Coolant flush

kcs

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Kubota B2650
Jan 9, 2021
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Virginia
I’m a new tractor owner. I have a B2650. Love the tractor. Has saved me lots of backaches. It’s time for me to flush and replace the coolant. I see in the owner’s manual of a pet cock on the engine block. I’m afraid if I open it it won’t close and leak or it will break off. Could some one help me with this. Thanks
 

lmichael

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Kubota G2160
Apr 23, 2021
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Rockford IL area
I doubt seriously it will break off. I just did mine on my G2160 with D782 engine. Though one thing that DID happen was no coolant would flow out. I removed the entire petcock and found the drain hole clogged with silt. I opened and cleaned it out, reinstalled the petcock and continued on to flush the system with distilled water really well. Than refilled with coolant diluted to 60/40 rather than 50/50 as I was sure some of the distilled water would still be in the system.
 

Fordtech86

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L3200
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Is the lower radiator hose easily accessible on yours? If so I would just remove it to drain it.
 
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kcs

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Kubota B2650
Jan 9, 2021
148
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28
Virginia
Looks like where it goes into the radiator is easy. The end going into the block is tight. It runs above the oil filter
 

GeoHorn

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I’m thinking that if/when coolant deteriorates ... so does rubber. It may be time to replace the hoses as well anyway.... if you pull the lower it may be a good time to replace it.
 

BruceP

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G5200H
Aug 7, 2016
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Richmond, Vermont, USA
When I did coolant-flush, I found that using gas-powered leaf-blower to blow into the radiator-top helped to blow out residual fluid from the cooling system drains.

Since my machine was over 25 years old and I had no clue when it was last done. (and overheating issues) I used some Prestone radiator flush before rinsing several times with distilled water. NEVER USE TAPWATER IN COOLING SYSTEM.
 

GeoHorn

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I used Prestone...(and don’t get me wrong... I believe Prestone is a superior product maker).... I used Prestone radiator flush in 3 different cars I owned back in the 70s and 80s,,,, and every one I used it in lost the water pump shortly thereafter.
I finally suspected the product as the cause of the problem and from then on I used ONLY tap water for a clean-out flush fluid....and never had another problem with water pumps.
 

lmichael

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Kubota G2160
Apr 23, 2021
609
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Rockford IL area
Those flushes use some very nasty chemicals. They have their place but if you do regular maintenance simply flushing with distilled water than using proper coolant mix is the best. BTW even the service manual (at least on my 2160) warns AGAINST using tap water and only distilled water
 
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kubotafreak

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GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Sep 20, 2018
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I used Prestone...(and don’t get me wrong... I believe Prestone is a superior product maker).... I used Prestone radiator flush in 3 different cars I owned back in the 70s and 80s,,,, and every one I used it in lost the water pump shortly thereafter.
I finally suspected the product as the cause of the problem and from then on I used ONLY tap water for a clean-out flush fluid....and never had another problem with water pumps.
Cant speak to the hoses from coolant only, since Ive seen 40 year old cars with hoses that can work. However, if a system EVER gets oil in the coolant, every hose will swell and pop in short order.

As far as the flushes, I have had great luck out of the fleetguard restore plus(one for rust and corrosion) #CC2638 A little goes a long way on the small displacement of Kubota engines.

I would only use 1 cup of concentrate.

There is also a fleetguard restore, that is good for any sticky/oily residue. #CC2611
 

GeoHorn

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The reason it is said not to use tap-water is because the OEM has no control over the quality of your “tap” water. Some folks have water softeners that use SALT in the process and that can introduce an electrolysis problem to your cooling system.
But the majority of municipal water systems do not have any excessive chemicals that would cause a problem.... ESPECIALLY if only used for FLUSHing.
Some private systems supplied by wells can have high levels of calcium and that can lead to calcium/lime residues in the system.... but even so, ... it’s not likely to cause a problem unless you have a leaky system that requires frequent refilling with more tap water containing calcium. (Thiink about your coffee-pot that slows down over a month of use due to calcium build-up. Running a pot of vinegar thru the pot promtly cleans the calcium out. I know about what I write....We have to do this at our ranch-house about once a month.). The total amount of calcium which precipitates out of a closed system containing less than 5 gallons is .... virtually .... ZIP.
And WHO boils all the water out of their cooling system on a daily basis?

So... I’m calling B.S. on the “don’t use tap water” warnings for anyone who isn’t on a water softener.
Unless your tap water destroys the plumbing in your home on an annual basis.... it’s fine to flush your vehicles cooling system with it.
 
