Coolant Bleeding

[HaveaCuppa]

Does anyone have an idiots guide to bleeding the coolant?

I’ve just refreshed my coolant pipes/rad/thermostat and went to bleed it today.

I removed the expansion tank cap, undid the bleed screw by the thermostat housing and let the air escape until coolant was flowing out with no bubbles. The bleed screw was then tightened.
I fired up the car, turned the heaters on and got it to temp, while squeezing the top rad hose regularly

I must have been outside for the best part of an hour and the rad fan never kicked in. Now the top rad hose got hot so the thermostat opened, but there’s still air in the system as you can hear it.

the temp gauge sat bang on in the middle too.


Any pointers?
Cheers

 

[Louis]

Turn the heaters off/go for a short drive and take some coolant with you.

I just kept the cap off and ran the car for 20 mins whilst squeezing the top hose.
Undid the bleed screw again and coolant pissed straight out with no air.

 

[JamesBryan]

It'll self bleed eventually.

 

[HaveaCuppa]

Turn the heaters off/go for a short drive and take some coolant with you.

I just kept the cap off and ran the car for 20 mins whilst squeezing the top hose.
Undid the bleed screw again and coolant pissed straight out with no air.

Cheers Louis, I’ll take it out this weekend once it’s all back together and try that way.

it’s not a huge amount of air but enough to hear when you squeeze the top hose.
I take it your fan never comes on whilst idling unless it’s proper hot out?

 

[Louis]

Cheers Louis, I’ll take it out this weekend once it’s all back together and try that way.

it’s not a huge amount of air but enough to hear when you squeeze the top hose.
I take it your fan never comes on whilst idling unless it’s proper hot out?

My fan came on during bleeding once up to temperature, but I didnt run the heaters iirc

I bled mine quite late too I think

 

[Amos91]

Cheers Louis, I’ll take it out this weekend once it’s all back together and try that way.

it’s not a huge amount of air but enough to hear when you squeeze the top hose.
I take it your fan never comes on whilst idling unless it’s proper hot out?

Bleed mine at the weekend in the garage and the fan came on. Coolant temp hit 96°C ish for it to switch on.

If you turn the AC on, does the fan come on too?

 

[NorthloopCup]

To bleed mine up I just kept putting my mouth over the lip on the header tank and blowing into it. But, you’ve got to be quick when you’re letting the pressure off as you could end up with a mouthful of coolant.

It’ll bubble and gurgle as the air comes out and the coolant level will drop.

 

[Brigsy]

As above blow method always works great on a cold engine especially on fussy engines like the R5gtt c1j. Type d coolant tastes like s**t though beware

I always go by the heater, if thats blowing hot with interior fan on, the cooling system is bled.

Last few f4r’s ive done, ive just opened the bleed bolt on the stat housing and let the coolant run out until no air coming out, refit and run it up to temp and level drops when stat opens, top up when cold. Best off driving it as the water pump circulates the coolant better with a bit of rpm.

 

[HaveaCuppa]

Bleed mine at the weekend in the garage and the fan came on. Coolant temp hit 96°C ish for it to switch on.

If you turn the AC on, does the fan come on too?

I’ve not turned my AC on yet as I got the system purged of all gas prior to fitting the new rad etc.
I’ll give it a try this weekend though to see if it’ll kick the fan into life.

To bleed mine up I just kept putting my mouth over the lip on the header tank and blowing into it. But, you’ve got to be quick when you’re letting the pressure off as you could end up with a mouthful of coolant.

It’ll bubble and gurgle as the air comes out and the coolant level will drop.

I’ve heard this way is pretty decent actually. Not that I’ve tired it but I’ll have a go if a good run doesn’t sort it.

As above blow method always works great on a cold engine especially on fussy engines like the R5gtt c1j. Type d coolant tastes like s**t though beware

I always go by the heater, if thats blowing hot with interior fan on, the cooling system is bled.

Last few f4r’s ive done, ive just opened the bleed bolt on the stat housing and let the coolant run out until no air coming out, refit and run it up to temp and level drops when stat opens, top up when cold. Best off driving it as the water pump circulates the coolant better with a bit of rpm.

Yeah, that’s what threw me. The heaters are blowing red hot, temp gauge is bang on and coolant dropped and is now level after a top up. but it’s just the fan that’s not kicked in. I’m going to take it for a run this weekend anyway, so I’ll Chuck some coolant in the boot just in case.

Cheers for the help chaps, much appreciated

 

[Amos91]

Fan will still turn on even if there isn't any AC gas in the system (as I found out).

 

[Brigsy]

Sounds fine to me, would not worry about fan not kicking in when idling and not driven, prob not hot enough. I only heard my fan cut in on hot days in traffic.

Take it for a drive, get engine hot and then once idling the fan will prob cut in ok.

I tried to get the rad fan to cut in on my f4rt Kangoo when idling on the drive, and temp would not get up high enough. Give up after annoying the neighbours for half an hour as no exhaust.

If your really concerned with checking the fan works, run an actuator test on clip and check the low/high speed fan. Thats all i did, and i only done it to check my wiring. If the coolant temp sensor is working, the ecu will run the fan when it sees the right temp.

 

[JamesBryan]

Pretty hard to get the fan running really.

Similar to @Brigsy i've hardly ever had the fan kick in, even on hot track days.

It does work too as I ran the actuator test as said.

 

[Rob]

Whilst this doesn’t help you one little bit, I recently did the coolant and waterpump on an e90, there’s a hidden setting to do a full automatic 12 minute bleed with the electric pump. I was incredibly impressed!

To help, as said, in relatively cold ambient, with the heaters going only idling, it’s quite unlikely the fan would run.