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Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

...after letting the car idle for ten minutes. So basically I've been looking into getting air out of my coolant system. Followed online advice and allowed the car to idle on a upward incline with the expansion cap off . After ten minutes the coolant starts boiling and bubbling over quite ferociously. To the point where it was spitting out of the tank. The odd thing is my coolant was slightly below minimum before trying this. Is this to be expected? I stopped just in case.

Thanks in advance for the responses.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

A couple of pics of the tank. Before and during the process. ??

ibb.co/n0y2H3s

ibb.co/FHdvmgL

Edited by OceanMan on 19/05/2022 at 19:44

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

I should add that I've had a coolant leak for a while that I still haven't got to the bottom off. Not sure if this could be related.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Big John

I should add that I've had a coolant leak for a while that I still haven't got to the bottom off. Not sure if this could be related.

Which engine do you have?

With a coolant leak as you've mentioned could this be a head gasket issue?

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - focussed

Did you remember to turn the heater to maximum temperature while you were trying to bleed the cooling system?

If the heater matrix is full of air that can cause the bubbling and boil over you had.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

I didn't remember to do that. I'll try it again later with the fans and heat on full.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

Does your cooling fan come on? If it does, I wouldn't expect your coolant to reach BP with the cap off.

I have to disable my cooling fan to get the coolant to boil, which I do deliberately to clear air pockets. I have a stack of funnels jammed into the fill port to give the coolant (or rather the trapped air) expansion room.

Your symptoms sound like a head gasket failure but that can be difficult to tell apart from an air pocket in the cooling system.

Test for exhaust gases in the radiator/ oil in coolant/coolant in oil is diagnostic of HG failure but not definitive.

Edited by edlithgow on 20/05/2022 at 09:07

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

I'm not too sure about.the fan but I think it's broken. I've had an issue with the car overheating, especially when idling in hot weather. I'll check the fan when I run the test again later. Honestly if it's a head gasket I wonder how much longer I can run the car for. I don't do many miles and if I can get another year out of it I'd be happy to scrap it after.

Edited by OceanMan on 20/05/2022 at 09:26

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Bolt

I'm not too sure about.the fan but I think it's broken. I've had an issue with the car overheating, especially when idling in hot weather. I'll check the fan when I run the test again later. Honestly if it's a head gasket I wonder how much longer I can run the car for. I don't do many miles and if I can get another year out of it I'd be happy to scrap it after.

if its broken you need to get it repaired replaced, as when you sit in traffic or driving below 30mph the fan is needed as it pulls in cooler air to keep engine at normal temp, driving or sitting still with engine running and no fan will cause engine to overheat and may cause head gasket to blow if it hasn`t already.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

Just tried it again with the radiators on. It started to bubble and boil over like last time but it seemed to take a bit longer. The fan isn't working at all. Should look into changing it.

If there's a coolant leak I'm considering trying the liquid stuff. I know it's hit and miss but honestly since I'm considering getting rid of the car anyway perhaps it's worth the risk rather than spending several hundred £ on a proper repair.

I think the engine is a 1.25 zetec by the way

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Bolt

Just tried it again with the radiators on. It started to bubble and boil over like last time but it seemed to take a bit longer. The fan isn't working at all. Should look into changing it.

If there's a coolant leak I'm considering trying the liquid stuff. I know it's hit and miss but honestly since I'm considering getting rid of the car anyway perhaps it's worth the risk rather than spending several hundred £ on a proper repair.

I think the engine is a 1.25 zetec by the way

may not be the fan it could be the thermostatic switch not working, maybe get someone to check the circuit out in case the stat has broken...good engine that one

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - elekie&a/c doctor
Cooling fan motor is a common failure on these . There is no dedicated thermo switch for the fan . It’s operation is controlled by the engine ecu .
Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

I see. So it's possible the fan doesn't need switching? Is there any way I could test that myself so I don't have to bother switching the fan if it's not necessary.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Andrew-T

Just tried it again with the radiators on. It started to bubble and boil over like last time but it seemed to take a bit longer. The fan isn't working at all. Should look into changing it.

