| Author | Message | |||
     Patrick Francis Experienced User Username: jackpot Post Number: 41 Registered: 11-2016 |
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 | |||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1258 Registered: 4-2016 |
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. | |||
| Jeff Young Grand Master Username: jeyjey Post Number: 314 Registered: 10-2010 |
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. | |||
| Patrick Francis Experienced User Username: jackpot Post Number: 43 Registered: 11-2016 |
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 ? | |||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1261 Registered: 4-2016 |
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? | |||
| David Gore Moderator Username: david_gore Post Number: 2480 Registered: 4-2003 |
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 * | |||
| Jeff Young Grand Master Username: jeyjey Post Number: 315 Registered: 10-2010 |
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. | |||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1262 Registered: 4-2016 |
Agreed. I just couldn't get it out as good as David & Jeff. | |||
| Patrick Francis Experienced User Username: jackpot Post Number: 44 Registered: 11-2016 |
Patrick - yes, the internals are fine. Thank you all , it has been an interessting lesson! | |||
| John Beech Prolific User Username: jbeech Post Number: 243 Registered: 10-2016 |
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 | |||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 542 Registered: 4-2015 |
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". . | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1136 Registered: 9-2004 |
This may help. http://au.rrforums.net/forum/messages/17001/899.html?1087328535 | |||
| Patrick Francis Experienced User Username: jackpot Post Number: 47 Registered: 11-2016 |
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.
Over to the other Patrick for the second part of your question - I wish I had a '25 chevy!  | |||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 543 Registered: 4-2015 |
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. | |||
| Patrick Francis Experienced User Username: jackpot Post Number: 48 Registered: 11-2016 |
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. | |||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 544 Registered: 4-2015 |
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. . | |||
| Patrick Francis Experienced User Username: jackpot Post Number: 49 Registered: 11-2016 |
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 | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1654 Registered: 5-2012 |
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? | |||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1147 Registered: 9-2004 |
Cut an old garden pond liner down to slide under the car, will catch most of the contents. | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1656 Registered: 5-2012 |
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. | |||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 547 Registered: 4-2015 |
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? | |||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1268 Registered: 4-2016 |
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.  | |||
| John Beech Prolific User Username: jbeech Post Number: 253 Registered: 10-2016 |
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! | |||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1269 Registered: 4-2016 |
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. | |||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1270 Registered: 4-2016 |
Tap looks like this John.  |
