car overheating

First, check that the air was bled out of your system when they replaced the water pump and radiator.

Then as your car warms up, check the temp of your upper and lower radiator hoses. Both should be hot. If one is and the other is not, then your thermostat is stuck closed.

If that checks out good, then I'd say you have a blown head gasket. Sometimes you'll see signs of water mixing with your oil and leaking out of your tail pipe, sometimes you won't.

What will happen is, exhaust gas is pushing its way past a small leak in the gasket and into your coolant. The hot bubbles eventually get trapped in the highest points in the heater core and radiator, which creates a lock that your water pump can't push past.

A quick way to test for this is to remove the radiator cap (or overflow tank cap if your radiator doesn't have one), and while someone revs your engine to at least 1,500 rpm, look at the coolant. If theres large bubbles (same time as engine revs), then that is the exhaust gas.


See the guides below for external leak check and head gasket check

https://www.2carpros.com/articles/head-gasket-blown-test


https://www.2carpros.com/articles/radiator-pressure-test

Will my car overheat if a vaccuum leak was detected from the injectors?

Do you mean there's a vacuum leak around the o-rings where the injectors plug into the intake manifold? That won't cause overheating but it can cause a high idle and a hesitation.

Okay thank you.. Can you help me find out why my car overheats then? I have changed the theremostat, head gaskets, intake gasket, cooling fans, sensors, radiator, radiator hoses and my connections.. Everything seems fine but when i drive for about 20 minutes it will get hot and on comes my tempurature light..

The head gaskets would have been my first suggestion. You might still consider having a mechanic perform a leak test at the radiator cap with a special tool.

Next wuld be to check if the radiator fan is turning on. A fast way to do that is by unplugging the two-wire coolant temperature sensor while the ignition switch is on. That should cause the fan to run. If it does not, there might be a blown fuse for the fan. The best way to diagnose it is by using the DRB3 scanner to command the fan to run.

Sorry for taking so long to reply. The site stopped working on my regular computer. Just want you to know I'm not ignoring you.

I am still having problems with the car overheating.. What would make the thermostat not open? it has a new one, and then fans are working.
I have the pressure tester and i dont see any leaks.. What could it be?

Concorde 2002, 3.5L, engine running excessively hot after 20 minutes of driving. Fine at an idle for 30 minutes of run time. Installed new radiator, new water pump, thermostat and new hoses. System bleed correctly so there is no trapped air. Fans have been tested and running at low and high speeds and coming on at correct temperature. No hydrocarbons in coolant, my mechanic does not know what else to check for. On or about the time this started to happen, air dam (2" black plastic trim under front bumper) was torn off. I've seen an on-line comment that this contributed to a similar problem. Could the loss of this change air flow through engine compartment and cause engine to hit higher temperatures?If not, any suggestions?

Yes, it helps deflect air flow. However, you mentioned it overheats when sitting in park.

You have replaced and double checked everything. The only things left is a timing issue and there still could be a head gasket leak even though it was checked. Have they done a compression test?

would it be caused from a EGR valve or a BP valve?

It does not overheat when parked and timing belts were replaced with the installation of the new water pump. I also had a new air dam installed and it still runs to hot. A compression has not been done. I can ask to have that done. The engine runs very smooth and has plenty of power. What else could it be?

An air pocket can prevent the thermostat from opening. Thermostats open in response to hot liquid, not hot air. You should see a bleeder screw on the thermostat housing. Be sure to open that after the thermostat was replaced.

Feel the lower radiator hose when the engine is hot. If that hose is cold, coolant isn't flowing. You might consider removing the thermostat to see if that makes a difference. If there is still no evidence of circulation, suspect a problem with the water pump. One possibility is the impeller can be worn away or it can be cracked and spinning on the shaft. Also check the tension on the timing belt since it runs the water pump. A loose belt will slip over the pump's pulley.

If you repeatedly find air coming from the bleeder screw, suspect the head gaskets are leaking. When those gaskets are replaced, the heads must be checked for cracks and for warpage. Warpage must be checked at an engine machine shop or by a mechanic who has a straightedge. The maximum allowable warpage with aluminum heads is .002" in any direction.

To check for leakage, first look for the presence of bubbles in the reservoir when the engine is running. If you see any before the engine has warmed up, suspect the head gasket. The clue is the engine isn't hot yet and there's no steam with those bubbles. Most mechanics can perform a test for you that involves a glass cylinder with two chambers partially filled with a special dark blue liquid. Air from the reservoir is drawn through that cylinder. If combustion gases are present, the liquid will turn bright yellow. Those gases will create that air pocket again that prevents the thermostat from opening.

This is a tough one. I have a couple more questions. First, and I know this may sound odd, was the thermostat replaced with a 195°F thermostat? I have seen situations where lower temp t-stat was used, opened fully when the engine was at 165° and the coolant circulated so fast, it never had time to cool in the radiator. The reason that popped into my mind is because your car does the opposite of what most do. It overheats when driving rather than sitting.

