Hey guys,

Just about to change the thermostat and sensor and just wondering if I should completely drain and flush the coolant system. The truck has only 42,000 kms and has been done once about 2 years ago at 37,000 kms (according to dealer maintenance records).

If I drain/flush should I just use a hose and maybe a bit of CLR (guy at work recommended it to me)?

OR

Should I just drain and replace the thermostat/sensor? If I go with this option how much do I have to drain the rad in order to change the two? I bought 2 jugs (approx 7L) and the rad holds 13L total. If it won't hurt and doesn't need a flush, i'll just top up whatever I drain.

Cheers

 

I just did this on my '01 Dak, I dropped most of the coolant by removing the lower rad hose, I swapped out all those spring clamps with a gear clamps. I found that there is a nice opening to slide a 1/4 drive ratchet with a 5/16 socket from under the bracket that holds the a/c compressor on, to use a gear clamp on the upper rad hose.
Another tip I found handy was to remove the water neck(13mm) then remove it from the hose,then swap out the Tstat and scrape the old gasket and then install new Tstat and gasket, make sure the tab marked front is orientated.

Refill with coolant and take for a rip to burp air then check coolant level.