Winter & coolant system maint. time is coming, have a Q.

[Scali62]

{ DONT WORRY, NO GREEN STUFF OR ORANGE STUFF QUESTIONS !}

What I'm wondering is when you flush out the cooling system is it necessary to back flush the engine block?
When I do mine I drain the old antifreeze & then add the flush then top it off with water. I then run it for 10 minutes with the heater on then drain the radiator again. I repeat the process 3 times till I can see that clear water is running out the radiator's petcock.
Does this do the job as well as backflushing ?
{ I prefer not to backflush it because the alternator's going to get drenched }
Thanks in advance for any replys

 

[SPITMAN]

The proceedure depends upon how much crud there is in your cooling system. If you are starting with relativly scale free passagways and all you want to do is get the old antifreeze out and end up with clear water as the only residual remaining in your system then the process of 3x rinses will work OK.

If you have added a flush chemical to the first rinse then I would do a total of five rinses to make sure all is clear.

BTW, taking the thermostat out will lessen the rinse time down to a couple of minutes of engine running each cycle -- the rinse water will circulate throughout the system (including the rad)much quicker and you will not be dealing with "hot" water.

Remember to add a premeasured amount of 100% antifreeze equal to half of your cooling system's stated capacity and then top up the balance with water (and more antifreeze if you want a greater than 50% mix) to ensure you have the correct amount of antifreeze in your system -- never premix the antifreeze before adding it.

 

[Flashlightboy]

Spitman,

I fail to see the harm or error in premixing. It's actually easier and doesn't require a great deal of effort plus it also makes topping off later a quick chore.

Is there someting I'm missing?

 

[Scali62]

Wow, really good info. here, thanks.
I never thought of removing the stat & I can see how that would make the process go faster & work better. Thank you for the advice...

 

[Scali62]

I just wanted to chime back in here real quick to point out having a spare gasket handy would be a smart thing if going the remove the stat route ,
Alan

 

[labman]

quote:

---

Originally posted by Flashlightboy:
Spitman,

I fail to see the harm or error in premixing. It's actually easier and doesn't require a great deal of effort plus it also makes topping off later a quick chore.

Is there someting I'm missing?

---

That is OK, IF your system drains completely. I never have been able to add back the stated capacity of the system. The straight stuff is cheaper too. You pay for the convenience of the premix.


Right on the stat gasket too. I once had to walk 2 miles in the cold to where my wife had my truck when I mislaid the one i had for the car.

 

[Flashlightboy]

How do you ever know how much of the water is out? The way I figure, it's just like draining the oil.

I don't buy the premixed stuff but instead I mix it at 60% water. I'm not sure how much is left after blasting water through every orifice because a warm engine block would tend to evaporate the water.

If there is a little water left in the block how much water would I have? 61%? 62%? 63%? Who knows but I'm really not interested in freeze protection as I am better cooling. I don't think a couple percent one way or the other is overly significant.

 

[Drew99GT]

If you flush the system and do not drain the engine block as well as the radiator, you will still have 100% water sitting in the cooling passages of the engine. That's why you add only coolent then top off the rest with water.

 

[MarkC]

If you know your cooling system capacity, after you get the water to run clear, drain it until it stops. Measure what you have, and subtract it from the total capacity. That's how much water is left in your car. If your capacity is 12 quarts, and you get out 6, there's 6 left, so add 6 of coolant and you have 50%.

 

[Flashlightboy]

Gadzooks I'm getting attacked from all sides!

It's like getting pummelled with antifreeze but only in stereo.

I have been duly slapped and I now will retreat under my rock from whence I came...

 

[SPITMAN]

Full marks go to those who realize that there may still be some water trapped in the engine after a rinse -- that's why you always add a premeasured amount of 100% antifreeze.

 

[badnews]

quote:

---

Originally posted by Drew99GT:
If you flush the system and do not drain the engine block as well as the radiator, you will still have 100% water sitting in the cooling passages of the engine. That's why you add only coolent then top off the rest with water.

---

You nailed it on the head.

 

[cousincletus]

Here's what I do:
Drain the radiator (sometimes pulling the lower hose is the easiest way to do this).
Refill with 50/50 mix.
Do this every year and havn't had any problems yet. Have never replaced a radiator or heater core in anything I bought new yet using this procedure.
BTW, a radiator can corrode from the outside in. You should hose the road salt from the radiator and A/C condenser frequently.

 

[SHOZ]

When I refill mine after a water flush I will undo the hose near the Throttle Body or find the highest point in the cooling system, then add 60/40 antifreeze which will usually drive out the water from the loosened hose.

 

[Al]

I don't like the flushing thing unless you remove the engine drain plugs. If you don't then you have tap water in there.

What I do is drain and fill with maybe a 30% mix of antifreeze and water (distilled/deionized) I'll run it a day or two and then drain and fill with the antifreeeze and demineralized water.