Are these symptoms all signs of the blue sensor?

[DanTheDoc]

Right, next issue:

I've read loads of info now and I've come to one question, do all of these symptoms point to the blue temp sensor?

Petrol smell from exhaust
More fuel being used
White smoke from exhaust (consistent with 'morning smoke' but the majority of the time)
Slight hunting at idle
'Throaty' sound in the exhaust (exhaust not blowing)

I'm currently at work so I'll test it as soon as possible but just want opinions to see if I'm hunching correctly.

Also, anything else that can cause all of the above?

Thanks in advance!

[daimlerman]

Conbined with loss of coolant,I would suspect a cracked cylinder head.

[DanTheDoc]

The oil shows no signs of water contamination and the level drops as you'd expect from an old car.

Is this consistent with a cracked head?

[daimlerman]

Head may be cracked over an exhaust port,or corroded by a fire ring.Both are almost 'normal' for an M20 engine that has seen poor maintainance as it's crept down the value ladder.Neither will cause oil/water mixing,but will cause loss of coolant and a steamy exhaust.

My M20'd car maintains it's coolant level,cannot remember the last time it was topped up.

Blue sensor is easily tested and eliminated,but remember to test at both the sensor and the ECU plug.

[DanTheDoc]

Thanks for the reply.

Should have probably stated in the first post, this is an M40 enigne, 318i, would this have the same problems?

[daimlerman]

I have limited playtime with M40 engine,my first E30 was a 316i touring that never needed more than oil changes and other routine stuff in the 4 years or so we ran it! Certainly never remember it needing frequent coolant top-ups.

In general,if this engine type develops 'expensive' problems,it's probably cheaper to replace it with a better s/h unit.

'Proper' BMW's have 6 cylinders....

[Brianmoooore]

and the level drops as you'd expect from an old car.

You do not have an 'old car', you have a BMW!
It's perfectly normal for the coolant level to stabilize about half an inch lower than it should on E30s, but if it continues to drop, then there is a fault.
A cracked head on a M40 is unusual, but anything's possible given enough neglect and lack of mechanical sympathy.
Remove the spark plugs and report back on their colour, and if one is noticeably different.

[e301988325i]

+2 on stable M20 coolant level, shame the same couldn't be said of the M54 POS.

[Billwill]

Worth testing the Blue sensor at the ECU.
Hunting at idle could be air-leaks at the hoses or intake gasket, dirty ICV, TPS switch not adjusted properly.
White smoke (which I had on my M40) could be worn valve stem seals.
Fuel smell and high consumption could be injectors need servicing.
Make sure you use NGK sparkplugs only!