coolant temp sensor dry

1. worazas Newbie Joined: Jan 2012 Posts: 10

   #1 17th December 2012, 10:48

   hi all,
   i had this problem with overheating light staying on all the time, so i've changed temp sensor (temp sender unit?) on the side of thermostat housing (blue with yellow ring, one wire coming out). Thing is, when i took it out there was no coolant coming out of the hole, does that mean it's not bleed properly? What would be the symptoms of air in the system? Because i've undone all 3 bleed points with engine runing and there was coolant coming out of all of them, heating works properly with hot air coming out. I also put another sensor on the rad so i can monitor coolant temp, and i can see when the thermostat opens up and hot coolant starts going into the rad, yet overheating light stays on. I'm waiting for code fault reader to turn up to see what it says and try clearing the errors, anything else i could check in the meantime?
   p.s.no coolant coming out of the sensor hole really bugs me...
2. vtrmann Frequent Poster Joined: Dec 2009 E yorkshire Posts: 947 53 black vtr

   #2 17th December 2012, 16:36

   It might be becuase theres no pressure pushing the coolant out when you unscrew it. Did you do it when coolant was cold?. I did mine while it was still warm (rushing) and it shot out soon as i unscrewed the temp sensor. Symptoms of air in system would be high temp and a water gushing sound when starting up i think.
3. worazas Newbie Joined: Jan 2012 Posts: 10

   #3 17th December 2012, 23:10

   I changed it when it was warm... temp is not high when i'm driving, barely reaches 40c in the rad if i don't get stuck in miles of traffic, even after 10min of crawling it does not go above 70-75c and there is no strange sounds...
4. Gandi699 Saxperience Post Whore Joined: Apr 2011 Posts: 9100 Amazon green VTR 16v, Inferno RS clio 182

   #4 18th December 2012, 00:29

   I dont think that water is meant to come out of the one that the gauge uses, only the CTS in the stat housing
5. worazas Newbie Joined: Jan 2012 Posts: 10

   #5 18th December 2012, 13:24

   You mean the one that sends info to ecu?
6. jphayward-2008 Newbie Joined: May 2009 Posts: 24

   #6 18th December 2012, 16:46

   On some heads, the hole for the sensor for the gauge in the side of the block isn't in the coolant channel. Only the ECU sesnor in the thermostat housing is.
   
   On my S1 rallye head the hole in the side of the head is just a blank hole. So its effectively measuring engine temp and not coolant temp. But then on my old 1.1 it was in the coolant channel.

   1 user thanked this post: worazas
7. Gandi699 Saxperience Post Whore Joined: Apr 2011 Posts: 9100 Amazon green VTR 16v, Inferno RS clio 182

   #7 18th December 2012, 21:15

   As above, mines got a very similar s2 rallye head and the temperature gauge sensor is not in the coolant channel

   1 user thanked this post: worazas
8. worazas Newbie Joined: Jan 2012 Posts: 10

   #8 19th December 2012, 08:18

   ok, that gives me some peace of mind, thanks guys