2011 Fiesta 1.4i Heating issues

[Ashlan]

Hi Guys

So i've been monitoring my fiesta temps and i noticed its been reaching higher temps than usual.

It reached the overheating light point of 120°C (248F) which is when i decided to change the thermostat + housing ad used new coolant. Now the car averages between 100°c - 117°c (212F - 243F) under load (uphill). This is still higher than the temps i used to see when the car was much younger. (used to average 92°C/198F uphill)

I've change the water pump during my cam belt service at 90 000km (56000miles) and there was nothing wrong with it. it was recommended to be changed while that side of the engine was stripped. i'm now doing 158 000km (98 000 miles). Would it still be my water pump or is my radiator blocked.

Fan still comes on at 105°C (221F) and temperature does fluctuate up and down but at higher values than normal.

 

[scotman]

I would investigate coolant flow through the radiator. And also if there is anything blocking airflow through the A/C condenser and radiator. Debris can build up and cause a cooling efficiency issue. You might also want to either confirm the coolant condition/strength. You also need to confirm that the cooling fans are functional in both low and high speed conditions. The high speed operation can be checked by turning the air-conditioning on MAX cold. The fan should be running at a high rpm to pull air through the coolers. You might also want to have a service garage perform system pressure check as you might have a poor sealing radiator cap.
A professional repair shop should be able to make a diagnosis within 1.5 hours of labor.

 

[Ashlan]

So i did an investigation on the flow. Coolant was changed last week so there isn't any doubt about the strength. The fan works at high speed, confirmed by an A/C test. i highly doubt it is the radiator cap as the seal on it is good.

I did however remove the front grill. Mk7 fiesta's have the worst airflow. basically half the radiator is blocked by the crash bar. anyway. i've attached some pictures of the radiator condenser. There isn't any dirt and debris on it however i noticed that the fins are bent, and seeing as though the radiator is behind it, it could be restricting flow. Thoughts?

 

[scotman]

That looks pretty bad. If it's an original condenser it's best days are past. If possible you should have a good look at what might be in the gap between the radiator and the condenser. Many times I have seen a accumulation of crud, dirt and plant fluff in the gap between the two. Looks like you are on the right track.

 

[Ashlan]

tried straightening the fins as best as i could and hosed it up abit to clean out some dirt. didn't check between the condenser and radiator as yet. However while test driving it. temp went up to 120°C (248°F) when i got home it was the same. so i popped the hood and checked the hoses. Hose at the top of the radiator (assuming its the radiator inlet) was extremely hot and pressurized however the bottom pipe leading into the thermostat was absolutely cold. Radiator fins were also cold. This is leading me to believe that the radiator is blocked. I changed the Thermostat and housing last week with the coolant so i doubt its that.

 

[Ashlan]

Checked the heater core pipes. Inlet hot outlet cold. Still think its radiator?

 

[Ashlan]

Took the car for a drive today. Inlet and outlet of the heater core was hot. however pipe between bottom of radiator and thermostat was cold. Car reached 123°C and the temp light on the dash came on

 

[scotman]

Looks like a flow issue. If you still have the original radiator, it might be time for a new one. Fortunately, these are not expensive to buy or difficult to install.
I will take a car with a bad radiator over one with a leaking head gasket any day of the week!
If you haven't already done a fiesta radiator replacement, don't forget to open the weep Valve and turn the heater on full blast when refilling the system! Just like a baby, it will require a period of "burping" to get it refilled without air bubbles.

 

[Ashlan]

Update on the overheating. So i took out the radiator to check whether it was blocked, turns out it wasn't, i caved and sent it to my mechanic to diagnose the problem.

Turns out... i was running the wrong coolant... all they did was replace the coolant and now the problems solved.

 

[Ashlan]

Was hoping my problems were solved however it wasn't! Car has been running hotter than usual. not really overheating but constantly running over 105°C. I decided to send the radiator for professional inspection and it was 30% blocked.

