Ultimate Cooling System Flush (Vinegar)?

jaymar

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So, came across this excellent thread from @NLXTACY on the 60 forum, and am wondering about the applicability / advisability of doing this on an 80, and how (other than vinegar gallon-count) the process might differ with an FZ.


My particular issue as that the radiator seemed to be running rust-colored mud when I bought the rig. I flushed, refilled and drove around 12x in a row. (Samples of first and last flush below--and, mind you, the liquid in those bottles has had several years to settle.) New hoses, water pump, rad cap and off I went. Some time later, the radiator sprang a leak near the top. Been topping off every few days. Got tired of doing that with Amsoil coolant and started using distilled water. (I know.) So, now things have regressed to what you see in the other photo. (Still waaay better than it was originally, believe it or not.)

Gotta finally do front main seal and oil pump cover, so gonna put in a pricey new rad that's been hanging around the garage while I'm at it. I need to get the system as pristine as possible before dropping in the new rad. And I thought @NLXTACY's method might just be the ticket. Not sure whether that means changing all the hoses again, too.

Thoughts on this?

IMG_0652.jpg

IMG_0602.jpg
 
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Vinegar is a mild acid. I've used it in other vehicles, have contemplated using it in the 80 for basically the same reasons as you.
I just haven't managed to fit it in with other work yet.
I don't see any reason not to do it.
I wouldn't be worrying about changing hoses if they are in good condition
 
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so long story short, i screwed up bad when i did my head gasket and managed to put my fuel return line on the line where coolant line is around the intake. well i managed to put gasoline in the coolant, and then fixed the problem, and had no idea i got gas in the coolant passages and RAD, i drove an hour and got to a buddies house and found out there was still gas in there, enough that we lit the fumes coming out of the RAD, so i don't think vinegar will hurt, ahahahahahah . i have since flushed my coolant system many times over to get all the gas out.
 
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I started from a similar place with my 80 and ran vinegar for a day or so in my 80 with no ill effects in the following 4 or 5 years to date.

I first flushed with the water hose into every hose/port that I could access to get most of the "chunks" out of the system. That included opening the block drain and pushing water into the heater cores in both directions, etc. I also removed the tstat for this and the following flushing though I reinstalled it for the vinegar run to help get things up to temp.

When I ran vinegar (white vinegar from grocery) I topped the system off with distilled water so ended up with 75% vinegar in the system roughly. I left the vinegar in the system for about 24 hours and ran/heat cycled it few times with the vinegar in the system. This included bleeding the air out of the system and running both heaters enough to ensure that they were cleaned as well.

After the vinegar I flushed with the water hose again into heaters, rad lines, etc. to try to get the acid and chunks all out. I may have done a brief run on tap water and baking soda to neutralize any remaining acid, but I don't recall exactly what I did. Since I flush with tap water I finish the process by connecting a shop vac set to blow and I blow the tap water out of the system to minimize deposits. You can put the shop vac outlet into different radiator hoses/inlets and leave it for a few minutes until no more spray comes out, etc.

I then filled with distilled and ran for a few days, followed by a drain and another shopvac blow out to remove the distilled water and was then pretty clean and ready for the refill.

Since all of that flushing 4 or so years ago I now dump and refill just my rad annually with 50/50 by disconnecting the lower rad hose (since this is easy). I also clean the overflow bottle and rad cap valve at the same time. There's still a light dusting of rust/red build up in the overflow every year but it's better every time I clean it out and the rad cap valve/seal stays pretty clean with no clogging at this point.

I've been considering one more vinegar flush in the next year or two as I assume that there are deposits that have built up over time in the engine but I may skip it and just continue my annual clean-outs since the system seems to put at least some, if not most, of the gunk that makes it into suspension in the coolant in the overflow tank over time.
 
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NLXTACY

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so long story short, i screwed up bad when i did my head gasket and managed to put my fuel return line on the line where coolant line is around the intake. well i managed to put gasoline in the coolant, and then fixed the problem, and had no idea i got gas in the coolant passages and RAD, i drove an hour and got to a buddies house and found out there was still gas in there, enough that we lit the fumes coming out of the RAD, so i don't think vinegar will hurt, ahahahahahah . i have since flushed my coolant system many times over to get all the gas out.
Oh man I remember that.
 
