I have just bought a used Kubota G1700 diesel garden tractor (D662 engine) with low hours. I have no service history so I will replace all fluids etc. It will be used for mowing and light towing with low hours each year. I want to keep it for a long time and aim to change the radiator coolant every other year and flush now and again. I would really appreciate some advice on engine coolants. I have read around the subject and believe Kubota recommended basic green coolant J1034/J814c. This is getting less easy to source in UK so I am thinking of upgrading. I have contacted BASF and they insist that a G30 OAT formula is correct for my application. I am not keen. Its seems overkill and I am concerned about compatibility in an older engine. A lot of people seem to use a hybrid G05 formula which has low level silicates and nitrites. Despite what BASF say this seems to make sense as it is the next step up from green coolant? I understand that the D662 is not 'wet sleeve' but will the nitrites protect other areas like the water pump or are nitrites unecessary or detrimental in this application? I have a shortlist and would appreciate views:
1) Comma Xstream G05 http://www.commaoil.com/productsguide/view/6/354
2) Motul Inugel expert/ultra (contains silicates but NO nitrites)
https://www.motul.com/gb/en/products/oils-lubricants/inugel-expert
https://www.motul.com/gb/en/products/oils-lubricants/inugel-expert-ultra
3) Motul also do a classic which I assume is a nitrite free green coolant? https://www.motul.com/gb/en/products/oils-lubricants/inugel-classic
http://arizonamotors.ro/userfiles/product_files_shared/MOTUL%20INUGEL%20CLASSIC%20-25%C2%B0C%20ARIZONAmotors.ro.pdf
Thanks in advance
1) Comma Xstream G05 http://www.commaoil.com/productsguide/view/6/354
2) Motul Inugel expert/ultra (contains silicates but NO nitrites)
https://www.motul.com/gb/en/products/oils-lubricants/inugel-expert
https://www.motul.com/gb/en/products/oils-lubricants/inugel-expert-ultra
3) Motul also do a classic which I assume is a nitrite free green coolant? https://www.motul.com/gb/en/products/oils-lubricants/inugel-classic
http://arizonamotors.ro/userfiles/product_files_shared/MOTUL%20INUGEL%20CLASSIC%20-25%C2%B0C%20ARIZONAmotors.ro.pdf
Thanks in advance