Hi guys, I’m really stumped at the moment with my coolant, I had the water pump and timing belt changed back in March, all good then I checked under the bonnet a couple months not entirely sure later and my coolant was well below the min line, so I filled it up and rang the garage back they done a pressure test and looked for any visual leaks - nothing was told to keep an eye, then few months later maybe longer I checked again and where I had filled it up to the max line it had gone down a bit again so I took it back l for some reason they done the exact same pressure test etc nothing, now I’m just thinking they haven’t really got a clue, I’m hoping it’s not the head gasket, another mechanic I know said it could be a hairline crack in the expansion tank, but surely that would have come up in the pressure test? Anyone have any ideas?

thanks

The hairline crack doesn't necessarily leak until the tank is hot. That's what I've read in some previous posts. You should also check the plastic connectors that connect into the coolant tank.

Mine was leaking slowly after I proactively asked Ford dealer to renew coolant tank and the two hoses with the plastic connectors. They had to order another coolant tank since the first one was faulty and leaked from the top connection. 

Also your coolant level decreasing could just be because there was some air in the system. The cooling system is relatively complicated and no doubt there can be some air in there after the timing belt and water pump change.

Is your Fiesta an ecoboost? If so, the 2013/2014 cars had a common problem of loosing coolant. I had a 63 plate that had this issue & was fixed under warranty at the time. 

2 hours ago, Rogue2 said:

Is your Fiesta an ecoboost? If so, the 2013/2014 cars had a common problem of loosing coolant. I had a 63 plate that had this issue & was fixed under warranty at the time. 

Mines just a Zetec same year however, did they say what the problem?

 

4 hours ago, Jeipii said:. 

Also your coolant level decreasing could just be because there was some air in the system. The cooling system is relatively complicated and no doubt there can be some air in there after the timing belt and water pump change.

I was told it could have been that there was air in the system but I have since refilled it and it’s still happpening so can’t be that now? 

Mine was a Titanium spec & they said that it was leaking from either the expansion tank (hairline crack on bottom) or one of the hoses. 
Not much help, but it’s somewhere to start looking.

When mine leaked, it only leaked after it had been used - hot engine - so a hairline crack in a hose or the expansion tank is most likely. 

12 minutes ago, Rogue2 said:

Mine was a Titanium spec & they said that it was leaking from either the expansion tank (hairline crack on bottom) or one of the hoses. 
Not much help, but it’s somewhere to start looking.

When mine leaked, it only leaked after it had been used - hot engine - so a hairline crack in a hose or the expansion tank is most likely. 

Did yours leave much obvious residue or was it like steam? Will check those out 

9 hours ago, Rundle123 said:

Did yours leave much obvious residue or was it like steam? Will check those out 

There was no residue but there would be a small puddle under the car. My car was garaged so was easier to keep checking it.

When I took it in, they said that if I had left it any longer it would have dumped the whole lot & buggered the engine. 

18 hours ago, Rundle123 said:

Mines just a Zetec same year however, did they say what the problem?

 

I was told it could have been that there was air in the system but I have since refilled it and it’s still happpening so can’t be that now? 

You said it had gone down some. How much was that ? The level can fluctuate easily so that the coolant level increases and then decreases back again. When I bought my Fiesta few years ago the coolant level could be up to way over max sometimes. Then one day it was just a little over max and another day when engine was hot it was way over max again. I'm not saying you don't have a leak, but it could just be the coolant level fluctuating a bit depending on air temperature etc. Now after my coolant reservoir was changed and some coolant added about a year ago the level hasn't changed that much into any direction even when engine is warm. I guess they got the air out for good this time. Before that the coolant level could occasionally increase a lot and then lower back to original level at some point.

But since it's better to be safe than sorry you have to obviously be 100% sure it's not leaking before having a peace of mind.

19 minutes ago, Jeipii said:

You said it had gone down some. How much was that ? The level can fluctuate easily so that the coolant level increases and then decreases back again. When I bought my Fiesta few years ago the coolant level could be up to way over max sometimes. Then one day it was just a little over max and another day when engine was hot it was way over max again. I'm not saying you don't have a leak, but it could just be the coolant level fluctuating a bit depending on air temperature etc. Now after my coolant reservoir was changed and some coolant added about a year ago the level hasn't changed that much into any direction even when engine is warm. I guess they got the air out for good this time. Before that the coolant level could occasionally increase a lot and then lower back to original level at some point.

But since it's better to be safe than sorry you have to obviously be 100% sure it's not leaking before having a peace of mind.

Yeah that’s interesting, it’s hard to tell sometimes as where I live there’s nowhere flat to check it exactly the same every time but I have had to put more coolant in and then when I eventually get park somewhere flat I check and it’s on the max line where I’ve filled it up so I’m certain it’s been going down 

3 hours ago, Rogue2 said:

There was no residue but there would be a small puddle under the car. My car was garaged so was easier to keep checking it.

When I took it in, they said that if I had left it any longer it would have dumped the whole lot & buggered the engine. 

Just really hard as there are no obvious signs of the engine struggling or anything like that 

Told to keep an eye on it so left it a few months before checking again...?  Good job you don't have a proper leak!   

Some coolant does get lost over time, if you're only topping up every few months I really wouldn't worry about it.  Assuming it's the NA 1.25 engine, the coolant level isn't as critical as it is on the EcoBoost.

18 minutes ago, TomsFocus said:

Told to keep an eye on it so left it a few months before checking again...?  Good job you don't have a proper leak!   

Some coolant does get lost over time, if you're only topping up every few months I really wouldn't worry about it.  Assuming it's the NA 1.25 engine, the coolant level isn't as critical as it is on the EcoBoost.

I’ve kept an eye on it weekly since I’ve noticed it going down the only time I left it for months was when the Cambelt and water pump was changed as I didn’t even know it was a thing, when I took it back to the garage they said they should have told me to keep an eye on the coolant but they never did 😂

It is the 1.25 engine