[jonesanto]

Hi, folks,

I need some advise about an issue we're facing on my brothers Swift. From last November whenever he opens coolant reservoir cap to check coolant level, coolant is gushing out with pressure, this is when the engine is completely cold in the morning. There is absolutely no visible leak from any pipes or under the car.

He does not face any overheating issues either, AC cooling has reduced a bit, but cooling is still within acceptable level. Car is a 2014 September model with 85K ODO. A well maintained car with all services done in authorized service centers only. Last year radiator was replaced along with some pipes, ERG, MAF sensor and intercooler was cleaned, AC also serviced last year because cooling was less.

There is no loss of power or mileage and car is running just running fine other than this coolant overflow issue. If we did not have the habit of checking fluid levels we would not even realize this issue.

When I tried to open the reservoir cap few weeks back, coolant came out with pressure and due to this we can't know what is the exact coolant level in the car. I topped up the coolant to the required level and the car was used for a week, next week I started the car first waited for a minute then opened the reservoir cap. This time coolant did not come out but I could clearly hear the pressure releasing sound. And it looks like coolant level was reduced a bit than last week, or is it due to car engine was running at the time?

I checked if the coolant was bubbling and in one minute two three small bubbles appeared, that's it. Radiator fan is working properly, no issues there. There is no oil mix in coolant and oil looks like how it should be, no increase in oil level.

Now could this be a symptom of head gasket leak or water pump issue or a simple reservoir cap issue? We have not taken the car to authorized service center yet.

Please advise.

[(Alok)]

Have you ensured flow of coolant in cooling system?

Apart from electronics, 3 things to be checked.

1. Rubber hose from radiator to coolant reservoir (clean it, if chocked).
2. Thermostat valve stuck (most probable in your case).
3. Water pump.

[R2D2]

Originally Posted by jonesanto

There is absolutely no visible leak from any pipes or under the car.

He does not face any overheating issues either, AC cooling has reduced a bit, but cooling is still within acceptable level. Car is a 2014 September model with 85K ODO. A well maintained car with all services done in authorized service centers only. Last year radiator was replaced along with some pipes, ERG, MAF sensor and intercooler was cleaned, AC also serviced last year because cooling was less.

When I tried to open the reservoir cap few weeks back, coolant came out with pressure and due to this we can't know what is the exact coolant level in the car. I topped up the coolant to the required level and the car was used for a week, next week I started the car first waited for a minute then opened the reservoir cap. This time coolant did not come out but I could clearly hear the pressure releasing sound. And it looks like coolant level was reduced a bit than last week, or is it due to car engine was running at the time?

I checked if the coolant was bubbling and in one minute two three small bubbles appeared, that's it. Radiator fan is working properly, no issues there. There is no oil mix in coolant and oil looks like how it should be, no increase in oil level.

Now could this be a symptom of head gasket leak or water pump issue or a simple reservoir cap issue? We have not taken the car to authorized service center yet.

I think you mean radiator cap when you say reservoir cap? The reservoir tank if pressurised has a vent hole that will automatically equalise pressure with the atmosphere.

You said the radiator was replaced which may have been due to corrosion due to rust or deposits in the system. Have you been filling coolant mixed with bore-well (hard) or tap water? Mix coolant concentrate with demineralised/distilled water only. Best is to use a premixed product.

The car's cooling system seems to have a blockage in the system, a faulty thermostat, or a water pump failure. I would advise you to get this attended to quickly. Cooling problems can leave you stranded, warp the engine head or worst of all result in engine seizure.

[MinivanDriver]

There is a blockage somewhere. When this happened in my M800, it was due to rust in radiator and the piping. Both were replaced. But the issue persisted. Later I learned that the small workshop where I had done the job had fixed a non original radiator. I strongly recommend having all elements of the cooling system checked for rust and replaced if there's any rust. A very important thing is to check in a good running car similar to yours and note at what temperature indicated by the gauge does the fan comes on and once it comes on while idling how much time does it take for the temperature to go down and the fan to shutoff. Then note the same for your car. If there's any variation, this can lead to engine overheating and needs to be addressed immediately.

