oneton

? am I wrong thinking 195*

db/sb

180° is the OEM thermostat temp...at least is it for a 2006 2.4...

843de

For the OP's 2007 LS with the L-61 2.2 you need a GM PN#12622410 (AC Delco #131-158), opening temperature 180°.

db/sb

If I'm not mistaken, all HHR's use the same thermostat regardless of year or engine. That's the same on used in most, if not all Ecotec powered vehicles from about 2001 until now.

Sister's HHR

My apologies for resurrecting an old thread ...



I, too, am about to flush my cooling system (have done this with all my vehicles over many years). My concern is that it appears that my LS 2.2's cooling system works in reverse of the cooling systems that I'm accustomed to and that are pictured on the Prestone Flush 'n Fill Kit's instructions. The instructions say to install the tee in the "heater inlet hose" and shows a typical, old-style V-8 or Inline-6 engine with the thermostat housing at the end of the top radiator hose, connecting to the intake manifold. So the thermostat on those engines controls the flow of heated coolant OUT of the engine, into the top of the radiator. Flushing through the heater inlet hose, therefore, allows a back-flushing through the heater core, out the heater outlet hose, through the water pump, through the bottom radiator hose, and up through the radiator (as well as down through the engine, via the heater bypass south of the thermostat housing, and out through the water pump, up through the radiator).


The 2.2's thermostat apparently controls the flow of cooled coolant INTO the engine via the bottom radiator hose. So it appears that, unless the engine reaches ~180 degrees to open the thermostat during the flush, I won't get a backflow up through the radiator, regardless of which heater hose I use to install the flush tee, since it appears the heater outlet hose connects to the thermostat bay on the engine side of the thermostat. In other words, regardless of which heater hose I use to install the flush tee, it appears that my flushing will for the most part just reach the heater core and the engine, flowing out through the fill cap in the top radiator hose, with some unpressurized flow down through the radiator via gravity.


Can anyone confirm this and give any input regarding my attempt at an effective flush? I have considered starting with a fully warmed engine to get at least a little back-flushing action through the bottom hose before the t-stat closes. I currently have a radiator flush product in the system and want to get all of that out before installing new coolant along with a new radiator and cooling fan (blades somehow broke off and damaged the radiator).


Also, since the heater OUTLET hose is more accessible and further from the heat of the exhaust (the heater inlet hose has a foil insulation around it from the factory), does anyone have an opinion as to using the heater OUTLET hose for the tee, if the flow pattern described above is correct?

donbrew

Read the Prestone directions again. I'm pretty sure they say to remove the t-stat.

The t-stat's job is to keep the coolant WARM enough, not cool. It opens at 180F and stays open, until the fan comes on at 217F and runs until the temp gets down to 180F, then it closes.

The bypass hose allows SOME coolant to go around the t-stat, so that you can have cabin heat quicker.