i would be looking at the head gasket, if it wont start the engine could be hydro-locked meaning the cylinders could be filled with antifreeze. probably not any long term damage if this is the case.
it can start but it won't go far as the engine will "explode" because of the increase of temperature. A thermostat regulates the temperature system of your car.. Usually the engine will run too cold with out a thermostat. That will hurt the efficiency of the engine.
follow the top radiator hose to the engine. that is where your thermostat is. you will have to drain the radiator, remove the engine side of the hose and remove the thermostat housing to access it. remove thermostat clean mating surface of housing and engine, install thermostat, install housing, secure radiator hose, fill with coolant. start engine and check for leaks.
It could be a Head Gasket, Thermostat, water pump, bad radiator or just needs coolant. start with the cheapest which is a thermostat.
Start at the radiator and follow the upper rad hose to the engine. The hose connects to the thermostat housing. The thermostat is located in this housing.
Thermostat turned all the way up,thermostat defective, thermostat wired incorrectly, heating unit wired incorrectly, fan or heat relay stuck closed are the things I would look at to start.
In very short: If the thermostat stays open, the warm-up time for the engine will be significantly longer, resulting in unwanted start-up wear. If the thermostat stays closed, the engine coolant can not circulate through the engine and cooling system, resulting in the engine overheating, as the coolant is used to keep the engine in a specific operating temperature.
To turn on the boiler for heating in the house, locate the boiler's power switch and turn it on. Adjust the thermostat to the desired temperature for heating. Wait for the boiler to heat up and start circulating hot water or steam through the heating system.
You CAN just remove it; but that introduces another set of problems. The computer monitors the engine temperature, and if the engine is not warming sufficiently the computer will start to report a fault. A cold engine does not perform as well, and if the thermostat is removed the engine will not be able to reach operating temperature. The thermostat restricts coolant flow into the radiator while the engine is cool. Once the engine warms to operating temperature, the thermostat opens, allowing excessive heat to be dissipated through the radiator. Removing the thermostat is NOT recommended and can significantly affect performance and engine wear.
If your dashboard gauge is ok and the needle is moving when the engine start to warm up but never attempt the middle you have to check the thermostat as follow: you start the cold engine and carefully you keep your hand on the hose which transfer the cooling fluid from engine to radiator. If immediatelly after starting the engine the hot water goes through the hose, is 100% shure that thermostat is blocked open and needs to be replaced. A blocked thermostat in the position closed will cause more damaged because the engine will be overheated and the headgasket will be "burned".
To change the thermostat on a 1999 Honda Passport, start by ensuring the engine is cool and disconnect the negative battery cable. Drain the coolant from the radiator, then remove the radiator hose connected to the thermostat housing. Unscrew the thermostat housing, replace the old thermostat with a new one (making sure to align it correctly), and reassemble by reversing the steps. Finally, refill the coolant, reconnect the battery, and start the engine to check for leaks.
When you start the engine, the thermostat is closed. After the coolant warms up the thermostat begins to open up allowing coolant to flow thru the raditor. When first started the temp will go a little past what the thermostat is set to open at. After the water begins to flow thru the radiator, the temp will fall to whatever the thermostat is set at. The thermostat holds the coolant in the engine until it warms up. As soon as the engine is warm, the thermostat opens allowing cold coolant outside the engine to mix with warm coolant. The temp drops, the thermostat closes again, until all the coolant is warm.
The thermostat is located in the cooling neck located at the end of the cylinder head next to the distributor. Instructions: Drain coolant, remove both bolts to thermostat housing (one bolt may not come completely out because of a sensor and expect much coolant to pour out), unstick the thermostat housing from the engine, remove thermostat from engine, clean all gasket surfaces, install thermostat in engine with the spring towards the inside of the engine, install gasket with thermostat housing, tighten bolts, fill coolant, start and check for leaks.