So i fitted the now clean radiator, added my coolant and burped the system. Fingers crossed i did that right however the car seemed to be behaving. I took it on a long distance trip, around 1500km, and it averaged an engine temp between 87 - 97 on the freeway and 99 to 102 in stop/go traffic. i was thrilled, however in the last 50km of the trip the engine spiked alil higher to about 110°C. now that is below overheating but i'm not happy with it. It does cool down significantly when engine rev'd and car is in motion but i'd like to know what could possibly be spiking the temp. The last thing for me to do would be to change my water pump (i'm trying to drag that out until my cambelt service at 188000km, currently at 160 000km). Any advise on what else i could do to help achieve lower temps?

 

[scotman]

I would be observing the coolant level very closely! As in marking the level of coolant in the reservoir and observing changes in the level of coolant after three or four drive cycles- days.
I think that the system may not be fully sealed. Either the fill cap is not sealing or there is a small leak somewhere in the system that is allowing air into the system and raising the operating temps. It could be a pinhole in a heater hose, a fitting that has a bad O ring seal or possibly a weeping heater core (do you smell coolant when the blower is on or find that the inside of your windows is getting a new film accumulation you hadn't noticed before?).
I would also be extra suspicious of the coolant reservoir itself. These are the the weakest link in the entire system. They age rapidly and become embrittled through the heat- cool cycles of normal use. When the reservoir fails it can be a catastrophic event if you are driving at high speed.

 

[Ashlan]

So I've been monitoring the levels, no drop at all and when i run the heater i don't smell coolant in the car, or in the engine bay for that matter. I've replaced the Thermostat and housing and check the seal on that, its good. Now that you mention the cap and reservoir i'll monitor those over the coming weeks. If the cap was a problem, my thinking is it would let air in and out during the heat cycles and not necessarily leak coolant?

 

[scotman]

Generally, if the engine is running hot because of a poorly sealed system, there is some coolant loss over time. I have recently experienced the failure of the reservoir. Fortunately, i caught it before it became a disaster. I had a Focus that the reservoir burst while driving in town at around moderate speed. There was a tremendous cloud of steam and my temperature gauge went from normal to damn hot within a few hundred yards.
I simply don't have ANY trust in the plastic reservoirs that are over three years old. I have a 2016 Fiesta ST. Guess what under hood component is getting replaced when it comes out of storage in late April!

 

[Handy Andy]

Yes, you might want to review the work done, one of the main areas I've heard from others not pertaining to this engine but others that have a similar system.

There's also some help here on this thread...https://www.fordfiesta.org/threads/detached-water-pipe.7406/post-16183

There is a "burp" line that arrives to the coolant tank from a spot of the engine that may not be able to return fluid or provide continuous circulation because of it being a "Dead spot" for coolant flow. If the line isn't positioned so the the trapped air from boiling (hot spotting) can't escape - it can warp the engine even blow out seals from the heat and steam - you get a pressure build - in some instances as those bubbles pop, it can make a loud bang or tick-ring sound as the air pocket pushes across the top of the motors coolant chamber inside the motor trying to find the outlet coolant hose and while doing so, trap even more steam and air.

The Thermostat also contains a bell-valve to burp - if it's in the wrong position - an air pocket gets trapped behind the thermostat.

Just make sure the Coolant recovery tank is properly set, positioned, so it's in the highest spot above the engines cylinder head - so the air bubbles and pockets can escape and leave the motor in a flooded with coolant condition and all the air can bubble up to the reservoir and stay out of the motor.

 

[Handy Andy]

If you have such a dashboard, locate that "TEST" mode button on startup - press it about 23 times after to get to this display...

And just leave the display in this monitor temp mode as you drive
Then you can see where the heat builds and cools
- for if the thermostat isn't working right - here's your evidence​

 

[Ashlan]

Generally, if the engine is running hot because of a poorly sealed system, there is some coolant loss over time. I have recently experienced the failure of the reservoir. Fortunately, i caught it before it became a disaster. I had a Focus that the reservoir burst while driving in town at around moderate speed. There was a tremendous cloud of steam and my temperature gauge went from normal to damn hot within a few hundred yards.
I simply don't have ANY trust in the plastic reservoirs that are over three years old. I have a 2016 Fiesta ST. Guess what under hood component is getting replaced when it comes out of storage in late April!

