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Bleeding air from cooling system - Zetec

Posted By: Ifixyawata

Bleeding air from cooling system - Zetec - 06/11/18 09:32 PM

Hi all:

I've read differing opinions but I know there are some very knowledgeable Zetec/Focus people on this board. I have had a seeping, developed to full blown leaking heater/coolant hose on my Focus and I just replaced it today. It's the one the runs from the thermostat housing to the front plastic'crossover' pipe, I didn't lose much coolant at all replacing it, I topped off the coolant tank and ran the car for about 5 minutes. The heat works and the hose is getting hot.

Do I need to burp air out of the cooling system on this car? I've read that because it's a pressurized tank, yadda yadda that it's sort of self-burping.
Posted By: SirTanon

Re: Bleeding air from cooling system - Zetec - 06/11/18 09:44 PM

If the heat works and the hose is getting hot - and I'm assuming this also means your heater puts out HOT air, not just warm - then I'd say you're not in any immediate danger. If I were in your shoes, I'd take the car out, somewhere close to home, and put it through the paces for 5-10 minutes.. Try your best to keep it at a somewhat consistent RPM range between 2000 and 2500 RPM. This should force any remaining bubbles of air to a spot they can burp out naturally.

Make sure you keep a close eye on the temperature while you're doing this, just to be safe.

Where I live, there's a highway very close by, with an exit near me, and another about 3 miles down. IMHO, this would be the perfect place. Get it up to highway speed, hold it at RPM, get off after 3 miles, turn around and go back.
Posted By: Kestas

Re: Bleeding air from cooling system - Zetec - 06/11/18 09:52 PM

I just keep topping off the coolant every morning until it can't take any more.
Posted By: KrisZ

Re: Bleeding air from cooling system - Zetec - 06/11/18 10:48 PM

Never had to bleed it on my old ZX5 when I changed the thermostat housing. If the level in the pressurized tank goes low, just top it off when the system is cold.
Posted By: slacktide_bitog

Re: Bleeding air from cooling system - Zetec - 06/11/18 10:54 PM

The Focus Zetec is one of the easier cars to bleed the coolant on. Just fill it, leave the cap open, turn the heat to full blast, let it warm up, and wait for the bubbles to stop.

Of course, if you're still having trouble with it, the Lisle funnel is awesome smile
Posted By: eljefino

Re: Bleeding air from cooling system - Zetec - 06/11/18 11:16 PM

Some cars that bleed hard, I remove the top radiator hose from the radiator and stretch it up as high as it'll go, and pour coolant in that to back-force it through the engine until it dribbles out the now-open radiator. This with the car on ramps so it's a higher spot.

Some cars with the thermostat up top make this hard, IDK how the zetec does it.

I think you should keep doing what you're doing. Grab the top hose and massage it to feel if you have any bubbles.
Posted By: Trav

Re: Bleeding air from cooling system - Zetec - 06/11/18 11:53 PM

As Kestas said keep topping it off til it stabilizes, if the hose is getting hot you have circulation and it will expel the air after a few cool downs.
Hard to bleed engines are becoming more common in the US but in Europe its been a problem for years especially on some diesels.4
Vacuum filling is the only way to get system filled quickly and air free, I highly recommend a vacuum filler for anyone doing DIY cooling system service.

Right now ECS tuning has a great unit on sale for under $60, they have a sale on it a few times a year. It is a well made quality piece at a great price.

https://www.ecstuning.com/b-schwaben-parts/coolant-refill-air-purge-tool/003466sch01/
Posted By: SubieRubyRoo

Re: Bleeding air from cooling system - Zetec - 06/12/18 12:37 AM

I 2nd Trav's note about vacuum units. My brother is a wrench also, and he says there are some Chevys and other vehicles that are darn near impossible to bleed without using a vacuum unit. If you can't use the Lisle funnel or have the bleeder line like the Ford/Mazda 2.5s, vacuum bleeder may be your best friend.
Posted By: demarpaint

Re: Bleeding air from cooling system - Zetec - 06/12/18 09:31 AM

Originally Posted By: Trav
As Kestas said keep topping it off til it stabilizes, if the hose is getting hot you have circulation and it will expel the air after a few cool downs.
Hard to bleed engines are becoming more common in the US but in Europe its been a problem for years especially on some diesels.4
Vacuum filling is the only way to get system filled quickly and air free, I highly recommend a vacuum filler for anyone doing DIY cooling system service.

