Help! Temp Gauge Giving High Readings At High Revs

[williamselby]

Help!
At idle, the temp gauge on my early Elan +2 reads 85 degrees. If I rev it up to 5000 rpm, the temp gauge creeps up quickly to the top of the gauge (130 degrees).

I have just replaced the voltage stabiliser with a new one, but this has made no difference. I've had this problem for a few months but in that time there has been no loss of water in the radiator and no other visible signs of overheating.

The workshop manual says that +2s were soon fitted with a 'choke' between the stabiliser and gauge. My car doesn't appear to have one, but it used to give perfectly stable readings without this.

Could it be a faulty gauge or sender unit? Has anyone experienced something similar? Is there diagnostic equipment that can be obtained to find out the actual temperature of the engine?

Any advice would be much appreciated as this seems to be an iritating fault that doesn't seem to want to go away.

[john.p.clegg]

nip down to your local B&Q,or plumbers merchants and purchase a central heating radiator thermometer,clamp this on your thermostat housing and hey presto!,you now know if you've e temperature problem or an electric/sender/guage problem
John

[williamselby]

Are you sure that this would give an accurate reading?

[john.p.clegg]

yes,when i first bought my plus2 i had to drive around with the window open and the heater on full blast just to keep the engine temp. down
that is until i decided after many other things(thermostats,recored radiators etc.etc.) to check the actual engine temp.
give it a go,you may be pleasently surprised
John

[JACKJABBA]

Is the car static when you are reving it up, or does it go up when you are driving?

My +2 would creep up to the high while driving it and would always need the fan on. I changed the coolant for a high quality (quite expensive) brand after flushing the engine. The car ran great after this and only gets hot if stuck in traffic in warm weather (25 C+ ) I was then talking to a neighbour who use to work on Elan's and he told me it was probably trapped air in the cooling system causing the problem and that I had probably got it out when bleeding the system.

If you have a spare temp sender, then connect it external to the cooling system. if it still goes up when the engine is reved up then its probably not your cooling system at fault.

[williamselby]

The temp goes upto the top of the scale both when I'm parked and I rev it up and on the motorway at high revs (even in sub zero outside temperatures) and falls back to 85 degrees the moment revs go down.

Strange isn't it?

[Robbie693]

Check your bottom hose, it goes through quite a tight kink and if its old then it may be restricting your coolant flow due to internal deformation. If it's spongy then you should change it anyway.

My car had a similar problem but I didn't have chance to fix it before some *** drove into it and wrote it off! :angry:

[Greg Foster]

You might check your grounds as the current may be travelling through the sensor to find a ground. I believe Dave Bean's catalog had something in there about grounding. Good luck! Greg

[Roy Gillett]

May sound stupid to ask, but does the reading change when you switch the headlights on? If so suspect the earth return (ground in the USA) that goes to the chassis on the transmission tunnel just behind the dashboard (Its on the RHS on mine but I believe it is sometimes on the left). If these bolts are loose and the earth is poor then all sorts of spurious readings occur when there is an electrical load or when the car twists a bit on cornering hard. Do the bolts up tight and all is well if that is the cause.

[williamselby]

Problem now fixed. Due to faulty voltage stabiliser and then incorrect use of negative rather than positive earth replacement.