My engine is overheating why?

Hello,

This could be a thermostat that is failing. It could be failing because when you got your flush done, it could have knocked something in your cooling system loose causing the problem. I have included a few links to guides for you to go through down below. Go through them and get back to us with what you find out.

https://www.2carpros.com/articles/engine-cooling-system

and

https://www.2carpros.com/articles/how-an-engine-thermostat-works

and

https://www.2carpros.com/articles/replace-thermostat

Thanks,
Alex
2CarPros

my 03 Altimas been great, this morning I took my brother to work which is about an hours ride from my house and about half of which is 60 mph. The car did fine there and back but today on my way to pick him up when I was almost to his work my car suddenly started to kind of whistle, I pulled to a yield sign and the car died. It started to get hot so I immediately cut it off. under the hood the water in the top radiator hose was rapidly bubbling and the bottom hose was cold any ideas?

Gonna need more to go on. First of all, was the radiator fan running? The cold lower radiator hose is a dandy observation that indicates no coolant is flowing. That can be caused by low coolant level, but a leaking cylinder head gasket is a possibility to. With that, combustion gases can pool under the thermostat and prevent it from opening. Thermostats have to be hit with hot liquid to open. Hot air won't do it.

You may see air bubbles in the coolant reservoir too if the head gasket is leaking. To check for that, your mechanic can perform a quick chemical test. That involves drawing air from the radiator through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present, the liquid will turn bright yellow.

The fan was on when the car was running and cut off when I cut the car off. Just yesterday I took my car to the shop and had my oil changed and my fluids toped off. They said only my windshield washer fluid was low and they made no mention of water in my oil. I suspect a bad thermostat. My car has 2 thermostats should I replace both? is there an easy way to roadside test them?

There's no easy way to test a thermostat. A former coworker was warned by three of us when he put one in a soup can, then heated it with a torch to see at what temperature it opened. The new thermostat had already solved the no-heat complaint. That stunt was the last straw and it got him fired for wasting so much time. (This was not an isolated incident).

Thermostats can fail by sticking open or closed, but they rarely close after the engine is warmed up and has been running. I won't say you can't have a bad thermostat, but I'd be very surprised.

Coolant in the oil is not how head gaskets usually leak. 90 percent of the time you'll get exhaust gas in the coolant and a loss of coolant out the tail pipe. When you DO lose coolant and can't tell where it's going, you can add a small bottle of dark purple dye to it, then search a day or two later with a black light. The dye will show up as a bright yellow stain that you can follow back to the source. If you find it inside the tail pipe, the head gasket is leaking.

Water pump was seized, I went ahead and threw in the new thermostat anyway. Thank you so much for your advice!

Dandy. Happy to hear it's solved.

My Altima is always giving a high output of heat and I would only drive for 15 min. Then I also notice when I do my normal oil change at 3000 miles my oil is OFF THE STICK aka NO OIL =(. I read up reviews of my car and theres alot of issues relating to the catalytic converter. What are my options as to resolving this overheating issue. Thanks

So you are saying your engine is overheating? How far has the coolant gauge gone up before you shut it off. Are the coolant fans coming on? Also, just because there is no oil on the dipstick does not mean there is no oil in the vehicle. If there were NO OIL in the vehicle then it would not be running. It is at leat a quart low. Are there any oil leaks?

my car overheats when i have the a/c on and i run it over 60mph the temperature bar starts rising. What can i do?

Start by making sure that your fans are working when the AC is turned on. Then, change your thermostat. I suspect that your thermostat is stuck closed. Also make sure that you have enough coolant in the radiator ans the reservoir.

My car is suddenly overheating.

Hi Kimbowhirley,

Unfortunately, this could be a number of things including a cooling system issue, sensor issue, or just a fan issue. The important thing is, don't drive the vehicle too far until this is repaired. You can do considerable damage to the engine if it gets to hot.

Here are some guides that walk you through the basics to find out the possible cause:

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

https://www.2carpros.com/articles/symptoms-of-an-overheating-engine

Once you limit it down I can assist further on how to diagnose the potential system. Thanks

I changed or replaced the thermostat at the engine block is there more the one thermostat or just the one? my car is still running hot and not sure why. i replaced the fans, the radiator, water pump, and now the thermostat. not sure what else it cold be.

Welcome to 2CarPros.

First, when you replaced the thermostat, did you place the jiggle valve at 12 o'clock? That is the position it need to be in for air to exit the system when refilling the coolant. You may have an air blockage if that wasn't done. See pic 1

Next, since you have replaced everything, don't get mad, but are you sure it is overheating and not a faulty coolant temperature sensor?

https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor

Does the car overheat when driving at highway speeds or only in stop and go traffic?

Last, since everything is new, my next concern is a bad head gasket. Here is a link that explains how to check for a problem with the head gasket:

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

Let me know if any of this helps, if you have other questions, or need help with it.

Take care,
Joe

Hello, I discovered today my car was overheating, I pulled over and put water in the radiator, I drove for about ten minutes and noticed it was still overheating. I checked the oil and discovered that it was milky in color. Seems water found its way into the engine. I already packed and towed it to my house. What do I do now please?

