M20 water Problem (can you help?)

[CabbyThompo]

Hi Guys, put a few posts on yesterday, tring to get my head round a water problem...
http://www.e30zone.co.uk/modules.php?na ... ic&t=36546

But after having another look, i kinda understand whats happenin but not WHY!!!
Here is what happens....

water fine and topped up, start engine, warms up, (flowing thru resovoir fine!) then when it gets to peak temp the resovir fills up and flyes out of the overflow?????

Any ideas?

Cheers Guys!

[jonbuoy]

If you are filling the water up when the engine is switched off you are creating an air lock. This maybe why the water is shooting out as the air will be forcing it's way out and pushing anything out of it's way! ie; Water.

Fill it up while the engine is running and see how you go

HTH

[Martinaston]

Did you bleed it correctly when you filled it ?
Put the heater on hot with the fan on 4 and fill untill you can get no more water in, then start it up and keep filling.
put the cap on and see if it goes over half on the guage, if it does check the fan is locking up when hot. You should be able to tell by the increased air flow through the rad but if your not sure people say stick a rolled up newspaper against the fan and it should shred it. (i've never tried that one though, i don't like the idea of a fan blade flying at me)

If the fans shagged the car will overheat and loose all the water so the temp guage no longer sits in the coolant and registers lower than normal, so you keep driving the car untill the head almost melts. (bye bye engine) Once an old head gets that hot it normally cracks between the exhaust port(s) and the water jacket.
It may be a hairline crack that holds pressure untill it reaches working temp and then lets the exhaust gas pass into the coolant.

or

If the one of the spark plugs is clean (steamcleaned) then it's corrosion on the head normally on the crown of cylinder 5 or 6 between the water jacket and the combustion chamber, that can be rebuilt with weld and then skimmed and re-used but you may still have the previous problem so you spend a lot of money for nothing.

If the manifold was replaced then i suspect it's been running too hot.

When was the last time you re-new'ed the antifreez ?

[CabbyThompo]

Ummmm..... thanks for all your advise! ive done what you said! an also spoke to someone who had the same problem, he said the fan!

When i did the newspaper thing the fan stoped!

do i need a complete motor or is it just the fan?

....and yes i will have the head properly looked at!

Cheers

[alpinac227]

I had the same, the head overheated and cracked. I replaced the viscous coupling which I suspect to be the cause. Whilst at it I also replaced the Water Reservoir cap, thermostat (note there is a bleed valve on top of the thermo housing to bleed air from may want to try this). I am considering an auxilliary electric fan, howver that's cos mine is an Alpina C2 2.7 which may require more cooling, depends how you run yours. On this forum it's been suggested to me to use the AirCon fan from E30 M3 or 7 series along with the temp switch. Do it before your head warps, wish I had !

[Martinaston]

If you've bled it correctly and the fan is shagged, try taking it for a run and as long as you don't sit in traffic or at the lights it should run ok as long as you have an air flow through the rad. But if it starts to overheat while your moving then you can be pretty sure the heads blown, so it will be a bit pointless replacing the fan at that point.
What you'll need is a new head

[Brianmoooore]

Anyone who cracks a head because of a duff viscous coupling should be prosecuted for driving without due care and attention.
The engine fan is only needed when the car is going slowly or stopped. Anything above 10MPH and it is redundant.
The instrument panel isn't there to give a bit of colour to the dash. It contains a temp gauge which is right in front of the driver's eyes.
No excuse for not knowing what your gauges are reading at all times, and it takes a minute or two for the gauge to climb from normal to the red zone.
On another point, all original E30 radiator caps should have been replaced by now. They were the subject of a recall.

[CabbyThompo]

cheers guys!, it can be driven but yeah overheats when on tickover or running low revs??

whats the easyest way of removing the coupling? (its being a B**ch!)

And does any1 know if the couling and thermo are the same as a 320i (G)

im lovin the e30 zone!!!, whoever started it up needs a big phat medal!!!

[alpinac227]

Viscous coupling is reverse thread, can't remember size of nut, but you have to give it a sharp tap/s (inertia etc)
The zone is ace..

[Mick01]

The coupling nut is a 32mm- you can get a water pump spanner to fit from Halfords at about £10. If the sharp tap (reverse thread) doesn't work then you may have to strip the coolant hoses off the engine and remove the radiator. This gives you access to the water pump pulley. I know it sounds a bit brutal but you can counter hold this with a chain type oil pump wrench and then remove the fan/coupling with the spanner.

[Brianmoooore]

. If the sharp tap (reverse thread) doesn't work then you may have to strip the coolant hoses off the engine and remove the radiator. This gives you access to the water pump pulley. I know it sounds a bit brutal but you can counter hold this with a chain type oil pump wrench and then remove the fan/coupling with the spanner.

Problems arise if some muppet's been there before and loctited the thing on. Chisel marks on the nut are also another bad sign. (You know who you are!!)
I keep a piece of flat steel bar handy with a 6.5mm hole drilled near the corner of one end. Remove one of the fan pulley bolts and bolt on the bar using a longer bolt. Bar locks up against the bodss on the front of the water pump pulley flange and holds the pulley still.