Coolant: To flush or not?

[WarNose]

I just bought my first diesel, a 1993 F350. The radiator was very recently replaced by the previous owner. It has clean new green coolant in it that the owner claimed had the proper SCA's in it. I just got a hold of some Penway universal 3-way test strips that say they are supposed to test for glycol, nitrites, and extended life coolant. So the test strips showed zero reading for either nitrites or extended life coolant. It showed 50% glycol. Since the coolant and radiator both look so new, would you all still bother flushing the system or would you just add SCA's until the test strips show good? Thanks for the advice.

 

[franklin2]

If you are going to flush and put green back in, I say leave it. But there are all kinds of different coolants you could use if you wanted to spend the money and upgrade.

Look at all the different choices on the right side of this link.

http://www.valvoline.com/our-products/antifreeze-products

 

[SDEconVan]

You might want to check the heater circuit, and flush it separately both directions. If it flushes dirty, then I'd flush the block (along with the new stuff too.) Also, are your test strips fresh? They go bad pretty quickly if stored in the wrong place... ...just things to think about.

 

[madpogue]

If the anti-freeze is fairly fresh, AND if the PO used DISTILLED water, I would just add the SCA.

 

[PwrSmoke]

If the anti-freeze is fairly fresh, AND if the PO used DISTILLED water, I would just add the SCA.

Right on! Why waste good coolant. Just add the SCA and run for a normal interval.

 

[IDIoit]

how do you know if distilled water has been used, besides calcium deposits?
taste test?

 

[PwrSmoke]

Probably can't, not easily anyway, but the difference between tap water and distilled is not huge and, IMO, not worth dumping perfectly good coolant.

 

[FORDF250HDXLT]

not only do you not know if distilled water was used but you also don't know if low silicate green coolant was used.if he lied about using SCA's then he probably didn't even use the proper low silicate coolant either.
if you add SCA's to regular coolant not only will the SCA's not do their job,but they wont mix properly with the coolant and you'll clog up the system and the engine will run hot.then you'll just need to flush it anyway.

in summary;
when in doubt,flush it.then you'll know it's right.

i do however agree with above posters.don't waste it.save it and use it for your gas cars and trucks.

 

[madpogue]

Um, call the seller, ask him what anti-freeze he used, and if he used tap water.

 

[FORDF250HDXLT]

Um, call the seller, ask him what anti-freeze he used, and if he used tap water.

that's not a bad idea.........generally.however he now knows he can't trust the seller.he was caught in a lie:

It has clean new green coolant in it that the owner claimed had the proper SCA's in it.
So the test strips showed zero reading for either nitrites or extended life coolant.

so if you call him he could say; oh i used napa's house brand,low silicate green coolant.but then what? would you trust him now? i wouldn't after i dipped for SCA's and the strip read blank after he told me he used SCA's.
the only way your going to know now,is to flush it.consider it normal green coolant in there and move on.it will be a lot safer this way.
if you use it for a gas engine,the worse case will be it's mixed with tap water (not the end of the world) but wont matter if it's low silicate (because your gas engine- as long as it's not a high compression hot rod lol wont need sca's mixed in,so no worries).

 

[IDIoit]

FWIW.
i dont trust many people further than i can throw my 87 CCC SSB.
if this was my truck, id be dumping the existing coolant and installing some peak fleet charge.
along with an oil change and a SD filter.
some things are just better done right off the bat, and leave the guessing games to other people.
i also note the date and the mileage and right it down on a piece of paper, taping it to the inside of the glove box.

cant remember everything all of the time.

 

[WarNose]

Thanks for all the input. I didn't know that the coolant should be low silicate and I already put the SCA in it. Now that I saw FORDF250HDXLT's post I went back and took another look. The pink additive is definitely not mixing with the green coolant. It was spilling out while the truck was running and it is easy to see pink liquid drops separate from the green liquid drops. I went to four local shops in the area and none had low silicate coolant. So seeing how hard it is to find this stuff, I'm positive that the guy did not put the right stuff. I'm off to NAPA right now to check there. A flush is in order for this afternoon. Thanks again. I'm learning a lot.

 

[franklin2]

Thanks for all the input. I didn't know that the coolant should be low silicate and I already put the SCA in it. Now that I saw FORDF250HDXLT's post I went back and took another look. The pink additive is definitely not mixing with the green coolant. It was spilling out while the truck was running and it is easy to see pink liquid drops separate from the green liquid drops. I went to four local shops in the area and none had low silicate coolant. So seeing how hard it is to find this stuff, I'm positive that the guy did not put the right stuff. I'm off to NAPA right now to check there. A flush is in order for this afternoon. Thanks again. I'm learning a lot.

Do you know about the block drains on either side of the engine? They work great to get ALL the coolant out. And another tip someone had, when you are at the store, get a couple of those radiator petcocks and install them for the block drains. Get the ones with the little spot for a hose so you can save all the coolant. If you go for some of that expensive permanent coolant(Napa carries that Zerex stuff) you will want to save it and any other chemicals you put in it and be able to pour it back in. I wish I had done that when I was working on the oil cooler, what a mess with the regular plug the factory uses. I use that GO5 coolant and I didn't want to have to buy a bunch of that again though it's not too expensive.