Fans cut in at higher temp since system drain.

[zippy500]

I have recently drained my cooling system. And now the fans seem to cut in at around 100 as opposed to just over 90 before hand. As far as im aware there are no air locks(system ffully bled), it hasnt overheated, i have no signs of leaks. Any thoughts why this should be. Other things I did was remove otter switch and clean it, remove engine temp sensor and clean it and replace 6 inches of the wire connceted toi it. My only view is perhaps the temp gauge is giving a better reading of the temp due to a better electrical circuit. Or the ratio of water to anti freeze is different which effects the temperaturs somehow. I have sat with engine running and it dosent get above 100 and fans go on and off as normal. any thoughts boys and girls.

[zippy500]

I have undone the rad bleed screw again, with no air coming out, the only thing to try now is to run engine from cold with expansion tank cap off for a few minutes I suppose. Weird this, I would have thought the fans would cut in at less than 90 if I had an air lock, not higher. Most odd. The investigation continues.

[zippy500]

All previous bleeding was done with heater on hot setting. The length of wire was cut the same length to allow for resistance change. One thing I did notice the old wire was very stiff, due to either old knackered isulation or higher gauge wire, this will change the resistance a little. The actual engine does not overheat, so if no air lock can be found shall i just forget about it( but keep a watchful eye on the gauge just in case)

[zippy500]

Quick update:
run the car this morning with cap off and heater open for 5minutes, then drove to work. Heater is luke warm, but car has still not overheated. So looks like a very stubborn airlock in the heater matrix. Anyone have a tips fpr getting it out. Would leaving the filler cap off even when the thermostat opes work. Although im a bit conserned about doing this for the obvious reasons.

[zippy500]

This is a pain, ran it again this morning with cap off, still no luck. How the hell am I supposed to get it out. Surely it cant escape until the thermostat opens? Oh well perseverance is required I feel.

[zippy500]

I have a pre serpentine engine so no seperate tank. Im going run it up later with cap off until the thermostat opens. I have done this once allready but switched off engine as coolant level dropped rapidly as not enought fluid in system. Im sure this will get the air lock out, I will then quickly piut the lid on and allow to run for a few minutes. I have tried the bleed valve on the rad several times. would be a good idea to have one on the heater matrix also me thinks. Cheers for the help people. Much appreciated.

[zippy500]

Right another update, ran engine with cap of again, until thermostat opened, kept cap of until water level started to rise then put it on and ran for a few minutes more. I now have heat from the heater, but the fans still cut in at 100 C. Im puzzled now, I will try this method again but Ill be amazed if its still an airlock. Dont know why im fretting really, It wont overheat, tonight he fans came on and it dosent budge abve 100. PS I know the gauges arent the most acurate things, just going on the readings I have. Just cant see why it should be about 8 degrees higher when nothing has changed other than the coolant and a bit of wire. Curious

[zippy500]

The wire was just wire, it was pretty well knackered so im wondering if it was causing a really high resistance itself and thus messing up the gauge readings. Of the top of your head what sort of temperature should fans cut in? The heater goes very hot or hot now, which is normal I believe. I have found another thing which probably isnt causing a problem, the connectors to the otter switch are covered in corrosion products from a slight mishap when I filled up the coolant tank, this may be causing a crap circuit and causing the fans to come on later. I have now put some new conectors on, but havent run the car up since