Morning folks,

Done a quick fluid check last night: topped up screenwash, checked oil, checked coolant – it was way below minimum.

This is on a diesel Ford Fiesta, barely over 18 months old, coming up 28k miles. Serviced at the start of December.

1) My relatively basic mechanical knowledge tells me that the coolant system is sealed, therefore it shouldn’t be able to evaporate/leak – right?

2) And if this is an issue, I’d be thinking that this would be covered via warranty since this wouldn’t be considered a consumable wear&tear part – right?

Any insight appreciated 🙂

Could be a coolant leak. Keep an eye on level.
Check the oil for any creamy like consistency (possible head gasket failure)

Yep is a sealed system. There will be a pressure release valve somewhere on it should the coolant system get too hot and pressurised but if that had been blowing you’d have seen the steam coming out. So either you’ve got a leak, which should be covered by the warranty or it’s not been checked/changed when it’s been serviced. To be fair I don’t think a coolant change would be required after 18 months or 28k miles. Give the dealer who serviced it a call (assume it’s the Ford franchised dealer) and get it booked in.

Our 1.3 fiat diesel used fluid at a very low rate but no one could ever find the source of the leak. We kept topping it up every 2/3 months for the best part of 3 years.

Ignore what may or may not have happened at the service. Note the level now and check next week, month. If it’s going down, check it in.

The pressure relief is usually in the cap. You shouldn’t be losing any coolant. A system with no leaks can run continuously and require no topping up. However Ford will probably view a small loss as acceptable and put more coolant in. Over 30k-ish miles you’ve not lost a lot. I’d let the dealer know & get more coolant put in. If you’re intending doing this yourself the usual caveats apply. Use the correct coolant and do it when the system is stone cold.

D.

Did you check it when it was cold or hot ( yes it makes a difference ) ?

Do you know for definite that it was at a higher level before? As already said, The issue is more whether the amount is actively dropping as time goes on indicating a leak – so you need to monitor it weekly (or daily) It *may* be that it was simply filled to a lower level from a service and its been like that for ages with no leaks. Although at 18months old, I would expect it to not have had a coolant change as yet.

Sometimes, with all the best will in the world, there are so many coolant pipes and joins in modern engines that you simply do get tiny leaks that are all but impossible to trace – but they are so small that they only lose tiny amounts of fluid over long long periods. So long as the coolant in the tank remains at suitable level, then it should be fine.

My big 4.2 V8 engine must drop about 100ml of coolant over about 3 months. I just monitor it and top it up once in a blue moon. I don’t see any leakage visible but can smell it after a run – Its just one of those things, and its certainly not worth the hassle of stripping down the engine bay for a tiny leak.

IIRC there isn’t a service interval for the coolant in Fords, it’s nominally there for the life of the car.

In reality you’ll not get to 100,000 miles or more without a water pump or something needing replacement and necessitating the system needing re-filling.

More worryingly my OH’s car is using coolant and oil (only 100-200ml a month) and she checks neither regularly[i] ever[/i]. It’s a perfectly good car (just had new clutch, exhaust, water pump, tyres), but I can almost guarantee it will meet it’s end on a motorway at 90mph either through lack of water or oil.