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Patrick Francis
Experienced User
Username: jackpot

Post Number: 41
Registered: 11-2016
Posted on Friday, 17 March, 2017 - 04:40 am:   Edit PostDelete PostView Post/Check IP

Hi Guys,
I have just emptied, flushed and refilled my cooling system, replaced the thermostat and viscous coupling (intermittent failure) which went in quite easily without having to remove the radiator etc. I use inorganic antifreeze, just because I am wary of some of the stories I hear and it makes me flush more often. I made up one of David or Robert's (I think) flushing guns which worked a treat, thank you.
The question I have is:
I flush every couple of years and starting about 10 years ago, I noticed that there is serious corrosion on both the aluminium elbows, bolted to the engine, that attach the upper and lower radiator hoses. The top one of these holds the thermostat. Funny thing is that the corrosion is only on the lip of the elbows in both cases (appx where the jubilee clip fastens) but nowhere else. The rest of the elbow is good and strong, and the rest of the aluminium that I can see and have examined seems solid.
I thought it might be that there is a reaction with the atmosphere (oxygen) with a miniscule porosity between the hose and elbow? Not sure.
Has anyone else experienced this, or know a reason?
Thanks
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Patrick Ryan
Grand Master
Username: patrick_r

Post Number: 1258
Registered: 4-2016
Posted on Friday, 17 March, 2017 - 05:15 am:   Edit PostDelete PostView Post/Check IP

Hi Patrick.

Yes this is why you can not use normal everyday ethylene glycol based coolant in a non pressurised system.

My 25 Chev is one of these systems.
I have to use a special racing formula as the same type of coolant we use today, can not be used in race cars due to it damaging race track surfaces and causing major traction issues if blowed out all over the track during a race crash.

As you have experienced it becomes corrosive in these situations over time.

If you replace these parts, give them a coating of grease (the other gents here will have many suggestions about what type) to the joints before sliding the hose on.

I have even seen gasket cement, or silicon used for the same purpose on other cars.
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Jeff Young
Grand Master
Username: jeyjey

Post Number: 314
Registered: 10-2010
Posted on Friday, 17 March, 2017 - 05:18 am:   Edit PostDelete PostView Post/Check IP

If you get galvanic action, it will erode the least noble element (the aluminium in this case) nearest the conductor (the water in this case). But that should mean the metal inside the lip, not outside.

I'm not sure what's causing what you're seeing.

Cheers,
Jeff.
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Patrick Francis
Experienced User
Username: jackpot

Post Number: 43
Registered: 11-2016
Posted on Friday, 17 March, 2017 - 07:30 am:   Edit PostDelete PostView Post/Check IP

Do I understand that the galvanic action is between the aluminium and the steel of the jubilee clip through a slightly porous or leaky hose to elbow seal ?
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Patrick Ryan
Grand Master
Username: patrick_r

Post Number: 1261
Registered: 4-2016
Posted on Friday, 17 March, 2017 - 08:52 am:   Edit PostDelete PostView Post/Check IP

Gents,

The Nulon guy explained it to me that it is the external parts that are in contact with the atmosphere that will corrode more on pressurised systems.

Am I right in reading Patrick, that the internals of the elbow is fine?
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David Gore
Moderator
Username: david_gore

Post Number: 2480
Registered: 4-2003
Posted on Friday, 17 March, 2017 - 09:04 am:   Edit PostDelete PostView Post/Check IP

Patrick,

Aluminium relies on protective oxidation of the base metal for corrosion resistance however it is prone to attack by alkaline solutions.

In your case, I suspect the cause of your problem may be differential aeration of fluid trapped adjacent to or underneath the jubilee clip accelerated by breakdown of the antifreeze resulting from the lack of aeration.

As mention elsewhere on this forum, I have found Molykote 111 Valve and O ring lubricant gives excellent results in facilitating later removal of hoses as well as providing corrosion protection of metal surfaces underneath the hoses.

http://www.dowcorning.com/content/news/iam_news32.asp

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwiLxofKjdzSAhVHF5QKHSIDCR4QFgg5MAE&url=https%3A%2F%2Fwww.revolutionindustrial.com.au%2Fmolykote-111-silicone-compound-valve-o-ring-lubric&usg=AFQjCNERE7c4ULxbTobXuHAy5cTdxQmlwg

*
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Jeff Young
Grand Master
Username: jeyjey

Post Number: 315
Registered: 10-2010
Posted on Friday, 17 March, 2017 - 09:35 am:   Edit PostDelete PostView Post/Check IP

I agree with David. I don't think this is galvanic (at least not in the normal sense).

Even if you flush the coolant, that won't necessarily change the small bit trapped between the hose and the pipe. That and the fact that it's exposed to more oxygen means it's eventually going to turn acidic.

I imagine the lubricants David suggests will solve this.

Cheers,
Jeff.
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Patrick Ryan
Grand Master
Username: patrick_r

Post Number: 1262
Registered: 4-2016
Posted on Friday, 17 March, 2017 - 11:05 am:   Edit PostDelete PostView Post/Check IP

Agreed.

