Terminal overheating... I think I know the answer.

[Tee Hee Johnson]

Hello,

My good lady wife's 2010 Fiesta 1.25 Zetec is having a sad time.

Missfires all over the place, cylinder 4 was 10's per second and the others 3 were basically anytime but not as bad.

Popped leads off and found water everywhere in the spark plug well... lovely, orange and tasting of coolant, bitter as hell.

Spark plugs came out a right mess, one was brittle and ceramic has cracked the other 3 were orange on the ceramic and down the threads... mix of rust and coolant I guess. 3 of 4 also have slightly orange heads, the ceramic before the spark magic happens.

Needed it moving, so put new sparks in today (to move it on the drive!) and its still missing on all 4... although not the 10's per second any more.

Wanted to see if its over heated, and that seems to be the case. Up to temp and no sign of fan coming on, 110oC-ish and the water started boiling and escaping. AC on and off, cant make the fan spin.

Bad times. Needs fan investigated at least, and also probably head gasket or crack in block (?) to be looked at first.

Any thoughts, or am I pretty much there?

Thanks!

 

[Gaygle]

Assuming it definitely was coolant and not rusty water? Was the car loosing coolant?

 

[Dup]

Did you check the oil? Sounds very much like head gasket failure to me.

 

[Tee Hee Johnson]

Thanks guys. Defo the same colour as the coolant and tasted bitter as hell.

It has had the coolant topped up a few times recently, but hadnt caught where it had been going.

The oil actually seems ok, level wise and appearance.

 

[bobuk]

If I remeber it there is a series of core plugs in the cylinder head that corrode and leak' need to replace plugs and leads, check compression and go from there, maybe check for HC in the cooling system, maybe also an air lock in cooling system.

 

[EdButler]

Im not familiar with the car, but even with Headgasket failure, the fan should be coming on. Did you check to see if the Thermostat was opening and the rad was getting hot after it hit ~80-90C?

The previous shape fiestas had a very common problem of water leakage from the washer jets. This dripped onto the rocker cover and caused very similar damage to the spark plugs, wells and coil connectors. Make sure you remove as much rust as possible as it would prevent a good electical connection.

 

[Tee Hee Johnson]

If I remeber it there is a series of core plugs in the cylinder head that corrode and leak' need to replace plugs and leads, check compression and go from there, maybe check for HC in the cooling system, maybe also an air lock in cooling system.

I looked at the core plugs, something I had never heard of… but they seemed ok. Drier than the rest of the block before the heat dried it out.

 

[Tee Hee Johnson]

Im not familiar with the car, but even with Headgasket failure, the fan should be coming on. Did you check to see if the Thermostat was opening and the rad was getting hot after it hit ~80-90C?

The previous shape fiestas had a very common problem of water leakage from the washer jets. This dripped onto the rocker cover and caused very similar damage to the spark plugs, wells and coil connectors. Make sure you remove as much rust as possible as it would prevent a good electical connection.

Thermostat seems ok, it’s heating and cooling the cabin when told. watching the engine coolant temp it steadily rises.

It rose all the way to 110oc odd and the water started boiling with no sign of the radiator coming on. This was monitoring it all with FORScan and my laptop.

Edit: just to add, the washer jet fluid is bright blue and I read about it potentially leaking on to the too of the engine… but that doesn’t seem to be the case

 

[sja360]

Cooling fan is dead?

 

[Tee Hee Johnson]

Cooling fan is dead?

Yeah, no sign of life from it. AC on/off, temp as high as 110oC and nothing.

 

[sja360]

Sorry that was my answer to it rather than a question. If possible try testing maybe even trying to rotate by hand.

 

[Tee Hee Johnson]

Sorry that was my answer to it rather than a question. If possible try testing maybe even trying to rotate by hand.

I can move it by hand, but thats all. I havent tried feeding it 12v yet tho.

 

[EdButler]

Thermostat seems ok, it’s heating and cooling the cabin when told. watching the engine coolant temp it steadily rises.

