More teething probs

Post Wed Jun 19, 2013 11:03 pm

Seems that they never stop with my project. Don't know if it's because I'm still a noob or I'm just unlucky but...anyway...

Got round to the coolant tonight. Pre-mixed my antifreeze/dionised water beforehand, jacked car up nice and high at the front, ignition stage 2, heater on full hot, filled from top hose with bleed valve open. Went okay, took over 4 litres, reconnected hose, tightened bleed valve and fired it up.

First prob: blower switch/resistor must be dying as it only works at full speed. Fan also sounds a bit pathetic. Hopefully an easy fix. But what was odd is the temp gauge twitched when you moved the blower switch. Strange.

Second prob: I idled the car for 5 mins or so, then switched off. Bled out some air, a little bit came out. Temp gauge (aside from aforementioned twitching) hadn't moved the entire time, which I thought was reasonable. Did some other jobs, then turned ignition back to stage 2 to play with the blower switch and noticed that the temp guage was off the scale. Struck me as very odd.

Seems I may have a wiring fault? Have I missed an earth somewhere or could it be something else?

Post Wed Jun 19, 2013 11:28 pm

Does sound odd, unless the temp gauge had a delayed reaction to the engine temperature, but I doubt it would have got that hot if only idled for 5 minutes.

Or, did you accidentally disturb the cylinder head temp gauge sensor when bleeding it?

Post Thu Jun 20, 2013 8:12 am

That's what I thought - surely with just 5 minutes of idling and with coolant in there it's nowhere near enough for it to get hot. Also the temp gauge shouldn't be twitching when I use the heater controls right?

Didn't go near the temp sensors (blue/brown) when bleeding and they are covered by the inlet manifold so wouldn't have thought I would have disturbed them.

Post Thu Jun 20, 2013 11:07 am

Ok, just read that the M52 coolant capacity should be 10.5 litres - perhaps that's the source of my prob!

Post Thu Jun 20, 2013 12:16 pm

I have a Fiat twin-cam engine that used to get very hot very quickly, but discovered that the previous owner had set the timing to TDC, when it should have been on 10 degrees BTDC. Once adjusted, it's run well ever since.

Post Fri Jun 21, 2013 9:29 pm

Yeah something in the temp gauge circuit is naffed as my temp gauge reads max as soon as ignition is on. Was going to try it with temp sender unplugged and again with the temp sender plug earthed and see what happens. I guess its a way to test whether or not the sender is broke. Any other ideas?

Post Fri Jun 21, 2013 9:56 pm

Check the brass nuts on the back of the instruments cluster, and tighten them if necessary.

http://www.e30zone.net/modules.php?name ... ts+cluster

Post Fri Jun 21, 2013 9:57 pm

if its just the dial normally its the screw is loose hex nutt at and the back of the dial my fuel dial was doing it and sorted it once tightened up

Post Wed Jun 26, 2013 5:30 pm

Ok tightened the brass nut, still persists. Straight to max temp as soon as the cluster has power. Unplugged brown temp sensor and it doesn't change a thing. It sounds to me like there is an earth somewhere where there shouldnt be one. But how do I test?

Post Sat Jun 29, 2013 2:34 pm

Resolved. Failure on my part (again!). For the information of the people, this is what happens when you plug the temp gauge into the oil pressure sender and vice versa. Associated symptom was no oil pressure light, but in the sunlight I had never noticed that. At least not until I had traced everything back through the C101...