Coolant filling

Toby_HDi · Post by **Toby_HDi** » 20 Dec 2008, 11:42

After a cambelt and waterpump change I tried to fill the car with coolant this morning....

I managed to get around 5.5 litres of Anti-freeze in (going for 50/50 mix and HDi cooling system with a/c is 11litres!) and then started topping up with water. I managed to get about 2litres in before it brimmed the expansion tank. I opened the bleed screws to push out the air but I cannot get anything from them. The coolant is now sat in the expansion tank to the brim.

I started the engine and ran at 1500rpm until the fan cut in, I thought this would push the air out but the coolant is still sat in the expansion tank.

I realised this wasn't working so not wanting to overheat the engine I switched off. I opened the bleed screws again to try to purge the air but nothing. It seems there is an air lock in the system and I do not know where it is or how to push it out.

This is really frustrating as the car started fine after the cambelt but I cannot drive her until the coolant is sorted.

Any help appreciated..
Thanks

citronut · Post by **citronut** » 20 Dec 2008, 11:53

sounds like your thermostat has not opened, when the fans cut in was the rad evenly hot all over or stone cold/patchy cold

regards malcolm

Clogzz · Post by **Clogzz** » 20 Dec 2008, 13:22

The coolant immediately passes through the heater matrix, even with the thermostat shut.
There’s a vent cap on the outlet side of the heater, at the top of the firewall.

AndersDK · Post by **AndersDK** » 20 Dec 2008, 13:43

I dont think you have completely emptied the cooling system, just letting the coolant flow out from any low placed coolant hose detached.

That could very well explain why you cant fill in the theoretical figure of 11liters of coolant.
The 11liters is from a completely dry system.
Meaning you would have to lift up every component involved and turn it around to let out the last drop of coolant hidden in there $\:D/$

Like when you replace the engine oil.
There is always some left in the oil filter, if you dont replace that as well.

Note : if you can not get any air to escape from the highest placed bleeds, then there is no air trapped in there.
This also means your engine can not overheat.
You could also try the external header tank method found under tips & tricks.
The main idea is to have a coolant level, which is well and truly the highest point on the system.
That will for sure force out any air trapped when the engine is running and turning the water pump.
Much the same is gained by parking the car nose steep up hill, and let the engine idle for ½ an hour or several fan cut in/out cycles.

nick · Post by **nick** » 20 Dec 2008, 14:16

The HDi (at least from my experience in the Xsara) doesn't seem to suffer from airlocks in the cooling system to the extent that some earlier PSA diesels did. Its quite an easy system to refill, and as Anders said, if you're not getting any air out of the bleed screws its because there's no air in there.

It is such a cold running engine anyway, I'm not sure you could overheat one at this time of year even if you wanted to! Mine takes about 8-10 miles of driving before the thermostat opens in this weather.

I would drive it as normal, checking the coolant level when cold every day for the first few days to see if any more air bubbles have found their way out, and top up if necessary.

Edit: my 1000th post, and its only taken me almost 8 years

citronut · Post by **citronut** » 20 Dec 2008, 17:32

Toby said he did not get anything out of the bleed valves, if nout is comming out there is probably not enough coolant in the system,

i do agree partly with Anders that you wil not get the full quantaty of 11lt's of coolant in if the hole system is not dry

regards malcolm

nick · Post by **nick** » 20 Dec 2008, 19:06

I didn't get anything to speak of out of the bleed valves on mine even using a large funnel as a "header tank" to raise the level, but its covered about 7k since then, the coolant level in the tank hasn't moved, and it shows no sign of overheating.

Toby_HDi · Post by **Toby_HDi** » 20 Dec 2008, 19:39

Thanks for the replys.

As stated I did not get anything out of the bleed valves - not even coolant!

I am just a bit confused as to why the coolant is sitting in the expansion tank and I have only managed to get about 8 litres of fluid in. I flushed the system prior to filling and surely there wouldn't be 4 litres still hanging about in there!?

Really frustrating, I don't want to drive it anywhere until I know it won't overheat. I am fairly sure there is something wrong, possibly something I'm doing wrong but I don't know what it is. Possibly citronut is right when he says the thermostat isn't open yet? Does this mean I need to run the engine for longer?

AndersDK · Post by **AndersDK** » 20 Dec 2008, 20:01

Ahhh - sorry about that Toby

Now I understand your problem I would certanly also be a bit anxious driving the car.
Of course you must get either air or coolant out of the bleed screws.
Have you tried removing the bleed screws completely and pegging down the stud ?