Start by checking the oil level. If coolant actually is sneaking into the oil, the level will be going too high. If you simply found a milky-white substance under the oil cap, that is condensation typical of too many short trips that don't get the engine warmed up for long periods of time.

Coolant leaking into the oil through a leaking cylinder head gasket is the least common symptom, but it is possible. To check for that, add a small bottle of dark purple dye to the coolant. Use a black light to look at the oil on the dip stick or under the oil cap a day or two later. If the dye has shown up there, it will be bright yellow.

It is much more common for a leaking head gasket to cause coolant to be burned in the engine and go out the exhaust. Use the black light to check at the tail pipe. If dye shows up there, suspect the cylinder head gasket is leaking.

I replaced my water pump and belts and flushed the cooling system. When I put it all back together and started it back up the engine got really hot. Everything was working before the water pump went out.

I’m assuming there is air trapped somewhere in the cooling system. However, I can't seem to find where it's trapped. I'm hoping the description below might at least help someone point me to where the blockage is, or possibly point to something else that's causing the problem.

Symptoms:
-Car starts out at a good temperature when starting cold, but after a few minutes it overheats
-Air blows out when I turn on the heater but no hot air
-Car runs fine when I turn it on. No rough running or extra exhaust so I would tend to rule out any head gasket problems.
-I can hear the heater core motor running.
-Just before it's about to overheat, the radiator jerks around a bit like it's super hot. The upper radiator hose is boiling hot. The other hose going to the thermostat is cold (which I suspect is normal since the radiator would cool the water on its way down?)
-Both heater hoses are warm, but definitely not hot like the upper radiator hose is. The heater hoses don't feel like they have much coolant running through them.
-Occasionally while the car is idling the RPM gauge jumps up and down from 1000 to 2000. This does not occur when I have the flush n fill cap removed.
-If I take the cap off the flush n fill kit in the heater inlet house I see no coolant. If I run the car for a few minutes and it reaches operating
temperature, some fluid sprays out periodically, but the interesting thing is is the temperature remains down. If I just keep adding fluid to the overflow tank, and let it shoot out the heater hose, the temperature stays down. If I cap off the heater hose again, after about a minute the car starts to overheat. Is this because the hot coolant can't get pass the heater core? This makes me think that the heater core may be plugged.

Actions take so far (all with heater turned on to max and blower on max):
-Replaced the water pump, pulley and belts
-Bled the cooling system 3 separate times following shop manual instructions (finally found the bleeder bolt and made sure it was open while bleeding).
-Took the water pump back off to inspect. Water pump looks fine and spins freely. Looked for any blockage in cooling hoses near water pump and found nothing blocking
-Changed the thermostat, making sure to install it in the correct direction.
-Replaced radiator cap
-Tried cracking open the flush n fill cap just a little but that still causes it to overheat.
-Flushed cooling system with thermostat removed and using one of those flush kits that attaches to the heater hose.
-Tried temporarily removing thermostat, no change
-Turned on A/C and the two radiator fans kicked in. When I run the heater on hot the two radiator fans only turn on if I've opened the flush n fill cap and let a lot of hot coolant escape for several minutes.

Questions:
-Could it be a clogged or bad radiator or heater core?
-What would you recommend I try next? I thought about disconnecting both heater hoses from the engine side and running the garden hose through one to see if it comes out the other end (should tell me if heater core is plugged?). Would attaching the garden hose also potentially clear the blockage?
-If this sounds like it could be a radiator problem, anything I could check on the radiator for overheating?

Hi jcollins23,

The problem seems to be of air trapped in the system. A clogged heater would not cause overheating, only no heater action.

The bleeder point is not at the highest of the cooling system.

After bleeding the system, was the radiator coolant topped up to full?

This guide will help

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

Did you run the engine for a while without the radiator cap and topping when the level goes down?

Turn on AC and run for a while longer, topping up if necessary.

I have this exact problem word for word. The issue ended up being the bbn previous owner had replaced the water pump. However when they put the serpentine belt they routed it outside the water pump rather than inside smooth side to smooth side belt. This causes the pump to spin backwards and basically does t circulate any water and pumps little water to the top of the radiator. Hope this helps someone.

Excellent addition to this thread! Please feel free to help out whenever you are on the site :)

This was how my belt was put on by previous owner this causes the car to overheat in just minutes and also some very violent reverse boiling to the top radiator hose exactly as you described.

lol, yep that would cause a problem for sure, thanks for the input.

I replaced the thermostat I have replaced, the water pump, radiator seems to be flowing and coolant kicking in, but when I drive it and then check the hoses the lower radiator hose is not filled with water. also, when I release the radiator cap or the reservoir tank cap no pressure seems to be there. So what would the problem be in my overheating problem?

It sounds like the radiator is plugged, there should be coolant in both hoses. The other item could be that the thermostat you installed is not opening. I would try a pressure test first, just to rule out a leak internally. Then test the new thermostat and radiator.