318i cooling problem

[318iM43]

Hello!

My car is 1997 year BMW 318i E36/M43. I will try to do my best to describe you the problem I have. It all started when I changed the coolant liquid. I drained the old coolant liquid from radiator and engine block. Added the new one and "bleeded" the system.Draw about 15km and checked the liquid level after engine was cooled down. Everything seemed normal. The next day I had to drive about 100km-s and when I arrived to my destination I noticed that theres steam coming out under the hood.The water was boiling in the radiator. The top side of radiator was expanded a little. The plastic cover near the radiator was bended as well. The top side of the radiator was hot like hell (upper hose too) but the down side was cold (lower hose was quite cold too) I cant say it was totaly cold.

All this time the tempreature indicator inside didnt show any signs of overheating. Heater was on and I got nice warm air in the salon.

So far I have tried to run the car without thermostat. The radiator still starts to heat up from the top and stays cold down side.

I know these symptoms are really bad and I may have to consider the worst possibility that it is the head gasket. What are the things I should check before going down to head gasket? I havent seen white smoke coming out from behind and liquid in the oil.

What should be the next steps I can do?
Thank you! Sorry if there allready is topic about it. I searched but could not find it.

[Jack Dabsy]

Very good explanation my friend !
Have you had the water pump off, because these often fail? This would be my next step after you tried the thermostat trick !
You should check this before we go for the Cylinder head !!

[318iM43]

Ok thank you. I will check it out tomorrow, but my water pump was replaced about 2 years ago. If the water pump will be ok any ideas where could I look after that. Is it possible that my radiator is just damaged by corrosion and electrolysis and wont cool liquid enough? Dont know how long theyr life time is, but I have heared that they are quite weak.
One question more. Any ideas why the tempreature indicator inside dont show that engine is overheating? It stays in the middle like it should.

[Jack Dabsy]

Could be a blockage (unlikely)... Go for the pump first mate... Then we'll address the Cyl-Head...

[318iM43]

If its the cylinder head then I can probably start thinking of a new car. Dont think its worth repairing. Will probably cost too much. Its cheaper to buy a bicycle

I will let you know if I find out.

[318iM43]

Today I removed water pump. It is ok and works fine. Changed oil and oil filter too to see if theres any coolant in it. Dint notice any signs of coolant.Bought a new radiator and replaced the old one. Old coolant looked good. No traces of oil in there.

Replaced the thermostat as well....now I cant get warm air inside the car. I think it may be bad thermostat.

I cant get the air out from the new radiator. It keeps on coming and coming. Any suggestions what may be wrong? Can the air in radiator cause my heating problem? Or is it a bad thermostat?

[beewee]

how about your heater fuses?
also like mine, sometimes the vent just remained on the cold side, you can see the control on your center airvent.

if not check the tubes near your gas pedal side, they should be hot.

beewee

[Jack Dabsy]

As above...
Raise the front-end to purge any air in the cooling-system...

[318iM43]

Thanks for the advice Dabsy! I think I got most of the air out now. Im geting warm air inside again

Im still little worried. The radiator (new one) is still geting very hot on the top side. The upper hose too, but lower one is cold. Is this normal? Shouldnt the radiator warm up evenly? Maybe theres some more air in the system? The thermostat im using has written 95°C on it and air temperature is around 2-4 °C

[Jack Dabsy]

Are you giving the thermostat a chance to open? The top of the rad WILL get hot first as the bottom-end is only cooled by engine oil ! Remember, heat rises - It's the combination of the t/stat and coolant-pump that evens things out...
Does your motor have a secondary heater-valve at the bulkhead?

[318iM43]

I think the thermostat will open, because I will get warm air inside. About the secondary heater-valve at the bulkhead I honestly dont know. How can I tell if I have it? My english is not very good at using "car terms" What should I look for and where?
Sorry if this sounds stupid.
Thank you!

[Jack Dabsy]

Do the rad fan(s) spin when she gets hot? (Bear in mind that the fan uses a separate temp sensor)
Or is it a mechanical viscous fan?