Coolant Airlock removal tips ?

[thetyrant]

Ok ive been lucky so far tapping into coolant system when fitting turbo and had no issues with coolant airlocks....until now!,  last night i was sorting a leak on one of the turbo coolant feed pipes and when i came to test driving it to work today after lunch i noticed cold heater and then temp gauge starting to go above half after about 1 mile!...stopped took coolant cap off while idling and massaged the big coolant pipe you can access from back then drove back home with res cap off and heater came hot again, parked it checked/tightend up all hose clamps to make sure no more leaks and went back to work.

Came to it again tonight to see if ok but heaters colds again and temp is rising!....tried the standard bleed procedure using under frunk bleed pipes and got some air bubbles but still not getting hot water to front of car!...after 3 hours faffing about ive given up for tonight and now feeding and drinking wine!... left it with rear jacked and res cap off...hoping for the best!

Im doubting its fixed in morning so any tips people have used to free up airlocks on these is welcome ?

To be honest im close to putting it all back to stock and selling the turbo kit as im starting to loose the will!!!....if i hadnt had a good drive on boost at weekend it would already be off the car, its so nice to drive with the turbo i just need to find the motivation to iron out the last few niggles!...problem is i want to get out on track asap so need things sorted!

TIA

[Bossworld]

I really went hell for leather squeezing/massaging the pipes, with the spare wheel well fully removed I had decent access to all four. I had swapped for silicone ones so they were a little less pliable but I was really ensuring a full flow of the coolant up towards the drain bits.

Forgive ignorance on my part but the piping that goes off to the turbo - how much higher/lower is it than the four factory hoses near the rad?

[Call the midlife!]

Assuming you're following all the procedures and have the heater set to full heat while you do it then my guess would be you've got a small leak somewhere letting air back in.

[Ardent]

I tend to recall a chat with Steve some time ago, he had a stubborn air lock, the work around was to raise the rear of the car whilst doing what you would normally do.

Just wish he was around to elaborate.

[JB21]

I just kept squeezing all the pipes I could get my hands to whist the engine was running. I then turned the car off and opened the coolant cap. Rinse and repeat. You can also pull the coolant tank of the body and raise it as high as you can whilst the engine is running so the air has an escape.

[Ardent]

@thetyrant

PM sent

[thetyrant]

I really went hell for leather squeezing/massaging the pipes, with the spare wheel well fully removed I had decent access to all four. I had swapped for silicone ones so they were a little less pliable but I was really ensuring a full flow of the coolant up towards the drain bits.

Forgive ignorance on my part but the piping that goes off to the turbo - how much higher/lower is it than the four factory hoses near the rad?

Yes ive been giving the 2 big pipes under frunk a good massage but no joy as yet and they remain cold, also been underneath back of car squeezing other end of these big pipes at engine they get hot here but it doesn't travel to front at other end of pipes, more effort needed I think.

Turbo coolant taps into the system that feeds the heater circuit from what I can see, its more annoying that ive managed to have these pipes on and off several times without getting a airlock then this time just messing about with clamps etc I get the lock, I think when I left it last night there was still a small leak and that's when air got in, if I had just gone for test drive last night im sure it would of been ok!...oh well

[thetyrant]

Assuming you're following all the procedures and have the heater set to full heat while you do it then my guess would be you've got a small leak somewhere letting air back in.

Yes followed the correct procedure and had car jacked up at the back, im pretty sure all leaks are sorted but as above it got a lump of air in last night I think as I didn't take it out after playing with clamps.

[thetyrant]

I just kept squeezing all the pipes I could get my hands to whist the engine was running. I then turned the car off and opened the coolant cap. Rinse and repeat. You can also pull the coolant tank of the body and raise it as high as you can whilst the engine is running so the air has an escape.

Thanks, so far Ive had cap off when squeezing pipes and engine running, might try it with cap on and maybe the extra pressure will help shift the air!

[moredun]

Why the rear jacked up?

Jack up front, remove radiator cap, make sure coolant to top of radiator then replace cap.
Open coolant bleed nipples under frunk at bulkhead, now top up coolant reservoir until no air bubbles come from bleed nipple.
Now you can start up engine, heater on hot and full blast, keep eye on coolant level etc
If the heater does not get hot enough, rev the engine 2-3K rpm a few times

  

[thetyrant]

Why the rear jacked up?

Jack up front, remove radiator cap, make sure coolant to top of radiator then replace cap.
Open coolant bleed nipples under frunk at bulkhead, now top up coolant reservoir until no air bubbles come from bleed nipple.
Now you can start up engine, heater on hot and full blast, keep eye on coolant level etc
If the heater does not get hot enough, rev the engine 2-3K rpm a few times

  

You obviously haven't seen the radiator and coolant layout on a roadster there is no rad cap at front only at rear on coolant bottle, hence raising rear unlike when there is cap on rad at front where you raise front.

Mine is just being stubborn!

