Coolant overlowing to resevoir tank

[x1conroe]

Hi Guys,

 

 

Car: 2013 Subaru Legacy 2.5i Premium with 94k miles.

 

 

I have a problem with the coolant overflowing to the reservoir on long drives. 1-2 hour drives will do it. I have not had any signs of overheating (no light, checked my OB2II reader in realtime with a phone app.) The coolant does seem to flow back down once it does sit overnight or so. All signs kinda point to a head gasket, I know.

 

 

 

I have ran a combustion tester, BT-500 from Amazon. Came back negative and I used basically all of the liquid. I have replaced the rad cap and the issue still persist.

 

 

I have taken it to a shop that specialized in Subaru. They also ran the combustion test it came back negative and they replaced the rad cap. They suggested I replace the thermostat and serpentine belt (i was at 90k at the time). So I replaced that, replaced the coolant and even added the coolant conditioner. Same results. They then said the next step is to replace the head gaskets. I agreed to and and a few days before my appointment they realized that my car was a chain driven CVT and not a belt driven CVT. They do not have the tools for it and it was irregular to see a head gasket problem on that car. They then sent me to the local Subaru dealership.

 

 

Here's the reply from the dealership: "So I talked to them about it, your particular car can be hard to diagnose head gaskets. It is not uncommon for them to pass hydrocarbon tests, which your's has, and there are no other signs showing up. We listened for the gurgling noise from the dash area when hot but did not hear it. Have you tried listening for that after a long trip? We also checked the oil and coolant for signs of intermixing but didn't see it. So it is hard to say because we have not confirmed it, but head gaskets would be the direction we are leaning. I asked about doing the radiator & water pump, the tech said if it was his car he probably wouldn't spend the money on those things because he doesn't think they are the problem, but again hard to say. The only sure way to know about the head gaskets would be to start disassembling the motor, or wait and see if more symptoms start coming up in the future. Let me know if we can help with anything."

 

 

Would it be worth replacing the radiator and water pump or do all signs definitely point to head gaskets? Could it be a cracked head?

 

 

Thanks for any input and i hope this has enough detail

[Alexmed2002]

Hi Guys,

 

 

Car: 2013 Subaru Legacy 2.5i Premium with 94k miles.

 

 

I have a problem with the coolant overflowing to the reservoir on long drives. 1-2 hour drives will do it. I have not had any signs of overheating (no light, checked my OB2II reader in realtime with a phone app.) The coolant does seem to flow back down once it does sit overnight or so. All signs kinda point to a head gasket, I know.

 

 

 

I have ran a combustion tester, BT-500 from Amazon. Came back negative and I used basically all of the liquid. I have replaced the rad cap and the issue still persist.

 

 

I have taken it to a shop that specialized in Subaru. They also ran the combustion test it came back negative and they replaced the rad cap. They suggested I replace the thermostat and serpentine belt (i was at 90k at the time). So I replaced that, replaced the coolant and even added the coolant conditioner. Same results. They then said the next step is to replace the head gaskets. I agreed to and and a few days before my appointment they realized that my car was a chain driven CVT and not a belt driven CVT. They do not have the tools for it and it was irregular to see a head gasket problem on that car. They then sent me to the local Subaru dealership.

 

 

Here's the reply from the dealership: "So I talked to them about it, your particular car can be hard to diagnose head gaskets. It is not uncommon for them to pass hydrocarbon tests, which your's has, and there are no other signs showing up. We listened for the gurgling noise from the dash area when hot but did not hear it. Have you tried listening for that after a long trip? We also checked the oil and coolant for signs of intermixing but didn't see it. So it is hard to say because we have not confirmed it, but head gaskets would be the direction we are leaning. I asked about doing the radiator & water pump, the tech said if it was his car he probably wouldn't spend the money on those things because he doesn't think they are the problem, but again hard to say. The only sure way to know about the head gaskets would be to start disassembling the motor, or wait and see if more symptoms start coming up in the future. Let me know if we can help with anything."

 

 

Would it be worth replacing the radiator and water pump or do all signs definitely point to head gaskets? Could it be a cracked head?

 

 

Thanks for any input and i hope this has enough detail

 

I have the same car and I have had a different issue with mine, but I have had to figure out if my headgaskets were the problem. Our engine doesn't usually have headgasket issues (2013 and up 2.5i). Mine has started to burn oil, which I am now learning is common on these engines. Subaru quoted me $2,800 to have my engine pulled out and re-sealed. I'd imagine they would charge you something similiar. This is why personally I am trying to sell mine with 88k miles, as I know there will be more problems in the future...

