Overheating problems

[scumfromohio]

A couple of weeks ago my car started overheating. It turned out to be a bad engine coolant filler neck and cap. I replaced both those. Then it started starting really crappy like stalling out right after i started it and puttering alot. I figured with it overheating although i was watching and putting coolant in it before i replaced the neck and cap it was probably the ect sensor. So i replaced that. Now it still starts funny occasionally and my heater takes forever to warm up. and the driver side vent gets hot at least 10 minutes before the passenger. And the overheating light will flicker occasionally but coolant is always full and it never feels hot. I checked the oil for a blown head gasket and the oil looks brand new as i just got an oil change. There's no coolant in my car on the floor so i don't think it's a heater core issue. Any help would be greatly appreciated. I don't know what else it could be. It's a 08 yaris hatchback. Only things I've ever replaced was the alternator maybe 6 months ago and the water pump maybe a year ago. It's got 240000 miles on it.

[dj92]

Where do all these recent thermostat failures come from? :D
I'd check that.

[scumfromohio]

Where do all these recent thermostat failures come from? :D
I'd check that.

Haha I'll give that a shot thanks man.

[CTScott]

Make sure the system is purged of air. A large trapped air bubble could cause that behavior.

[scumfromohio]

Make sure the system is purged of air. A large trapped air bubble could cause that behavior.

After reading this actually sounds like my problem. I just jack up the car take the radiator cap off remove what coolant is in there and start the car and set the heat on high? From what i read.

[CTScott]

After reading this actually sounds like my problem. I just jack up the car take the radiator cap off remove what coolant is in there and start the car and set the heat on high? From what i read.

Just remove the cap and run it until the thermostat opens. Then, watch the fluid swirl and keep adding fluid as needed until the bubbles stop.

There is also a small petcock on the back side of the block that you are supposed to open when you initially add fluid to a drained system. If you open that now quite a bit will drain, as it is only about half way up the block, but opening that for a few seconds may help burp it.

[scumfromohio]

Just remove the cap and run it until the thermostat opens. Then, watch the fluid swirl and keep adding fluid as needed until the bubbles stop.

There is also a small petcock on the back side of the block that you are supposed to open when you initially add fluid to a drained system. If you open that now quite a bit will drain, as it is only about half way up the block, but opening that for a few seconds may help burp it.

Got a few really big air bubbles out. Test drive a little but hard to tell because my car was warm. I'll be able to tell tomorrow morning for sure. I'm staying hopeful been dealing with this for a few weeks haha.

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[scumfromohio]

Didn't seem to fix what I can add is, it seems my reserve stays full but the engine coolant neck loses what I put in it and gets no more. Like this morning it was empty but reserve was full and it was still overheating. So I waited for it to cool down and poured it straight in the radiator cap and it's fine.

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[CTScott]

Didn't seem to fix what I can add is, it seems my reserve stays full but the engine coolant neck loses what I put in it and gets no more. Like this morning it was empty but reserve was full and it was still overheating. So I waited for it to cool down and poured it straight in the radiator cap and it's fine.

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So, you either still have air in the system or you have a leak. I find that to get all of the air out you have to leave it running for a crazy long time (like 30+ minutes in cold weather)

[scumfromohio]

So, you either still have air in the system or you have a leak. I find that to get all of the air out you have to leave it running for a crazy long time (like 30+ minutes in cold weather)

Yeah I left it running for at least 45 minutes, I'm thinking there's gotta be a leak somewhere cause of how fast it's losing coolant. I work maybe 50 minutes away and the coolant was out of the engine filler neck twice. So it was completely empty 2 times and I poured it in there 2 times. But idk at this point

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[CTScott]

Yeah I left it running for at least 45 minutes, I'm thinking there's gotta be a leak somewhere cause of how fast it's losing coolant. I work maybe 50 minutes away and the coolant was out of the engine filler neck twice. So it was completely empty 2 times and I poured it in there 2 times. But idk at this point

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Is there significant white smoke out of the exhaust?

[scumfromohio]

Is there significant white smoke out of the exhaust?

None what so ever, but I pull over as soon as the overheat light blinks.

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[CTScott]

None what so ever, but I pull over as soon as the overheat light blinks.

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Hmmm. And, no sign of wetness under the hood? Any sign of moisture or smell of coolant from the A/C vents?

Also, remove the oil filler cap and see if there is any foaminess on the bottom of it.

[scumfromohio]

Hmmm. And, no sign of wetness under the hood? Any sign of moisture or smell of coolant from the A/C vents?

Also, remove the oil filler cap and see if there is any foaminess on the bottom of it.

There's no smell of coolant inside the car or from the vents. It's hard to say about wetness under the hood cause I'm not the most accurate coolant pourer. Haha so I've spilled a bit. I'll check for foaminess tonight. I was thinking about renting a pressure tester tomorrow and giving that a shot what do you think? Thanks for all your help man.

