coolant drain and refill question

[flinter]

Hi,

When time comes to service and drain and refill coolant, one should refill with the coolant concentrate, mixed with distilled water and NOT the dilluted 50/50 mix? I have read that the 50/50 coolant should ONLY be used for top offs. Is this true?? Or is that theory car specific? I own a 2017 Hyundai Elantra SE 2.0 engine and I am at 42,000 miles.

Also, can I trust a well respected independent shop to properly do a coolant drain and refill, or is the dealer the better choice?

Just wondering.

Thanks

 

[doitmyself]

There is no difference between store bought 50/50 or self-mixed 50/50 concentrate and water if you use distilled or deionized water,(no need to nit-pic about the purity of distilled water).

Approximately 1/2 of your coolant is in the radiator and 1/2 in the engine block, give or take a bit. If you completely flush out your system with water, about 1/2 of the total capacity will remain plain water in the engine block. If you add 50/50 to the radiator after a complete flush, it will be diluted by the water left over in the engine block. That is the only reason you cannot use 50/50 after a complete flush with water. After a complete flush, you add the correct amount of concentrate to the radiator (1/2 the total system) and finish off with water to get a complete fill.

I don't like to mix different coolants. For me, a drain and fill of just the radiator (1/2 the system) is fine IF you replace it with the exact same coolant. If you cannot determine/purchase the OEM coolant and choose something different, then I prefer to do a 100% flush and start new with whatever coolant you choose. Hyundai/Kia seem to be a bit vague in their coolant identifications. Others here are not as hesitant to mix coolant brands or types.

You will have to visit the shops your are considering and ask how they do the fluid change. Even dealers often use non-oem fluids (BG comes to mind).

Edited to answer Pelican's concerns.

 

[Pelican]

Hi, When time comes to service and drain and refill coolant, one should refill with the coolant concentrate, mixed with distilled water and NOT the dilluted 50/50 mix? I have read that the 50/50 coolant should ONLY be used for top offs. Is this true?? Or is that theory car specific? I own a 2017 Hyundai Elantra SE 2.0 engine and I am at 42,000 miles.
Also, can I trust a well respected independent shop to properly do a coolant drain and refill, or is the dealer the better choice?
Just wondering. Thanks

You can and indeed should use a 50/50 mix as the water part is distilled and therefore void of impurities.
Any good independent shop can do it, some have a machine to do this which makes it mess free.

 

[Pelican]

Approximately 1/2 of your coolant is in the radiator and 1/2 in the engine block, give or take a bit. If you completely flush out your system with water, about 1/2 of the total capacity will remain plain water in the engine block. If you add 50/50 to the radiator, it will be diluted by the water left over in the engine block. That is the only reason you cannot use 50/50 after a complete flush with water. After a complete flush, you add the correct amount of concentrate to the radiator (1/2 the total system) and finish off with water to get a complete fill.

He doesn't have ANY plain water as this is still the original fill which is done with distilled water.

 

[JustinH]

Any shop with a vacuum fill system can change your coolant in quick order. Check the book but 42k may be too soon to do anything with the coolant on a Hyundai. My local shop charges $49 to flush and vacuum fill with prestone premix, or $39 if you bring your own coolant.

 

[JHZR2]

I don’t know where the concept that 50/50 is only for top ups comes from...

I can get some ambiguity if someone has done some pure water flushing, but that’s why they have those little meters.

I just make my own 50/50 with distilled, and it’s great. Plus I have more jugs to return used coolant in.

 

[samven]

There is no difference between store bought 50/50 or self-mixed 50/50 concentrate and water if you use distilled or deionized water,(no need to nit-pic about the purity of distilled water).

Approximately 1/2 of your coolant is in the radiator and 1/2 in the engine block, give or take a bit. If you completely flush out your system with water, about 1/2 of the total capacity will remain plain water in the engine block. If you add 50/50 to the radiator after a complete flush, it will be diluted by the water left over in the engine block. That is the only reason you cannot use 50/50 after a complete flush with water. After a complete flush, you add the correct amount of concentrate to the radiator (1/2 the total system) and finish off with water to get a complete fill.

