I've just put an '89 Jetta [gas] back on the road after a year on blocks. I'm getting a significant amount of fuel in the oil system. Time for new rings?

The fuel mixture is heavily dependent on the engine temp, a bad reading can cause it to run too rich, resulting in fuel in the oil. I'd check the engine temp sensor for the fuel injection. It's a two pin electrical connector located at the water outlet on the cylinder head (hose to the radiator). Using a multimeter the resistance between the two sensor pins should be about 2000-3000 Ohms @ 68F, 800-1000 Ohms # 122F and 225-275 Ohms @ 194F (operating temp).

The fuel mixture is heavily dependent on the engine temp, a bad reading can cause it to run too rich, resulting in fuel in the oil. I'd check the engine temp sensor for the fuel injection. It's a two pin electrical connector located at the water outlet on the cylinder head (hose to the radiator). Using a multimeter the resistance between the two sensor pins should be about 2000-3000 Ohms @ 68F, 800-1000 Ohms # 122F and 225-275 Ohms @ 194F (operating temp).

Many thanks Boschmann - this had never occured to me [or my dealer's cheif mechanic] - I wanted to go the the expensive solution first.