Bleed air from cooling system after fluid change

[prydey]

Hi guys.

I have a 2006 LS focus 2L. I drained the coolant via the drain plug on the bottom of the left radiator tank. Drained about 5L out, give or take. The book says its 6.5L system, but obviously it doesn't all drain out. Filled it back up but it only took about 4L until the header tank was full. I then ran the car with the cap off, and with the heater on full, until well after the car had warmed up (10-20min). I expected the level to drop as the air dissipated out. It hasn't changed.

I took the car for a drive. It warmed up as per normal, but then the temp gauge dropped back to about 1/4. Drove around for around 10min. with the heater on. Everything seemed fine. Got home, popped the bonnet and the level is still the same. Also there was no pressure in the system. I was able to remove the cap as soon as I popped the bonnet. Hoses felt hot to touch, but no pressure.

From inside the cabin, I'm pretty sure I could hear the sound of water running when I turned the car on. This has me believing there is still air in the system, most probably in the heater core or somewhere in the heating system (although the heater works well).

Could the cap be cactus? The car has always seemed to take quite a while to warm up. Prior to doing the flush, the level was good. If the cap was no good, wouldn't it force water out the overflow?

Any ideas to sort this out? I'm assuming if it is just air pockets it will just sort itself out naturally over time. Just have to keep an eye on the level.

[russellw]

The Workshop Manual (in our Tech Portal HERE) describes the bleeding procedure. You'll want section 303-03B.

Cheers
Russ

[GTLEGEND]

Hi Russ,

Seems like yourtech portal is missing a section on LS Focus?For Cooling system there are 3 sections 303-03A B And C. Section B is for 2.5L but OP says its a 2.0, so it could be 2.0 Duratec section A or 2.0L duratorq diesel section C which has a completely different bleeding procedure. Below is the missing bleed procedure if it is a diesel. Particular note on the EGR bleed screw.


GENERAL PROCEDURES Cooling System Draining, Filling and Bleeding — 2.0L (24 122 0)

241220
Draining 1. WARNING: When releasing the cooling system pressure, cover the coolant expansion tank cap with a thick cloth to prevent the possibility of scalding. Failure to follow this instruction may result in personal injury. NOTE: The cooling system pressure will be vented to the underside of the coolant expansion tank. Release the cooling system pressure by slowly turning the coolant expansion tank cap between 2 and 3 turns. 2. Remove the coolant expansion tank cap. 3. Raise and support the vehicle. For additional information, refer to Section 100-02.[Jacking and Lifting, DESCRIPTION AND OPERATION, Lifting] 4. Remove the engine undershield.



5. NOTE: To avoid the removal of an excessive volume of coolant, the cooling system should only be drained from the radiator drain plug. Drain the cooling system. • Allow the coolant to drain into a suitable container.


6. Install the radiator drain plug. 7. Lower the vehicle.
Filling and Bleeding NOTE: Make sure the interior heater temperature control switch is in the hot position. 1. Switch the interior heater blower off. 2. Remove the bleed screw from the exhaust gas recirculation (EGR) cooler coolant hose.


3. Fill the coolant expansion tank to level with the bottom of the coolant expansion tank filler neck and until coolant begins to flow from the bleed hole in the EGR cooler coolant hose.
303-03C-15 Engine Cooling — 2.0L Duratorq-TDCi (DW) Diesel 303-03C-15
GENERAL PROCEDURES (Continued)
G334275 en 10/2005 2006.25 Focus
4. Install the bleed screw to the exhaust gas recirculation (EGR) cooler coolant hose.


5. Start the engine. CAUTION: Do not allow the coolant level in the coolant expansion tank to fall below the minimum mark. 6. Raise the engine speed to 2000 revolutions per minute (RPM) and maintain for 2 minutes. 7. Top up the coolant expansion tank coolant level to the MAX mark. 8. Install the coolant expansion tank cap. 9. Raise the engine speed to 2000 RPM and maintain for approximately 13 minutes until the thermostat opens. 10. Increase the engine speed to 4000 RPM and maintain for 5 seconds. 11. Decrease the engine speed to 2000 RPM and maintain for 15 minutes. 12. Switch the engine off. 13. Check the cooling system for leaks. 14. Allow the engine to cool. 15. Top up the coolant expansion tank to the MAX mark.

[prydey]

Thanks guys. I didn't undo the EGR bleed screw. Will sort it this afternoon.

[prydey]

Originally Posted by prydey

Thanks guys. I didn't undo the EGR bleed screw. Will sort it this afternoon.

whoops, was reading it on my phone earlier and didn't notice the above procedure was for diesel. I have a petrol. Will look up the correct procedure.

[prydey]

Originally Posted by russellw

The Workshop Manual (in our Tech Portal HERE) describes the bleeding procedure. You'll want section 303-03B.

Cheers
Russ

Russ, the sections for cooling are the wrong way around. The section marked 303-03 for focus ST 2.5, is actually for the 1.8 and 2l versions, and the 303-03B, is actually for the 2.5L.

[prydey]

Following the correct procedure in the tech portal (which is pretty much what I did yesterday anyway) has made no difference to the level of coolant in the header tank, which has stayed at that level from the moment I filled it.

Either I've managed to fill it up without any air becoming trapped anywhere, or there is some stubborn air somewhere in the system.

either way, the car drives fine, warms up fine, and temp gauge sits where it used to, and the heater pumps out hot air.

Just have to keep an eye on it. Just strange that I put less in than what I drained out, and the level from dead cold, to hot, isn't changing at all.

[stefcio007]

Have you tried idling the car without the cap on for 20 minutes? That's what I did for a friends car when we filled it up after it lost quite a few litres of coolant to the point the heater did not work anymore.

Nearly been 2 years and no visible issues. (knock on wood)

[prydey]

Yep, tried that first. That's the way I'd always done it on older cars. Ford procedure says to have the cap on and rev @ 2500rpm etc. Tried that too.

Been keeping an eye on the level and it hasn't moved in 3 days now.