Temp Guage E30

[mike1516]

I have an E30 323i 1985 which I'm slowly getting around to fix things (Very Small budget from 'er indoors!)
I have changed the themostat as the temp gauage never read above the first line. Having done the change the temp still does not go over the first line on the guage. Is this normal for this car? Any help greatly received and new to this forum malarky!!

[georgen]

My 325i sits about the same in normal driving and maybe slightly higher in traffic. In my experience, the 6cyl motor temp guages sit between 1/4 & 1/2 in normal conditions, so I would say that it's nothing to worry about fella.

[mike1516]

Thanks mate Thats a great help

[stranter]

This sounds like it's not getting out of the blue. I'd change the temp sender.

Stewart

[mike1516]

Thanks it does go out of the blue zone and then rests between just above the first line?

[TRANSPORTER]

MMMM georgen, you,ve got me a little worried now, My thermostat was sticking so changed for new, engine temp gauge now sits between halfway and three quarters, sometimes higher if stuck in traffic, "viscous Fan". obviously if she gets that hot i,m turning on the heaters to take some heat out of the system, I,d rather be hot than stranded on the road side. My other halfs E36 compact "electric fan" runs around the same temperature range but doesnt get as high as my Touring in traffic ". So i,m thinking that all is well with my cooling system??

[stranter]

Well mine sits about 1.5mm below the centre all day long - new viscous, new rad, new hoses, new thermostat. Just out of the blue and just above the first line seems a touch low. I'd replace the temp sender as a precaution.

Transporter, have you changed your viscous fan clutch? What condition is your rad in? Did you properly bleed the cooling system when you changed the thermostat?

While out of the blue and not in the red (nothing in this game for two in a bed) is fine, the needle should sit at halfway or just below. Unless in extreme driving conditions, such as heavy load in hot weather, the needle shouldn't pass the centre. Sitting at two thirds all the time is at least indicating running hotter than normal

[TRANSPORTER]

Fair one stranter, will have a bleeding session asap, didnt actually bleed the system when I changed the thermostat topped it up with cap off until coolant was being pumped back into the expansion tank. Bit cowboyish I know and know way to treat a classic.

[mike1516]

Wow you guys seem to know your stuff. Ihave to admit I just filled her up to the mark on the expansion tank didn't know you had to bleed it as well. Will get it sorted soon as. By the way Rad and all assocated parts are ok and in good nick. I know the rad and fan were new about 2 years ok so think they should be ok.

[Brianmoooore]

Thanks it does go out of the blue zone and then rests between just above the first line?

There is nothing wrong with the cooling system of your car! This position is well within the 'normal' range.

[georgen]

Fair one stranter, will have a bleeding session asap, didnt actually bleed the system when I changed the thermostat topped it up with cap off until coolant was being pumped back into the expansion tank. Bit cowboyish I know and know way to treat a classic.

To bleed, warm the engine, hold the heaters wide open and let all the bubbles escape from the thermostat bleed screw. A few high revs should shift any air in the system. Once you have water running from the bleed screw, retighten the screw and take the car for a run. Check the level when you stop again and all should be fine.

[Heyho]

I've not owned or worked on any beemers which don't settle pretty much in the middle of the coolant temp gauge. My old 320 used to sit either bang on central, or a mm or 2 under. Same with my E34, and with my current E46.

A fairly common fault on E30s was the nut on the back of the temp gauge coming loose, causing incorrect readings, as the gauge earthed through the nut.

[Brianmoooore]

On 99% of E30s in full working order, the temp gauge sits somewhere between the first white line and slightly over the centre white line. The difference in these two readings is a very small change in temperature, and anywhere in this range is acceptable.
According to the owners handbook, anywhere out of the blue sector and away from the red sector is acceptable, but if the gauge settles anywhere outside of the range I gave above, there is usually some underlying cause.
A loose brass nut on the rear of the gauge causes it to read about half a sector high, or usually, because the connection is intermittent, the gauge flicks between the two positions.