Coolant Flushing Question

[kschachn]

How do you flush out all the old coolant when the new stuff is pre-mixed? I have a 1996 Honda Accord I recently acquired for my daughter, and I'm pretty sure the coolant in there now isn't the Honda blue and I want to replace it.

In the old days with the coolant concentrate you could drain all the existing fluid and then do some plain (or distilled) water flushes. Then after draining out as much of the plain water as possible, you could add enough concentrate to achieve the proper concentration mixture. This way you got rid of all the old fluid and ended up with just the new stuff.

With the pre-mixed stuff though (Honda Type 2) the only thing I could do is use the new stuff to maybe do one or two flushes.

Any suggestions?

 

[VK56VD]

Do 4-5 flushes with distilled water to get rid of the old fluid so there are no compatibility issues between two different chemistry formulations.

If possible, buy the Genuine Honda stuff that is not pre-mixed.

I assume if the stuff is pre-mixed, you'd want the highest concentration of the pre-mixed stuff in the system versus the concentration of distilled water.

 

[Papa Bear]

Use concentrate, not pre-mixed.

 

[kschachn]

Originally Posted By: Papa Bear
Use concentrate, not pre-mixed.


I would, if it were available. It isn't. Only Honda Type 2 is now sold.

 

[VK56VD]

I'd buy 2 of these containers then. After flushing the cooling system with distilled water 5 times, I'd fill it with the pre-mixed stuff, drive around a few days, than drain and refill again with the pre-mixed stuff.

 

[kschachn]

Yeah, that is what I think I am going to do. I picked up four gallons at the Honda dealer over lunch ($60!) and I'll work on it this weekend.

Originally Posted By: Spartuss
I'd buy 2 of these containers then. After flushing the cooling system with distilled water 5 times, I'd fill it with the pre-mixed stuff, drive around a few days, than drain and refill again with the pre-mixed stuff.

 

[kschachn]

One last thought, what about installing one of those flushing tees in the heater hose? That would help to make sure all the old coolant was out.

The thing about those is that you can add coolant to the radiator and watch for it to come out of the tee - making sure that at least most of the water is gone.

You don't actually have to install the tee permanently, you can make a "cheater" heater hose (with the tee) that you only use for flushing. That's what I did years ago when I had one of those things.

 

[mechtech2]

Unless there is a problem, forget the flush.
Drain and refill.

 

[VK56VD]

The tee will help. Worst case scenario, refill with distilled water close the cap, let the car run and drain it out again, over and over, until clean water only comes out. Put the temperature on hot as well.

 

[Patman]

Originally Posted By: mechtech2
Unless there is a problem, forget the flush.
Drain and refill.


I agree, if you drain and refill the rad once a year there should never be a need to do a full flush. If you've left the coolant change for a long time, you can always do 2 or three "drain and refills" of the rad, spread out over a few weekends.

 

[Smoky14]

Most all Honda's have a block drain, not always convenient to get at but it's there. You will get approx 95%+ of the old stuff out.
I think it's a total rip off that they don't sell the concentrate

 

[kschachn]

I just got this car for my daughter. The previous owner had very good maintenance records but they only state when the coolant was changed. Unlike his oil change records it doesn't say what type of fluid was used. In any case, it's rather dark looking and I want to get as much of it out as possible.

Originally Posted By: Patman
Originally Posted By: mechtech2
Unless there is a problem, forget the flush.
Drain and refill.


I agree, if you drain and refill the rad once a year there should never be a need to do a full flush. If you've left the coolant change for a long time, you can always do 2 or three "drain and refills" of the rad, spread out over a few weekends.

 

[kschachn]

Yeah, I know where that drain is located. It is inconveniently located near the inconveniently located oil filter, rather high up on the back side of the block (access to which is blocked quite well by the driveshaft). What makes it more inconvenient is that my ramps are too high to fit under the front air dam, and there aren't any strong looking (at least to me) points to rest on jack stands. Also, once you do get it up in the air the only way to shimmy under the car is from the front, so you're looking straight up at the oil filter and coolant drain plug. Either one wants to drain directly into your face when opened.

Originally Posted By: Smoky14
Most all Honda's have a block drain, not always convenient to get at but it's there. You will get approx 95%+ of the old stuff out.
I think it's a total rip off that they don't sell the concentrate

 

[Cory]

Originally Posted By: kschachn
What makes it more inconvenient is that my ramps are too high to fit under the front air dam,


Just extend your ramps with some 2x4s. I do exactly this with each of our 300Ms.

 

[rationull]

Originally Posted By: kschachn
... there aren't any strong looking (at least to me) points to rest on jack stands.


Don't know about that particular car, but the recommended stand placement points on my Civic are the spare tire jacking points next to the wheel wells. Would that work on this Accord?

 

[kschachn]

Duh, good idea. I don't have that problem with my other two cars and I've never had to deal with it before. I almost went out and bought new ramps, what a dope.

Thanks.

Originally Posted By: Cory
Originally Posted By: kschachn
What makes it more inconvenient is that my ramps are too high to fit under the front air dam,


Just extend your ramps with some 2x4s. I do exactly this with each of our 300Ms.

 

[kschachn]

I don't know, I will go look. The FSM for my two Toyotas has a nice placement diagram, but I couldn't find it in the Honda manual. I'll check it out. Thanks.

Originally Posted By: rationull
Originally Posted By: kschachn
... there aren't any strong looking (at least to me) points to rest on jack stands.


Don't know about that particular car, but the recommended stand placement points on my Civic are the spare tire jacking points next to the wheel wells. Would that work on this Accord?