Author Topic: Cleaning the cooling system  (Read 1292 times)

0 Members and 1 Guest are viewing this topic.

Offline Bainford

  • Twin Cam 3682R
  • Super Member
  • *******
  • Joined: Jul 2012
  • Location: Nova Scotia
  • Posts: 1,711
Cleaning the cooling system
« on: Thursday,June 18, 2020, 12:17:33 PM »
I am about to embark on some cooling system repair and maintenance on my Twin Cam. This work will include changing the radiator and most of the rubber hoses. I will clean out the transfer pipes (in situ, as best I can), swirl tank, heater core curcuit, etc as well. My coolant has always been a bit murky looking and a bit rust coloured. With the system opened up, it is a great time try to flush the engine coolant passages.

I have heard of cleaning/descaling methods that include filling the engine passages with vinegar, or with CLR. Let soak, then flush with water. repeat if necessary. Has anyone tried any of these methods? Is there a danger with aluminum corrosion with either of these products? I am also concerned about aggravating the water pump as well.

Any insights are appreciated.
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline Grumblebuns

  • Super Member
  • *******
  • Joined: Aug 2012
  • Location: San Diego area
  • Posts: 1,528
Re: Cleaning the cooling system
« Reply #1 on: Thursday,June 18, 2020, 03:03:28 PM »
Trevor, personally, I'm not sure that attempting to chemically clean out the engine block is really worth while. I've attached a picture of my twin cam block after a complete strip down. You can see the extensive corrosion on the outside of #4 cylinder. Will even that amount of rust have any effect on heat transfer and engine cooling requiring any action at this time? I don't think so. I would be more concerned about any chemical treatment causing the rust to flake off plugging up the radiator over time.  For the engine, I would wait until a rebuild to properly do a hot tank or a pyrolytic oven to get the block completely cleaned out and concentrate on the cleaning the coolant transfer tubes and the radiator/heater core.

Joji Tokumoto

Offline jbcollier

  • Super Member
  • *******
  • Joined: Nov 2013
  • Location: Edmonton, Alberta, Canada
  • Posts: 5,959
Re: Cleaning the cooling system
« Reply #2 on: Thursday,June 18, 2020, 07:18:51 PM »
With the mix of aluminium, cast iron, copper and steel components, there isn’t a chemical flush that’s harsh enough for the steel and cast while still safe for the aluminium.  We used to remove the thermostat and lower hose and then reverse flush the engine with water and compressed air.  Repeat until it flows clear and clean.  Do the same for the rad.

Do the rad separate from the engine so hunk from the one doesn’t clog the other.

More importantly, use a proper antifreeze/corrosion inhibitor and change as per the manufacturer’s recommendation.  Much, much easier to regularly replace your coolant and prevent corrosion than to try and clean it out while the engine is in service.

Offline EuropaTC

  • Super Member
  • *******
  • Joined: Jun 2012
  • Location: Lincolnshire, UK
  • Posts: 3,129
    • LotusLand
Re: Cleaning the cooling system
« Reply #3 on: Thursday,June 18, 2020, 10:02:43 PM »
I've not heard of the vinegar idea although I can see where it comes from and I guess it would work to some extent.

Very often I used inhibited HCl to clean off rust which is very good at chewing away rust on items for inspection which left the pure steel untouched.  You can buy commercial products to do this or IIRC very crudely use ZnCl in HCl to give a similar effect. There are also biological cleaners which are probably less risky to use. I'm 15yrs out of date with the technology so there are probably better things around now.

But....

With any chemical cleaner, they tend to work best if left for a long time and ideally circulated as well. That's hard to do on the Europa unless you have an electric pump on hand.

It's quite difficult to clean an engine block like this. IMO you need the head off and probably a core plug out coupled with some serious flushing if you aim to remove any silt around the bores. Cleaning the transfer tubes is ok, likewise the radiator and header tank because you can get a good flow/flush there, but the elephant in the room is the engine block itself.  No reason not to have a go, but don't expect perfection !

On the corrosion, as John says there's an unhelpful mix of metals and I think you'd struggle to get a simple formulation for all (although the bacteria/biological ones might ?). 

If I was desperate to do this then I would use something designed for rust alone based on a calculated risk. The logic goes something like this;

  • you would be very concerned if something was corroding at over 1mm/yr and in some combinations you might see anything up to 100mm/yr. (fizzing !).
  • assume 100mm/yr in your chosen cleaning solution - which is extreme and I can't think of any off hand
  • if you left it stewing for a day then you might manage 100/365 mm of removal, roughly 0.3mm.
  • in practice you probably will leave it for a few hours at most so the actual metal removal will be minimal


So.... yes, you can do this and maybe the risk isn't as bad as you imagine,  especially if you use an inhibited/biological system.

Is it worthwhile ? I'm not convinced, I reckon I'm with Joji on this one, there's a good chance you'll disturb something that's been quietly lying in the block and push it round to the water pump, etc. 

Personally I'd just flush out the easy bits, radiator, header tank, transfer pipes and heater matrix (from the engine bay) and call it quits, leaving the block alone.

Brian
edit to add; you might find most of the corrosion is from the header tank if it's steel. The inhibited antifreeze works very well at reducing steel corrosion but at the header tank you have an air/water interface as the levels rise and fall. This introduces oxygen to recently wetted and warm surfaces and that's quite difficult to inhibit, so you get some rusting. The Header tank on my car was in a very rusty state and despite acid cleaning I couldn't get it "good" - hence the stainless one that's there now !



