overheating problem 320i M20B20 SORTED

[d1mkaz]

my temp was in the middle constantly, but few days ago, I toped up coolant, and forgot to put on cup, stupid me, did about mile or so, stopped to shop, when came back maybe in 5mins, started the car and coolant red light was on, looked under the car and sow water leak, opened bonnet, the cup was still there, near coolant tank, but no water to be seen, so filled it up with water, and everything seems ok, when driving, temperature in the middle, but when stop, engine running, it starts growing, the heater working fine, all hoses are hot, thermostatic valve seems working too, did about 150 miles today, when coming back home stuck in traffic, on tik over, temperature coming up, so need to accelerate only then it drops down. what can that be? air lock? engine? what's the best way to check?

was trying to check radiator, it's difficult to get to it, but noticed, that one part of it warm even hot and another not.

if it's air lock, should not it be gone after 200miles on motorway???

[stonesie]

Have you tried the bleed point on top of the thermostat housing? also bleed it at the top heater hose on the bulkhead.


Usually when the heater is hot then its all ok but it's worth checking, also when you remove the pressure cap with the engine running is there a flow of coolant comeing back into the header tank from the radiator?

[d1mkaz]

Have you tried the bleed point on top of the thermostat housing? also bleed it at the top heater hose on the bulkhead.


Usually when the heater is hot then its all ok but it's worth checking, also when you remove the pressure cap with the engine running is there a flow of coolant comeing back into the header tank from the radiator?

sorry ,my technical english is really bad

1. bleed point on top of thermostat housing. where is that exactly? is it where 3 big hoses connected and where thermostat is? where should I look for bleed point?

2. top heater hose on bulkhead??? how do I bleed it?

3. pressure cap? is that the cap on coolant tank? then yes, opening it coolant starts coming off

sorry again, If I could take a look at those on picture or something.

may be I'll go and make some, then post them here

[d1mkaz]

is that what I need to bleed? I marked red circles. do I need to run engine, and undo screws?

[zaust]

Do the news paper test with the fan when the temp is up to fella.(if the paper get's shredded it's good and if the fan stpos it's mullered) You might only need a new viscous fan coupling.

[commando]

Sounds like viscous fan

[d1mkaz]

checked fan, it rips off everything even when engine cold
then did that:

-Have the ignition on (engine off), heaters turned right onto hot, medium fan speed, make sure the car is on level ground
-Remove the rad cap and top up with coolant mix until at the top
-Remove bleed screw
-Keep topping up rad until coolant flows out of the bleed hole and there are no bubbles in the flow
-I find it sometimes helps by squeezing the rad hoses to push the air through the system
-start the engine and allow the car to idle and get hot. Once hot, the heater should be hot, if not try again!

thanks to stuartgallafant explanation in this post:

http://www.e30zone.net/modules.php?name ... emperature

temperature sticked in the middle, drove car couple miles to petrol station with heater on full
then back with heater off, stopped, had breakfast (about 10 mins) while engine running
the temperature went slightly up, but when accelerated to 2000 rpm it dropped back
drove another couple miles
seems sorted

thanks to everyone,
brilliant website