I have partial good news.
I went back to the garage telling me I had to stop driving it when it’s overheated. They mentioned the engine also takes coolant.
I asked them whether the garage, I had my radiator flushed at, did it wrong pouring coolant into the radiator instead of the coolant reservoir. The reservoir was below the minimum mark. Then they poured some coolant into the reservoir and told me I should fill the reservoir between the maximum and minimum mark. They said they have to diagnostic whether there’s a leak somewhere.
When I started my van and went back home, there’s still a bit shaking underneath the van. When I arrived home, I tried the heater and air conditioner. The heat run very good. As my friend said "It’s hotter in hell. " Air conditioner run good too. My van behaved like a brand new van!
I searched internet whether it is necessary to fix head engine gasket. The web site of Bar’s Leaks said symptom of a blown head gasket: overheating, loss of coolant *** without visible leaks***, engine misfiring etc.
My van was almost overheating. The reservoir was below minimum level. My van is stilling shaking when I start it or sometimes whiling I am driving fast than 40M/hour.
If the engine takes coolant, my van has head gasket leakage, all coolants it took will be gone sooner or later when the engine starts. This may be why the reservoir is below the minimum level.
It seems I should fix the gasket first and then to see if my van is still shaking or not.
Is it risky to try the Bars’ Leaks? Should I try it?
How do you guys think?