I'm using the old conventional Prestone green coolant (ethylene glycol) in my 21- and 12-year old CRV and Kia Sportage. I know I'm supposed to replace the coolant every 3 years at most. The danger of this stuff is silicate dropout if left too long in the car. My question is: if I drain the radiator only and do not do a flush to get the coolant in the engine block out, and then refill only the radiator, will the old and new coolant work together and give a year or two of adequate protection? Or will the old coolant behave independently of the new coolant and still precipitate the silicate?
Mixing old and new conventional coolant in car
- Thread starter berniedd
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How old is this coolant your using? Prestone has not made a silicated green coolant in many years.
On my Santa Fe (Kia's parent company) I used conventional coolant and I just did a spill and fill on the radiator every 2 years regardless of miles (and I drive a lot), and never had an issue. It went to the scrap yard on it's original cooling system components (including water pump that is timing belt driven) at 300K miles.
For long life coolants I just spill/fill the radiator at 1/2 the allowable interval so that by the time I do the second spill/fill all the coolant in the system has been more or less changed out. No issues to report there either.
For long life coolants I just spill/fill the radiator at 1/2 the allowable interval so that by the time I do the second spill/fill all the coolant in the system has been more or less changed out. No issues to report there either.
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I just want to ease the concerns of the op regarding old coolants.
It is a custom in Eastern parts of Europe to drive your coolant until it starts looking like
your oil. Little to no issues with the average 20 year old car. I would not sweat it.
It is a custom in Eastern parts of Europe to drive your coolant until it starts looking like
your oil. Little to no issues with the average 20 year old car. I would not sweat it.
I had some old no-name house label green coolant I bought on sale at the super market for $2 per jug 20 years ago. I was all dust covered when I bough it. (bought all 10 jugs) My research said 2-3 years shelf life max. The silica had fallen out of solution, into a gel as of last year on the remaining 2 jugs. I shook it up and used in in my 19 year old Ford Explorer, no problems at all. I'm sure it was all mixed in once circulated in the cooling system.
Coolant is one of the most over-sold maintenance times in North America. I think new cars are now lifetime coolant filled?
Coolant is one of the most over-sold maintenance times in North America. I think new cars are now lifetime coolant filled?
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Originally Posted by Chris142
How old is this coolant your using? Prestone has not made a silicated green coolant in many years.
It is 4 years old.
How old is this coolant your using? Prestone has not made a silicated green coolant in many years.
It is 4 years old.
berniedd, your question seems to contain terminology mistakes ("old conventional Prestone green"). The common all-makes Prestone coolant at stores is a silicate free, OAT type of coolant. It is NOT conventional IAT silicated coolant.
If your vehicles already have Prestone type OAT coolant in them, then it should be o.k. to install the 4 year old product, assuming that it was stored in proper conditions.
In any other situation, you are taking a risk that the 4 year old Prestone coolant is not compatible with what is currently in your vehicles. In general, you do not want to mix different coolant chemistries: OAT, HOAT, IAT, etc..
Also FYI, even today's conventional IAT green coolants like Zerex Green are low silicate compared to products of yesteryear. I don't know that silicate fallout is a concern anymore, unless going way beyond the recommended interval.
If your vehicles already have Prestone type OAT coolant in them, then it should be o.k. to install the 4 year old product, assuming that it was stored in proper conditions.
In any other situation, you are taking a risk that the 4 year old Prestone coolant is not compatible with what is currently in your vehicles. In general, you do not want to mix different coolant chemistries: OAT, HOAT, IAT, etc..
Also FYI, even today's conventional IAT green coolants like Zerex Green are low silicate compared to products of yesteryear. I don't know that silicate fallout is a concern anymore, unless going way beyond the recommended interval.
I have conventional green coolant in my 1998 Expedition and I did what you want to do.I got 2.5 gallons out and uses Prestone universal yellow to replace.My green coolant was six years old and wanted to add some protection.I know it's not the best way but I couldn't see paying $150 either.Both are the same chemical make up so I'm safe with mixing.
Originally Posted by DrDanger
I just want to ease the concerns of the op regarding old coolants.
It is a custom in Eastern parts of Europe to drive your coolant until it starts looking like
your oil. Little to no issues with the average 20 year old car. I would not sweat it.
and no radiator or water pump failures?
I just want to ease the concerns of the op regarding old coolants.
It is a custom in Eastern parts of Europe to drive your coolant until it starts looking like
your oil. Little to no issues with the average 20 year old car. I would not sweat it.
and no radiator or water pump failures?
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