Redblock coolant passage cleaning rust with white vinegar

[DET17]

I'm prepping a low mile 94 RB which has a fair bit of rust showing in the coolant passages (years in a storage unit dry).

Iron block sages around the web swear by a gallon of white vinegar, topped off with distilled water.... soak the iron block right up to the head junction plane for 24 hours. Drain it out and give another flush with distilled water, then send it.

I also read that muriatic acid is much more potent and can potentially eat more..... and that the WV is the preferred safe cleaning mild acid.

Anyone done this with a Volvo iron block tractor engine? Share your results please.

Edit - adding a pic to show just how crusty this particular engine's cooling passages are.

 

[302ftw?]

What would be the danger on performing the same action for a motor in car?

 

[283SD]

What would be the danger on performing the same action for a motor in car?

Possible clogging the radiator/heater core

 

[rb92673]

If it is a bare block, I have heard of people soaking it in molasses to clean it.

 

[DET17]

So "as bought" the engine had a replacement water pump. I cleaned up the gasket flange area of the pump as well as the mating surfaces where the pump lives. I leveled my engine stand and plan to fill thru the top of the old WP and hopefully get that white vinegar/distilled water mixture as close to the deck as possible. Prep work done:

I've got a section of an old WP suction hose somewhere; I'll install that on this used sacrificial pump and clamp off the hose. That should give me a waterline as close to the deck as possible. Also, the red steel suction pump which lives on the exhaust side of these blocks must be reinstalled. I just eyeballed it, and the top end seems to be above the HG level. I'll update this once I get the full setup ready for the mild acid.

 

[Dicktater]

Don't mix water with the vinegar it's pretty mild as is, you can also get vinegar at some farm stores that is a bit stronger than household vinegar.
Below is a motorcycle fuel tank that was in very bad condition that I filled with WV and it cleaned up nicely the next pic is what the vinegar looked like afterwards,when done clean with a mixture of baking soda and water.

 

[VolvoLatAm]

I would use thermocure instead

 

[HiSPL]

I'd probably use Evaporust. Won't take as long and will do a better job.

 

[Dicktater]

Lots of ways to skin a rusty cat but you can buy vinegar cheap at the dollar store, I wasn't in a hurry and let it set for weeks but I don't think anything will do a better job it's all some type of acid.

Store bought vinegar is 5% acidity and you can buy vinegar that is 30% acidity and it's safer to use than some of the other stuff.

 

[DET17]

Great tip! Tractor Supply shows a gallon of 30% "vinegar cleaning concentrate" for $19 (which is what I ended up paying at Homer Depot).

TS had none onhand.... said it was a "seasonal product". HD to the rescue, stock on the floor.

 

[Tonyte619]

Molasses works great and is very safe, but would take at least a week of soaking.

 

[DET17]

Finally some spare time revealed itself.... bought the 30% vinegar solution (reportedly 6x stronger than standard vinegar). I leveled the B230 in both planes so it was ready to fill as close to the deck HG line as possible. Pulled a spare WP gasket from my collection, cleaned up the surface of the block as well as the WP that came with the subject engine. Installed a return side hose on the WP to contain the vinegar solution; also installed the WP suction pipe which extends behind the block to the heater hoses (high end above the HG so to contain the solution). With all these preparations in place, installed the used WP and began filling with the 30% acid vinegar.

As soon as I began pouring the vinegar solution into the WP, this revealed itself:

It appears at least one of the core plugs (don't call them freeze plugs) has rotted thru from the inside. The other 3 on the intake side of the 94 B230F look at least as rough as this one, which means they all need replaced to be safe. Fortunately I purchased a bag of these years back when 15a was cleaning house and purging his RB parts collection:

Reading several old threads from TB sages on changing these plugs, the following advice seemed constant:

1. don't polish the bores in the block once you get the original plugs removed
2. use a retention liquid such as Indian Head varnish or Permatex #1 to coat the pristinely cleaned plug bores
3. don't push your old dead plugs down inside the block (considering adding a wire for safety)
4. freeze the Genuine VOLVO cup type plugs for 20 minutes in the household freezer (dry ice better)
5. set the frozen plug flush with the block surface using a socket and deadblow hammer
6. once the core plug has achieved room temp, strike the center with a ball peen hammer (don't get crazy with it)

I'll do some more investigation on removal techniques.... sure looks like I will be installing the set of 4 on the intake side.

