12-71 coolant change details

I am planning to do the coolant change on our 81 12V-71 TA Detroit's soon.

Here is where I am at so far:

• I have found a local source for the Detroit coolant.
• I have also found 5gal containers and lids. The store is uline.com if you are looking for cheap pails!
• I found a local disposal place that can take up to 50 gallons per day.
• I also know each engine will be around ~25 gallons of coolant each.

One thing I am unclear on is the exact drain locations for the coolant. Our local mechanic has mentioned there are a handful and I wanted to reach out and see if anyone has a good handle on that so I can know right off the bat how to do it.

Thanks for the help as usual!

Front of engine above main pulley. HE or HE piping. Oil cooler. Water jackets (2). Rear block (2); one is over and above the starter so protect it. I counted 7.

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Originally Posted by racclarkson@gmail.com

Front of engine above main pulley. HE or HE piping. Oil cooler. Water jackets (2). Rear block (2); one is over and above the starter so protect it. I counted 7.

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Thanks Robert. Did you just drop each drain into to the pan and scavenge it from there? I was thinking about trying that after using a transfer pump to empty the heat exchanger reservoir as best as possible.

The drains have petcocks on them so you don't need to drop them into the bilge. My recommendation
would be to drain the old coolant and replace all the petcocks with new units that incorporate a small
hose barb that you can attach a length of hose for future easy clean coolant changes. It seems that
no matter how careful you are there will still be some spilled coolant with the original petcocks.

Walt

While its out pipe a drain in it like Robert did. I wish I had seen his pictures before I recently changed mine. I will do this next time. I would get a couple of spare petcocks too in case one of them is frozen and needs replacing.

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Originally Posted by MVCaprice

Thanks Robert. Did you just drop each drain into to the pan and scavenge it from there? I was thinking about trying that after using a transfer pump to empty the heat exchanger reservoir as best as possible.

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Do oil cooler first, then HE. You’ll get majority from there.

Is it worth pulling the heat exchangers and getting them cleaned at that time as well? Seems like it would be easy enough to do. Anything else that would make sense while the coolant is out?

Where are you located? I'm down in Florida and i used Napacool, available at napa and distilled water. Of course we don't really face many freezing conditions so it may not work for you?

EDIT: I have 8v-92's, may not be the same recommendations for 71's

Quote:

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Originally Posted by MVCaprice

Is it worth pulling the heat exchangers and getting them cleaned at that time as well? Seems like it would be easy enough to do. Anything else that would make sense while the coolant is out?

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It's be a good time. If not, you can clean the entire raw water system in place at a later date.

Only flush and fill with distilled water, PH too high in tap water. Get lots of cases of distilled water.

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Originally Posted by rustybucket

Where are you located? I'm down in Florida and i used Napacool, available at napa and distilled water. Of course we don't really face many freezing conditions so it may not work for you?

EDIT: I have 8v-92's, may not be the same recommendations for 71's

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I'm in Seattle. I have read that the Detroit coolant is better for our engines. I have also found over time on some of my other projects that the zerex/napa etc auto coolant is pretty low grade when compared with Delo ELC / Cat/ Detroit marine /industrial grade coolants.

Quote:

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Originally Posted by MVCaprice

I'm in Seattle. I have read that the Detroit coolant is better for our engines. I have also found over time on some of my other projects that the zerex/napa etc auto coolant is pretty low grade when compared with Delo ELC / Cat/ Detroit marine /industrial grade coolants.

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You can buy DD Power Cool in 50/50 premix. Shouldn't pay more than $8.50 gal. Last I bought was $5.45/gal.

Quote:

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Originally Posted by racclarkson@gmail.com

You can buy DD Power Cool in 50/50 premix. Shouldn't pay more than $8.50 gal. Last I bought was $5.45/gal.

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Pacific Power Group up here wants the following for their powercool:

10.56 per gallon concentrate
premix 7.19 per gallon

Typical!

In my search for good prices on powercool i came across this DD press release showing they they make 3 different versions of powercool:

http://www.prweb.com/releases/2004/11/prweb175673.htm

Are you folks using the off highway or the marine version? Seems like with most being in florida/southern us the marine may be the right route. I may be able to get away with that as well.

Quote:

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Originally Posted by MVCaprice

I'm in Seattle. I have read that the Detroit coolant is better for our engines. I have also found over time on some of my other projects that the zerex/napa etc auto coolant is pretty low grade when compared with Delo ELC / Cat/ Detroit marine /industrial grade coolants.

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Actually the Napacool is not a coolant per se, it's an additive package that is added directly to distilled water. It is a fleet additive package, not what I would call an auto grade.