You need to know whether this is actual 'boiling' (water at over 100°C) or gas (airlock or combustion product) being expelled. I would have thought it unlikely that enough of the system would get hot enough for steam to form in the overflow tank ?

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - John F

Sadly, the symptoms of having a coolant leak for 'some time' developing into what you now describe puts CHG failure at the top of the list of most likely diagnoses. The failure is probably now so bad that the piston in the combustion chamber next to the failed bit of gasket between the cylinder and the coolant passage is not only just sucking a tiny amount of coolant into the cylinder during the induction stroke but also blowing gas into the cooling system during compression and explosion.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

This is obviously worrying to hear, but would this not have shown up on an MOT? I had one done less than two months ago and it wasn't mentioned, but the coolant leak was.

Aso if it is a chg failure what can I expect to happen? Will the car suddenly not start one day? Honestly if I can get a few months - 1 year low mileage use I'd be happy.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Andrew-T

This is obviously worrying to hear, but would this not have shown up on an MOT? I had one done less than two months ago and it wasn't mentioned, but the coolant leak was.

The purpose of the MoT test is roadworthiness, not mechanical perfection. A car with a failing head gasket may present no safety problem, and provided the exhaust emissions are within limits it may well pass with an advisory of coolant or other leaks. Testers are not permitted to dismantle anything, but will usually comment on any visible signs of trouble.

Fixing a failing head gasket (you really need to determine if that is what it is, which may not be simple) can be moderately expensive (mostly labour) but not difficult. Quite likely the car will struggle on for some time, until you get bored with adding coolant every time you go out.

Edited by Andrew-T on 23/05/2022 at 09:47

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - John F

This is obviously worrying to hear, but would this not have shown up on an MOT?

No it wouldn't.

Also if it is a chg failure what can I expect to happen?

It'll just get worse, needing more frequent top-ups and visible steam from the exhaust. I wouldn't waste money on coolant, would just use water....unless it lasted till January! The coolant may start mixing with the oil, causing it to look like salad cream on the dipstick and mayonnaise around the oil filler cap.

Will the car suddenly not start one day?....

Probably not, but it will eventually struggle with not much power from the affected cylinder.

Honestly if I can get a few months - 1 year low mileage use I'd be happy.

You might be lucky.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Andrew-T

<< It'll just get worse, needing more frequent top-ups and visible steam from the exhaust. I wouldn't waste money on coolant, would just use water....unless it lasted till January! >>

Just to clarify - don't waste money on more antifreeze. 'Coolant' is what circulates in the cooling system, which may contain antifreeze or not, as you choose. Antifreeze also contains corrosion inhibitor, so long-term it's worth having, and most modern(ish) cars come with lifetime coolant. Mine has been going since 2008 and doesn't appear to have degraded much.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

<< It'll just get worse, needing more frequent top-ups and visible steam from the exhaust. I wouldn't waste money on coolant, would just use water....unless it lasted till January! >>

Just to clarify - don't waste money on more antifreeze. 'Coolant' is what circulates in the cooling system, which may contain antifreeze or not, as you choose. Antifreeze also contains corrosion inhibitor, so long-term it's worth having, and most modern(ish) cars come with lifetime coolant. Mine has been going since 2008 and doesn't appear to have degraded much.

Can't remember the source, but a long time ago I saw a comparison (or compared myself from separate sources, not sure but I think the latter) of "typical generic" coolant constituents, and automatic washing powder, and they were apparently quite similar, the latter having corrosion inhibitors in it to protect the washing machine.

I have never tried this, but IF I was using plain water as a coolant replacement I might add a pinch of washing powder to a fill.

The detergent intended for automatics (if they still make a distinction, havn't bought washing powder for over a decade and still have half the box I bought then) has/had less foaming agent in it, so would be a better/less bad choice in this role.

Obviously here in Taiwan freezing protection isn't required, but antifreeze is what's on the shelves, apart from one allegedly German brand of corrosion inhibitor that I wasnt able to find anything about so havn't used.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - focussed

Sadly, the symptoms of having a coolant leak for 'some time' developing into what you now describe puts CHG failure at the top of the list of most likely diagnoses. The failure is probably now so bad that the piston in the combustion chamber next to the failed bit of gasket between the cylinder and the coolant passage is not only just sucking a tiny amount of coolant into the cylinder during the induction stroke but also blowing gas into the cooling system during compression and explosion.