Right now ECS tuning has a great unit on sale for under $60, they have a sale on it a few times a year. It is a well made quality piece at a great price.

https://www.ecstuning.com/b-schwaben-parts/coolant-refill-air-purge-tool/003466sch01/

Thanks for posting! I grabbed one. Some cooling systems I've encountered can be a PITA to bleed.
Posted By: Ifixyawata

Re: Bleeding air from cooling system - Zetec - 06/12/18 10:41 AM

Thank you all for the replies. I turned on the bluetooth OBDII scanner and watched my coolant temp on my ride in to work, seemed to run about 210 - 220 the whole time except for the brief period of "robust accelleration" where it did hit 233, but it came right back down into the 215 range quickly.

When I got to work I opened the hood with it still running and checked and lo and behold I still had coolant. I verified by opening the cap as you can't really see through the old clear bottle very well but sure enough there's coolant in there. What's strange is there didn't seem to be any hiss or relief of pressure when I opened the overflow tank/bottle, and the coolant in there was really only warm to the touch. Yes, I touched it because curiosity. Is this normal?
Posted By: Trav

Re: Bleeding air from cooling system - Zetec - 06/12/18 12:24 PM

Sounds like there may be air in there somewhere.
Posted By: Ifixyawata

Re: Bleeding air from cooling system - Zetec - 06/12/18 04:43 PM

I'm currently taking my lunch break in my car, have it running with the cap off, well see if this helps
Posted By: Trav

Re: Bleeding air from cooling system - Zetec - 06/12/18 04:51 PM

Be careful not to overheat the thing, then you have a problem. Check fan operation, make sure it is coming on and going off when the temp drops.
Posted By: Ifixyawata

Re: Bleeding air from cooling system - Zetec - 06/12/18 04:57 PM

Originally Posted By: Trav
Be careful not to overheat the thing, then you have a problem. Check fan operation, make sure it is coming on and going off when the temp drops.


Been running at idle for about 15 minutes and just now at 200F
Posted By: KrisZ

Re: Bleeding air from cooling system - Zetec - 06/12/18 05:24 PM

You may want to increase the revs a bit, to about 1500-2000 RPM. It will speed up the bleeding process. Monitor the temps during this time of course.
Posted By: Ifixyawata

Re: Bleeding air from cooling system - Zetec - 06/12/18 05:35 PM

Originally Posted By: KrisZ
You may want to increase the revs a bit, to about 1500-2000 RPM. It will speed up the bleeding process. Monitor the temps during this time of course.


I did just that, never really saw the temp go above 210-212-ish. Checked after I shut it down and found that the coolant in the tank was very hot at that point, more like it should be, it seems.

Does anyone know, does this tank have an actual overflow somewhere or is it a completely closed system? I guess I'm not too familiar with how it all works exactly, it's certainly more complex than the SBC/SBF cooling systems I'm used to seeing.
Posted By: KrisZ

Re: Bleeding air from cooling system - Zetec - 06/12/18 06:13 PM

My Mazda 3 also has the same system and there is no overflow. The cap on the tank is pressure rated and there is no pressure cap on the radiator. Your zetec should be the same. There should be a small house or two going into the top of the tank, that's where the overflow is returned and that's how the system bleeds itself. But unlike traditional overflow, there is always a steady stream coming out of those hoses, which increases with RPM.
Posted By: Ifixyawata

Re: Bleeding air from cooling system - Zetec - 06/12/18 06:19 PM

Originally Posted By: KrisZ
My Mazda 3 also has the same system and there is no overflow. The cap on the tank is pressure rated and there is no pressure cap on the radiator. Your zetec should be the same. There should be a small house or two going into the top of the tank, that's where the overflow is returned and that's how the system bleeds itself. But unlike traditional overflow, there is always a steady stream coming out of those hoses, which increases with RPM.


Looking at a picture of the tank on rockauto, looks like there are two small hoses at the top and one larger one (heater hose size) on the bottom:




"8555" is the one I replaced.
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