Van overheating

Have you heard the fan turning on? Lots of other problems can result from not having the thermostat installed. The engine CAN over heat because the hot coolant won't stay in the radiator long enough to give off its heat. More commonly the engine won't get hot enough to switch to "closed loop". That will result in a loss of fuel economy.

This guide can help

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please run down this guide and report back.

If the upper radiator hose is hot, coolant is circulating. There's two fans for the radiator. Be sure both are turning on. Look at the cooling fins between the tubes in the radiator. If they crumble when you scratch them, they are corroded away and the radiator isn't able to give up its heat to the air. That will cause more overheating at highway speed.

If it does not overheat on the highway, insufficient air flow is the problem at lower speeds. Look for a bug collection in front of the AC condenser or anything else that is blocking air flow through the radiator or allowing air to bypass it.

If the upper radiator hose is not too hot to hold onto for very long, suspect a leaking head gasket. Combustion gas can form a pocket under the thermostat which will let it close. Thermostats open in response to hot liquid, not hot air. Your mechanic can perform a test that draws air from the radiator through a glass cylinder with two chambers partially filled with a dark blue liquid. If that liquid turns bright yellow, combustion gases are leaking in.

So you have an idiot for a mechanic is what you're saying? You have not solved the problem, just covered it up. Engine parts expand and fit properly when the coolant temperature reaches 195 degrees. 99 percent of engine wear takes place in the few minutes before that temperature is reached. You're running it constantly in a state of excessive wear.

The pistons are oval-shaped when cold. As they reach normal temperature, they expand more one way. The engine designers know that and account for that. They fit properly at normal operating temperature. The piston rings don't seal as well below the proper temperature so there's more blowby which condenses in the oil to form sludge. Instead of burning off and being drawn out by the PCV system, the hydrocarbons build up and reduce the oil's ability to isolate moving parts from each other and to carry dirt and contaminants to the filter.

Once a pre-determined temperature is reached, the coolant temperature sensor signals the Engine Computer to go into "closed loop" at which point is begins fine tuning fuel metering based on readings from the oxygen sensors. When the temperature is too low, it stays in open loop and fuel delivery is a rough guess. The computer will set the fault code "engine running cold too long" in memory. That will not trigger the Check Engine light, however, many self-tests are not performed until normal operating temperature is reached. There can be sensor problems or other running problems that may be detected but not recorded so that valuable information will not be available.

How do you know the water pump "fixed" the problem? If it did, why did your "mechanic" have to remove the thermostat? What does he know that the engine designers don't? Why did you use block sealer? If the test was positive for a leaking head gasket, you should understand thermostats don't open in the presence of hot air that pools under it from that leaking gasket. They only open in the presence of hot liquid. By removing the thermostat, no air can collect there. It will find its way to the overflow reservoir.

I'd hardly call that "fixed" and I certainly wouldn't be so proud as to want to share this solution. Everything you've replaced was to address the symptoms, not the cause of the problem. Why do all other engines run fine WITH a thermostat?

Could be a problem with the coolant temperature sensor or the engine temperature gauge sending unit giving the computer improper input signals therefore not energizing the fan relay or computer itself.

You said you replaced the radiator but how about the thermostat? Now is the engine fan coming on? You put in antifreeze so I take it is still leaking? Has the water pump been checked and all the hoses? I would take it to a shop unless you can do this and have a pressure check done on the cooling system and find the leak. If you do this keep in mind to never pressure the system more then you radiator cap say's on it. If you cap say's 16 lbs then keep the pressure with that. If you have no external leak it could be an intake gasket or something like that too.

If you are using coolant there is a leak it may be internal like an intake gasket but coolant don't just diapear. So it is either using it or it is leaking or it was overheating and boiling it out. You didn't say if the coolant fan was working. Let me know what happens.

Yes I think the mechanic is on the right track with the information given. With a new thermostat and fan relay you should be back in business. Let me know how it goes and thanks for your support and have a great weekend.

Hey guys, if I may interject, If you havent done it already, check the engine coolant temperature sensor too;thats what is gonna tell the computer to kick the fans on. And since you've replaced the harness that might do the trick

Do a block test to make sure combustion gases are not making it into the cooling sysytem and also retest the Stat. Make sure there's no airlock in the system.

If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.

Awesome, come back whenever you need to, we'll be here for ya

Hi:
It sounds like you replaced everything there is to the cooling system. Your idea of checking the cat conv is a good one. The only other thing I can think of will deal with ignition timing or a vac leak. Check to make sure that it is within specs.

Also, TSB stands for Technical Service Bulletin.

Let me know whatyou finds.

Joe