Looking at the images of the coolant header tank, there is no evidence of carbon or oil in the coolant, the tank looks clean and so does the coolant.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

I checked the oil and there was no "mayonnaise" or "salad cream" residue there either. I'm holding out hope that it's something less depressing than a gasket head failure. I may be away for 2 weeks though so I'll drop it off at a mechanic then. I appreciate all the replies here but I must admit I'm overwhelmed by all the suggestions with terms I don't understand and wouldn't know where to start fixing anything myself.

Edited by OceanMan on 23/05/2022 at 19:26

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - bathtub tom

I checked the oil and there was no "mayonnaise" or "salad cream" residue there either.

It's no good 'checking the oil' (I presume you mean you looked at the dipstick?), you need to remove the oil filler cap and look at the underside.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

I did both. Couldn't see anything white there.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

You can probably test the fans basic function (as opposed to its control) by wiring it directly to the +ve and -ve terminals of the battery. If its working and you get it the wrong way round it'll go backwards, telling you which is the right way round.

Since its apparently ECU controlled you should disconnect it before you do this, to avoid frying your cars brain.

If its working, but not being switched on, and is turned on via a relay, you could/should test the relay.

As a temporary work-around lash up you could just wire it on all the time, but remember to disconnect it when you stop or it'll flatten your battery.

Operating without a fan is begging for the sort of trouble that you seem to have.

When I had/have a break in the wire from the temperature sensor (a recurring problem) I hard wire the power side of the relay to a power extension lead that runs into the cab. Shorting the pins of the plug together with an aluminium bike foot peg (which also acts as a heat sink) gives me manual fan control from inside the car.

And sparks.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

It occurs to me I'm maybe taking a too "traditional" view of this, and maybe newer cars with ECM's (which I've so far managed to avoid) might have more fragile fans.

IF, for example, the fan has on-board smarts and does its own power switching, say under control of a 5V duty cycle signal from the ECM, and you put 12V through that control input plug, you might bust it.

Better be sure which pins are the power supply before doing anything.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - elekie&a/c doctor
Apart from the possible fan issue, I think the problem is being made worse by the fact the engine is continuously loosing coolant. Once the happens , air pockets are being created and end up with an air lock . Unfortunately due to the design of the cooling system , where the thermostat is located near the bottom of the engine , bleeding to get the air out can be a right pain . Sometimes filling the system via the top hose , rather than the expansion tank , can help alleviate the problem.
Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

Do you have a more detailed breakdown on how I'd do this? I'd love to give it a try. Would there beaa breakdown on YouTube or something?

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - sammy1

Someone has already mentioned the switch on the thermostat but what about the thermostat itself? My experience of all fiestas is that their cooling systems can be a nightmare when not working. The Thermostat is old so worth changing it?

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

Good tip thanks. I'll look into that when I can. Could an old thermostat be the source of the leak?

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - sammy1

Good tip thanks. I'll look into that when I can. Could an old thermostat be the source of the leak?

NO but the gasket could be leaking. Also worth checking the water pump gasket If the thermostat is not opening correctly pressure could be blowing coolant back to the filler bowl. Any small coolant leak would not cause the boiling. Whatever the problem you do risk blowing the head gasket which would be expensive. If you are unsure of what you are doing worth paying a garage for an hours labour to correctly diagnose the problem

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - John F

If the thermostat is not opening correctly pressure could be blowing coolant back to the filler bowl. Any small coolant leak would not cause the boiling.

Is it really boiling? the OP uses this wording.......

After ten minutes the coolant starts boiling and bubbling over quite ferociously

We need to know whether the 'bubbling over' is caused by either the engine overheating causing boiling or gaseous pressure from a leaking failing CHG. I have no idea whether the Fiesta coolant circulates through the car heater when the thermostat is closed, but if so, and if the heater is throwing out really hot air before the bubbling starts and the radiator is still cold, it might help with the diagnosis.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

Do you have a more detailed breakdown on how I'd do this? I'd love to give it a try. Would there beaa breakdown on YouTube or something?

