[CroMath]

Any overheating problem is FAR more likely to be connected to the timing belt/water pump work than muzzling VCM. Who did the timing belt/water pump job? A genuine Aisin kit (like from Rock Auto) is the go-to recommended package for a very good reason - those are great parts.

Muzzling VCM does not affect the operation of the cooling system in any way - the radiator, radiator cap, engine coolant, water pump and thermostat all have absolutely no idea that a VCM disable device was ever installed in your vehicle. It makes no difference to them - these parts do their jobs the exact same no matter what else you have plugged in somewhere.

Like @WiiMaster asked, how do you know the engine is overheating? The cooling system in a gen 4 Odyssey is extremely robust - a true, genuine overheat on these vehicles is so rare as to be practically unheard of. What is actually happening under the hood? Do you have any measurements we can refer to? If so, how did you get those measurements?

 

[CroMath]

1. The AC vents in side vehicle blows very hot air thought we did not turn on either cooling or heating in the Van.
2. The PSF reservoir is very hotter than usual.
3. Hope the picture attached about the boiling of coolant will help you understand what I mean.

Any concrete advise to trouble shoot these issues.

1. HVAC vents blowing hot air when it is not called for is not indicative of an engine overheating problem. It is indicative of an HVAC problem. If you set the HVAC system to blow cold (or nothing at all) and hot air is getting in, that's because the blend doors are not stopping the hot air coming from the heater core.
2. "Very hotter" is a comparative descriptor. How do you know what the normal temperature of the PS reservoir is? How do you know what the current temperature of the PS reservoir is?
3. I don't know what that picture is showing.

The overheating "problem" sounds like a giant nothing burger to me.

If the temperatue gauge is where it should be, you're fine.

Until we can get some hard data like unmuzzled coolant temp readings from an OBDII scanner or an infrared thermometer pointed at a rad hose (i.e. actual numerical indications of the engine coolant's true temperature) or even a picture of the engine coolant gauge from the instrument cluster, I just don't see how we can be helpful in diagnosing a cooling system problem. We have no hard evidence of a cooling system problem.

I don't want to sound like some kind of jerk here, but I haven't seen anything that leads me to conclude something is wrong with the cooling system.