problem filling with coolant please help

[Keg_gt]

ok just completed a massive service. changed the oil pump, water pump cam belt and tensioner etc.
i have now done it all but i cant get it to fill with coolant i opened the bleed valve tried filling form the engine and it just wont go in the pump is defo pumping coolant. im so confused if this is an air lock how is it best to remove it.
so you know i replaced the rad too with one form an automatic also swapped the thermostat complete housing off a working car.
help help help please

[E30BeemerLad]

crystal ball is in for a service this week mate, so tell us what car it is.

Assume it is an M20?

[Keg_gt]

yeah sorry mate m20 325 pre facelift

[Keg_gt]

could do with a crystal ball now just cant see what is wrong

[leeparkes]

roughly how much coolant did you put in? (litres)

[Keg_gt]

got in about 4 litre ish by removing various pipes but that was it

[Keg_gt]

after removing the pipes coolant was going to water pump when i removed the pipe from the water pump coolant was going through. when i undid the 2 17mm bolt heads on top of the thermostat housing coolanf poured out the pipes to and from the rad had no coolant in them

[leeparkes]

they say the m20 holds about 10 litres of coolant but that is with the system bone dry,
there is still quite a lot of coolant in the system (pipes/block etc)
i always jack the front of the car up to bleed the system!

[Keg_gt]

yeah its up at the front and was dray as all pipes removed and water pump was replaced so very little in the block itself

[Elecblondie]

I'd see where the coolant level is after leaving it over night.

[leeparkes]

has the car been run up to temperature, and is it a new thermostat?

[Keg_gt]

will do but surely it should not take all night to drain through as the other one sat next to it took no time at all

[Keg_gt]

well was warming up but as there is no coolant in it im very caucious not a new thermostat but was working well as far as im aware

[Elecblondie]

If you're nervous I find it easier just to leave it overnight rather than getting stressed by it, normally settles fine. I'd probably have let the car idle for a while, while watching the temp gauge, first. There's no magic trick to getting more in that I know of.

[Keg_gt]

ok so just let it warm up. just seems strange the othere one was instant. i have that complete thermostat housing on mine now. at least i know that works ok as previosly tested on the other one

[mark_i]

I'm doing this right now, 3 key points:

1/ You have to get a minimum of 10 litres of coolant into the M20 system before starting the engine.

2/ fill the system in two separate places: header tank(fills the block and head) and bottom hose(radiator)

3/ take your time when filling, pouring coolant at the rate of 1 litre per minute avoids airlocks.

Slow and boring, but the job gets done properley and no worries about overheating and cracked heads.

Top up the sysstem with the last litre when system is leak tight at thermostat temperature

[Elecblondie]

Doesn't help when you've already poured in 4 litres quickly though unfortunately, I'd stand by letting it settle over night and continuing tomorrow.

[Keg_gt]

ok will have a look today now and see what is happening. any other ideas will be greatly appreciated

[Ilkorin]

Not sure if it all applies here, but if you find you still have an airlock after it's all filled up, run it a tiny without the header tank cap to let it all cycle a bit.......Don't do this when hot.

[Keg_gt]

forced the water in witha hose seemed to be ok but on the way home the gauge read one before hot but it seems all over the place and when i turn the engine off straight away it reads one incrument lower

[fowler]

should not need to force the water in prob got lots of air locks in the system. have you run the car at idle with the heater on full hot and the expansion cap off as this will doo most of the work for you. sounds like you might have not filled th system enough if temperature is reaching that hot. as that is well over normal operating temperature

[Keg_gt]

ok will check level in a mo just really confusing me now. so run it with expansion cap off and bleed valve closed

[fowler]

yes mate with the heater on full heat aimed at the window with some coolant at the ready to top the expansion tank up prob run for about 15-20 mins like that.
Then place expansion cap back on and idle for another 10 mins to get up to pressure while keeping an eye on the temp gauge the using the bleed screw to sse if any air is present in the system.

[Keg_gt]

its just not takming on any fluid the bleed valve bleeds water and now im just so confused the temp gauge reads completly different when the engine is off. it reads one off from cold but when running it goes one before hot when held at 1000 rpm on idle which has suddenly become lumpy its is up and down with the revs

[Morat]

What you need is a steep road, preferably a quiet residential street with speedbumps. Then you can pootle up and down hill a couple of times which will tilt the engine back and forward while the waterpump is running.... Go slowly and keep a watchful eye on the temp gauge. If you're getting heat from the heater then you should be OK. Bleed it every time you turn round.

[fowler]

its just not takming on any fluid the bleed valve bleeds water and now im just so confused the temp gauge reads completly different when the engine is off. it reads one off from cold but when running it goes one before hot when held at 1000 rpm on idle which has suddenly become lumpy its is up and down with the revs

1. do you have hot air out of the heater ???
2. Are the hoses to and from the thomostat getting hot ???
3. when car has been running and is at 2/3 of the guage are the hoses hard to squeeze ???
4 leave car overnight with expansion cap off to see if asny fluid is taken from the expansion tank
5. try again tomorrow if you can defo sounds like a air lock if
HTH
Regards
Ben

[Keg_gt]

ok will do hot air is coming out. most hoses seem warm apart form the one from the thermostat to the bottom of the rad

[fowler]

they should be both a similar temp when the stat opens could be a dodgy stat dude opening slowly

[Keg_gt]

its wierd when i turn the engine off straight away it reads about one incrument lower on the temp gauge

[Brianmoooore]

I've only glanced quickly through this thread, but I'm not sure there is anything wrong with this car!
Removing the water pump won't empty a M20 of coolant by any means, and the amount you put in was probably all there was room for.

[Keg_gt]

i know what you mean but it wasn't leaving the expansion tank and going in to the rest of the cooling system

[Jesus325iTouring]

How are you getting on?

My touring has in the past been murder to refill,other times easy

I have in the past disconnected the left hand pipe which goes through the bulk head and into the matrix,i've then back filled the system from here,seems to have helped when the cooling system just doesn't want to play.

Also,I have found,if you tried unsuccessfully to bleed the system more than 3 times,just leave it until the next day when the car is cold again.
I've always found it 10 times harder to bleed a hot M20.

[Brianmoooore]

i know what you mean but it wasn't leaving the expansion tank and going in to the rest of the cooling system

It won't until you open the vents - and the one on the thermostat housing may be blocked even with the nipple removed.

[Keg_gt]

heaters are on full and the bleed nipple lets fluid out too

[Brianmoooore]

In that case it's full! What's the problem with the car?