Not sure who or what this is directed to, but there's this

www.youtube.com/watch?v=5FFMhptloDI

This guy has done some pretty good critical analyses of the usual CTEK recommended "quality" battery charger (which turned out to be cheap Chinese junk) compared to Lidl/Aldi models.

Here he's looking at a 2009 Ford Fiesta fan motor, ditto, though maybe not Chinese.

Its built to autodestruct, because the springs destroy the commutator ring when the brushes wear out.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

It was directed to edlithgow when they spoke about testing the fan. For some reason their response wasn't quoted in my post but I definitely sent it as a reply to them

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

The guy in the video I link to above says there was no overheating warning (temperature display?).

It could be, I suppose, that its bust, but its claimed on one of the Ford forums that there is actually no temperature display on some models. (Mk 7?)

www.fordownersclub.com/forums/topic/94872-engine-f.../

Very poor if true.

Edited by edlithgow on 26/05/2022 at 04:02

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Bolt

The guy in the video I link to above says there was no overheating warning (temperature display?).

It could be, I suppose, that its bust, but its claimed on one of the Ford forums that there is actually no temperature display on some models. (Mk 7?)

www.fordownersclub.com/forums/topic/94872-engine-f.../

Very poor if true.

AFAIA there is an overheat warning light on the dash instead of the temperature guage, which all base models had, but there was always the possibility the light didn`t come on if the water wasn`t over the temp sender, ie the water capacity at the time wasn`t high enough to cover the sender unit, so didn`t reach the temp needed to switch the light on.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

The guy in the video I link to above says there was no overheating warning (temperature display?).

It could be, I suppose, that its bust, but its claimed on one of the Ford forums that there is actually no temperature display on some models. (Mk 7?)

www.fordownersclub.com/forums/topic/94872-engine-f.../

Very poor if true.

AFAIA there is an overheat warning light on the dash instead of the temperature guage, which all base models had, but there was always the possibility the light didn`t come on if the water wasn`t over the temp sender, ie the water capacity at the time wasn`t high enough to cover the sender unit, so didn`t reach the temp needed to switch the light on.

Never been sure whether, in an overheating condition, steam in an air pocket would be enough to activate a sensor,

If it wouldn't, If one took a cheery view of manufacturers, one might think they would put the sensor a bit lower down, where it was less likely to be in an air pocket.

All the sensors I remember locating were in the head.

OTOH I suppose if the water pump fails the head area is going to get hottest fastest.

When I was last having overheating issues I got an IKEA meat thermometer probe thingy and put it in the overflow pipe from the coolant reservoir, with the wee display box wired to the scuttle where I could see it through the windscreen. Never had an incident while it was in place, though, so I dunno if it provided any warning, or where it is now.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - bathtub tom
Never been sure whether, in an overheating condition, steam in an air pocket would be enough to activate a sensor,

I've heard of cases where drivers have noted the temperature gauge going into red and then falling back. This is because the coolant was boiled off. The drivers continued, assuming all was OK, resulting in the inevitable. One case , the engine seized and had smoke pouring off it, no doubt due to the dirt and oil. The driver got a water container from the caravan they were towing and poured the contents over the engine as they thought it was going to catch fire. Hot cast iron will crack when cold water's poured over it!

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Gibbo_Wirral

Not sure if it helps but I had a similar problem on my 2008 Peugeot 308 1.4.

No head gasket or thermostat issues. Expansion tank fine when cold, but full and bubbling over when hot.

It turned out to be a blocked radiator.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Bolt
Never been sure whether, in an overheating condition, steam in an air pocket would be enough to activate a sensor,

I've heard of cases where drivers have noted the temperature gauge going into red and then falling back. This is because the coolant was boiled off. The drivers continued, assuming all was OK, resulting in the inevitable. One case , the engine seized and had smoke pouring off it, no doubt due to the dirt and oil. The driver got a water container from the caravan they were towing and poured the contents over the engine as they thought it was going to catch fire. Hot cast iron will crack when cold water's poured over it!