[thetyrant]

Little bit of progress this morning before having to go into work, left car overnight with rear up on stands and res with plenty of coolant in it, when i came to it this morning level had dropped so gave all pipes a good squeeze and then fired up car and let it warm up, now have heat out the heater which is good and hot water to one side of the rad, however its only side and outlet on other side isnt gettin hot even when upto temp so still some air in there.

I think part of the issue is the bleed screw on side of rad isnt the best, i have to open it a lot to get fluid to come up into the extension tube and by this time its leaking out past the bleed screw so difficult to get all air out as at that point its lot lower than rear res tank, tonight i will drop car down off axle stands and reverse it onto drive so front is a touch higher which should help get last bit of coolant out the radiator bleed screw....i hope!

Based on this i dont think the rad has ever been properly bleed before, there was evidence of some coolant in the extension tubes so someone has had a go in past and the fact car has always run quiet high coolant temps (90-93c pretty much all time) since i got it and before turbo install leads me to believe is not been using all the radiator capacity, probably a big pocket of air in the top of it and will be interesting to see if it runs any cooler once i get all air out.

See how we go tonight, fingers crossed!

[Bossworld]

Little bit of progress this morning before having to go into work, left car overnight with rear up on stands and res with plenty of coolant in it, when i came to it this morning level had dropped so gave all pipes a good squeeze and then fired up car and let it warm up, now have heat out the heater which is good and hot water to one side of the rad, however its only side and outlet on other side isnt gettin hot even when upto temp so still some air in there.

I think part of the issue is the bleed screw on side of rad isnt the best, i have to open it a lot to get fluid to come up into the extension tube and by this time its leaking out past the bleed screw so difficult to get all air out as at that point its lot lower than rear res tank, tonight i will drop car down off axle stands and reverse it onto drive so front is a touch higher which should help get last bit of coolant out the radiator bleed screw....i hope!

Based on this i dont think the rad has ever been properly bleed before, there was evidence of some coolant in the extension tubes so someone has had a go in past and the fact car has always run quiet high coolant temps (90-93c pretty much all time) since i got it and before turbo install leads me to believe is not been using all the radiator capacity, probably a big pocket of air in the top of it and will be interesting to see if it runs any cooler once i get all air out.

See how we go tonight, fingers crossed!

Is it the stock radiator or the usual cool parts replacement? If the latter, the O-ring supplied is the wrong size, and usual preference is to re-use the Toyota bleed screw with a new O-ring (6 x 2.5)

[thetyrant]

No idea   it was on the car when i bought it is there a way to tell ?  if this o-ring is wrong would it give the issue im having with me having to fully open the bleed to get fluid into extension ?

[Carolyn]

It's normal to have to unscrew the bleed screw out a long way. 

Is the turbo coolant system is tapped off the heater circuit in any way?  If so, this could be part of the issue.  The thermostat is on the return from the radiator.  If it doesn't open, the coolant will not circulate through the rad.  The return from the heater supplies heat to the back of the thermostat allowing it to open.

If anything impedes, or short-circuits this the thermostat will either not open, or be very slow to open.  An air-lock in this part of the system will also cause the symptoms.

It's probably more than a coincidence that you did something to that part of the system and the symptoms appeared. 

I would have to see the actual set-up to know for sure, but I've had experience of a partial blockage in the heater return pipe that caused exactly the problems you report.

We did an engine swap on JVanzyl's car.  The new engine had been stored for some time and the guy had put a plastic cap inside the heater return pipe that is bolted to the side of the cylinder head, as part of an effort to seal the engine.  I went through all kinds of madness until I happened to find it!

Once I got that out (and it wasn't a complete blockage, but enough to cause an air-lock) it bled up just fine.

[JB21]

I didn't need to bleed mine at all. Read online this is the only way to do it but no need in my experience. Just lots of squeezing of all the pipes, following the flow. let the coolant get up to around 90-100 degrees using torque pro, engine off and unscrew the coolant tank cap, rinse and repeat. Radiator fans kicked in on the 3rd cycle of doing this and coolant fully recirculating.

[thetyrant]

It's normal to have to unscrew the bleed screw out a long way. 

Is the turbo coolant system is tapped off the heater circuit in any way?  If so, this could be part of the issue.  The thermostat is on the return from the radiator.  If it doesn't open, the coolant will not circulate through the rad.  The return from the heater supplies heat to the back of the thermostat allowing it to open.

If anything impedes, or short-circuits this the thermostat will either not open, or be very slow to open.  An air-lock in this part of the system will also cause the symptoms.

It's probably more than a coincidence that you did something to that part of the system and the symptoms appeared. 

I would have to see the actual set-up to know for sure, but I've had experience of a partial blockage in the heater return pipe that caused exactly the problems you report.

We did an engine swap on JVanzyl's car.  The new engine had been stored for some time and the guy had put a plastic cap inside the heater return pipe that is bolted to the side of the cylinder head, as part of an effort to seal the engine.  I went through all kinds of madness until I happened to find it!

