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"Open heart surgery" for coolant change?

Joined
14 April 2002
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2,273
OK - I did this on my Honda Odyssey and not my NSX but was wondering why I shouldn't try this on our NSX.

Basically here is what happened. About 5 years ago I purchased a coolant change kit from an auto parts store. Basically the kit consists of:

- A funnel
- A collection tank
- A collection tube
- A hose "mender"
- 2 hose clamps

Basically you find the large radiator tube going into the top of the radiator. You cut through it (OMG!), you loosely put the hose clamps on. You then install and tighten the hose clamp to the funnel on the radiator side and tighten the collection tank on the engine side.

You then put some water in the funnel (I used hose but you would use distilled on your NSX) and run the engine. After about 10 minutes the thermostat kicks in and you have to keep running the water through till you have collected (neatly) all the old fluid and the water coming out is clear. You then fill up with antifreeze through the funnel (for me this was easy as the Honda fluid uses premixed distilled water so no 1/2 and 1/2. Eventually once you have reached capacity (again you notice the engine coolant coming out is green again) you quickly stop the engine, fill the overflow tank to 75%, insert the hose mender, tighten down the 2 hose clamps (the mender even has indents so the clamps are very secure), and you are done. Next year it is even easier as I can remove one side of the hose clamp and repeat.

So far not a single drip, no spill on the ground, easy to recycle the container of fluid, and aside the bear it was getting the plastic mender to go into the damn pipes (used a little soap water to help) - a piece of cake. Also - no bubbles (all of this is done at the highest point in the system).

So the questions are:

- why is this not more common (I did some research and they no longer sell the kit but on the other hand there are a lot of people that do this with marine engines for some reason)?

- why wouldn't one do this with the NSX considering what an environmental and otherwise PIA this is?

Any thoughts appreciated.
 
Sounds neat.. But a few notes:

1. NSX radiator is not the highest point of the coolant system in the car; it's actually in the engine bay near the bleed point.
2. I believe for marine engines, the risk of spilling coolant in the ocean/lake or near it has far greater implication than spilling on your concrete garage floor. Nemo wouldn't like it.
3. It probably takes 2-3 times more water to replace the coolant than the normal procedure; all of which have coolant mixed in it.

You should be glad you own Hondas. They take mechanics into consideration when they design their cars. Some other car companies (major ones), are impossible to service without tearing things all apart.

Eddy
 
I'm not a boat guy, but I know my brother's boat has a Mercruiser 350 (equivalent to a chevy 350) and doesn't use antifreeze. It has a system where it pulls the water from the bottom of the boat and uses that water to cool it. You will see guys running their boats on their driveway with a hose attached as a substitute for the river/ocean water.

As far as the procedure matteni described, most modern engines do not recommend tap water as you mentioned, so you would have to have a huge supple of distilled water to do that procedure.

I drained the coolant on my NSX and I found it a big PIA. I took me 20 minutes just to find the two drains for the engine block!
 
hlweyl said:
I'm not a boat guy, but I know my brother's boat has a Mercruiser 350 (equivalent to a chevy 350) and doesn't use antifreeze. It has a system where it pulls the water from the bottom of the boat and uses that water to cool it. You will see guys running their boats on their driveway with a hose attached as a substitute for the river/ocean water.

As far as the procedure matteni described, most modern engines do not recommend tap water as you mentioned, so you would have to have a huge supple of distilled water to do that procedure.

I drained the coolant on my NSX and I found it a big PIA. I took me 20 minutes just to find the two drains for the engine block!

Well - to clarify - the entire system on an Odyssey (per the shop manual) holds 10 L on a rebuild. So in reality you would only need 3 gallons of distilled water and 3 gallons of antifreez / distilled water mix if you didn't want any tap water to ever be in the system. Since the tap water was only in the system for a couple of minutes - I didn't see the harm in it (considering all the people who end up using tap water when away from home, emergencies, etc. Also - you are flushing all the tap water out immediately just like you are flushing out all the old antifreez.

I too have done the fluid on the NSX and unless you have access to a lift and the worlds biggest collection pan - it is a huge environmental mess and a major PITA. Even experianced folks end up with bubbles from time to time. With the new system now in place on the Odyssey - I can do the change every year VERY easily and collect/recycle 100% of the fluid. With the NSX I have to do it at night with the hose running under the car to wash all the antifreez down the drain without the neighbors scoffing at me!

:eek:
 
I can see your point Nick. I used the prestone kit before on one of my old cars and is so much easier than draining the block. What I was trying to say is that using those kits with a garden hose attached, even after you flush it you are still left with regular water in the block. So after you fill the radiator back up, the coolant mixes with the residual water left over from the flush.

Question for you though on your Odyssey, what are they recommending for you coolant change interval? From what I remember, the first coolant change interval on my 01' is something like 125000 miles.
 
I don't have the book here and I do know the 2002 recommends the first change after like 10 years but my 1999 recommends it after 60,000 miles for "severe conditions" (by memory - don't quote me on this).

Also - not saying there is no tap water still in the system but if you saw how dramatically it goes from completely clear (water) to coolent color you would think like I do that it is nearly all coolent at that point.

Also - the kit I used has no hose connection. Just a funnel. The hose connection ones flow the fluid the other way (I believe from a web article I saw on DIY network).
 
hlweyl said:
What I was trying to say is that using those kits with a garden hose attached, even after you flush it you are still left with regular water in the block. So after you fill the radiator back up, the coolant mixes with the residual water left over from the flush.

I re-read your question and I think I get it now. To answer your question - the Honda coolant comes pre-mixed with pure distilled water so you don't follow the "kit" instructions for leaving the water in and adding 1/2 of the pure coolant - like you normally would with Prestone or some other coolent that wasn't pre-mixed. IMO that is what makes this technique even better/easier when everything is pre-mixed with distilled water by Honda themselves.
 
matteni said:
To answer your question - the Honda coolant comes pre-mixed with pure distilled water....

As of the last time I bought Honda coolant you could buy it either way - straight or pre-mixed. Just a heads up for people to make sure they know which one they have (or which one to ask for) before they assume all Honda coolant is pre-mixed... unless Honda has changed to only selling pre-mixed in the last 12 or 18 months.
 
I beleive the pre-mix is specifically called "Type II". Also it is kind of pricey considering it is half water (good water though:)). I paid just a little less for a gallon of the premix then the regular, but you need twice as much.

HTH,
LarryB
 
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