I just couldn't get it out as good as David & Jeff.
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Patrick Francis
Experienced User
Username: jackpot

Post Number: 44
Registered: 11-2016
Posted on Friday, 17 March, 2017 - 05:25 pm:   Edit PostDelete PostView Post/Check IP

Patrick - yes, the internals are fine.
Thank you all , it has been an interessting lesson!
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John Beech
Prolific User
Username: jbeech

Post Number: 243
Registered: 10-2016
Posted on Saturday, 18 March, 2017 - 05:48 am:   Edit PostDelete PostView Post/Check IP

Flushing gun? Huh? Tell me more, please, because I am due to flush Tootsie soon.

As for the antifreeze, Patrick, in short words please explain what we should be using in the Shadow because your mention of what you do for your '25 Chevy threw me. E.g. for Tootsie, I presume I should be buying the usual green stuff I get from Autozone and subsequently mix 50:50 with water, right? The Shadow is, of course, a pressurized system so
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Christian S. Hansen
Grand Master
Username: enquiring_mind

Post Number: 542
Registered: 4-2015
Posted on Saturday, 18 March, 2017 - 06:23 am:   Edit PostDelete PostView Post/Check IP

Patrick R...
I second John B. How can the presence or absence of a pressurized system have any affect on the type of antifreeze/corrosion inhibitor used? Pressurization is simply to allow the coolant to run at a hotter temperature without boiling and subsequent loss. Please clarify. Thanks.

Ditto on the info for "flushing gun".

.
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1136
Registered: 9-2004
Posted on Saturday, 18 March, 2017 - 07:10 am:   Edit PostDelete PostView Post/Check IP

This may help.
http://au.rrforums.net/forum/messages/17001/899.html?1087328535
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Patrick Francis
Experienced User
Username: jackpot

Post Number: 47
Registered: 11-2016
Posted on Saturday, 18 March, 2017 - 09:02 am:   Edit PostDelete PostView Post/Check IP

Hi John
I have attached a document that I copied and pasted off a tee one document that was written by David or Robert I think (forgive if I am mistaken) with a pic of the flush gun.
application/vnd.openxmlformats-officedocument.wordprocessingml.document
Reverse flushing of engine.docx (173.4 k)

Over to the other Patrick for the second part of your question - I wish I had a '25 chevy!
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Christian S. Hansen
Grand Master
Username: enquiring_mind

Post Number: 543
Registered: 4-2015
Posted on Saturday, 18 March, 2017 - 09:11 am:   Edit PostDelete PostView Post/Check IP

Sorry...document is a zipped file that opens to code only. Why not either link to an unzipped version or cite the pages from T-One? Thanks.
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Patrick Francis
Experienced User
Username: jackpot

Post Number: 48
Registered: 11-2016
Posted on Saturday, 18 March, 2017 - 10:03 am:   Edit PostDelete PostView Post/Check IP

Sorry Christian - didn't realise, I just uploaded a word document from my desktop. The picture of the flush gun is in Patrick L's link above. The rest of the prose i will Upload when I get back to my computer later tomorrow.
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Christian S. Hansen
Grand Master
Username: enquiring_mind

Post Number: 544
Registered: 4-2015
Posted on Saturday, 18 March, 2017 - 11:58 am:   Edit PostDelete PostView Post/Check IP

Patrick F...
Yes, please do. The T-1 Topics link would be best as it is also referenced in that same link but without mention of which T-1 issue. The photo is nice but absent a clear description of how it is used, lacks that detail.

Over time I have invented/improvised my own connections for various flushing operations and would like someone else's ideas as a supplement to my own.

For what it is worth, I am a believer in also back flushing from the drain petcocks on the engine block. My Shadow has two, one on each side, and the Silver Cloud I am currently preparing to flush has one situated at the rear of the block where sediment is alleged to collect so my feeling is that flushing from this point forward and out the lower radiator hose connection, as well as up and out the thermostat housing (stat removed of course) as well as the traditional back flushing from the lower rad hose connection and up and out thermostat housing can only be a plus advantage. I also flush with alternating bursts of compressed air into the block thru those same petcocks as well and I liked the gun arrangement that can presumably alternate conveniently from pressurized water via garden hose to pressurized air with either a valve or pull of the trigger. It is quite possibly an improvement over the makeshift arrangement I now use and further detials would be worthy of consideration. Thanks.

.
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Patrick Francis
Experienced User
Username: jackpot

Post Number: 49
Registered: 11-2016
Posted on Saturday, 18 March, 2017 - 05:05 pm:   Edit PostDelete PostView Post/Check IP

OK Christian, here we go
""
Reverse flushing of engine & radiator is a good idea after the
repairs, ie thermostat relief valves, headgaskets etc. Must use
a reverse flush pressure type and use as follows,

First disconect the radiator bottom hose from the n/s engine
alloy pipe fit a reverse flush tool to the rad hose fit a water
hose to the end of the flush tool.

Remove the top hose from the thermostat housing & position
downwards. Leave the rad cap on.

