fill line. Usually the druck press gauge and the rpms are about the same while driving. But, when this happens, the oil temp gauge goes up, the druck press starts to go down (doesn't match rpms), and there seems to be a power loss. It happens after about 20-30 minutes of driving, yet it doesn't happen all the time. I'll pull over to check the oil level but it is always ok.

Sometimes the oil temp will rise slightly out of the box yet stay there and not rise any further. Anyone want to take a stab at this mystery? Other than changing the oil and filter, any suggestions? Anyone else had this problem?

Bill Verburg

That sounds like either a sump venturi problem or a pressure relief valve problem. Both were supposed to be cured on the 80 SC models though. Engines starting with 628 2539(49 state)and 658 1060(Calif.) What happened on the earlier SCs was that cavitation caused by the sump screen would prevent the scavange pump from removing oil from the sump, a lot of oil ended up in the sump causing oil press. to drop and oil temp to rise. A few minutes at idle/low speed would cure the symptoms.

The cure was a new sump screen(930.107.314.00)

The other problem which was actually addressed first was the pressure relief valves. There are 2, a safety valve just downstream of the oil pump and a pressure relief valve downstream of the thermostat. The pressure relief valve cap faces downward on the lower surface of the right hand crankcase. The safety relief valve is mounted horizontally in the left crankcase just aft of the oil pump. If them pressure relief valve does not operate properly, the safety valve will open dumping excess oil into the crankcase.

The cure here was a new pressure relief valve spring (930.107.521.01), screw cap (999.064.026.02), spring guide (930.107.533.00). At the same time, the safety valve screw cap was changed over to the new type used on the pressure relief valve

The above was taken from an article by Al Caldwell. it can be found in "Up~Fixen" vol VIII
Saftey Relief Valve #s 29-32, Venturi # 41


Pressure Relief valve #s 29-32