Overheating Engine overheats. I have replaced the waterpump and thermostat. When engine is cool, I can squeeze top radiator hose and it is collapsable. When engine warms up and starts to build pressure the top hose gets hard and you cannot squeeze it shut. I pulled the thermostat out and put it in a boiling pan of water and it opens up. Can it be an air lock somewhere in the collant system?

sounds like the radiator is blocked either coolant flow or ext air flow through the matrix the thermostat can get ruined when the system overheats so allways change the stat after a overheat problem GET THE RAD CHECKED FIRST if ok check the coolant pump

Most common reason for overheating is 1. low coolent lvl 2. faulty thermostat (stuck closed). 3. Faulty water pump preventing coolent from circulating through engine.

Check coolent lvl in radiator when engine is cool by removing the cap and filling it up till you can see the coolent, replace cap and try. If you have the proper lvl of coolent. Replace your thermostat, which is located under the thermostat housing (right underneith where your top radiator hose connects). Fill with coolent and see if that helps. Next test is to start the car and let it run till it gets to normal operating temp or near (180 to 220 degrees F) Pinch your upper radiator hose and see if you can feel a gush, or flow of water rush through the hose when you release your pinch hold on the hose, (by pinch, I mean to try and totally squeeze the hose together) If you don't feel the rush of coolent through the hose, then your waterpump is faulty. If your car quits overheating, but your heater hoses don't get hot, then they are probably stopped up at the point where they connect to the engine. Its a common area for gunk, rust, and corrosion to build up.

Is it losing it out on the ground? Could be head gaskets or intake manifold gaskets have failed.

replace thermostat.then bleed coolant system, this is how you do it.fill the cooling coolant system with 50 / 50 dexcool and water to raise boiling point,straight water will evaporate boil away cause engine to overheat catch fire thats why you need 50 / 50 mixture antifreeze and water.to bleed coolant system first fill coolant system until coolant stay at the full cold mark on the the coolant overflow jug,then you start engine allow it to idle,place the heater and ac control in any ac setting except max and the temperature control to the highest setting,run engine until lower hose to water pump is hot. with the engine hot run the engine speed up to 3000 rpm and allow it return to idle, repeat this 5 times. slowly open the bleed valve on the thermostat housing or look for bleed valve at the water pump heater hose.open bleed valve for 15 seconds to expel any trapped air.then top off the coolant as necessary,and when top radiator hose hot thermostat open up.keep adding cooling to overflow until coolant level stop at full cold mark dont over fill coolant.if engine seem like overheating while looking at cooling gauge turn off engine wait a while until cool off add more coolant until coolant level stay stable and dont drop any.when open radiator overflow cap use large rag over the radiator cap to keep from getting scald open radiator cap a little at a time but dont open radiator cap until engine cool down first.replace the radiator overflow cap, thermostat,and engine coolant temperature sensor and check the cooling fans fuses and relays see what happens.

Are you bleeding the air out of the cooling system, you must do that or it will get air pockets and overheat.

CAR OVERHEATING FIRST CHECK FOR LOW COOLANT IN THE RADIATOR COOLANT OVERFLOW JUG.IF COOLANT LEVEL IN OVERFLOW JUG LOW REFILL ADD COOLANT BACK TO THE FULL COLD MARK.PUT RADAITOR CAP ON COOLANT OVERFLOW JUG START ENGINE LET IT IDLE UNTIL IT OPERATING TEMPERATURE.MAKE SURE TOP RADIATOR HOSE GETTING HOT WHILE ENGINE WARM UP.IF TOP RADIATOR HOSE DONT GET HOT WHILE ENGINE IDLING YOUR THERMOSTAT COULD BE STUCK CLOSE CAUSING CAR TO OVERHEAT.IF TOP HOSE IS GETTING HOT.CHECK FOR COOLANT LEAKS CHECK TOP RADIATOR HOSE AND BOTTOM RADIATOR HOSE FOR LEAKS.CHECK FOR LEAKS AT THE RADIATOR CORES AND PLASTIC SIDE CONTAINERS.IF ALL IS GOOD ENGINE OVERHEATING WHILE IN A LONG TRAFFIC LINE, COOLANT FANS NOT COMING ON.COULD HAVE FAULTY ENGINE COOLANT TEMPERATURE SENSOR OR BLOWN COOLING FAN FUSE OR RELAY.COULD HAVE PCM FAULT.MAKE COOLING FAN ELECTRICAL CONNECTORS AND WIRING NOT DAMAGE OR BROKEN.

I might need a little more information to accurately diagnose situation but I always like to start with the thermostat.(touch top radiator hose if it is cool with temp reading high its probably thermostat) This device is supposed to open up when the engine reaches operating temp. to allow coolant to flow. If it is stuck it could easily cause the overheating condition you are experiencing. Some more info such as does it only overheat when sitting still or will it overheat when moving down the road. If only when sitting still I would suggest a problem with the cooling fan. If it is a gradual increase while driving based off the age of the vehicle I might suspect a clogged radiator. If this dont help try telling me more about it and I will be happy to provide more insight.

There are a couple of things that make a vehicle overheat. Your thermostat could be stuck closed not allowing the coolant to circulate, or your waterpump has gone out. Its possible your radiator has clogged up from minerals and or rust from the water.

Make sure you don't have a leak or a bad hose. The lower hose sometimes will get weak from oil contamination and the water pump will actually **** it closed.

When the car is warm feel your top radiator hose and see if it is cool. That would indicate a stuck thermostat. If it is hot then put on a pair of gloves and squeeze the hose, you should feel the pulsing of the waterpump and the water flowing by (like a garden hose). If not that is a good indicator of a bad pump.

When driving down highway only, it overheats? When running steady, I take it you mean, sitting idling? If it's only overheating at highway speeds, and all else has been checked out & is o.k., I'd take a close look at rad hoses for soft spots (easy to squeeze) that may be causing hoses to collapse at highway speeds & restricting flow of cooling system. Another thing to try is, turn your heater on high fan & high temperature when it starts to heat up & see if temperature gauge goes down (cooler) at all. If it does, then rad not doing it's job properly.

you have air trapped in the system. very hard to "BURP AIR"

park uphill on ramps if possible. With cold engine, leave radiator cap loose and fill radiator and reservoir. run engine until thermostat opens. squeeze upper radiator hose with hand. SHould be hot. Have heater on hot and blower on too. Repeat as necessary. May take several attempts.

Go here and we can help if that does not work

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