Mixing / Flushing Coolant

[GeeDog]

Hi all,

I bought my V35 coupe about 5 months ago, and it had green coolant in it. I have no idea if it's the original "from the factory" coolant, or has been replaced in Japan at some stage by Nissan or other coolant, or if the compliance workshop replaced it with Nissan or another brand when it was complianced in May last year. As with all the other fluids, I wanted to change it - mostly because I just didn't know what it was or how old it was. Also, when it was 44 degrees here last week, my car's temp went to about 3/4 of the guage while I was driving up a steep hill at about 90, with the a/c on full. This is the only time I've ever seen the guage go over half way.

I've bought some genuine Nissan coolant, which cost a bit more than Nulon or similar but not enough to worry about. I'm trying to flush as much of the old coolant out as possible, but I'm not sure how anal to be about it.

Basically when I drop the coolant, I'm only getting about 4 litres out. I then replace that with 4 litres of distilled water, go for a drive to get the thermo open & mix the coolant / water, let the car cool down & then do it all again. So far I've done this 5 times, and obviously the coolant mix is getting weaker each time - the colour has gone from a deep green to something that looks like weak green cottees cordial.

If I knew that the existing coolant was Nissan, I would have stopped after a couple of flushes. Because I don't know, I'm not sure how much I need to dilute the existing coolant before putting the new stuff in.

Does anyone know if green coolant is all the same basic stuff, and therefore ok to mix brands, or should I be trying to get it as clear as possible before adding the new coolant? The distilled water is cheap, but it's a bit time consuming.

[Haino]

just drop it all, flush it through with water a couple times and put new coolant in, it'll be fine. It's just a bitch without a hoist

[grae35]

All coolants are not the same so it is best to flush as much of the old stuff out as possible

.

I have personally never had any issues swapping brands but some cars are more prone to electrolysis issues (eg some v6 commodores) and who knows what chemical reactions will occur. Having said all that though you have already flushed it 5 times so it must be getting pretty close to clear.

The cooling system on my 2004 6speed manual v35 is 8.7litres capacity plus 0.8 litre for the res tank. They are 8.5 litres for the autos. If you are only draining about half of that it is probably because you are only opening the radiator drain plug and not the 3 engine cylinder block drain plugs (front, right and left sides). They are very hard to get to so dont worry if you cannot find them.

My suggestion is flush one more time and (assuming the nissan coolant you bought is a concentrate - to be diluted 50:50) pour 4.35litres(manual) 4.25litres(auto) into the radiator and top up with demin water. That way you know you have the full amount of conc required.

Don't forget to use the air relief plug in the hose at the rear of motor to get all air pockets out of the block. (see other posts this forum) and the top up res tank.

[GeeDog]

Seems to be all good. I got the last flush with just a tinge of colour. I didn't remove any of the engine drain plugs - decided that was likely to cause more problems than it fixed.

The Nissan coolant says to mix between 30:70 and 50:50 with water, depending on the minimum temp you want to run in. I mixed 30:70 (or as close as I could get) - put almost 3 litres of concentrate in & the rest is water.

Thanks for the input.

[R6n350GT]

Any idea how to flush engine without using engine? my engine is brand new and needs to be broken in but i dont want to run it while flushing coolant before tune for turbo is done and engine broken in.

Any ideas ? Thanks!

[scotty nm35]

There is a drain bung up beside the thermostat that you would need to remove to get all the coolant out of the block. Then flush with the hose and repeat.

[R6n350GT]

There is a drain bung up beside the thermostat that you would need to remove to get all the coolant out of the block. Then flush with the hose and repeat.

Hey Scotty block has never had coolant in it, radiator is empty, everything new and not filled yet.

How can i get fluids filled so there are no air bubbles without turning engine on and thermostat open?

[Deep Dish V35]

I was going to say its easier if you park the car on a hill, nose up. but if it doesnt drive you might have trouble....

[scotty nm35]

The only option would be to purge the air from the block, using something similar to my coolant mod. Otherwise it's impossible to get all the air out.

I have a Lisle funnel that clips onto the radiator, allowing the bubbles to release. It doesn't work too well on VQ's but it may help get it close to full. Perhaps making up something similar for the rear bleeder may work, I had planned to make a funnel like this to sell with the coolant mod but the cost was already blowing out.

http://www.ebay.com.au/itm/Lisle-Radiator-Cooling-System-Spill-Free-Funnel-24610-/400080285135?pt=Motors_Automotive_Tools&hash=item5d26a4adcf&_uhb=1#ht_2372wt_1393

[R6n350GT]

Thanks Scotty im looking at it now, what about a wet n dry vacuum cleaner sucking the rear bleeder hose? Plus that funnel plus jack front of car up?

[Deep Dish V35]

i wish i knew about that block plate mod before i did the plenum spacer... wouldve been the perfect time to do it. my car has always run at 2/3 temp and this mod is the only other thing i can think of doing.

even with the lisle funnel fitted , i had to rev the engine to pump the coolant and bubbles out, turn the engine off to let it settle and burp itself, then go again. and after all that, i can still hear the hidden waterfall

[scotty nm35]

It's only an hour job to fit Deep dish.

The air bubbles make their way up to the bleed point quite well if the heater is off, but there is no way to get the air from the block cavity. You would need to tip the car on it's side for that. Must have been designed on a Friday arvo.

The Pathfinder had a similar design to mine, obviously Nissan had issues due to high load towing at the testing grounds, and had to re-design the cooling system to promote cooler running and stop flash boiling off the block liners.