Turn the water hose on fully, when the water is flowing from
the top rad outlet pressurize the reverse flush tool with
compressed air, the water will be seen to bring up all the
sediment from the bottom & top of the rad.

When the water is flowing clear & freely the rad is ok.

Next is the engine block. Turn the heater water control off
re dash control. Remove the thermostat housing, remove the
thermostat refit the housing. On the water alloy pipe on the n/s
fit the reverse flush tool, turn the water on when it is flowing
out the thermostat housing pressurize the flush tool this may
take a few attempts before the water clears as all the
sediment around & below the wet linners is forced out.
When completed a new themostat should be fitted & an
inhibbiter type antifreeze used.}

Have included photo below of my cooling system flushing gun adapted from a compressed air engine cleaning gun. The inspiration for this gun came from a similar unit made by George Shores from the ACT Self-Help Group however I use a cup adaptor rather than a cone adaptor to connect to the system. Using 700kPa water and 700kPa [100psi] air pressure; this is very effective in removing muck from the system.
""

Hope this helps
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1654
Registered: 5-2012
Posted on Sunday, 19 March, 2017 - 02:08 am:   Edit PostDelete PostView Post/Check IP

Whats the best way to catch the dirty water? It would make a mess of the driveway if you were to flush the rad contents onto it. An oil change drain pan would likely be too small. Park the car on the lawn perhaps? How do you deal with this?
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1147
Registered: 9-2004
Posted on Sunday, 19 March, 2017 - 09:59 pm:   Edit PostDelete PostView Post/Check IP

Cut an old garden pond liner down to slide under the car, will catch most of the contents.
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1656
Registered: 5-2012
Posted on Monday, 20 March, 2017 - 02:14 am:   Edit PostDelete PostView Post/Check IP

Thanks Patrick. Our local hardware store stocks them at $35. This will be the way I go when I reverse flush my engine. This is not on my immediate agenda but I have always wondered how to deal with this issue.
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Christian S. Hansen
Grand Master
Username: enquiring_mind

Post Number: 547
Registered: 4-2015
Posted on Monday, 20 March, 2017 - 07:08 am:   Edit PostDelete PostView Post/Check IP

Assuming that the contents captured in the pond are such that you would not have wanted them simply flowing out from under the car and down the street, what do you plan on doing with all of it now? Let it evaporate I suppose?
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Patrick Ryan
Grand Master
Username: patrick_r

Post Number: 1268
Registered: 4-2016
Posted on Monday, 20 March, 2017 - 10:49 am:   Edit PostDelete PostView Post/Check IP

Hi Christian,

Have you seen what a 50/50 mix of Ethylene Glycol does when spilt on an engine, radiator, or the ground when left un cleaned etc?

The cooling system in the 25 Chevrolet, is non pressurised, and open to the air due to the overflow.
The image below is from a friends Chevrolet showing the corrosion around the overflow using standard EG mix.

If the top tank runs low, as mine does (the coolant level sits about 25mm above the honeycomb core) it just expels anything above this level, thus leaving 90% (100mm)of the top tank washed in coolant as it exits the top hose into the top tank. When sitting for any time this will start to corrode inside the tank and then when next used wash away and clog the already small honeycomb tubes.

Of course, inside the engine will be ok, it is only where a non pressurised system expels a lot of coolant thus leaving the top tank susceptible to corrosion.

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John Beech
Prolific User
Username: jbeech

Post Number: 253
Registered: 10-2016
Posted on Monday, 20 March, 2017 - 12:14 pm:   Edit PostDelete PostView Post/Check IP

I suppose everyone remebers to engage the heater (after the engine warms) so as to be able to drain/flush the water/ethylene-glycol mixture from this miniature radiator while you're at it, right? Anyway, I'm going to tackle this job soon as well. Good timing for this thread!
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Patrick Ryan
Grand Master
Username: patrick_r

Post Number: 1269
Registered: 4-2016
Posted on Monday, 20 March, 2017 - 12:32 pm:   Edit PostDelete PostView Post/Check IP

Hi John,

I just did mine a few weeks ago and I was given the best advice from David Gore.

As I was going to use the factory fitted drain tap which is on the left hand side of the bottom radiator tank, he advised to be sure to get the engine well and truly HOT before trying to open this tap.

I did so, and it was a little to tight for fingers, but a minor nudge with some pliers, it undid so easily.
Of course be sure to relieve any pressure in the system first.

Finally, do NOT over tighten the tap, I just simply nipped it up by hand. What is the worst that can happen. it may drip???

If so nip a little more.

Mine was right first time.

Refilling was a different matter.

It was like a comedy act with my wife, a funnel a length of hose and me standing on top of a wheelie bin!!

David wanted me to supply the image on the forum of us doing this.

I pre mixed the 50/50 coolant with de mineralised water into a 20L drum so I was sure what I was putting in was definitely 50/50.

I do this every 2 years, regardless of distance travelled.
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Patrick Ryan
Grand Master
Username: patrick_r

Post Number: 1270
Registered: 4-2016
Posted on Monday, 20 March, 2017 - 12:36 pm:   Edit PostDelete PostView Post/Check IP

Tap looks like this John.

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