Next, when it overheats, does it ever boil over where coolant is coming from the overflow? I ask because you could have a bad temp sending unit and you are not seeing the correct temp from in the car. They actually make a thermometer to check coolant temp in the radiator.

Finally, when it is overheating, has anyone checked to make sure that both the lower and upper radiator hoses are not collapsed? I have delt with hoses that will pinch shut at higher RPM's causing an overheat situation.

Let me know.

Joe

okayy thank you.. Can the overheating be caused by an EGR valve, a BP valve, or a knock sensor?

Nope. The EGR valve allows exhaust gas into the engine at highway speeds only. While that gas feels hot to us, it is "inert" and takes up space so less fresh gas and air fits into the engine. That means less heat is produced in the engine and less fuel is burned.

A knock sensor picks up pinging in the engine, and in response, the Engine Computer retards ignition timing a little. In a very severe case, some of that fuel and air might finish burning in the exhaust manifold rather than in the engine. Heat from the exhaust manifolds doesn't transfer into the cooling system so it won't cause overheating.

Not sure what you mean by a "BP" valve.

Okay thank you!, you are really helping.. and i mean a bypass valve?. Do you think that would cause the overheating.? I am looking for other alternatives that will cause the overheating..

where is my thermastat located .

i anted to know where my themastat is located on my 2002 chrysler concorde LXI 6 cylinder 3.5l?

I'm not aware of a bypass valve but there is a bypass passage. That gives the coolant someplace to go while the thermostat is closed.

When the overheating occurs, feel the lower radiator hose. If it is real hot, the heat is not leaving the radiator. That can be due to air flow blockage, a fan that's not turning on, a fan that's wired wrong and blowing the wrong way, a missing shroud that lets the hot air go back around and through the radiator rather than drawing cool air in. Related to that, look for a missing rubber strip under the front edge of the hood. That is a seal that forces air through the radiator.

If the lower hose is not hot, the coolant may be not circulating properly. Check the water pump impeller and be sure the timing belt is tight and not slipping. You may have to flush the cooling system and try removing the thermostat to verify it is not sticking closed. If the coolant is not circulating, the air from the heater will not be as hot as normal.

A clue to a fan-related problem is the overheating will not occur while driving at highway speeds.

Okay. My heater works real hot. My car is still overheating and I believe that the coolant is not circulating properly. It seems to be circulating from the heater hose to the thermostat.. Can you help?

Double-check that the fan is turning on and blowing the right way. You said you replaced the radiator. Was that a new or used one? If it was used, check if the cooling fins are rotted away. That will reduce its ability to give off the heat to the air.

The radiator is a new one..

I attached a picture of my water pump and the way it is rotating... Isnt it going the wrong way? What can I do about this?

The following facts exist with the situation or have already been done:

1) a new water pump has been installed
2) both fans are working properly but still the water gets too hot in the system
3) There is no stuck thermostat because we pulled the thermostat out completely.
4)There are no major water leaks and the car is not losing any water really at all so that is not the problem.
5)The reservoir cap appears to be fine and sealing with all its rubber components in place.
6) whenever you unscrew the air bleed valve on top of the engine block, it temporarily fixes the overheating problem for a few hours or maybe one day, then the heating problem comes back.
7) The car and engine runs great both before and after the car starts to overheat. However, always pull over before heating gets into the red area on temperature gauge.



Knowing all the above things, I was thinking some of the below things might be the problem.

1) the radiator is not working properly, and therefore water is not circulating at all but just boiling in place. Maybe a good flushing of the radiator could fix the problem. How can you tell whether the radiator is blocked or not working thereby causing the water to just sit and boil?

2) I hear something about heater cores getting blocked but do not even know if a 2004 chrysler concorde has a heater core or if it did and it got blocked whether it could cause the car to overheat?

3)the head gasket leaks or the heads are cracked, but I do not understand how that could cause a car to overheat. Moreover, the engine runs super great - get up and go and everything - which causes me to believe that the overheating problem has nothing to do with a head gasket leak or cracked heads. Then again maybe a car can run just fine and haul but still have a head gasket leak or cracked head, as I do not know the answer to that?

4) Maybe the radiator works fine and the water is flowing thru the entire coolant system fine, but that somehow air is getting into the system, and it is only this accumulation of air that is getting in with the flowing water which is the overheating problem. However, if the overheating problem is solely caused by air somehow getting into the system with the water, then I do not understand how just air could cause the vehicle to overheat or how to fix such a problem?


Do you guys have any ideas on what is the problem with the car based on all the things I told you above?

Mike

Nope. It's going the right way. The vanes throw the coolant outward and centrifugal force is what creates the force that makes it flow.

You will need to get the radiator core cleaned by a radiator repair workshop, flushing will not fix a part blocked radiator, if you do have a head gasket problem, you will be using coolant as with all head problems, there is a breach between the cooling system and the combustion chamber, if you are not using coolant i doubt that there will be a head problem, a blocked heater core will not cause an over heat problem, get the radiator cap pressure tested as it may look ok, but if it is not holding correct pressure this can be a problem, start here.