Coolant Mystery

[uluz2a6]

2004 Ion 2.2
Engine removed to re-ring and replaced.
Water pump replaced
Thermostat replaced (twice, as it was my first suspect)


Engine is great. Coolant system has me baffled. There is no heat through cabin. Heater core lines seem not to have coolant flowing through them (cool to touch). Upper radiator hose is hot, so I fear a blockage at coolant junction hub (thermostat housing area). Once at full heat, coolant "pulses" back into reservoir through small hose.

I replaced thermostat again assuming new one was bad out of the box, but no change.

Coolant system had no prior issues.

What is behind the snap ring at thermostat housing? Could the failure be in there?

Anyone had this issue?

[fdryer]

Did anyone use sealer? Sometimes repairs create new problems. If coolant was drained and replaced from major engine work, unless the cooling system was flushed of all old coolant, allowed to run with plain water and heater checked before draining water and refilling with antifreeze, its anyone's guess where blockage occurred. There's definitely blockage somewhere. Drain coolant and save it if it's new antifreeze. The heater core does not have a shut off valve so coolant always circulates. Both heater hoses should be hot so there's a blockage somewhere. Remove both heater hoses to the engine and manually force garden hose water thru each hose to flush the hoses and heater core. Examine the two engine coolant fittings for blockage. With cooling system opened, check the coolant container hoses for blockage.

[uluz2a6]

Thanks for the reply I admit I use a tiny bit to hold O ring in place, but nowhere near enough to do what you are suggesting. I have purchased 4 Ions where the shop that did timing set used tones of seller to reattach front cover that in turn clocked oil passages to crankshaft journals and wiped out the engines.

I did decide to remove and replace the pipes and thermostat housing from my pile o sh#t lying around and it cured the issue. I haven't cut open the hub to reveal the blockage yet. I will update if I learn a culprit

[fdryer]

Gasket sealer, when used correctly won't be any concern. Its sloppy overuse of it that can create problems. The sealer I was referring to is the universal type cooling system sealer whether in powder or liquid form, added into a cooling system. It circulates freely to the leak site and begins to plug the leak. GM used ginger root tablets after finding aluminum castings developed porous leaks. Members found them and showed pictures. GM put out a service bulletin for dealers to address factory defects. These tablets are like oversize pills, when dissolved in coolant, expand as fibers to plug casting leaks. Stores sell them along with liquid sealant made for cooling systems. Normal cooling systems don't require cooling system sealer of any kind.