Maxim Taylor Posted November 27, 2017 Share Posted November 27, 2017 Took my new toy out for a spin yesterday and noticed that the coolant temperature gauge read only 40 to 50. Ambient was around 8. Sat in traffic the temperature rises as normal and the fan does cut in.So a few questions:1) Surely the block temperature can’t be this cold, I assume they have a thermostat.2) Is the sender for the gauge separate to the ecu temp sender? I’m hoping so, and the ecu is seeing a higher block temperature than this, or the ecu will be throwing in extra fuel!Thanks for the newbie help....car is fantastic. Link to comment Share on other sites More sharing options...
elie boone Posted November 27, 2017 Share Posted November 27, 2017 Yes it can read this low with these ambient temperatures, use a piece of cardboard to block of 1/3th of the radiator and oilcooler Link to comment Share on other sites More sharing options...
MADMALC Posted November 27, 2017 Share Posted November 27, 2017 Are you certain it has a thermostat fitted?My SLR had the same issue and when questioned Caterham replied that they thought the engine was for racing so did not fit one. They fitted one FOC and it then had a 'normal' temperature reading. Link to comment Share on other sites More sharing options...
Maxim Taylor Posted November 27, 2017 Author Share Posted November 27, 2017 No I’m not certain, but I have no idea who to ask!i am considering blocking off part of the radiator. Link to comment Share on other sites More sharing options...
MADMALC Posted November 27, 2017 Share Posted November 27, 2017 I would start by asking the party you purchased it from.An infra red thermometer like this https://www.amazon.co.uk/s/?ie=UTF8&keywords=infrared+thermometer&tag=mh0a9-21&index=aps&hvadid=2978598332&hvqmt=e&hvbmt=be&hvdev=t&ref=pd_sl_5p3k5yv24i_e will help to see if the thermostat is there and operating. Link to comment Share on other sites More sharing options...
Maxim Taylor Posted November 27, 2017 Author Share Posted November 27, 2017 Thanks for your help, I’ll speak to Caterham South tomorrow and see if they can answer. I’m strongly suspecting you’re right and there’s no thermostat. Even a low temp one has got to be better than none at all. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted November 27, 2017 Member Share Posted November 27, 2017 Is the sender for the gauge separate to the ecu temp sender?If you'd like a wiring diagram please send me a Private Mail with the year, model, engine and your email address.Jonathan Link to comment Share on other sites More sharing options...
Maxim Taylor Posted November 27, 2017 Author Share Posted November 27, 2017 Thank you. Pm sent Link to comment Share on other sites More sharing options...
JNC Posted November 27, 2017 Share Posted November 27, 2017 I think you will find the temperature gauge is a bit erratic on the 620 I know two owners that have commented on the operation it's either cool or raging hot and not much between .Both cars are new less that a year old. Link to comment Share on other sites More sharing options...
Mark w Posted November 27, 2017 Share Posted November 27, 2017 Early 620 cars had no thermostat fitted . Caterham changed the inlet pipe to a new machining that can accommodate a thermostat . It has a thicker flange . If you have the thick flange version you cannot tell if it has a thermostat fitted inside but you can tell if it definitely doesn’t if you have the thin flange version fitted ! Some early cars has the upgraded pipe and thermostat retrofitted .The gauge under reads by circa 10 degrees compared to the temperature sender used for engine coolant measurement ( per Easymap ) the Fueling map runs a richer mixture below 60 degrees as read by the coolant sender . Link to comment Share on other sites More sharing options...
Mark w Posted November 27, 2017 Share Posted November 27, 2017 Jonathanif you have a 620 wiring diagram I’d love a copy . All my attempts to secure one have failed ! Link to comment Share on other sites More sharing options...
Mark w Posted November 27, 2017 Share Posted November 27, 2017 The one at the back of the first photo and the one on the left in the second photo are the modified part .I should imagine any car built since mid 2016 has this fitted as standard .I believe the stat fitted is 82 degrees . Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted November 27, 2017 Member Share Posted November 27, 2017 if you have a 620 wiring diagram I’d love a copy . All my attempts to secure one have failed ! Just been checking my library and the Caterham Cars website for Maxim. I'm a bit worried that I can't find anything specific: only the generic non-160 2015 Assembly Guide, amendments and Handbook.Jonathan Link to comment Share on other sites More sharing options...
Maxim Taylor Posted November 27, 2017 Author Share Posted November 27, 2017 Mark, that’s just the information I was looking for. Perfect! I’ll take a look at mine and see what I have. It’s a June 2016 registered, so I might well have the early type.Jonathan, thanks for looking. Link to comment Share on other sites More sharing options...
JNC Posted November 27, 2017 Share Posted November 27, 2017 Maxim I believe your car is one of the early cars . Link to comment Share on other sites More sharing options...
Maxim Taylor Posted November 28, 2017 Author Share Posted November 28, 2017 Mark, I measured my flange. 19mm thick. Link to comment Share on other sites More sharing options...
Maxim Taylor Posted November 28, 2017 Author Share Posted November 28, 2017 Winter mod ready for testing: Link to comment Share on other sites More sharing options...
Mark w Posted November 28, 2017 Share Posted November 28, 2017 Maxim I measured "my flange " tonight and would say that if yours is 19mm you have the upgraded part . Unless someone has gone to the bother of removing the stat i would guess that your car has one and you are just suffering from a bit of overcooling .Even with the thermostat fitted mine does this when the air temp is below about 10 degrees .You might want to wrap some of the oil cooler area as well if using on the road in these temperatures. Link to comment Share on other sites More sharing options...
Mark w Posted November 28, 2017 Share Posted November 28, 2017 PS In response to you question about the sender for the coolant there are two .A single wire unit at the back of the engine on the outlet pipe serves the sender and a multi wire plug in a similar position serves the ECU . Link to comment Share on other sites More sharing options...
craig2003 Posted December 8, 2017 Share Posted December 8, 2017 My 620R (May 2016) didn’t have one fitted but is in now having it done. Your temps are the same as mine Link to comment Share on other sites More sharing options...
7 wonders of the world Posted December 9, 2017 Share Posted December 9, 2017 Providing the cooling system still utilises the bypass then it will.work perfectly with the 82 degree stat. With the oe water pump pulley that are overcooled and can suffer cavitation at high rpm. Link to comment Share on other sites More sharing options...
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