Once I got that out (and it wasn't a complete blockage, but enough to cause an air-lock) it bled up just fine.

Ah ok i think its just a bad seal on the bleed screw now, looking at pictures on here of coolparts bleed it looks same as mine, as in round with a slot in it and not a butterfly shape like toyota so no doubt part of the problem and making bleeding more difficult, lifting front will help get last bit of air i think and will see if i have a o-ring to suit.

Turbo coolant is spliced into the heater circuit yes, basically the sharp angle coolant pipe that goes to heater under PCV valve is removed and turned the other way to feed into turbo, then a new pipe from turbo back onto cars coolant system above gearbox completes the circtuit, no doubt this is where my problem started and as mentioned before ive been lucky not to have to bleed anything depsite unhooking this turbo coolant feed several times, ive always used clamps on pipes and tried to get coolant flowing out of pipes before reconnection and been ok up until now.

This morning all was working ok upto a point so think im nearly there, just rad wasnt getting fully heated and returning back to engine/stat etc which im thinking is last bit of air issue, also i think its been like this for awhile to be honest and only me getting air into heater circuit which has then got into main coolant feed pipe showed up the problem, when i ran car up this morning it warmed up as it used to and stopped around 93c sitting there same as it did prior to issues but the rad was still cold on exit side, looks like the heater circuit on its own is able to hold coolant in the 90's temp wise without really using main rad fully!

Yesterday when running it up and heater circuit was airlocked the coolant temp was hitting 100c before i shut it off.

[thetyrant]

I didn't need to bleed mine at all. Read online this is the only way to do it but no need in my experience. Just lots of squeezing of all the pipes, following the flow. let the coolant get up to around 90-100 degrees using torque pro, engine off and unscrew the coolant tank cap, rinse and repeat. Radiator fans kicked in on the 3rd cycle of doing this and coolant fully recirculating.

Sounds like you were lucky and it burped out any air on its own, ive seen that before on other cars, also its worked for me a few times since fitting turbo as well.

[moredun]

[/quote]

You obviously haven't seen the radiator and coolant layout on a roadster there is no rad cap at front only at rear on coolant bottle, hence raising rear unlike when there is cap on rad at front where you raise front.

[/quote]

You need to raise the front of the car, not the rear, both radiator and heater matrix are at the front ...

If your radiator has no cap, it has side bleed nipples ...

and the highest point for coolant bleeding is the bleed nipple under frunk beside the bulkhead

Note: all at the front of the car, not the rear.

[Carolyn]

I've found that raising the rear with the cap off the bottle and the bleed points open, allows the system to fill.

I've done this several times.  It always works. 

You must use the bleed tubing, though.

[thetyrant]

You need to raise the front of the car, not the rear, both radiator and heater matrix are at the front ...

If your radiator has no cap, it has side bleed nipples ...

and the highest point for coolant bleeding is the bleed nipple under frunk beside the bulkhead

Note: all at the front of the car, not the rear.

Ordinarily no you dont that is what the extension tubes that go on the bleed points are for, they effectively raises the front water level threshold to aid bleeding, you need the fill point as the highest level in system so the pressure is greater pushing the coolant into the system, res bottle is already highest point but raising the rear further aids this as give more pressure as its a bigger drop to front.

Problem ive got at moment is i cant get the rad bleed screw to seal externally and also allow coolant into the tube to allow expansion and air to bubbles out, i managed a bit more at lunch time with some careful twiddling of rad bleed screw and massaging pipes under bonnet, this got a fair bit of air out so hopefully thats it but will try same again later before running car see how it goes.

I could really do with removing the bleed screw and sorting out the o-ring to allow proper bleed procedure but i will need to raise up front of car to prevent too much coolant escaping and way ive got car in garage at moment i cant get jack under front..DOH!... so will treat that as last resort.

[Carolyn]

With the cap on the expansion tank, you can remove the bleed screw and very little will come out.  Done it.

[thetyrant]

With the cap on the expansion tank, you can remove the bleed screw and very little will come out.  Done it.

Ah yes never thought of that of course i might do that then at least i can bleed correctly, although i am cautious in that at moment it seals ok when fully closed so might be opening a can of worms if i take it right out!, will see what happens tonight and also what i have o-ring wise then go from there i think.

[moredun]

How to drain and replace coolant.

http://brollachan.net/images/Coolant.pdf

[thetyrant]

How to drain and replace coolant.

http://brollachan.net/images/Coolant.pdf

Thanks ive had a read of that previous, it doesnt say raise the front though...in fact it says......

 "NOTICE:
 In order to do sure filling of the coolant, perform the operation where the vehicle can be kept evenly flat" 

Raising the end of car coolant is being poured into (rear in this case but front typically on a front engine car yes) to give more pressure on system is common practise so im not sure why your arguing and we will just have to agree to disagree on this occasion, lifes to short