[poconoracing]

That sounds like it might be a very small internal head gasket leak. Only Might be. Its an expensive guess. DO NOT shoot the parts cannon at it. Buy/Or have the shop pressure test the cooling system with UV dye in it.

 

Natural expansion of the coolant will make the overflow bottle 'fill' as the car heats up. I'm assuming you are talking about coolant actually spilling out of the overflow bottle. If you are just talking about the level in the bottle going up and down with no coolant loss....there is nothing wrong with the car. That is 100% normal

 

Pump up the system up on a COLD motor to 18 or so psi with the dye in it and leave it.

 

If it loses more than 1 psi over an hour, look for the leak with a UV light.

 

If you don't see it external, pull the plugs and look internal. Make sure you check the heater core and it's connections.

 

You'll find it. The coolant is going somewhere

 

Heres a video gives you the idea. The UV dye helps you find really small leaks. Hope that helps.

 

Edited April 16, 2020 by poconoracing

[Scubaboo]

Isnt a certain anount of hot expanded coolant supposed to flow to the overflow tank, then flow back to the radiator when it cools?

[cww516]

Yup, that's what it's there for, more or less, and that's why you have hot and cold lines on the side of the reservoir.

 

When the level increases, does it always decrease back to the same level when the car cools off (overnight, or long enough to get down to ambient temperature)? If it's always at the same level hot and always at the same level cold, I'd call that normal.

[moral hazard]

That sounds like it might be a very small internal head gasket leak. Only Might be. Its an expensive guess. DO NOT shoot the parts cannon at it. Buy/Or have the shop pressure test the cooling system with UV dye in it.

 

 

Id agree this would be the best way forward.

 

In the past when I had a small headgasket leak, I would keep driving it and check coolant levels often. Eventually a small leak would become a big leak and I'd take care of the headgasket job at that point. Would end up driving for a year before it got too bad.

[creep_nu]

Id agree this would be the best way forward.

 

In the past when I had a small headgasket leak, I would keep driving it and check coolant levels often. Eventually a small leak would become a big leak and I'd take care of the headgasket job at that point. Would end up driving for a year before it got too bad.

 

that's what i've done with all 3 of mine that needed head gaskets. just keep it topped up until you start seeing bubbles coming out the reservoir when it's hot, or the engine starts to run rough change the gaskets then. probably not the actual best advice since you *can* end up doing some damage, but...

[x1conroe]

That sounds like it might be a very small internal head gasket leak. Only Might be. Its an expensive guess. DO NOT shoot the parts cannon at it. Buy/Or have the shop pressure test the cooling system with UV dye in it.

 

Natural expansion of the coolant will make the overflow bottle 'fill' as the car heats up. I'm assuming you are talking about coolant actually spilling out of the overflow bottle. If you are just talking about the level in the bottle going up and down with no coolant loss....there is nothing wrong with the car. That is 100% normal

 

Pump up the system up on a COLD motor to 18 or so psi with the dye in it and leave it.

 

If it loses more than 1 psi over an hour, look for the leak with a UV light.

 

If you don't see it external, pull the plugs and look internal. Make sure you check the heater core and it's connections.

 

You'll find it. The coolant is going somewhere

 

Heres a video gives you the idea. The UV dye helps you find really small leaks. Hope that helps.

 

 

 

It does spill out of the overflow bottle, thus loosing coolant. It'll go back down when it has been sitting but I'll have to top off anything i've lost. Many thanks for the info!

[x1conroe]

Id agree this would be the best way forward.

 

In the past when I had a small headgasket leak, I would keep driving it and check coolant levels often. Eventually a small leak would become a big leak and I'd take care of the headgasket job at that point. Would end up driving for a year before it got too bad.

 

 

 

 

Thanks for your input!

[NVAKeith]

It does spill out of the overflow bottle, thus loosing coolant. It'll go back down when it has been sitting but I'll have to top off anything i've lost. Many thanks for the info!

 

Don’t forget to top off the actual radiator as it will have an air pocket in it. But only open it when the car is cold!

[Alexmed2002]

Don’t forget to top off the actual radiator as it will have an air pocket in it. But only open it when the car is cold!

 

For sure. Otherwise you'll have an explosion of hot and burning coolant...