My vmax is overheating

I dont think this is connected to the alternator, unless you have been removing wires or hit the thermostat switch in the radiator or hit the thermostat housing and the valve is blocked up. if its boiling up and the fan is not kicking in and the main pipe from the top is cold then the thermostat is not working, if all the pipes are hot and the fan is not turning on then its the thermo switch on the radiator or the motor has decided to go.

There is a thermo switch, and there is a temperature control sensor.
Also replace the radiator cap. Check for good flow in the radiator, have it back flushed.

I am immediately inclined to think that the thermostat you currently have installed is the wrong one for your van. If it isn't overheating, then the thermo is opening at a hotter level than normal. Either that, or the thermo you have is opening late. If you want an easy test to see if this is the issue, remove the hose that goes to the thermostat, remove the thermostat, put the hose back, fill up whatever water came out and drive it around for awhile and see if it made a difference. If it now seems to open cooler, then the thermo needs to be replaced. If that doesn't work and it still seems the same, I would check the water pump or the belt that goes to it to make sure they are working correctly

Step 1:

When the thermo..do not work,there is an easy way to know...let the car running for at least 10min..turn it off..touch upper and lower hoses...if any of them is hot and the other is cold...thermos..not working.

Step 2:

check if fans activate when it reaches normal temperature, if they dont,replace fan switch at the botton of radiator,or check if the fans are burned.

Step 3:

you can flush the radiator by the usual way,but it will not unclog any cell of radiator...you must send it for service... but before u do it..do the cheap and easy staff...by the way...that car operate with a different cooling system...thats a closed pressured...so changing the cap of the reservoir helps ...since it has some valves that goes broken when is not change...hope it helps...

the coolant sensor is in hot water and doesn't have to have circulation work
Check with a service center but as water circulation is controlled to maintain correct engine operating temperature
it should have a thermostat in the system

REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP.CHECK MECHANICAL COOLING FAN.SHOULD HAVE RESISTANCE WHEN TURN WITH HAND.IF FREEWHEELS FAN CLUTCH NEED TO BE REPLACED.CHECK TO MAKE SURE AUXILIARY ELECTRIC COOLING FAN RUNNING HOT WIRE COOLING FAN IF FAN RUNS.YOU HAVE FAULTY THERMO SWITCH LOCATED AT THE BOTTOM OF RADIATOR ON THE LEFT HAND SIDE ON 4 CYLINDER ENGINE FOR V6 ENGINE THERMO SWITCH LOCATED ON THE LOWER RADIATOR HOSE ON THE RIGHT HAND SIDE OF THE ENGINE COMPARTMENT. CHECK FOR BLOWN COOLANT FAN FUSE OR FAULTY RELAY.IF THE AUXILIARY ELECTRIC FAN DONT RUN WHEN HOT WIRED THE ELECTRIC FAN FAULTY.

Typically its either the thermostat or radiator fluid issue. On mine, I flushed the radiator twice, changed out the thermo and then inspected it for a while. Still overheated. I noticed the auxilary fan wasn't coming on, fuses were good, thermo is good. I just hotwired the dang thing to a switch inside. Works great. Engine stays cool now.

Could be a stuck thermostat or bad temperature switch preventing the cooling fan from turning on.

hopefully its just a bad thermostat. replace it

Hi,

To my knowledge, the thermal switch is normally located attached to the radiator. This senses the coolant's temperature inside the radiator and upon reaching a predetermined level switches on the radiator fan. Further, to my understanding, either the A/C or the heater must be engaged for the fan to activate.

As to your other concern, overheating; In my country, most overheating issues on Volkswagen models are resolved by:

• entirely removing the thermostat (not applicable in cold regions);
• wiring the fan to switch on once the engine is running (with or without the A/C or heater being turned on);
• replacing the radiator thermal switch for the fan to a lower temp.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards. Thank you for using FixYa