My apologies if I sound like a total plank but it's my first Radiator / coolant flush in the Magna 2004 TL ;-)

I have a bottle of Nulon Radiator Flush & Clean and it says to add to the radiator and then run the engine for 20 mins before letting cool down and emptying. How do you add the liquid to the radiator if it's totally full of coolant? Do I have to undo the lower hose and let some coolant out to make space? It doesn't say anything about adding it via the coolant filler cap, just the radiator cap.

I have plenty of info from here for the additional task of flushing all the coolant out afterwards but didn't want to balls up the job at the very first stage with the Nulon Radiator Flush

Thanks,

Andrew

A quick (and not very environmentally friendly) way would be to remove the overflow tube (when cold) from the overflow bottle, (aim at the ground with a zip tie) and go for a half hour drive. Or disconnect overflow tube at radiator, (when cold) fork out $5 for a length of tube from supa-sheep and aim at ground and go for 30 min drive.

This will cause the radiator to heat up, empty out through the overflow tube (onto the road) and upon cooling, leave you enough space to add your flush treatment.

An easier way (don't know about TL, but my TJ has one) is to use the radiator drain tap on bottom left side of radiator when cold, (with cap off) and simply drain some fluid out into a bucket.

Thanks for the reply. After you mentioned the radiator drain tap a little hunting around and I found it (white). Drained out enough to equal approx what's in the cleaner bottle and then was able to pour the cleaner in via the radiator cap as instructed on the bottle info. Just been for a 20 min drive and waiting for everything to cool down then will start the flush / refill coolant process. Quite interesting doing this yourself and the money I saved I got a Kincrome 3/8 Torque wrench for my next job..... changing the rear spark plugs :-)

Cheers.

Whenever I do a flush I always drain the radiator first, then refill the radiator with clean water and the flusher. (No need to use green coolant for a short period like this.) Then I flush the radiator a couple of times with fresh water before finally filling with the green stuff.

Incidentally I always buy the green coolant concentrate and make it roughly 50% stronger than the instructions. Dunno if this is the right thing to do but I've never had a significant corrosion problem in any car. My Magna has 350,000 ks on the clock and hasnt even had a water pump replaced. I had to replace the water pump in my Pajero at about 280,000 ks. but that still sounds like a pretty good run according to what I have read on the Pajero forum.