Overheating problem

[votivequagmire]

Some advice I'm after.

My engine seems to overheat mainly while around town.
Seems to lose a bit of water in the process.

Now I've changed the rad as the seal was broken at the top after getting caught with no antifreeze in the cold snap we had

I have also replaced viscous coupling on fan as also running freely what ever the temperature of engine.

I have replaced the thermostat which as you are aware is a sealed unit which fixes onto the three rad pipes.

The only anomaly I have noticed is a strange whining coming from the heater blowers when switched on.

Now my question is this, is it possible the heater matrix was also damaged in the cold snap we had which is not allowing water to go through it properly?
Also with regards to the thermostat, the pipe leading to the bottom of the radiator to the bottom of thermostat remains cold.
Does this mean the thermostat could be faulty or that it possibly has an airlock?
I've tried to squeeze the air out and into the rad and it feels like there is water there but stays cold.

Any advice gratefully accepted.

[samy_tee]

maybe head gasket.... i had similar problem with mine

firstly i would bleed the system properly which invloves running the car with the rad top off untill its warm. wait for it to cool down. open the bleed screew and fill rad with water again while squeezing pipes untill cold water runns out of bleed screw. and repeating this proccess. but ..this may not be 100% accurate. best to get a manual.

also

does the heater work fine?

no traces of oil in the water?

the oil? is that ok... nice and black or white and frothy?

"anomolies" with the heater matrix is usally the first sign of a of a head gasket problem as it is the weakest part of the cooling system.

i took mine to a garage and they put a pressure guage on top of my radiator. the system usualy runs at 20-30 psi (i think)

but the pressure said 100+

thats when i knew it was head gasket.

[votivequagmire]

Yeah, sorry I should've mentioned engine, d'oh.
It is the M10. I had the 318i version a few years ago but it was on a B plate and it all went pear shaped. Not much to salvage.

Got me a E plate 316 now with carb and same M10 block etc.

I think I may have gotten rid of old thermostat. will have a look though.

My heater still seems to work ok. Oil is ok if a little thin after getting a bit warm. when i unscrew rad cap when hot there is a lot of pressure and a little boiled water gets out. if the bottom pipe stays cold, is that a sign of anything? i thought either airlock or faulty thermostat?

[votivequagmire]

I will have good rumage around for the old 'stat and try it without the stat attached.
Will let you know how far I get closer to the weekend.

[votivequagmire]

A quick question.... samy_tee made a reference to a bleed screw?
I don't think I have one on my car? Do I? Where would it be situated if I do? At least I don't think I've seen one?