 

[283SD]

HCL Acid, if you can get it. Dilute it 50/50. Be very very care full, baking soda to neutralize it.

 

[DET17]

The rust removal project resumes:

Filled the RB tractor via the top seal port on the water pump with the 30% vinegar solution; you can see the "menisci" in this pic. Planning to give it a 2 week soak and then drain out to inspect via the standard RB coolant drain (which I removed and cleaned prior to this vinegar soak):

As I noted in a separate MAINT thread, this block also received a full set of 8 OE core plugs (aka "frost plugs"). It's important to mention that when I pulled these plugs, I discovered that the #1 cylinder bottom area was full of rust/sediment up past the bottom edge of the core plug! This location is directly behind the water pump; I'm sure this 94 engine was not treated well witnessed by the amount of visible rust in the cooling passages. I've never seen that much rust & crud accumulated within an iron block. Since I wasn't stripping this block for a "boil out" and machining work, I chose to scrape all the crud loose with a LONG flat bladed screwdriver, then used an outdoor hose & sprayer on JET setting to flush as much of it out onto my driveway. Made quite a mess, and soaked my pants in the process. However I succeeded in removing the accumulation of rusty crud. Perhaps this is common in these old iron blocks? I can't say, as this is the first one I've pulled the core plugs out of. I'm sure the cleansing will help the cooling of the #1 cylinder, as well as protect my radiator from becoming clogged with the same crud.

The 2 week de-rusting cycle has begun; I've got a second gallon in case the first pass is not successful.

Last mention, related: the steel WP suction pipe along the exhaust side of the block was quite rusty and the insertion end at the back of the WP is deteriorated. I purchased a stainless replacement from STS Machine; using the original here to contain the 30% vinegar from pouring out the back of the pump.

 

[Boxtoy940]

Its Painful watching you take on this task after already having built and sold a Masterpiece; you deserve a better Starting Point than that... ..Figuring you have lots of time to Hum with the Shamans....

 

[DET17]

Actually, I do have a better starting point. It's going to languish a bit longer and then move across state lines.

Fear not.... if I continue to live then this machine will rise out of the ashes......

 

[DET17]

Back at the Swedish Underground Garage after 10 days away. Here's what I found growing out of the RB as a result of the 30%vinegar bath:

Our resident Chem E's or Chemists can explain this I'm certain.... iron oxide reacting with the vinegar = ???

I'll drain the coolant cavity tomorrow and we shall see how the cast iron looks within. FWIW, all this "growth" cleaned off with plastic scraper blades, but it sure was cool looking.

 

[adamdrives]

Evaporust works really well for rusty tools and parts. I used it on some transmission hard parts that had been left outside. I believe they have an automotive product for exactly this purpose as well if you end up needing more cleaning.

 

[240 240]

I remember when I did this.

Thread 'I keep flushing and flushing but the crap won't go away.'

Apr 10, 2024

Car Poop Thread.

on the 945Turbo I made a grave mistake last year and left plain water in the cooling system for like 6-8 months. I wasn't driving it at the time and just forgot.
I am now in the process of getting this road worthy again. Nothing overheating, which is good.

I've flushed several times.

flush#1
abouth 6 months ago.
I did 30% vinegar solution with water mixed because it was bad. turbo metal coolant line sprung a leak. fixed it.
let the car sit drained.

Flush #2-3
about 3 months ago.
i did more 30% vinegar solution and hose water because big scale was still coming...

• 240 240
• Replies: 68
• Forum: maintenance & nonperformance

Best thing was to just drive the car with a wix water filter plumbed to the heater lines.

 

[DET17]

Evaporust works really well for rusty tools and parts. I used it on some transmission hard parts that had been left outside. I believe they have an automotive product for exactly this purpose as well if you end up needing more cleaning.

I have heard of Evaporust, but never tried it. I think the gallon jugs of 30% vinegar were around $19 for the pair at Homer Depot. 10 days gave most of the coolant interior passages a nice silver color.... I'm putting the 2nd gallon in this morning and letting it sit another 2 weeks. We shall see if anything else is needed thereafter.