Quote:

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Originally Posted by MVCaprice

In my search for good prices on powercool i came across this DD press release showing they they make 3 different versions of powercool:

http://www.prweb.com/releases/2004/11/prweb175673.htm

Are you folks using the off highway or the marine version? Seems like with most being in florida/southern us the marine may be the right route. I may be able to get away with that as well.

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I use standard Power Cool. One source carries pre-mix only, another branch carries concentrate only. I prefer the pre-mix, but I can easily see going to a lower concentration around here as a more efficient cooling mix. Here are the 2-cycle specs from DDC:

https://brandon314.files.wordpress.c...selections.pdf

I think the marine stuff you linked to is spec'd for MTU motors. Haven't bothered to check it out, but if it says "MTU" or "marine" get out the wallet.

Detroit now also has a coolant with a cleaning agent in it. My Detroit tech up north put it in my Bertram last fall as when I purchased it, the coolent was filthy in one of the engines. I had both done just to start fresh. He said you can only use it up north in heated storage as it’s freeze point isn’t as low as the normal Detroit coolant. Just an FYI.

I am just about ready to go on this.

Attachment 24826Attachment 24827

Should be good times!

I just changed the coolant in my 12v71. Seams like it is never going to stop draining. You may want to replace your hoses and clamps at this time. Since it is all drained down. Also take off the fuel cooler and remove the heat exhanger and perform the DD recommend procedures. All though the wood bleach is getting hard to find. I have TA engines. The exhaust elbows always seam to clogged the most.

I agree the hoses are easy to swap at this time and great insurance. I'm going to do the water pumps 2.5" , 3" & 3.5" hoses in the area at this time. I am also replacing the overflow lines which are super old with clear silicone (which should be easy to see any coolant in and i have a handful of gaskets to get the heat exchanger work done. I dug into my service manual and took a pic to share of the DD recommended cleaning procedure:

Attachment 24856

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Originally Posted by VIKING63

I just changed the coolant in my 12v71. Seams like it is never going to stop draining. You may want to replace your hoses and clamps at this time. Since it is all drained down. Also take off the fuel cooler and remove the heat exhanger and perform the DD recommend procedures. All though the wood bleach is getting hard to find. I have TA engines. The exhaust elbows always seam to clogged the most.

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So far i have found 5 drains. Two on the back part of the block underneath the exhaust manifolds which looks to be at the lowest point. One on each of the bottom back of the exhaust manifolds (salt water???) and one at the bottom of the expansion tank to water pump hard line. What am i missing? Any where else to expect a drain?

Quote:

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Originally Posted by MVCaprice

So far i have found 5 drains. Two on the back part of the block underneath the exhaust manifolds which looks to be at the lowest point. One on each of the bottom back of the exhaust manifolds (salt water???) and one at the bottom of the expansion tank to water pump hard line. What am i missing? Any where else to expect a drain?

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Front of block above main pulley opposite side from water pump and bottom of oil cooler. Always possible someone replaced drain cock with a plug. The manifold drains are coolant. No salt water there.

Quote:

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Originally Posted by racclarkson@gmail.com

Front of block above main pulley opposite side from water pump and bottom of oil cooler. Always possible someone replaced drain cock with a plug. The manifold drains are coolant. No salt water there.

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Thanks Robert! The seven drain magic number I have been looking for.

I actually found there are 8 drains. There was an additional drain at the bottom of the transmission / oil cooler unit. A couple of the drain cocks were failing so i bought replacements. I am also doing hoses at this time as some of them looked horrible.

I decided that i wanted to pull, inspect and clean the HE while i was in there. Here is what they look like:

Attachment 24930Attachment 24931

Also, When you folks have reinstalled the HE (after cleaning) do you apply the gaskets dry or do you use a gasket tack material or sealant in addition to the paper gaskets? My gut is to use a gasket tack material, but I wanted to ask and see what has been working for folks before I throw them back in a week or two.

Quote:

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Originally Posted by racclarkson@gmail.com

Front of engine above main pulley. HE or HE piping. Oil cooler. Water jackets (2). Rear block (2); one is over and above the starter so protect it. I counted 7.

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I covered that when I answered you originally and mentioned oil cooler drain. I think I posted again showing a ball valve I installed there (oil cooler). So where is #8???

Quote:

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Originally Posted by racclarkson@gmail.com

I covered that when I answered you originally and mentioned oil cooler drain. I think I posted again showing a ball valve I installed there (oil cooler). So where is #8???

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You may be right now that I think about it. :)

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Originally Posted by MVCaprice

You may be right now that I think about it. :)

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Then we both might be in trouble.

Any thoughts on the condition of the HE's? Common deposit level?

Well the HE's cleaned up good! I am thinking that i will use "high tack" along with the paper gaskets to seal her back up. Any suggestions?

Attachment 24976Attachment 24977Attachment 24978