Being new to my 2003 Mini S this will be my first time around for doing a coolant change/flush. In reading threads and watching videos it appears that by just splitting the bottom hose and draining only gets about 50% of the coolant from the system. ( I assume this is what the dealer or repair shop would do) I see that using a shop vac to suck the fluid out appears to get much more if not all coolant out. Unfortunately I need to be more stealthy about my repair work that is done in a parking lot.(no 110v power)

Has anyone drained the 50% through the bottom hose - add back that 3/4 gallon with distilled H2O, drain refill again with H2O, and drain. Then top off with 3/4 gallon of straight antifreeze to mix with the distilled water left in the system. This should get out most of the old mix and be close to the 50/50 ratio required.
THX for looking

 

From my experience on a R50 (not exactly the same cooling system, but similar enough) you get much more than 50%. I'd say at least 75%. The coolant system hold 6L of coolant, I nearly emptied at 5L bottle when refilling it, so at least 4.5L (75% of the total capacity) went back in.

I wouldn't be too concerned about not flushing 100% of the coolant: the leftover old coolant will be diluted enough for that not to matter (much like with oil): what's important is to replenish the additive that protects your cooling system (or at least that's my understanding so far).

To refill, you can buy 50/50 premixed coolant so you don't have to bother about mixing in the right quantity.

 

If you're system is filled with the OE coolant (the blue stuff) then you're not gaining much by doing a system flush. Unlike traditional coolants which lose electrolytes over time, the OE coolant uses OAT corrosion inhibitors which do not get depleted.
If you're unsure, you can test the SG of the coolant with those little turkey baster testers you see in the parts store.

I'm not a fanboy of "lifetime fluids," especially when it comes to lubricants. But there's some solid science behind the coolant debate.

 

When I did my cooling system flush, I emptied the radiator and also removed the block plug on the back side of the engine. That got a lot out. I did that several times with water flush in-between. Final fill with coolant mixed with distilled water and then bleed the system.

 

Looking at the maintenance done by previous owner the coolant has not been changed for some 10 years - It's time. Surprising that the dealer and other mechanics let it go that long.

 

yikes 10 years, 50/50 with distilled water and the Pentosin Blue aka MINI Blue Coolant. Thats what i use.

 

This is news to me, though I will definitely confess that chemistry is not my strong suit. I've always been under the impression that the coolant ought to be changed every 2-3 years, which is what I've always done. It's usually pretty rusty looking when I change it.

I usually use the method that the OP is proposing. I drain what I can, refill with distilled water, run up to temp, drain again and repeat until the drained water looks sufficiently clear, or I run out of patience/distilled water. then I add 3 liters of undiluted coolant. I do use a coolant tester to help make sure i'm not out in left field when it comes to the concentration of coolant/water.

 

Racingguy04- Thank you for the reply- May I ask how many gallons of distilled you start with before your bored ? Do you bleed the system each time your drain ? Think it is a determent to drain with the front wheels 3" higher than rear ? Getting out as much of this 10 yrs old fluid makes sense to me.

 

Related question, I am going to be replacing my thermostat housing in my 2013 Roadster. I will replace the coolant as well. Has anyone had good/bad experience with PEAK Original Equipment Technology Antifreeze + Coolant for European Vehicles - Blue?

 

Dealer techs go by the book. However, I had several professional auto mechanics -- who were neighbors -- tell me they changed the coolant every 4 years in their personal cars and advised me to do the same.

The coolant change helps prolong cooling system components like hoses, water pump seals (which in turn prolongs water pump bearing life), radiators and heater cores. My first car had 4 hoses. Two radiator hoses and two heater core hoses. Hoses cost a couple of dollars each and I could replace them on my driveway. But later cars had way more hoses -- for instance my Porsche Boxster with two radiators (one mounted in each front fender -- and while I don't recall the number of hoses I recall (years ago) being quoted nearly $1000 to replace them all. But with regular coolant changes the hoses were fine even after 16 years and over 300K miles. The original water pump lasted 172K miles. The replacement water pump was good when I sold the car 145K miles after installing it.

 

The official coolant interval spec is every four years, so they definitely didn't do it by the book.

 

I flushed my coolant system 5 years ago...(2018) I read this thread and it got me thinking.... should I be flushing it again???


That looks pretty good to me... I think I'm going a few more years????

 

Looks clean so far.

But its get gunk in their from the engine and over time. It was more common on the Gen 1 MINIs to get dirty and clog the heater core, on Gen 2 MINIs i can do the same thing. Gaskets and rubber break down over time and tiny bits move through the system. Pull the expansion tank caps and look in their for what i call water marks with gunk. Clean and your good so far. Dirty and it will need flushed more so.
They can get caught in the radiator or heater core. Its cheap insurance. Also if you flush the system backwards with water, you can push out some of those tiny pieces, or use a flush treatment.

https://www.northamericanmotoring.co...e-plugged.html

https://www.northamericanmotoring.co...t-working.html

https://www.northamericanmotoring.co...-in-cabin.html

Also what other people don't think about is when people work on the cooling part of the system they sometimes get residue/dirt from the repair in the coolant. Then acquire the car down the road and don't know what pervious work was done. Oil residue/burnt and coolant quality show the history of the MINI.

My cars always have an upgraded part being developed so we flush them here at the R&D shop more then most other MINI would be done. At almost 300K on my R52 and the heater core is going strong.

 

"My cars always have an upgraded part being developed" Such a tease - Please tell us more about this part-

 

Now I cant tell all the insider stuff here, but we got some things in the works