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[CTScott]

There's no smell of coolant inside the car or from the vents. It's hard to say about wetness under the hood cause I'm not the most accurate coolant pourer. Haha so I've spilled a bit. I'll check for foaminess tonight. I was thinking about renting a pressure tester tomorrow and giving that a shot what do you think? Thanks for all your help man.

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Pressure tester might not be a bad idea. Also, I have noticed that if you disconnect the radiator with hoses that are a few years old and reuse the hoses, that they often don't reseal well unless you replace the stock hose clamps and tighten the heck out of them.

[scumfromohio]

Pressure tester might not be a bad idea. Also, I have noticed that if you disconnect the radiator with hoses that are a few years old and reuse the hoses, that they often don't reseal well unless you replace the stock hose clamps and tighten the heck out of them.

OK so pressure test was fine it stayed the same pressure for 10 minutes. We ran it for a good while and after an hour or so coolant started coming out the reserve again, but the filler neck and radiator cap are both brand new.

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[CTScott]

OK so pressure test was fine it stayed the same pressure for 10 minutes. We ran it for a good while and after an hour or so coolant started coming out the reserve again, but the filler neck and radiator cap are both brand new.

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Coolant will go into the reserve tank as it gets hot and expands. Is it overflowing the reserve tank?

[scumfromohio]

Coolant will go into the reserve tank as it gets hot and expands. Is it overflowing the reserve tank?

Yes, its over flowing the reserve tank. That's the only place I can think I'm losing the coolant. When I seen it, it was only a little bit, but it has to be going somewhere ya know.

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[CTScott]

Yes, its over flowing the reserve tank. That's the only place I can think I'm losing the coolant. When I seen it, it was only a little bit, but it has to be going somewhere ya know.

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If it starts at the "cold" level in the reserve tank and then overflows it when the engine is hot, then you still have air in the system. Air expands far more than coolant does, so the air bubble pushes the coolant out.

[scumfromohio]

If it starts at the "cold" level in the reserve tank and then overflows it when the engine is hot, then you still have air in the system. Air expands far more than coolant does, so the air bubble pushes the coolant out.

I was burping it for over an hour tonight. I noticed that whenever the fan in the front of the car would turn on or I would turn on the heat the coolant which I filled to the top would lower a good amount. So at first I thought it was just air bubbles, but then I noticed a growing puddle underneath the car. I'm wondering if it's dumping when the fan turns on or heat is on. Maybe the heater core. But shouldn't that dump inside the car? Idk, I know the pressure test came back no leaks. http://img.tapatalk.com/d/14/04/02/u8usugu4.jpg

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[CTScott]

The fan kicks on about the same time that the thermostat opens, so at that time the coolant start fully circulating beyond the engine.

If the heater core is leaking the coolant will go into the bottom of the airbox, where it will drain from the condensate drain tube (which is mounted to the bottom of the firewall on the passenger side).

Park the car over a dry spot and try it again, noting where under the car it seems to be leaking from.

[ex-x-fire]

It might have an internal head gasket leak, this is when combustion chamber gases get into the cooling system. Any air that's in the cooling system expands a lot when heated. They have testing tools to determine that.
On cars that I work on that seem to have air in the cooling system, I unhook one of the heater hoses & fill it up. A funnel on the radiator might help too.
To be honest my mechanical experience with the yaris is limited, it been the most reliable car I've owned.

[scumfromohio]

Well it was tons of air bubbles caused by a problem with the head gasket. It's all fixed up. Thank you guys for all your help

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[frambach]

So, with 240,000 miles you had to replace the head gasket?

Was that due to it overheating? And then, if the answer is yes, did it overheat because of a faulty thermostat?

Just trying to establish what I might need to keep an eye on as mileage on our little guy climbs.

Thank you for your input.

[scumfromohio]

So, with 240,000 miles you had to replace the head gasket?

Was that due to it overheating? And then, if the answer is yes, did it overheat because of a faulty thermostat?

Just trying to establish what I might need to keep an eye on as mileage on our little guy climbs.

Thank you for your input.

I can't say for sure what caused it. A couple months ago my serpentine belt broke and I didn't realize it and kept driving. Which in turn killed my water pump and thermostat. But then no problems for a few months probably cause I towed it home as soon as it started overheating when the water pump went out. Then my coolant engine filler neck and radiator cap went which kept causing my car to overheat, but I couldn't figure out what it was. As soon as it would overheat I would stop and put coolant in it but I guess at some point it may have overheated a little worse then I thought. So I believe the filler neck and radiator cap is what caused the overheating to mess up the head gasket. But with the history I can't say for sure I'm just going with what happened later on. I've talked to a few people with civics who have gone through tons of radiator caps but I've never heard of that till this. At 240000 I can't complain about replacing the head gasket especially since this car hasn't given me any problems til the water pump. It probably wouldn't of happened if I would have just taken it to someone when it all first started but I wanted to try and fix it myself haha, oh well.

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