Is the thermostat easily accessable inside the engine compartment? My van over heats, has water in the radiator, when engine is started the level in the radiator rises as if the pump is turning but I don't have warm air at the blower as if the thermostat is closed.

replace thermostat

Let the engine cool down then remove the radiator cap. With the cap off, start the engine and let it idle. Watch the water in the radiator. As the engine heats up, the water will rise as it expands during heating. When the thermostat opens, (and this may be your problem) the level will drop, and you will be able to see the water recirculating through the radiator. If this doesn't happen, the thermostat is not opening (stuck closed). If you can see the water recirculating when you start the cold engine, then the thermostat is stuck open. Either condition will cause overheating. Start with the easy fix first (thermostat) before going to the water pump.

you need to replace thermostat and radiator cap.look under hood around engine compartment.look for a radiator cap near radiator,add 50/50 antifreeze and water to coolant system to bring up boiling point.pure water will cause engine run hotter because water evaporate away,remove radiator pour coolant in the radiator until coolant stop dropping in the radiator now some vechicle pour coolant in the coolant overflow jug,pour coolant until coolant level stop dropping and the coolant level stay at cold full mark.start engie let idle few minutes, watch coolant level in radiator if coolant start dropping add more coolant, when coolant level stop dropping put radiator cap back on let engine idle until both top radaitor hose and bottom coolant hose get warm turn off engine wait until it get cool then take a large rag slightly open radiator just a litle at a time to keep from getting scaled.once radiator remove add more coolant if low,put radiator cap back on start the engine let it idle watch the temp gauge if temperature gauge going hot zone stop engine wait until cool then add more coolant,keep doing this until engine stop overheating going into hot zone and coolant level stop dropping,make the coolant overflow jug coolant level stay at full cold mark, dont let jug run empty if so air will get in the coolant system causing engine to overheat.

Check the level of antifreeze/water in the coolant recovery tank. This is the white, plastic tank located near the radiator. The level should be checked while the engine is running.

Also, open the cap on the radiator (only when the engine is cool! wait at least 45 minutes after driving it) and start the engine. Once the cap is removed, with the heater on full blast, look in the hole under the cap. You should be able to watch the water flowing rapidly from one side of the radiator to the other. If the water is stagnant, I can almost guarantee you that your thermostat has gone bad. This is the most common cause of coolant system failure.

Good luck with it!

-Brian

Try this.

With the engine cool remove the radiator cap. Now start the engine and let it warm up to the point where the thermostat opens. You can usually tell when this happens by checking the temperature of the upper radiator hose, and the coolant level in the radiator. It will start getting a lot hotter quickly when it does and the coolant level should drop.

While the engine is warming up, watch the coolant in the radiator for air bubbles. Fill up the radiator as needed while continuing to watch the coolant level. Having the radiator cap off while doing this allows the trapped air to escape more easily. If you do have a large air blockage then when the thermostat opens you should see a large drop in the coolant level. You want to keep the Radiator full. Once the air bubbles seem to have stopped you can replace the radiator cap.

You may have to repeat the process a couple times if there is a large amount of air trapped in multiple pockets.

A cracked head or block you can usually diagnose as there will be a lot of small bubbles coming out constantly while the engine is warming up, and even more bubbles if you rev the engine higher as the compressed air/fuel will be forced into the cooling system.

Overheating can seriously damage a car's engine if left unchecked. Although overheating simply means that a car's engine temperature exceeds normal operating temperatures, the causes of overheating are varied. What follows is a brief list of some of the most common causes of engine overheating.

Faulty Radiator
1. A car that overheats will often have a faulty radiator. A radiator is responsible for cooling hot engine coolant that picks up heat from inside a car's running engine. A radiator "radiates" the heat from engine coolant out into the outside air. A faulty radiator loses its "radiating" effects and allows engine coolant to become overheated, thus rendering it ineffective at adequately cooling and engine.
Faulty Water Pump
2. A faulty or malfunctioning water pump prevents adequate engine coolant flow and can cause a car to overheat. A water pump serves to pressurize and propel engine coolant throughout a car's engine and radiator to increase the heat-reducing capabilities of engine coolant. A faulty water pump loses its ability to adequately pump and propel engine coolant, and can cause a car to overheat.
Coolant System Leaks
3. A leaky engine coolant system reduces the level of circulating engine coolant, which increases engine temperature and leads to engine overheating. Radiators, water pumps, and coolant system hoses and seals--all of these coolant system parts can develop leaks, which can result in low coolant levels and engine overheating.
Faulty Thermostat
4. A car thermostat regulates the flow of engine coolant. A thermostat is a heat-sensitive valve that opens when a car engine reaches a set operating temperature and closes when a car engine is cold and warming up. If a thermostat gets stuck in the closed position, coolant will be prevented from reaching the engine, which will quickly lead to engine overheating and potential engine damage.
Low Engine Oil Level
5. Engine oil, in addition to lubricating an engine's internal parts, helps to keep engine operating temperatures reduced by eliminating friction within the engine. If engine oil levels are low, friction and heat build up inside an engine, a condition that causes increased engine operating temperatures and can lead to engine overheating.

The RPM while driving were higher than when you pulled into the Driveway.
Check and top off the Radiator Fluid. Low levels cause this fluctuation. Make sure the engine is cool. Remove the radiator cap. Turn the engine on and turn both the front and rear heater on high when filling. Make sure you use only straight Radiator Fluid (not mixed) in the Reservoir. Replace the cap before it reaches normal operation temperature.
Now check the heating inside with the van. Is it any better?
IF NOT: There maybe a problem with the thermostat, egine coolant temperature sensor, or with the Water Pump itself. I would start with the Thermostat replacement, followed by the Sensor, before replacing the Water Pump. Work $mall and up to Big to save you money.

Check your coolant fan for proper operation.

Check coolant level when cool. Make sure cooling fan at rad is working, and then I'd change thermostat.

This could be a multitude of things:

Stuck closed thermostat.

Cooling fan not coming on.

Clogged radiator.

Low on coolant.

Water pump failing/leaking.

Head gasket blown, leaking exhaust into antifreeze.

Clogged catalytic converter.

Thermostat: If the Van heats up, then feel the upper radiator hose. If it's cold, then your thermostat is closed. Replace thermostat.

Coolant: If low, simply fill with distilled water and coolant. Low levels will let engine over heat.

Radiator: If there are cold-to-the-touch spots on the radiator after it should be warmed up, then a clogged is probably occuring. Have radiator flushed.

Head Gasket: If you smell exhaust fumes in your coolant reservois tank, then you got a blown head gasket.

Cat Converter: Only can be tested if off the car. Or you could try a non-contact thermometer. These are also good to testing cold spot on radiator or if thermostats are open.

Cooling fan: If mechanical it'll be spinning. If electrical, it should come on automatically with the A/C, or when it gets hot.

Water pump: Will be leaking from the front if it needs replaced. On a van, it's a tough job.

Good luck!