Same goes for just a temp overheat warning light,(some didn`t have temperature gauges) they have been reported as flashing once and not staying on, giving the impression the problem had gone away but was in fact getting worse, I never did like the idea of just a warning light as the light flash can be missed.. there were complaints about it to Ford IIRC years ago but they weren`t the only ones to fit them instead of gauges

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

Had this looked over by a garage. They fixed the fan and said the leak is the thermostat housing and didn't mention any head gasket issues.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

Good. Did they tell you how they fixed the fan?

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

They said they switched the fan @edlithgow thanks for yours and everyone else's responses to the thread btw.

I wonder if it's possible that there actually *is* a head gasket issue as well as the leak and fan problem. That would sting!

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

Certainly possible, but its also quite possible you've dodged the bullet.

Keep an eye on it, and in particular look out for signs of oil and coolant mixing.

And keep your fingers crossed of course.

PS Good idea to use "swapped" or "replaced" rather than "switched" when talking about electric gizmos.

Avoids confusion.:)

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

I've been driving this semi regularly since my last update. All seems okay. At one point the car was feeling very sluggish and weak when pulling away (hadn't driven it for a week at that point) and I was terrified, but that only happened twice. Haven't noticed any other issues.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - John F

Thanks for keeping us informed. Always interesting to know outcomes, and pleased to hear it was just an overheating and leak issue. Coolant looks nice and pink in the original photos which is always a good sign, as opposed to a mucky brown appearance.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

Thanks for keeping us informed. Always interesting to know outcomes, and pleased to hear it was just an overheating and leak issue. Coolant looks nice and pink in the original photos which is always a good sign, as opposed to a mucky brown appearance.

Yes indeed. I checked the coolant today and it still looks pink and at the exact level as a few weeks ago so I'm convinced the leak is stopped.

Also: Everyone here seems very dedicated and knowledgeable about cars, and also very helpful and thoughtful in their responses, so I really don't mean this in a disrespectful way but I was very happy to learn that nearly everyone who replied to this thread was completely WRONG!

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

Also: Everyone here seems very dedicated and knowledgeable about cars, and also very helpful and thoughtful in their responses, so I really don't mean this in a disrespectful way but I was very happy to learn that nearly everyone who replied to this thread was completely WRONG!

I suppose there is a tendency to assume the worst.

For example, I've been told that I needed a full engine rebuild because I had metal settling out of my oil, that I needed a new master cylinder because of a brake failure (which was almost certainly due to old brake fluid), that I wouldn't be able to rebuild the brake calipers or carburetor, that treating rust was a waste of time, and that my air pocket was certainly a blown head gasket.

I suppose people feel obliged to prepare the naive optimist for harsh reality, plus there's the "counsels of perfection" thing.

If you are the prophet of doom, its sadly the nature of things that you are going to be right eventually.

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - Andrew-T

<< I really don't mean this in a disrespectful way but I was very happy to learn that nearly everyone who replied to this thread was completely WRONG! >>

It's always hard to diagnose purely from a verbal description, especially when there may be several possible causes. The lesson seems to be that it may take some time for an airlock to dissipate ?

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - edlithgow

The lesson seems to be that it may take some time for an airlock to dissipate ?

Certainly can (and did on my Daihatsu, until I started deliberately boiling the coolant to clear them), but I don't think that was specifically indicated here.

As I read it, this was primarily overheating due to a failed cooling fan.

Edited by edlithgow on 23/07/2022 at 03:18

Ford fiesta 2009 - Coolant resovoir tank full and bubbling over... - OceanMan

<< I really don't mean this in a disrespectful way but I was very happy to learn that nearly everyone who replied to this thread was completely WRONG! >>

It's always hard to diagnose purely from a verbal description, especially when there may be several possible causes. The lesson seems to be that it may take some time for an airlock to dissipate ?

And I probably didn't give enough information about the situation for an accurate diagnosis. I think another lesson is that I'm an i**** and should have got my fab fixed almost two years ago when the garage warned me. Oh well, it should be a lesson but who knows if I'll heed it!