Need a little help

[Catherine Gray]

So I'm leaking coolant from the seam where the thermostat housing and the coolant outlet pipe meet I know the parts aren't bad they aren't even two years old so I figure its the gasket (which was not replaced when the parts were) I just don't know what size to get I've seen sizes ranging from 69mm-53mm and just want to make sure I order the right size. Thanks guys

 

[joegr]

Impossible to answer without knowing the year of your LS and the engine (V8 or V6).

 

[Catherine Gray]

Sorry completely forgot to put that in its an 04 V8

 

[joegr]

Okay.

The seal between the "coolant outlet pipe" and the thermostat housing is Ford part 8590 (you add your car and year to get the full part number). You have to get the Ford seal.

The o-ring between the 9N499 elbow from the engine/water pump to the "coolant outlet pipe" is Ford part 707299-S300. This is probably the one that you want, because most of us would call the 9N499 elbow the coolant outlet pipe and would call the coolant outlet pipe the crossover/thermostat housing. If you want to play around with a non-Ford part, then an o-ring that is about 5.7mm thick with an inner-diameter of 52.5 to 53 mm should work. Note that you need to get one with the right material (tolerant to coolant, able to handle the heat, doesn't expand/shrink too much) and the right compressibility.