Whats gone wrong.

[mrogers]

Finally the e30 is on the road but its ran into a little trouble.

Took her on her first long test drive, in traffic and noticed the temp guage was sat at 75% rather then the normal 50%. So went back and decided to make sure that there was enough water and anti freeze.

Anyway, Took off rad cap and started engine whilst filling water and having the heaters on hot. All was fine. Ran car like this for 20 mins heat from the blowers was hot and temp needle was on 50%. Then after 20 mins temp guage went to 60% and suddenly water stated spewing out of the expansion tank. Turned off engine, replaced water (2.5 litres) but now she still sits at 75% but the heater only blow cold.

[mrogers]

325i auto h plate

[mrogers]

anybody?

[Rav335uk]

Faulty Viscous ????
Do the paper test, roll it up engine running and see if you can stop the viscous with the paper, if it does, you need a new one.

[Speedtouch]

Has the cooling system been bled properly to eliminate air locks?

[mrogers]

Has the cooling system been bled properly to eliminate air locks?

Thats what we were trying to do, but i looked at my book "101 BMW Projects" and it said the 325i was self bleeding??

[Brianmoooore]

i looked at my book "101 BMW Projects" and it said the 325i was self bleeding??

Is the next project " how to change my cracked cylinder head"?
If filled very carefully, with the front of the car slightly uphill, and the heater set to hot, it may be considered almost self bleeding. There is a bleed screw on the thermostat/water outlet housing, at the top front of the engine, and often the top heater hose needs to be pulled of the stub pipe on the bulkhead to release air.
If the second overheating took place while the car was stationary, then probably the viscous fan coupling is faulty, as suggested above, and you now need to bleed at the heater stub.

[mrogers]

Car was pointing uphill with the heaters set to hot and we were slowly filling the expansions tank whilst squeezing the all the rad hoses, plus running the engine at 3,000 rpm to circulate the water. At no point did the water reading on the temp guage go above 3/4, but its an old car and that maybe giving an inaccurate reading anyway.

Just to clarify i need to undo the release valve on the thermostat and top up water there with the engine off, the re-tighten before i start the engine with the rad cap off?

[oomz1975]

Faulty Viscous ????
Do the paper test, roll it up engine running and see if you can stop the viscous with the paper, if it does, you need a new one.

Do this.

[Speedtouch]

Just to clarify i need to undo the release valve on the thermostat and top up water there with the engine off, the re-tighten before i start the engine with the rad cap off?

You top up the coolant reservoir, undo the bleed valve and run the engine until warm. You will probably hear air/steam hissing out of the valve. You need to run it until it is just spouting water with no hissy fits of air, and of course, keep the reservoir topped up. Once satisfied that all is well, close down the valve. You may need to repeat the operation a number of times.

Don't forget, you need the correct anti-freeze mix at all times of year to prevent corrosion of the alloy cylinder head.

[mrogers]

Spent all afternoon in the rain trying to sort this out. Rolled up a newpaper stick it in the fan and I could stop it. Also thought I would remove the thermostat as the heaters were not blowing hot hair anymore (were yesterday) and found only half a thermostat? the outer bit is their but no inner bit. Spent the next 2 hours removing all of the pipes to see if the inner bit was stick in a pipe somewhere but could not find anything.

So I know the viscous is in need of replacement, but why do I suddenly not have hot air?

Filled her back up and bled the system but no difference.

[Rav335uk]

Find the rest of the thermostat first.
Have you checked you water pump too

[mrogers]

Havent checked the water pump, took all the hoses off and could not find anything. If it had gor into the water pump would there be no water returning into the header tank, its flowing back into there fine.