Hey guys, 2006 XB here. I have a coolant leak that seems to stop when temp control is all the way to cold. Seems to be coming from the front of engine, thermostat housing I assume since it's hard to see the bottom of the housing, at the block. Is the housing an integral part of the block, or does it bolt on? Which way is it better to get to it: a/c pump off (bottom), or air intake off (top)?

 

From what I can see the heater control only directs air through or around the heater core in the heater box under the dash and does not control coolant with any type of valve. It may just be a coincidence that you get a leak when you use the heater control. You may want to check for radiator damage, cap, expansion bottle, or hose clamps leaks.

 

Checked all that, the only coolant crusting I can see is right at the point where the o-ring gasket resides, right in front of the thermostat, and a bit more around the housing. Someone told me that could still be the water pump.Make any sense?

 

that depends on what you mean by the front of the engine. If you are talking the belt end that is where the water pump is and they do leak in fact mind will leak if I get the radiator fans to turn on at 205 degrees engine temperature but if it stays below that usually not a problem. Typically I get a line of pink on the sound deadening insulation under the hood right above the belts. Any crusty residue around the fittings means that it is leaking and you should probably think about replacing the gaskets there with a good cleaning of the metal surfaces before reassembly.

 

By the front I mean toward the front of the car, facing the radiator. The thermostat is facing that way as well. So I guess that would be the left side of the engine then... I was just told that the water pump weeping hole is right at the bottom of it, so if it was leaking, the inside of the pulley should have pink residue as well, although I don't have any sign of splashing like you mentioned... Did you check your pump?

 

Its been leaking a little since it was new and the local dealer didn't think it was worth replacing under warranty when I mentioned it so it's still in. Supposed to have been a lot of defective pumps around that time but they didn't recall the ones in the xb. I run the ScanGauge and watch the temp when stuck in traffic on hot days and if needed run the heater to keep it under 200 so pressure doesn't build up and cause it to leak. There are times that I smell the coolant a little but I have never seen a big loss of coolant and once in a while I top off the expansion bottle with fresh pink from the gallon I bought. I have 51k on it after almost 7 years.