Bleeding a radiator on an S3

[sleeptalker]

Hey all,

Quick question - i've just had a radiator recored and the garage told me they can be prone to air locks and that I should bleed it after a short while.

Can anyone advise on how best to do this?

Cheers!

[Roy C]

yes, they are prone to air locks. The bleed screw is top left (nearside) of the radiator - see picture.

[jimed]

The rad bleed point is lower than the top of the swirl pot so you can leave the rad bleed open whilst you fill the system at the swirl pot. With the heater control set to hot fill the system and when it starts to come out of the rad bleed allow a little out to get a decent flow (and hopefully ensure all air is out)then tighten it up by hand. Fill the swirl pot and squeeze the hoses to get any immediate air out then start the car up and let it warm slightly, then rev it gently - the water level in the swirl pot will drop so top that up whilst holding the revs then put the cap on and leave until fans come on then switch off and ensuring the header tank is half full or so allow to cool. Overnight seems to work well; then fill the swirl pot to the top and fill the header tank to about 1/3 and all should be OK. I then recheck the system a couple of times topping up the swirl pot and maintaining the header tank level at just above the sensor thing (mine has one but not sure all do - its not connected though) and when the swirl pot stays full when cold that's it.
I've not had any trouble with the rad bleed after the initial fill but if you want you could check that after the initial fill and cool cycle.
Jim

[sleeptalker]

Brilliant - thanks for your help guys - what a great forum this is!

So tomorrow's list of jobs to do grows a little more:

Attempt to remove door card and work out how to adjust slightly drooping door
Bleed radiator
Clear any blockages in drain holes

Love this project of mine :0)

[page3]

You'll probably need to bleed the radiator for the next 5-10 journeys to get all the air out. I did.

[sleeptalker]

OK i'll make sure I keep an eye on it.

Out of interest is the result of an airlock noticeable in terms of the temp gauge creeping up higher than normal or is it just something that you must remember to do and not something you'd notice otherwise?

[Barkychoc]

Roy C said:

yes, they are prone to air locks. The bleed screw is top left (nearside) of the radiator - see picture.

I've got a rad just like that one. Wait a minute....

[jimed]

The problem with an airlock is that air expands much more than water when it gets hot, so the result is that you can get plenty of water blown out of the system which doesn't help the cooling! The only answer is to ensure you get it all out.
Jim

[page3]

sleeptalker said:

OK i'll make sure I keep an eye on it.

Out of interest is the result of an airlock noticeable in terms of the temp gauge creeping up higher than normal or is it just something that you must remember to do and not something you'd notice otherwise?

Mine definitely ran a bit hotter until fully bleed. Also, it would swing between temperatures much quicker.

[Rower]

Do not forget to make sure the heater is on when you bleed it.

Rower

[sleeptalker]

Hi

Well I had a go at the weekend and all's good thanks to all of your advice.

I can't fully open my bonnet due to the lower profile tyres and camber on my road so you can imagine me wedged between bonnet and block as I reached over to loosen the bleed valve while it was all running (!) but a very small amount of air came out and I topped up the coolant in the swirl pot (a good litre I'd say) before sealing it back up, topping up the expansion chamber to about half full and letting the blowers in the car belt out some hot air.

Temp never gets near 90C on the indicator panel even stuck in London traffic now and the blowers still pump out hot air when asked to so am I right to assume all is well?

I'll check again this weekend having done a hundred mile "test" ride to the coast this sunday just passed...

[tvrgit]

Worthwhile putting the front wheels of the car up on a couple of small blocks while you bleed it. This has 2 advantages:

1. You can get the bonnet open to reach better; and

2. It puts the bleed screw nearer to the top of the system so bleeding is more effective anyway.

[jimed]

It all sounds Ok Andrew but do check after the next few runs in case there is still a little air in the system (as a little can be a problem still) and when it is still full that's it!
Jim
PS I'd thought of the driving it up on some small blocks (worth keeping a couple in the boot?) but the other Andrew beat me to it.

[TVR653X]

I recently had to do this. I completely flushed the radiator too, go all the crap out of there, then filled it back up (had a TVR owning engineer helping me, otherwise I'd have been a bit confused!). However, my fan doesnt work at all. Is this a fuse?

[tvrgit]

TVR653X said:

I recently had to do this. I completely flushed the radiator too, go all the crap out of there, then filled it back up (had a TVR owning engineer helping me, otherwise I'd have been a bit confused!). However, my fan doesnt work at all. Is this a fuse?

could be a fuse, but more likely the 2 wire connector under the middle of the radiator, live and earth to the fan

[TVR653X]

tvrgit said:

TVR653X said:

I recently had to do this. I completely flushed the radiator too, go all the crap out of there, then filled it back up (had a TVR owning engineer helping me, otherwise I'd have been a bit confused!). However, my fan doesnt work at all. Is this a fuse?

could be a fuse, but more likely the 2 wire connector under the middle of the radiator, live and earth to the fan

I'll have a look next time I've got the car out!

[phillpot]

TVR653X said:

tvrgit said:

TVR653X said:

I recently had to do this. I completely flushed the radiator too, go all the crap out of there, then filled it back up (had a TVR owning engineer helping me, otherwise I'd have been a bit confused!). However, my fan doesnt work at all. Is this a fuse?

could be a fuse, but more likely the 2 wire connector under the middle of the radiator, live and earth to the fan

I'll have a look next time I've got the car out!

Check connections to the little stat thing clamped onto pipe between rad and swirl pot whilest under there ( joining the two wires together should bring fan on)!

Edited by phillpot on Wednesday 7th October 21:54