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AFAIK Prestone and other similar bottled cooling system cleaners are weak Citric Acid, Vinegar is weak Acetic Acid. IMHO the advantage of the bottled cooling system cleaners is that the concentration and time (that you leave it in for) has been calculated. Either acid if left in too long or too strong a concentration might cause damage to the radiator or heater core.
 

jaymar

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AFAIK Prestone and other similar bottled cooling system cleaners are weak Citric Acid, Vinegar is weak Acetic Acid. IMHO the advantage of the bottled cooling system cleaners is that the concentration and time (that you leave it in for) has been calculated. Either acid if left in too long or too strong a concentration might cause damage to the radiator or heater core.
Don't care about radiator damage as it's already shot and going bye-bye. Heater core another matter, thanks for the tip. But how long is too long?
 
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How strong the mixture and how long it's in there are obviously related factors here. Cleaning cooling systems with vinegar is widely used so general Google searches will turn up tons of reading on the subject. Some folks recommend 1 quart plus water for the whole system, others 1 gallon and distilled water for the whole system, 50/50 vinegar to distilled, 100% vinegar, etc. I used to run it straight in systems with no aluminum (salt water cooled sailboat engines) but mix with distilled and don't leave it in as long when there is AL in the system.

I'd say that if you are in doubt that you can start with a mild approach and inspect/repeat based on how clean things get. You can remove the tstat housing easily enough for instance to see how clean things are there before/after the vinegar treatment and you may do this to aid your post clean flushes anyway. The inside of hoses, etc. all can help you get a sense for how effective your efforts are. Vinegar and distilled water are cheap so worst case is you have to do this two or three times before you get the mixture strong enough and/or the time long enough to do what you want without AL damage. Further you can run your own tests by dropping some AL pieces in the vinegar you plan to use to gauge how aggressive it is. Not all vinegar is the same acidity anyway so there aren't going to be perfect 1 size fits all prescriptions here.
 

jaymar

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How strong the mixture and how long it's in there are obviously related factors here. Cleaning cooling systems with vinegar is widely used so general Google searches will turn up tons of reading on the subject. Some folks recommend 1 quart plus water for the whole system, others 1 gallon and distilled water for the whole system, 50/50 vinegar to distilled, 100% vinegar, etc. I used to run it straight in systems with no aluminum (salt water cooled sailboat engines) but mix with distilled and don't leave it in as long when there is AL in the system.

I'd say that if you are in doubt that you can start with a mild approach and inspect/repeat based on how clean things get. You can remove the tstat housing easily enough for instance to see how clean things are there before/after the vinegar treatment and you may do this to aid your post clean flushes anyway. The inside of hoses, etc. all can help you get a sense for how effective your efforts are. Vinegar and distilled water are cheap so worst case is you have to do this two or three times before you get the mixture strong enough and/or the time long enough to do what you want without AL damage. Further you can run your own tests by dropping some AL pieces in the vinegar you plan to use to gauge how aggressive it is. Not all vinegar is the same acidity anyway so there aren't going to be perfect 1 size fits all prescriptions here.
One more reason to hate on aluminum.
 
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Again, as everyone gets "anal" about flushing their cooling system and getting out every last bit of color from the inside of a cast iron block that lives with liquid in it.......

Why? Flush it with distilled water and move on. As you use the acids, flushes, power whatever's, you WILL erode head gaskets, heads, blocks, core plugs (freeze plugs) and will likely CREATE new problems. Fix it until it's broke.

My 60 year old Studebaker engine had never been opened and rarely had the coolant changed (as in probably 4 times in 60 years). I pulled the engine to replace all the core plugs because we were prepping for a long distance trip. The coolant was LITERALLY held in by the grease and dirt packed into the outside of the core plugs. As soon as I removed the grease, the core plugs were leaking. When I pulled the block drain plug, the steel plug was eroded away on the inside so there was less than 1/3 of the original plug in there due to the electrolysis that took place inside that engine all those years.