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BruceP

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.... it’s fine to flush your vehicles cooling system with it.
Perhaps I should have been more specific. It is not the flushing which is the problem... it is any RESIDUAL tap-water which may be sitting in nooks/crannies of the system. The FINAL flush should be with distilled water... just before adding the antifreeze-mixture.

The chemistry of antifreeze which protects iron, steel, aluminum and brass can be reduced when there are unexpected dissolved minerals in the water. Also, the 'protective' properties can end up actually harming your cooling-system when mixed with tapwater.

Since there are at least 5 different antifreeze 'formulas'.... one really needs to understand which formula they are working with.... especially when you get into HOAT (Hybred Organic Acid Technology) formulas.

Diesel engines with sleeves are subject to cavitation corrosion. This throws another monkey-wrench into the mix. Special antifreeze formulas are required to protect against this problem.

NOTE: I beleive kubota engines do NOT have sleeves.
 
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GeoHorn

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Perhaps I should have been more specific. It is not the flushing which is the problem... it is any RESIDUAL tap-water which may be sitting in nooks/crannies of the system. The FINAL flush should be with distilled water... just before adding the antifreeze-mixture.

The chemistry of antifreeze which protects iron, steel, aluminum and brass can be reduced when there are unexpected dissolved minerals in the water. Also, the 'protective' properties can end up actually harming your cooling-system when mixed with tapwater.

Since there are at least 5 different antifreeze 'formulas'.... one really needs to understand which formula they are working with.... especially when you get into HOAT (Hybred Organic Acid Technology) formulas.

Diesel engines with sleeves are subject to cavitation corrosion. This throws another monkey-wrench into the mix. Special antifreeze formulas are required to protect against this problem.

NOTE: I beleive kubota engines do NOT have sleeves.
That is a bunch of boilerplate you’ve re-posted. Please provide evidence that using (municipal) tap water to flush OR supply a system caused measurable harm.

The 1983 Volvo-powered boat (cast iron 4-cyl automobile engine) I operated for 37 years on a combination of lake-water, sea-water, and tap water is still giving it’s newest owner great service with absolutely no cooling system problems and still running it’s original water pump.
 
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lmichael

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Kubota G2160
Apr 23, 2021
609
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Rockford IL area
I still go with what the manuals say. For about $4.00 you can do the whole job with pure distilled water and not take any chances. I will go with that every time.
 
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lynnmor

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B2601-1
May 3, 2021
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Red Lion
I have well water that is acidic and it ate the copper pipes in just a few years. I changed the entire house to plastic plumbing and now am a believer. I may flush a system with the well water, but the final flush and fill will be with distilled.
 
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SDT

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multiple and various
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When I did coolant-flush, I found that using gas-powered leaf-blower to blow into the radiator-top helped to blow out residual fluid from the cooling system drains.

Since my machine was over 25 years old and I had no clue when it was last done. (and overheating issues) I used some Prestone radiator flush before rinsing several times with distilled water. NEVER USE TAPWATER IN COOLING SYSTEM.
Clever idea regarding the leaf blower.

Complete agreement regarding tap water.

SDT
 
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SDT

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Interesting. :unsure: my waterpump started to leak the next year after the flush. :confused: Perhaps you have a point there (y) (I never made the connection)
Bingo.

I got tired of changing water pumps after using radiator flush chemicals about 40 years ago and haven't changed a water pump since I stopped using such.

SDT
 
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SDT

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Perhaps I should have been more specific. It is not the flushing which is the problem... it is any RESIDUAL tap-water which may be sitting in nooks/crannies of the system. The FINAL flush should be with distilled water... just before adding the antifreeze-mixture.

The chemistry of antifreeze which protects iron, steel, aluminum and brass can be reduced when there are unexpected dissolved minerals in the water. Also, the 'protective' properties can end up actually harming your cooling-system when mixed with tapwater.

Since there are at least 5 different antifreeze 'formulas'.... one really needs to understand which formula they are working with.... especially when you get into HOAT (Hybred Organic Acid Technology) formulas.

Diesel engines with sleeves are subject to cavitation corrosion. This throws another monkey-wrench into the mix. Special antifreeze formulas are required to protect against this problem.

NOTE: I beleive kubota engines do NOT have sleeves.
Agreed.

In one of my former lives as a design engineer for GM, I read an engineering report regarding tap water in cooling systems and have used only distilled water thereafter.

SDT
 
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lmichael

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Kubota G2160
Apr 23, 2021
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Rockford IL area
Is the Kubota plain old green ethylene glycol or is it a HOAT like most Asian companies use? I used regular green (Mopar actually) from when my buddy and I had an automotive repair business. Still had one jug of Mopar left LOL as we worked primarily on Chrysler mini vans. I still have jugs of Mopar trans fluid I don't know what to do with LOL