« Last Edit: Thursday,June 18, 2020, 10:05:50 PM by EuropaTC »

Offline Bainford

  • Twin Cam 3682R
  • Super Member
  • *******
  • Joined: Jul 2012
  • Location: Nova Scotia
  • Posts: 1,711
Re: Cleaning the cooling system
« Reply #4 on: Friday,June 19, 2020, 09:51:01 PM »
Lots of good wisdom there. Thanks guys.

The desire to clean out the system is one of opportunity rather then necessity. I blew a lower radiator hose the last time I drove the car, and this has compelled me to change all the hoses, and while I'm at it, the thermostat. I am also taking this opportunity to fit a new aluminum radiator I bought a few years ago. With the system opened up, it's a good time to clean it out.

Given the circumstances, I'll stick to some vigorous garden hose flushing and maybe some compressed air through various ports, and give the header tank and transfer tubes a thorough scrubbing. That will get things in order. Also considering fitting a temporary strainer of some sort just before the radiator inlet to catch any junk that may be disturbed by the cleaning, lest I clog up that nifty new rad.
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline jbcollier

  • Super Member
  • *******
  • Joined: Nov 2013
  • Location: Edmonton, Alberta, Canada
  • Posts: 5,959
Re: Cleaning the cooling system
« Reply #5 on: Friday,June 19, 2020, 10:17:29 PM »
You can use an acid flush on the transfer tubes.  With cast and steel, I use muriatic acid 1:1 with water.  It cleans really really well.  Plug the lower end and fit a rubber elbow to the other end.  Fill and leave it say 15 minutes.  FLUSH THOROUGHLY.

Do not use this where there is any aluminium.  The reaction is almost an explosion.

Hardware stores and paint shops carry the acid.

BE VERY CAREFUL !!  It is very caustic.

Offline EuropaTC

  • Super Member
  • *******
  • Joined: Jun 2012
  • Location: Lincolnshire, UK
  • Posts: 3,129
    • LotusLand
Re: Cleaning the cooling system
« Reply #6 on: Friday,June 19, 2020, 10:59:17 PM »
Also considering fitting a temporary strainer of some sort just before the radiator inlet to catch any junk that may be disturbed by the cleaning, lest I clog up that nifty new rad.
That's a cute idea, especially with a shiny new Al rad.   In fact if you can get something that doesn't significantly affect the flow rates it's not a bad idea for longer term to catch anything that suddenly gets on the move. I like that one !

Brian

Offline BDA

  • Super Member
  • *******
  • Joined: Jul 2012
  • Location: North Carolina
  • Posts: 9,968

Offline Bainford

  • Twin Cam 3682R
  • Super Member
  • *******
  • Joined: Jul 2012
  • Location: Nova Scotia
  • Posts: 1,711
Re: Cleaning the cooling system
« Reply #8 on: Saturday,June 20, 2020, 05:12:12 PM »
They make such a thing: https://www.amazon.com/Scott-Drake-ACC-GANO-8-Radiator-Coolant/dp/B00FGSN7Q0/ref=sr_1_3?dchild=1&keywords=Radiator+filter&qid=1592663573&sr=8-3
Cheers, BDA. One is on its way to my place now. That looks the perfect rig. Never occurred to me to look for a bespoke coolant strainer. 
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline BDA

  • Super Member
  • *******
  • Joined: Jul 2012
  • Location: North Carolina
  • Posts: 9,968
Re: Cleaning the cooling system
« Reply #9 on: Saturday,June 20, 2020, 05:30:30 PM »
That one looked like a a good unit for our cars but for those who are interested in coolant filters, there are lots of them out there. For example, Summit Racing has several. It might be worth looking around.

Offline Bainford

  • Twin Cam 3682R
  • Super Member
  • *******
  • Joined: Jul 2012
  • Location: Nova Scotia
  • Posts: 1,711
Re: Cleaning the cooling system
« Reply #10 on: Saturday,June 20, 2020, 05:36:16 PM »
You can use an acid flush on the transfer tubes.  With cast and steel, I use muriatic acid 1:1 with water.  It cleans really really well.  Plug the lower end and fit a rubber elbow to the other end.  Fill and leave it say 15 minutes.  FLUSH THOROUGHLY.

Do not use this where there is any aluminium.  The reaction is almost an explosion.

Hardware stores and paint shops carry the acid.

BE VERY CAREFUL !!  It is very caustic.
I’ve had a little experience with muriatic acid, and even have a couple jugs onsite. Potent stuff, that. PPE, including respirator a must. I’ve used it full strength to clean very rusty tools and parts. Out of curiosity I selected the rustiest, scaliest brake shoe piece from the junk pile and placed it in the acid. After five minutes the acid was very active, almost like a boil. Five minutes layer I plucked it out and there was no trace of rust whatsoever. Next time I will be diluting it.

And it’s worth repeating your warning about not using it with aluminum. The reaction can be violent.

I’ll give the tubes an initial scrub and inspection, and if needed mix up a mild batch of acid. Ditto the header tank, especially given Brian’s observations on its particular proclivity for corrosion.
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline GavinT

  • Super Member
  • *******
  • Joined: Oct 2016
  • Location: Queensland, Oz
  • Posts: 1,224
Re: Cleaning the cooling system
« Reply #11 on: Saturday,June 20, 2020, 08:35:55 PM »

And it’s worth repeating your warning about not using it with aluminum. The reaction can be violent.
Yep.
Aluminium reacts with muriatic (hydrochloric) acid to liberate hydrogen.
Don't smoke . . even if you've got 'em.