They're awful, its not just the ford with this problem. Had many vehicles crack or even pop a plastic bottle. I've been at a disadvantage because my gauge cluster does not have a temperature gauge, it only has an overheat light so i've been using the torque app to monitor temps and recently purchased an OBD gauge so i can monitor it properly. I do alot of long distance and i love my car so i'm trying to work out all the issues so i can jump in and confidently drive 1500km.

Yes, you might want to review the work done, one of the main areas I've heard from others not pertaining to this engine but others that have a similar system.

There's also some help here on this thread...https://www.fordfiesta.org/threads/detached-water-pipe.7406/post-16183

There is a "burp" line that arrives to the coolant tank from a spot of the engine that may not be able to return fluid or provide continuous circulation because of it being a "Dead spot" for coolant flow. If the line isn't positioned so the the trapped air from boiling (hot spotting) can't escape - it can warp the engine even blow out seals from the heat and steam - you get a pressure build - in some instances as those bubbles pop, it can make a loud bang or tick-ring sound as the air pocket pushes across the top of the motors coolant chamber inside the motor trying to find the outlet coolant hose and while doing so, trap even more steam and air.

The Thermostat also contains a bell-valve to burp - if it's in the wrong position - an air pocket gets trapped behind the thermostat.

Just make sure the Coolant recovery tank is properly set, positioned, so it's in the highest spot above the engines cylinder head - so the air bubbles and pockets can escape and leave the motor in a flooded with coolant condition and all the air can bubble up to the reservoir and stay out of the motor.

I noticed that line but haven't taken much note of it because it was never a problem. i will check if the line is blocked and monitor it going forward. Had no idea the system was designed with a dead spot, seems silly.

I have changed my theromostat and followed the workshop manual in doing so, the little valve is suppose to be position at the top. I'm fairly confident thats not the problem because i can see the temperature change when the thermostat opens up.

is there a way to burp the dead spot to make sure that no air is in that section? the reservoir i have has these semi hard lines from the back of the engine to the coolant tank and from the radiator to the coolant tank

 

[Ashlan]

T

If you have such a dashboard, locate that "TEST" mode button on startup - press it about 23 times after to get to this display...

View attachment 4734
And just leave the display in this monitor temp mode as you drive
Then you can see where the heat builds and cools
- for if the thermostat isn't working right - here's your evidence​

This is handy in a pickle. Thank you.

 

[Handy Andy]

I "sight it in" - look across the top of the intake side of the motor - like you're looking for "clearance" and level you'll see that line and how it routes from that back corner - towards the front then onto the Fuel rail bar clips - then up - at an angle - to the reservoir - with the "nipple" being below the seam - immersed in fluid.

If the hose is going to the wrong side of the seam, upper versus lower, plugged, or not properly positioned (kinked) - or you lack fluid, that can cavitate and pull air into the motor instead of the fluid. causing the pocket. A leak near the bottom of the motor or a weak cylinder head gasket can also push air into the head this way and force a building of pressure faster than it can remove it, potentially bursting the system

I had an old Chevy that needed a similar setup to keep a rear air pocket from forming so they routed it as a heater hose with a branch or fork off of it to do the same thing - pull out the air pocket to return to the top of the radiator and another hose routes to circulate in the water pump -

 

[LionsTooth]

It may also be a head gasket going bad. Are you smelling coolant at the tailpipe? If you are losing water and cannot find the source this could be it. Losing water at the cylinders will cause overheating.

 

[Dean72]

If you have such a dashboard, locate that "TEST" mode button on startup - press it about 23 times after to get to this display...

View attachment 4734
And just leave the display in this monitor temp mode as you drive
Then you can see where the heat builds and cools
- for if the thermostat isn't working right - here's your evidence​

Um... why haven’t I heard of this test mode and how do I access it?


2014 Ford Fiesta SE Hatchback
Cold Air Intake
OBX Header with high-flo cat, resonator, and DC Sports muffler and 2.5” exhaust
N2MB Two Step
FRPP Suspension
17” Focal with 205/45s
3M Dark Smoke Vinyl Wrapped Lights