Also you should run the engine without the pressure cap fitted on the expansion tank. Its right here - taking place of the cap - you fit the home made high fluid level extra expansion tank to raise the top level of the fluid.
Something like a 2L Cola bottle with bottom cutted off.
It really does make small wonders in hard cases.

Sorry if I sound too much redundant on what you already have tried.

nick · Post by **nick** » 20 Dec 2008, 20:01

Did the radiator and top hose get hot when you ran it?

Mandrake · Post by **Mandrake** » 20 Dec 2008, 20:24

I would definitely recommend using a header tank when refilling a drained coolant system.

It may be slightly different on that engine but on my 2.0 petrol you can't get anything to come out of the top bleed valve on the heater hose without a header tank.

Start with all the bleed valves open (in the case of the one that is like a tyre valve cap you have to remove it completely, and don't drop it down the engine like I did

) and with a header tank bottle attached to the expansion tank.

You also need to tie the overflow pipe that comes out of the top of the expansion tank upwards or somehow hold it up in the air otherwise you will never be able to fill the level above the expansion tank.

Now add more water/coolant gradually until you see it running out the lowest bleed point and then close that bleed point. Continue adding more until it is running out of the next bleed point and close that and so on. There are only two on my engine, I don't know about yours.

Once all the bleed points are closed put enough water/coolant in the header tank so that it is an inch or two above the top of the expansion tank and then start the engine and let it idle.

It's probably a good idea to wear some safety goggles if you have some just in case there is an air lock as it can cause a gush of water out the expansion tank if you're unlucky when the thermostat opens.

Let the engine idle and periodically check the top radiator hose by hand and the temperature gauge. Make sure the gauge doesn't go over 90 deg c. The radiator hose will stay cold for a few minutes and then will suddenly get hot at around 80 deg as the thermostat opens.

If you don't feel the top hose getting hot within 5 minutes or the temperature reading reaches 90 while the hose is still cold, turn the engine off, let it cool a bit, and check again - there must be an air lock.

The header tank will start to gurgle and the level will drop - keep it topped up just above the level of the expansion tank - eg 1 inch or so inside the header tank.

If it looks like it's going to suddenly overflow the header tank run and turn the engine off - you've got an airlock, and you need to go back and check the bleeding again after it's cooled off a bit.

Assuming all is well let it idle for a few more minutes until the radiator fans come on and then go off, then turn off the engine. The temperature should stay between 80 and 90 during this time.

Let the level drain down if necessary by putting the drain tube back down where it belongs - with the expansion bottle pressure cap off it will drain back down to the correct level and then put the pressure cap on. If it is low, top it up to the normal level.

A few hours later top the level up AFTER the coolant has completely cooled - because the level will have been brimmed when the water was hot and the radiator cap was off, it will contract a bit, so top it up and put the cap on and next time it gets hot the pressure cap will equalize the level correctly.

Done! 8)

PS I agree with Anders - a significant amount of water doesn't drain from the system when you drain from the bottom of the radiator. Unless there is a drain plug on the bottom of the engine (and there isn't on mine) one to two litres of coolant will still sit in the bottom of the engine and the lower radiator hose, so it's normal that you can't get the full amount in, but 4 litres sounds like an air lock.

Regards,
Simon

Toby_HDi · Post by **Toby_HDi** » 20 Dec 2008, 20:54

Nick - I didn't actually know as I didn't feel the hose

Anders - That's quite alright, I did use a 'header tank' I used a 2pint milk carton. Just have a problem with making it airtight.

Mandrake! Top post! Thank you very much...

I do believe I only have the two bleed points, one on the matrix outlet and one on the thermostat. I think the one on the matrix outlet is like a tyre valve cap so will try removing that one completely.

Also I did have the overflow still attached so will remove that.

Will it be ok to just continue where I left off with trying to get the water in? I put 5.5 litres of antifreeze already.

AndersDK · Post by **AndersDK** » 20 Dec 2008, 21:08

Toby_HDi wrote:Will it be ok to just continue where I left off with trying to get the water in? I put 5.5 litres of antifreeze already.

If you mean continue to top up with water - then yes.
You are completely safe even if you hit a 1:3 mix coolant:water.

Toby_HDi · Post by **Toby_HDi** » 20 Dec 2008, 21:13

AndersDK wrote:If you mean continue to top up with water - then yes.
You are completely safe even if you hit a 1:3 mix coolant:water.

Yes, so far I have 5.5l Antifreeze and managed about 2l of water

Toby_HDi · Post by **Toby_HDi** » 21 Dec 2008, 00:04

Something I forgot to mention...

My milk carton is not really suitable. It doesn't fit into the expansion tank properly. What do other people use and how do you make it airtight. How do you keep it in position while you go about closing bleed screws etc?