I don't like to mix different coolants. For me, a drain and fill of just the radiator (1/2 the system) is fine IF you replace it with the exact same coolant. If you cannot determine/purchase the OEM coolant and choose something different, then I prefer to do a 100% flush and start new with whatever coolant you choose. Hyundai/Kia seem to be a bit vague in their coolant identifications. Others here are not as hesitant to mix coolant brands or types.

You will have to visit the shops your are considering and ask how they do the fluid change. Even dealers often use non-oem fluids (BG comes to mind).

Edited to answer Pelican's concerns.

This if you do a complete flush and fill as stated. 50/50 is ok if just doing the radiator and if you have a leak but be careful. If the water has evaporated from time or overheat but not boil over only the water has left and you only need to add water although this is much less likely with modern cars and pressurized overflow. The best thing to do is check with a hydrometer before adding anything.

 

[Oro_O]

Modern coolants have very long lives on the initial fill. Hyundai, like Toyota, etc. recommend 120k miles on the factory fill (then 1/2 that on subsequent fills). I am very pro-maintenance and certainly don't abide by all recommendations (like ps and AT change intervals - way too long), but this is one that is reasonable. I wouldn't consider messing with the fluid in a 2017 at 42k miles for a long while.

 

[Gebo]

While miles are an important factor in changing coolant, time is more important. That coolant is "breaking down"
all the time. Not just when the engine is running.

When does Hyundai recommend changing based on time? I would use the 50:50 mix if I were having someone else do the
change. OR...I would have my coolant premixed in 2 or 3 gallon jugs before hand. I would not trust anyone to mix it properly
in using distilled water or the correct mixing ratio of 50:50.

 

[flinter]

Gebo,
The owner's manual say to change at 60K.

 

[AutoMechanic]

I have never heard that theory before I’m sure it has been said though. Personally I always buy the concentrate and mix my own because it cost the same price as the 50/50 so I feel I would be wasting money on the 50/50 paying for half a gallon of water and half of coolant.

 

[mk378]

On a pure drain and refill without the complication of flushing with water, premix the replacement coolant. Either buy premixed or mix it yourself outside the car, the result is identical.

 

[R18Civic]

Do a 50/50 mix. I used straight coolant when I did my head gaskets and overdid the coolant to water ratio.

 

[Oro_O]

Gebo,
The owner's manual say to change at 60K.

The website says 120k, and that's for normal AND severe service. You can check here:

Hyundai Recommended Maintenance Schedules

Hyundai Motor America provides the Maintenance Menu for all 2000 and later model year vehicles.

www.hyundaiusa.com

It would be very odd if Hyundai were still installing a 60k mile coolant 15 years after other major manufacturers improved their chemistry...

 

[DGXR]

I just do a drain & fill on the the engine block and radiator at the recommended intervals. Keeps the system clean, no flushing required, always use the same ratio coolant (bought 50/50 or mixed water with concentrate).

 

[Gebo]

Gebo,
The owner's manual say to change at 60K.

what about time?

 

[doitmyself]

what about time?

Oro is correct. The owners manual states 120,000 miles or 8 - 10 years: https://owners.hyundaiusa.com/conte...nual/2017/elantra/2017_Hyundai_Elantra_OM.pdf ....page 7-18

I think flinter just sent us out on a snipe hunt (Google it), LOL. In Indiana corn country the "snipe" hunt involved setting a person on one end of a 100 acre corn field and asking them to wait while the remaining gang drove the "snipes" towards him. The gang then went back to the shed to finish the Euchre game, leaving the poor soul sitting forever at the field waiting for imaginary snipes.

flinter, even by BITOG standards, you have to at least go to 1/2 of the change interval . I imagine most here would say that even going to 3/4 of the interval is acceptable!