Mo Murphy Posted July 30, 2015 Share Posted July 30, 2015 As part of my slow and laborious Air con install of a Td5 air con system into a 200 Tdi, I have happened upon the need for 2 coolant temperature switches, one to switch on the fans and one to decouple the compressor clutch when coolant temp is too high, PRC3505 and PRC3359 respectively. As I dont have a 300 Tdi, for which a thermostat elbow with 2 tapped switch holes is available, I need to find a way of inserting them into the coolant. Has anyone done this already ? Has anyone any suggestions on a simple method and on the best place in the coolant system to place them (I assume somewhere near the thermostat given the standard 300 location). TIA Mo Quote Link to comment Share on other sites More sharing options...
western Posted July 30, 2015 Share Posted July 30, 2015 drill & tap the 2 blank holes on top of thermostat housing, as that's what they are used for on a 200tdi with factory fit air con. http://www.allbrit.de/UNI.cfm?PAGE=747974&SPRACHE=EN would be the easiest way to get them to read the coolant temp. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 30, 2015 Author Share Posted July 30, 2015 Bravo Ralph, well done old chap, that's perfect ! ? Mo 1 Quote Link to comment Share on other sites More sharing options...
western Posted July 30, 2015 Share Posted July 30, 2015 prc3359 is used on both all LR Tdi engines for air con switching, you just need to find out what the thread size/type is, prc3359 http://www.lrseries.com/shop/product/listing/9788/PRC3359-ENGINE-THERMO-SWITCH.html?search=PRC3359&page=1 prc3505 http://www.lrseries.com/shop/product/listing/9799/PRC3505-SWITCH.html?search=PRC3505&page=1 Quote Link to comment Share on other sites More sharing options...
ejparrott Posted July 30, 2015 Share Posted July 30, 2015 I wondered what they were for! Quote Link to comment Share on other sites More sharing options...
miketomcat Posted July 30, 2015 Share Posted July 30, 2015 I may have a tap that you could borrow for that job. I've got an m22x1.5 (i need to double check the size) tap I bought to tap exactly those blanks for my rad fan switch on the ibex. Mike Quote Link to comment Share on other sites More sharing options...
Boydie Posted July 30, 2015 Share Posted July 30, 2015 Mo, I'm not too sure that you need either switch - in the UK anyway, one switch turns the compressor off when the coolant temp rises above 110*C to reduce load on the engine, the second turns on the A/C coolant fans when the coolant temp rises above 115*C to assist the mechanical fan and the idea is really for tropical ambient temperatures - as in well above 40*C. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 31, 2015 Author Share Posted July 31, 2015 You're probably right Boydie but summer trips to Southern Europe and North Africa would suggest it would be a sensible precaution for minimal effort ? Quote Link to comment Share on other sites More sharing options...
Pepé le Pew Posted July 31, 2015 Share Posted July 31, 2015 PRC3359 is intermotor 50070 and PRC3505 is intermotor 5000. Both are M22x1,5. http://smpe.elcome.co.uk/ecat/ViewPart.asp?p=50070&cid=24381928&pt=10&i=4775 http://smpe.elcome.co.uk/ecat/ViewPart.asp?p=50000&cid=24380602&pt=10&i=4711 Eric. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 31, 2015 Author Share Posted July 31, 2015 Thanks Eric. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 3, 2015 Share Posted August 3, 2015 Aren't the switches the other way, the lower temperature switch to activate the fans and the highre to kill the AC if the cooling system still can't cope? Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted August 3, 2015 Author Share Posted August 3, 2015 You are indeed correct Mr Snagger. Mo Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted September 2, 2015 Author Share Posted September 2, 2015 All done, thanks to Anderzander who found an old spare and the boy Ross who machined it up for me. Much obliged fellas ? Mo 1 Quote Link to comment Share on other sites More sharing options...
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