I also removed 3 LBS of core sand from the inside of the water jacket of the block. How this engine ever ran cool, I'll never know.

I have since replaced the radiator, heater core, and all hoses. I have more cooling problems NOW, than I have ever had, and I have owned and driven this car for 40 years.

Just do regular coolant changes and don't worry about removing every last iota of debris and color from the system. Otherwise, you're going to create more problems.
 
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Hey @BILT4ME

Always enjoy and appreciate your posts here, thanks for the good info you bring!

I'll attempt to answer your "Why?" question. The quick answer is to make the 80 more reliable in situations where flushing isn't getting enough of the build-up out of the cooling system.

If you run an 80 with a lot of gunk in the coolant you are at risk of experiencing a handful of issues with the cooling and hvac/heat systems. With my 80 the main issue that I had, even after flushing was the valve on the rad cap repeatedly clogging up and preventing proper flow from the overflow tank as the engine temp cycled. I flushed/backflushed multiple times over a period of weeks and while the coolant was getting cleaner the clogging would resume over time and after heat cycles as more of the rust build up would break loose, start moving through the coolant and collecting in various points, notably in my case the rad cap. Running a mild acid solution for a brief period helped loosen up more of these contaminants and made the follow-up flushing more effective. Being able to stop doing the flushes was also welcome after so many of them. I've continued to see low levels of rust come out of the system in the years since but the cap clogging hasn't returned post vinegar so I think I did just enough cleaning in my 80s case.

Even though it's been a hassle and you've had issues with it I'll still say that you were better off cleaning the system on your Studebaker. Sounds like it was a very extreme case so not that relevant in comparison to most 80s but leaving that much gunk in the system would have put you at risk of debris becoming mobile and then causing clogs/hot-spots at various points in the system, most likely on a long trip or hard push too I'd guess. I assume we've both been doing this long enough to have encountered clogged rads, overheated engines, etc..

Of note, by the time I did the vinegar treatment on my 80 I'd already replaced the HG, resealed the oil cooler and done other work that gave me a good sense of what the inside of the cooling system looked like (not good unfortunately). I've done lots of flushes over the years and few vinegar/acid treatments and I agree that you can do more harm than good but every situation is different and based on @jaymar 's picture I think that some vinegar along with lots of flushing could make sense.
 
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Hey @BILT4ME

Always enjoy and appreciate your posts here, thanks for the good info you bring!

I'll attempt to answer your "Why?" question. The quick answer is to make the 80 more reliable in situations where flushing isn't getting enough of the build-up out of the cooling system.

If you run an 80 with a lot of gunk in the coolant you are at risk of experiencing a handful of issues with the cooling and hvac/heat systems. With my 80 the main issue that I had, even after flushing was the valve on the rad cap repeatedly clogging up and preventing proper flow from the overflow tank as the engine temp cycled. I flushed/backflushed multiple times over a period of weeks and while the coolant was getting cleaner the clogging would resume over time and after heat cycles as more of the rust build up would break loose, start moving through the coolant and collecting in various points, notably in my case the rad cap. Running a mild acid solution for a brief period helped loosen up more of these contaminants and made the follow-up flushing more effective. Being able to stop doing the flushes was also welcome after so many of them. I've continued to see low levels of rust come out of the system in the years since but the cap clogging hasn't returned post vinegar so I think I did just enough cleaning in my 80s case.

Even though it's been a hassle and you've had issues with it I'll still say that you were better off cleaning the system on your Studebaker. Sounds like it was a very extreme case so not that relevant in comparison to most 80s but leaving that much gunk in the system would have put you at risk of debris becoming mobile and then causing clogs/hot-spots at various points in the system, most likely on a long trip or hard push too I'd guess. I assume we've both been doing this long enough to have encountered clogged rads, overheated engines, etc..

