This is an FYI for Gen-1 owners. I hope it might help someone with diagnosis.

I'm about to pick up my 2004 "S" with OEM water pump and SC, and just over 95,000 miles, as it just got repaired (by Johnny's Auto Clinic of San Pedro, CA). The problem was a coolant leak at the "O" ring between the water pump and the rest of the engine. I have heard that that is not unusual. What I think is strange (to me, anyway) is that the coolant would NOT leak when the system was pressurized, but ONLY at night, after the engine had cooled completely, and the parts contracted. Apparently, as the engine warmed up, the critical parts would expand enough to form an effective seal with the O-ring, even though it was no longer working properly.

The symptom was a puddle of coolant every morning under the front of the car, but NO evident leaking during the middle of the day -- even after the car sat for as much as 3-5 hours (between parking in the morning and lunchtime, and again after lunch until time to drive home. Obviously, I was topping it up every day before I got it to Johnny. Even then, he did find a small leak under pressure in the to radiator hose, and fixed that (it was a small leak, and was spraying onto the block, so that it probably evaporated and didn't puddle). After that fix, though, Johnny's guys "artificially" pressurized the system COLD, and let it sit overnight, so THEN they located the o-ring leak.

 

This is pretty common, I keep the water pump orings in stock cause we've seen so many.

 

Could this cause water movement problems?

 

By the time you take the car apart to get to the water pump, are you better off just putting a new one in and checking the oil in the SC?

 

Mister E - You are correct. That's exactly what Johnny's did. Everything's back to being beautiful again!