Hello All,

Between bouts working on my 240, I've been trying to solve a coolant leak that just has me stymied. The car has 145K.

Although I just changed my coolant and swapped out the thermostat, I've now changed out the thermostat gasket three times, this last time with a 'shmear' of RTV. Since I had just removed the thermostat housing it was only logical that I must have done a poor job on the thermostat housing, or there was a nick or some problem with the housing. Not so, as it turns out because I've pressurized the system, sprayed soapy water around that housing as well as used crumpled up paper towels under the thermostat housing and there are no leaks there. I'm also certain that none of the hoses or hose connections are leaking and the radiator, although original is fine.

With it so "busy" from above as well as below, hampering any good view, I still can't figure out where the leak is. The drips always end up on the underside of the oil filter. I don't think the coolant sensor is leaking (too far away) but I wonder if the HEPU water pump I installed in 07 (when I changed the T-belt) when the car had 105K is leaking. Although I did the job, I don't recall much. Should I peel back the wheel-well flap? Will I be able to view the pump without removing the belt?

Any thoughts you might have as to how to proceed would be appreciated.

Marty Wolfson