[jonesanto]

Hi, Alok,

1. Rubber hose from radiator to coolant reservoir (clean it, if chocked). > Radiator and pipes are new, so I doubt there is any blockage here.

2. Thermostat valve stuck (most probable in your case) > This needs to be checked, like I said car is used on a daily basis and there is no heating issue at all, temperature needle is at required level for Swift.

3. Water pump > This needs to be checked.

Originally Posted by R2D2

I think you mean radiator cap when you say reservoir cap? The reservoir tank if pressurised has a vent hole that will automatically equalise pressure with the atmosphere.

You said the radiator was replaced which may have been due to corrosion due to rust or deposits in the system. Have you been filling coolant mixed with bore-well (hard) or tap water? Mix coolant concentrate with demineralised/distilled water only. Best is to use a premixed product.

The car's cooling system seems to have a blockage in the system, a faulty thermostat, or a water pump failure. I would advise you to get this attended to quickly. Cooling problems can leave you stranded, warp the engine head or worst of all result in engine seizure.

Thanks R2D2, yes, radiator cap is what I meant. I usually mix coolant with distilled water only, but the last top-up I used tap water. I have not taken the car to the service station because there was no heating issue or no visible leakage any anywhere, also radiator and pipes have been replaced last year, so I was thinking cooling system is running fine. I will take the car to the service station immediately.

Originally Posted by MinivanDriver

There is a blockage somewhere...

Hi, MinivanDriver, like mentioned before, radiator and pipes can't be the culprit here, because they are brand new, now water pump and thermostat, I have no idea what condition they are in. Now, the car performance and engine temperature going by the temperature gauge, it is just like when it was brand new. So this coolant overflow could be a symptom that engine is gonna overheat. I will pay a visit to the service station. I just hope there is no major issues.

Any idea how much does Swifts water pump and thermostat cost?

[R2D2]

Originally Posted by jonesanto

Thanks R2D2, yes, radiator cap is what I meant. I usually mix coolant with distilled water only, but the last top-up I used tap water. I have not taken the car to the service station because there was no heating issue or no visible leakage any anywhere, also radiator and pipes have been replaced last year, so I was thinking cooling system is running fine. I will take the car to the service station immediately.

This behaviour is not normal. I would suggest you get the entire cooling system checked. Since you have to top off the coolant/water there may be a leak somewhere that is not visible to you with a casual glance. I have seen quite a few engines dying a premature death due to cooling system failures. Get this checked ASAP.

Note - A gentle hissing sound of pressure being released from the radiator is normal - only **IF** the engine is warm. Always wait for the engine cool down i.e. it should not hotter than warm to the touch before opening the rad cap. For your safety cover the cap with a thick rag when opening to soak up any coolant overflow. Make it a habit to check coolant levels at least once a month yourself.

Cost of water pump - Approx 2K as per Boodmo, price for only thermostat is not available. But they have listed a thermostat housing assembly which is about 1.4K. These prices are best confirmed with your dealer.

[IndigoXLGrandDi]

Was the air trapped in the cooling system removed when the radiator was replaced?

Irrespective of that, I would suggest bleeding the cooling system (once again even if done at that time).

Also I think there is some obstacle in the cooling system (other than air) that may be causing non-release of the pressure built up when the radiator has cooled down. And hence the Coolant gushing out.

Are you sure the radiator was replaced with OE?

[ringoism]

Sounds like a head gasket leak that's allowing cylinder pressure to pass into the water jacket. Could be a cracked cylinder head even, but I don't know if that's common/likely on Swifts (is on some cars if overheated). Our Marshal had same behaviour a few years back, in that case a cracked cylinder liner (but the DI is a wet-sleeve engine, swift probably isn't).

