Coolant change interval

[19jacobob93]

Hi guys
Been on the oil section for a while but it's now time to flush and change my coolant!
I got my coolant changed at a garage nearly a year ago but it was just with cheap stuff. I plan on doing it myself some time soon. I just bought the coolant, distilled water and a new thermostat and gaskets.
I bought some long life coolant (caliber brand from supercheap auto) which has an apparent life span of 5 years or 250,000kms.
Should I trust this or should I still change it after about a year (about 60,000kms) or take it up to two years or so?

Another question, i got a bottle of flush, would it be okay to just use tap water with the flush as it will only be in for 20-30 minutes?

Thanks!
Jacob

 

[901Memphis]

Extended life coolants typically do well with their rated time and mileage as long as you get all the old stuff out. You probably won't benefited much from flushing every year with extended life coolant unless your system is problematic. If you're obsessive compulsive just cut the 5 years in half and call it every 2-3 years depending on how much time have.

Alternatively if you flush it good you don't have to flush it every year just do a drain and fill or two every year with 50/50 or whatever mixture you use.

I would try to use Distilled water for the flush if possible, any contamination reduction is a plus in a cooling system.

What concentration are you planning on running? 60/40?

 

[Kuato]

I typically change my coolant at about 75% of its rated lifespan. In your case it would be a little earlier at 3 1/2 years.

 

[19jacobob93]

Okay that's good, at least I can rest knowing my cooling system should be good for a few years. The reason I'm changing it after a year is because the stuff the garage used looked very cheap and watery. I've since added some concentrate but I don't think it's ever had a flush in 14 years that's all, I've never really done a service on the cooling system so I'm not obsessive just yet!

I don't have enough distilled water for the flush

I'll use tap water which should be okay in there for 30 minutes tops, I know people who only top up on tap water and they seem to never have a problem haha
Still won't risk that and I'll save the distilled for the fill.

I have a 5L bottle of concentrate that makes up to 15L, my car takes about 11 so it will be about a 50/50 concentrate

 

[Boss302fan]

Flushing is fine with tap water as long as its not extremely hard water. Here in the USA our water is not really hard compared to Europe. Just make sure you buy premixed 50/50 coolant or mix a concentrate with only distilled water.

 

[Tanama]

As mentioned above, try to remove as much old coolant as you can. The old coolant might degrade the effectiveness of the new coolant. Two flushes, (that is fill the system, start the engine, and wait for the thermostat to open), with plain water should suffice to remove the old stuff. Do not forget to open the air conditioner heater to ensure full coolant circulation. The flush can be done with regular tap water, it really serves to remove debris contained in the cooling system and improve some cooling efficiency. Rain water is also a good choice.
The coolant service limit is dictated by the anticorrosive additive package life span. As long as you don't exceed the coolant time limit, your system will be fine.

 

[Kuato]

While a flush usually works well, I have always had good results just doing a radiator drain and fill. With the "old style" green stuff, it was every 18 months to 2 years.

With the new coolants rated at 5 years, every 3.

Never had a corosion problem or cooling or freeze problem.

 

[19jacobob93]

Thanks for the advice everyone. Could have done with it earlier actually!
I ended up just draining and filling back up at 50/50 concentrate. I replaced the thermostat and gasket and also the housing gasket after a little clean. There was some slight corrosion on the housing at either side of the gasket but nothing too major, hopefully more frequent changes in the future and at a higher concentration will prevent this further.
When I filled it back up I forgot to put the heater on, the thermo was closed preventing coolant from getting past the radiator and entering the engine which lead to it overheating rather quickly as the block was bone dry! (Not a problem for these engines)
After letting it cool down I put the heater on and started it, with a few good old squeezes of the odd hose I managed to get all the air out the system and were all sweet now.

Just another question, are there any downsides or dangers with running too strong a concentrate?

 

[Tanama]

Below 30% coolant concentration you lack proper corrosion protection. Above 75% concentration you degrade the cooling capabilities of your radiator, not a problem in extreme cold or polar locations.
Thermally speaking, plain water is your best coolant. But it can freeze and lacks corrosion protection. The antifreeze (mostly glycols) depress the freezing point of the solution. As for boiling, the cooling system pressure increases the boiling temperature point.

 

[Kuato]

Originally Posted By: 19jacobob93


Just another question, are there any downsides or dangers with running too strong a concentrate?


As quoted by Tanama, reduced cooling efficiency above 75%. Since you don't see freezing temperatures in Queensland, you should never have a worry with 50/50.

 

[19jacobob93]

Thanks for the answer, makes sense!
Reading the bottle it says a 50/50 mix is okay down to -15c. Like you say it never really gets below about -1 here on the coast but I take trips down to the Australian alps most winters where it can but not often get down to the -20s (yup it's not all beaches and desert down here!) would I benefit from adding a bit of extra concentrated stuff?

Because it never gets too cold here I see people with nothing but tap water in their radiators! I don't know how they sleep at night but I guess it will have maximum cooling for our summers

 

[artificialist]

Originally Posted By: 19jacobob93
Because it never gets too cold here I see people with nothing but tap water in their radiators! I don't know how they sleep at night but I guess it will have maximum cooling for our summers

Eventually they will have worse cooling when using nothing but tap water.
Limestone builds up in the radiator and engine block, it it conducts far less heat than any metal.

Plus without corrosion additives, their engines will not last.

Anyway, I don't trust 5 year coolant to last more than 3 years. I have found that usually it usually putrid at the 4th year.

 

[901Memphis]

Never pass 70/30 on either side. Not enough water will result in poor thermal transfer from the engine to the liquid since straight antifreeze doesn't move heat or hold it as well. I would error on the side of 60/40 with the water being 60.

Shooting for 50/50 is best and that way if you're math is slightly off your still sitting pretty.

 

[Eddie]

My last Mazda CX7 turbo said 10 years or 120,000 miles on the F22 coolant. At 7 years and 80,000 miles the coolant still looked like new. Ed

 

[19jacobob93]

My car holds about 10L so a 5L bottle of concentrate and a 5L bottle of distilled water takes it just above the max mark, so it basically gets a perfect 50/50 mix

It seems to get up to operating temp much quicker now which could be the new thermostat, but still stays at the 'O' on 'normal'