I have an Octy MK-I with a coolant leakage issue. Since last couple of months I frequently need to refill the coolant tank with either coolant or water at every 150Kms interval else the coolant level drops and warning sign comes up. I have noticed coolant coming from the bottom tray of coolant expansion tank but only when the engine is under pressure.  The leak does not appear initially or in a cold dead engine. I am trying to zero in on the problem.

It can either be a simple leakage from any of the coolant circulating pipes or it can be a leak from the expansion tank itself but it seems unlikely (else coolant would have leaked irrespective of the engine pressure state) or a head gasket issue or worst of all an engine crack.

 

Can anyone helps me with resolving or finding the issue or let me know if someone is facing the same issue?

 

Note: I have not seen any white smoke coming out which can signal an engine crack but I am not sure about this conclusion.

Note: In the expansion tank, at the time of refill bubble erupts in the running engine. Is this normal?

 

it might be a hair line crack in the expansion tank that only opens when hot and under pressure.

 

id look really carefully at that first, especially if theres coolant under it.

Thanks for your response. I sure will take a look at that.

 

On another note, there is another coolant trail that I found at overflow outlet. What might be the reason for that? 

where are you talking about in relation to the overflow outlet?

 

I am talking about overflow outlet of expansion tank.

Inspected the expansion tank as you suggested and found no cracks in it. What other possibilities are we looking at?

any chance of some photos of where the puddles /wet areas are forming that you can see?

 

Hey I sure can provide some photos but the water puddles that I saw under the expansion tank was made by the coolant thrown out by overflow spill way of expansion tank. So I assume puddles are only there because the water in the cooling system is boiling. 

On another note I replaced the expansion tank and the issue still persists. 

So the current scenario is,

- Water/Coolant is still leaking. 

- Water/Coolant is still getting boiled after 100 - 150 Kms

- Water/Coolant is nowhere to be seen externally other than the puddles due to overflow of expansion tank. 

- No white smoke is noticed through the exhaust.

- No oil is noticed in the Water/Coolant.

- Top-up of coolant is still needed at every 100kms to keep the engine temperature at 90.

 

I am still unclear of the source of this leak.

when was the thermostat replaced last? given the engine is boiling the coolant, there is something else not right whuch stopping the intercooler from regulating the temperature. 

 

it may not be leaking, you may be losing it through the expansion pressure release. 

When you look through the translucent expansion tank with the engine running, do you see a regular flow of coolant running back to the tank if an assistant lifts the rpm to 1000 - 1200 ish?, or does it just sputter back or even no flow at all?.

 

When was the water pump/cambelt last changed?.

As per my knowledge thermostat has not been replaced till now. 

 

The flow of the coolant through the cooling system is regular. I can see the coolant coming back and completing the cycle while the engine is running.

UPDATE: 

I took a drive of 500 Kms in the last two days and noticed that whenever I am switching on the AC unit, radiator fans starts and the engine temperature decreases while the same doesn't happen with fans when the engine temperature goes above 90. 

 

Observations under switched on AC unit (Fans working):

- No overflow of coolant through expansion tank noticed.

- Coolant slightly reduced after 250 kms

- Engine temperature was either 90ºC or less than 90ºC (Mostly it was 70ºC)

Check for broken wires at the radiator thermoswitch.

 

Hi Wino, Can you please guide me to the radiator thermoswitch?

Usually 100mm or so above the bottom coolant hose connection to the radiator.  Access may be easier from below, not sure what's in the way of access from above on your engine/car.

Edited 16 December, 20205 yr by Wino

Checked the radiator thermoswitch and it seems alright. Any other issue that can be the culprit for this problem? Please let me know.

I have ordered OBD-II for diagnosis. Once it arrives I will convey its scans as well. till then if anyone has any clue about what else can go wrong with my vehicle please do let me know. 

Hi Burhan. I had a coolant leak and it was from the thermostat housing. After changing it everything is fine.

Thank you everyone for your help. My issue resolved by cleaning the fuse located above the battery. Radiator Fan 2nd Stage terminal fuse has caught a lot of carbon and was getting neglected all the while. I cleaned it's terminals and now engine is appropriately maintaining the optimal functioning temperature. Found no coolant leak. I was loosing coolant through overflow spillway of expansion tank due to excessive boiling of coolant and water, cause of non-functioning radiator fan (2nd Stage). 

 

I hope this helps someone in need.

I have attached Schematic representation of fuse box in engine compartment for reference.

well done,

 

im claiming an assist on it given i had suggested there wasnt a leak, that it was loss through the over pressure blowing out the expansion 

 

 

@mac11irlYes you did. And you sure deserve an assist.

Unfortunately I don't know how the assist system works. 

6 hours ago, Burhan said:

@mac11irlYes you did. And you sure deserve an assist.

Unfortunately I don't know how the assist system works. 

there isnt an assist system

its just a phrase im claiming i was actually helpful in fixing your car

 

UPDATE:

Spotted a liquid trail underneath while I was parking the car. 

 

Observations: (Travel distance 300 Kms)

- Engine doesn't require coolant refill at all. Very little or negligible drop in coolant level.

- Engine temperature is maintained at all times. 

 

Any Idea about the liquid trail left by my car? I have eliminated the possibility of a blown head gasket and engine crack from the above observations.

Does AC unit leave any water trail after operating for a while?

Yes, A/C drops water from the evaporator drain pipe.