It rose all the way to 110oc odd and the water started boiling with no sign of the radiator coming on. This was monitoring it all with FORScan and my laptop.

Edit: just to add, the washer jet fluid is bright blue and I read about it potentially leaking on to the too of the engine… but that doesn’t seem to be the case

I think you misunderstand mate. I mean the engine thermostat. It's a valve that opens when the coolant heats up to 90c to allow it to be cooled by the radiator.

These can get stuck closed meaning the radiator won't be doing it's job. You can check it by feeling the temperature of the radiator when the car reaches 90. If it's not getting hot, either the thermostat is stuck or the water pump is broken.

 

[Tee Hee Johnson]

I think you misunderstand mate. I mean the engine thermostat. It's a valve that opens when the coolant heats up to 90c to allow it to be cooled by the radiator.

These can get stuck closed meaning the radiator won't be doing it's job. You can check it by feeling the temperature of the radiator when the car reaches 90. If it's not getting hot, either the thermostat is stuck or the water pump is broken.

Sorry, I know what the thermostat is.

I thought if in the cabin it was blowing hot and then cold as requested, the thermostat was working ok? As the thermostat in the engine bay has done its job, and moved the water around when the temp hit the level. I thought that if the thermostat was stuck either open or closed, the cabin would not heat or cool as normal.

Thanks

 

[Dg834man]

I thought if in the cabin it was blowing hot and then cold as requested, the thermostat was working ok? As the thermostat in the engine bay has done its job, and moved the water around when the temp hit the level. I thought that if the thermostat was stuck either open or closed, the cabin would not heat or cool as normal.

There are two cooling loops in the system one goes to the heat matrix in the car default route, second route goes to the radiator, this is so the car gets warm in the cabin quickly, once it hits operating temp the thermostat opens and starts cooling the engine via the radiator.

 

[Jonnycoupe]

Sorry, I know what the thermostat is.

I thought if in the cabin it was blowing hot and then cold as requested, the thermostat was working ok? As the thermostat in the engine bay has done its job, and moved the water around when the temp hit the level. I thought that if the thermostat was stuck either open or closed, the cabin would not heat or cool as normal.

Thanks

Its not a house thermostat... its what opens when the engine gets up to temperature around 91C to allow coolant to the radiator to manage the cooling system temperature, if it doesn't open the coolant will exceed 100 and over pressurise and vent like you are experiencing.
Cabin temp is just regulated more by flaps and mixing the cold and hot air.
Often fan control can be the in the radiator which is pointless if teh rad isnt seeing hot air - more modern cars just use the sensor readings on the engine so thats unlikely in this case.

 

[Tee Hee Johnson]

Update for anyone who cares.

Thermostat seems fine, monitoring the temp it gets up to 80oC odd and then slowly starts going down. Then it goes up and up until boiling/bubbling in expansion tank.

Few developments tho, I found water coming from the back of the expansion tank. So thats been replaced, and the bubbling/boiling is gone all the way up to 117oC.

The radiator fan is off and dead, no sign of life with a straight 12v.

Gonna replace the fan and then see what going on with misfiring. Compression test showed between 190-200 psi accross all 4 cylinders.

 

[bobuk]

Check for exhaust gases in coolent header tank.

 

[adam cool dude]

Have you checked fuses to see if one has blown? I had a rad fan that melted on a downpipe and blew the fuse as when I replaced the fan it still didn't work.

Does the car have tax and mot as the rad fan is irrelevant when moving so if it stays cool while driving normally you know it is all down to the fan. Fan is simply there to cool when the car is stationary.

 

[Tee Hee Johnson]

Have you checked fuses to see if one has blown? I had a rad fan that melted on a downpipe and blew the fuse as when I replaced the fan it still didn't work.

Does the car have tax and mot as the rad fan is irrelevant when moving so if it stays cool while driving normally you know it is all down to the fan. Fan is simply there to cool when the car is stationary.

I checked the fuses, all ok. Swapped matching ones around for the sake of checking.

I’ve not been on the road with it, only getting it up to temp whilst sitting I. The driveway.