Engine coolant reserve tank empty after 12000 KM

[cyssero]

Hi all,

My engine coolant was topped up / flushed at the last service (45,000km interval).

Concerningly, the reserve tank is nearly empty after 12,000km. The manual suggests the coolant is in a closed system and any usage should be very slight. It's clearly noticeable (probably 1/3rd below the LOW line) and I'm wondering what's causing it.

Car is due for a service soon anyway so it will certainly be brought to their attention but I'm wondering if anyone here would know why it's being consumed so quickly. Manual also suggests it could be indicative of a leak. Then again, it doesn't say how long coolant should last for in the reserve tank. Hoping if someone can advise if this is normal consumption or if there is something more sinister happening.

Appreciate any input and advice.

[aspir3]

If you got your coolant flushed last service it is probably just air pockets in the system slowly getting filled with coolant. This is normal after coolant change.

Top it up and then see if it moves.

[cyssero]

Good advice aspir3, thanks. Have booked in my next service and asked them to take a look at it. I guess they will top it up and check for anything suspicious while they're at it.

[The X]

If you got your coolant flushed last service it is probably just air pockets in the system slowly getting filled with coolant. This is normal after coolant change.

Rubbish. Dealers are supposed to run the engine to get it warmer than operating temperature, to get the coolant circulating through the system to avoid the issue of air pockets. If you have air pockets, the dealer is not following the procedure as per the service manual. I got my mine flushed @ 30,000/24 as service manual states 45,000 or 24 month whichever comes first.

As for losing so much coolant. Definately not normal.Even account for normal evaporation, does not account for so much loss. At 20 months, I had to top it up from 2/3 of the way between the HI / LO marks as we were coming into summer and aware that the service interval at 24 months, was going to replace it. If i knew I wouldn't have bothered topping up.

If it was a radiator leak, you've be pissing coolant everywhere and smelling it too. Check the overflow resorvoir bottle for leaks and the small hoses tubes leading to from the resoirvoir. Could be these low/no-pressure hoses that might be leaking instead...

[cyssero]

Thanks Pete, will do.

I should add that it has gone from 'full' to below 'low' in less than 3 months (the time it has taken me to do about 12,000KM).

I have photos of when they replaced/topped up the coolant as I was slightly concerned it wasn't full enough, they assured me they don't always top to full in case it overflows. Sounds like they were trying to fob me off but I didn't peruse it at the time. Even then, it was nearly full (more than 2/3rd between full/low markings).

[aspir3]

Pete if it done properly then yes your coolant should not be low, but we all know dealers tend to cut corners and get the job done as fast as possible. Idling the car often does not flush out all the air pockets. Often you need to drive the car several times allowing the coolant to cool right down in between to get them all out.

Easiest way for dealer to get it right is to measure the amount of coolant that was removed and replace the exact amount.

[cyssero]

Hi all,

Just an update - car is in for service and I explained the issue to them. They ran a pressure test and found no leaks and said the radiator itself was full. They've topped up the reserve tank and I will continue to keep an eye on it.

[aspir3]

Did they pressurise the reserve tank?

Sounds like the reserve tank or hose from radiator to reserve tank is leaking.

[cyssero]

Not sure but thanks for the pickup, will ask them when I go in. Something has to be off given the amount of reserve coolant it ran through in a short amount of time.

EDIT: Didn't remember to ask them, but they did top it up fully. Root-cause may not be solved yet so I will monitor it up until next service.