Funny thing happened today. For the first time in well over six months it was warm enough to drive with the heating turned off in my '96 328i. In fact I think the E30 will leave it's hibernation in the garage soon :-)
Anyway, I noticed after about 50 miles the temp gauge was just above the
3/4 mark. Turned the heater on half way and it was fine. Check the coolant and it was fine, heater blew nice and hot so there must have been plenty coolant in it. Drove 30 miles home with the heater half on, no problems.About a month ago the car blew the coolant hose from the back of the head to the heater. I had to very gently drive about 18 miles (mostly down hill) like that but it was -12C outside and I kept the coolant topped up, car never went into the red zone as I stopped quite a bit to let it cool (with the bonnet open on a freezing night). I even drove with the bonnet open and hooked on the safety catch to increase airflow to the engine. Car has been fine since, used no coolant and no overheating. But I've always had the heater on.
If there were any head gasket / head warping I'd surely be losing coolant? Even if the cylinders were pressurizing the cooling system (had that on an M60 and an M40 before).
I replaced the thermostat a year ago incidentally.
So I'm thinking it might be a failing water pump? Pretty sure I have the pump with the metal shaft and plastic impeller. When these fail do they do so catastrophically or might they just slip a bit and cause my problem?
Can't see it being the viscous coupling, it was only about 18C today and I was doing
60ish mph.I'll give the radiator a good hose off in case there's lots of winter gunk blocking the cooling fins. But failing that I'm thinking water pump. If I'm not losing ANY coolant then the head must be fine surely?
Any thought other than replace the water pump?