-Eric

[SS-Traveller]

Originally Posted by jonesanto

...my brothers Swift. From last November whenever he opens coolant reservoir cap to check coolant level, coolant is gushing out with pressure, this is when the engine is completely cold in the morning.

Is the coolant reservoir cap the pressure cap on the radiator? Or are you talking about the cap on the coolant overflow tank?

Originally Posted by jonesanto

Now could this be a symptom of head gasket leak or water pump issue or a simple reservoir cap issue? We have not taken the car to authorized service center yet.

Please advise.

If it is the pressure cap you are talking about, then replace it and see what happens. If it doesn't sort out the issue, you might be looking at replacing the head gasket.

[jonesanto]

Originally Posted by R2D2

This behaviour is not normal....

Originally Posted by SS-Traveller

Is the coolant reservoir cap the pressure cap on the radiator? Or are you talking about the cap on the coolant overflow tank?

If it is the pressure cap you are talking about, then replace it and see what happens. If it doesn't sort out the issue, you might be looking at replacing the head gasket.

Thank you R2D2, SS-Traveller, I was talking about the coolant box cap right next to the battery.

I visited the service station. Explained the issue, SA told me to drop the car there and told me he will let me know the status.

Evening I got a call saying, they could not find any issue with the car.

Tested the car for overheating = No issues.

Tested water pump = No issues.

Tested thermostat = No issues.

Compression test = No issues.

Checked all the pipes and under body for any leak = Found nothing.

Only thing which is left to check is head gasket. According to SA, head gasket issue for a car which is not even 5 years old with no history of overheating is highly unlikely. Radiator and hoses are new, changed six months back to be precise, so blockage in any of the hoses are also minimal.

Before going and opening the head gasket he wanted to change the pressure cap and see if that makes any difference. Like SS-Traveller mentioned

Unfortunately they don't have stock and promised me they'll get the part in three working days.

So, I will have to wait and see what happens after the pressure cap replacement.

[R2D2]

Originally Posted by jonesanto

So, I will have to wait and see what happens after the pressure cap replacement.

Thanks, do let us know how it works out. But should it continue I would recommend getting a second opinion on the probable cause.

Cheers!

[SS-Traveller]

Originally Posted by jonesanto

...the coolant box cap right next to the battery.

I'm not sure which cap you mean. Kindly post a photo to clarify.

[govigov]

I would just jack the front of the car, and run the car in the heater mode with the a/c on. This would make sure that the air trapped in the lines are removed. When you squeeze the heater tubes passing into the firewall, is it filled with water? Also, when the car is hot, these tubes should also be hot. I think it is just residual air escaping. jacking the front of the car should make the radiator the highest point and it should make the air easier to escape.

[jonesanto]

Originally Posted by R2D2

Thanks, do let us know how it works out. But should it continue I would recommend getting a second opinion on the probable cause.

Cheers!

Sure, R2D2, I will update the progress and if the issue persists, then we will think about what can be done next.

Originally Posted by SS-Traveller

I'm not sure which cap you mean. Kindly post a photo to clarify.

Hey, SS-Traveller, sure, I will post a pic soon.

Originally Posted by govigov

I would just jack the front of the car, and run the car in the heater mode with the a/c on. This would make sure that the air trapped in the lines are removed. When you squeeze the heater tubes passing into the firewall, is it filled with water? Also, when the car is hot, these tubes should also be hot. I think it is just residual air escaping. jacking the front of the car should make the radiator the highest point and it should make the air easier to escape.

Hi, Govi, thanks, I am not sure I follow you. "Run the car in the heater mode with the a/c on." Car has got auto climate control, so what temperature I should set it? There is nothing wrong in trying this method out.

[govigov]

Hit the auto button and turn the dial until it says high. This should ensure that the proper valves are open and that the coolant is flowing to the heat exchanger to blow out hot air. This should make the car very uncomfortable for you to sit in. If it does not blow hot air, report back.