Looked online and saw the actuator under the dash. I'm thinking now it may not be that, if turn the van off when the heat has been hot the actuator should stay in that position.

 

I had a radiator leak and I would have no heat until the engine was fully warm, then I would have intermittent heat. It sounds like you aren't getting hot coolant from the engine all the time. Check your radiator level with the engine running, warmed up and full heat on in the cabin.

 

This does sound very similar. Years ago my son had an old Subaru where the temp gauge would shoot up - but there appeared to be enough coolant in the reservoir and radiator, We did a 'burbing' procedure to remove trapped air in the system which resolved that. Part of the process required adding coolant while the engine was up to operating temperature. If I didn't have the coolant system flush scheduled Tuesday I'd definitely do as you mentioned.

 

This is terrible advice. Opening a pressurized cooling system at operating temp causes the coolant to flash boil. Before the cap is off it will be spraying everywhere and scalding any exposed skin.

Besides, even if that wasn't an issue, there is no advantage to checking the coolant with the engine running. Even leaving the cap off during warm up, the coolant will heat up, expand, and start dumping out of the radiator before a proper level check could be performed. That's why the overflow reservoir is there - to collect the excess coolant when this happens. After the engine cools down, a vacuum forms in the cooling system and draws the necessary amount of coolant back out of the reservoir to keep the system topped off. It's not going to hurt to check the radiator level, but it must be done cold if for no other reason than safety.

As long as there's no leaks, the valves in the radiator cap are working properly and there's nothing blocking the flow between the radiator and reservoir, the system will function as it should which includes bleeding air through the overflow reservoir. Sometimes air can get trapped in the heater core but in most cases that only happens after the cooling system has been drained significantly for repairs and even then it's resolved by cranking the heat full blast for 10-15 minutes.

 

When we did my son's Subaru procedure we started the engine cold with the radiator cap off, waited until the thermostat opened which was when the coolant level in the radiator went down. It's certainly dangerous to remove the cap after the engine has reached operating temperature Sounds like the 'burping' procedure doesn't apply to newer vehicles since the reservoir will compensate for air in the system.

 

Got the coolant flush done yesterday. This morning after the temp gauge read just 1/4 on the scale - already there was some heat. After getting to normal temperature there was consistent heat. I wonder then as georgef and scari01 stated - could the coolant level simply have been low, but not appearing to be? The level in the reservoir and radiator appeared normal, but maybe there's more than meets the eye.

 

So much for that - same trouble with heat this morning. When going home same thing, when stopped at a light for a while the heater air temp cooled down significantly. After moving and no long stops from that point on the heat was fine the remaining 10 minutes or so. Also like a few months ago the check engine light came on (went off after a while a few months ago). At least I believe it's the check engine light, a yellow engine shaped icon. I'll need to look that up.

 

The icon went away. One morning last week there was again no heat after idling about 7 minutes. A couple minutes after driving for the first time the temperature gauge went above mid way. Turned around and went home as the destination was 80 miles away. Used my own car.

Brought it to another shop the next day (fortunate that the temp. gauge stayed around normal). The radiator was replaced - the repair shop said there was a hole in it. I never saw any antifreeze under the van or in the engine compartment. Seems to be the same thing scargi01 experienced. The thermostat and hoses were also replaced. The heater has been working. I've noticed the temperature gauge is slightly lower than before after completely warming up.

Sorry for the 3 consecutive posts. I saw an edit/delete option, I could edit but didn't see a way to delete a post which is what I wanted to do.