Of note, by the time I did the vinegar treatment on my 80 I'd already replaced the HG, resealed the oil cooler and done other work that gave me a good sense of what the inside of the cooling system looked like (not good unfortunately). I've done lots of flushes over the years and few vinegar/acid treatments and I agree that you can do more harm than good but every situation is different and based on @jaymar 's picture I think that some vinegar along with lots of flushing could make sense.
Thanks for the understanding of "Why".

Some folks go a little overboard and go extreme. The fact that you've had multiple instances of the radiator cap clogging and other issues would be indicative of serious issues from the PO. (Bar's Leaks?)

I, too, had the brown sludge in my 80 when I got it. I did not flush it right away, as I should have, but drove it for almost 2 years as I made my list and gathered my parts.

What did it for me was my radiator exploding. I had a fan belt fail, lock up my water pump, temps spiked suddenly, the radiator cap did not relieve because it was gunked up, the radiator was old and brownish, so everything came together and it literally split the top tank one end to the other, right down the middle. Sounded like a tire blowing out.

I pulled the radiator and stuck a garden hose into every orifice on the engine, heater cores, both directions and flushed for hours.

After I got it all back together, I filled with distilled only, drove it for the day and drained, then refilled with distilled water. I did this six times one day after the next to get all of that out. I never used any acid or "flushing" chemicals because of the possibility of attack on the different metals.

After the last one, things were fairly clear, then I filled to a 50/50 mix of Toyota red.

The PO on my truck had the HG done about 45K miles prior to my ownership. The cooling system had a mix of Red and green coolant, thus the brown sludge. I was VERY concerned the I blew the HG when the radiator went, but I did compression tests, oil analysis, all kinds of stuff to prove it was OK. I have since put on 100K on it and while my coolant is not the "Fruit Punch Gatorade" it once was, it is definitely NOT the brown sludge of when I bought it.

People dump all kinds of crap into cooling systems and fuel tanks that don't belong there. It's very possible you had to do this because of your PO.

I get that.

It's the folks that don't know any better and go total OCD until you can eat off of the interior, when it doesn't NEED to be that way. Then turn around and dump in Bar's Leaks because they have a coolant leak somewhere.
 
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Echoing what Bilt4Me wrote, be careful if anyone decides to do any sort of flushing. If it's really gummed up you might not have a choice, or IME if really bad might be better to rip out the old radiator, hoses, etc. to avoid damaging the heater core; that's when the hard work comes if the heater core is plugged/leaking. I had to relearn this lesson last year; the only thing that was stopping the leaks were the multiple bottles of sealer the PO had added (but didn't reveal during the sale). Turned out to have a cracked block and likely leaking HG so it would've revealed itself sooner or later.
 
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@BILT4ME Yeah, there's no telling what was in my 80s cooling system when I got it. It seemed like a finely crafted mix of green/red sludge, corrosion and also residues from stop-leaks, etc. I did the HG as PM but if you had seen the coolant passages you may have too :) My 80 had a new rad. when I got it which, while nice was a red flag for me to really go through the cooling system. If I had driven it I'm sure I'd have had adventure like you did.

It's a fine line between doing necessary service and going overboard and this forum definitely encourages going overboard. Good to understand what you are up to before you put anything into your cooling system!
 

jaymar

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Reading the pros and cons--which both make sense--I find myself right back where I started: If it's good enough for Joey (and an even older 60), it's more than good enough for me...

Just one mitigating thought: Could be that on an older vehicle, the vinegar ate up a bunch of junk, but also left enough to hold things together--and an 80 won't have that buffer. But, probably overthinking here.
 
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Ha,ha. I’m guilty of filling my old radiator back in the days with carbonated water in a attempt to clean it.
 
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One thing, I’d maybe do like someone said above and do it incrementally so as to maybe gradually break stuff down? Idk, full strength all at once might plug something up that you wouldn’t want to plug up? I, also, am likely overthinking. 😂
 
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Citric acid works great and often starting with a quick soap flush to degrease will get best results. We use citric acid to flush heat exchangers regularly and do a post flush with something alkaline no neutralize.
 

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