Coolant Volume Discrepancy When DraIning and Refilling the Coolant on L3240 HST

[Chewwy]

I am doing the 400 hr service on my Kubota. While doing this, I decided to also drain and refill the coolant.

Per the owners manual the coolant capacity is 6.3 US qts. I drained the coolant using the radiator drain plug (with the radiator cap removed). This is what the service manual says to do, nothing more.

When I refilled it it with clean water, it only took slightly less than a gal. I thought maybe it needs to run a little to flush any air out of the system. I ran it until the temp guage was in the normal range. Added maybe a half cup of water and it was again full. I only needed to add about a gallon of water to the coolant system that is supposed to hold over 6 qts.

This tractor has never run even the least bit overheated. The coolant that I drained was bright greenish yellow. There was no sign of any rust or other discoloration.

I thought about loosening the lower drain hose to try and drain more coolant but it is no lower in elevation than the drain plug and like most everthing else on this machine, it requires a very small contorsionist to gain access. My knowedge of radiators is that the lower galley of the radiator os open all the way across similar to the top galley. I could not envision any way that loosening the lower hose would drain anymore coolant.

Is it possible the listed coolant volume also includes the volume in the recovery tank to the full mark (it might hold at most 1 qt of coolant)?

Any other ideas out there about what may be going on here?

 

[Snobdds]

If you drained your block, it would get you closer. There is a lot of coolant in all the passages.

If we do the math...

4/6.3 = 63.5%. You took out 63% of the coolant. You have 36.5% left of old coolant.

.365 * (4/6.3) = 23.17 you have 23.17% of old coolant.

.2317 * (4/6.3) = 14.71 You have 14.71 % of old coolant left.

.1471 * (4/6.3) = 9.34%

Etc...

I just drain what I can out of the radiator each year and refill. After 5 years all the coolant is not older than 5 years old. You will never get the full amount out and be able to refill to the listed capacity. It's better to just do the % math and do yearly maint.

 

[Chewwy]

If you drained your block, it would get you closer. There is a lot of coolant in all the passages.

If we do the math...

4/6.3 = 63.5%. You took out 63% of the coolant. You have 36.5% left of old coolant.

.365 * (4/6.3) = 23.17 you have 23.17% of old coolant.

.2317 * (4/6.3) = 14.71 You have 14.71 % of old coolant left.

.1471 * (4/6.3) = 9.34%

Etc...

I just drain what I can out of the radiator each year and refill. After 5 years all the coolant is not older than 5 years old. You will never get the full amount out and be able to refill to the listed capacity. It's better to just do the % math and do yearly maint.

Thanks! So this percentage that is left this is not that unusual in your experience?

I would expect some coollant to remain in the engine, but have never run into this high a percentage left.

 

[RjCorazza]

None of that seems unusual. Next time if you want to go to the trouble, flush with distilled water several times. That way you end up with distilled water in the block, add coolant concentrate to the correct final solution.
Also, if you don't have one... consider getting a refractometer for measuring coolant concentration. They are very accurate, easy to use, and inexpensive.

 

[Snobdds]

Nope, it's pretty normal.

Yes the only other way is to buy about 24 gallons of distilled water and do 6 flushes. Then add in 1/2 the capacity of full strength coolant and top off with distilled water.

However, just doing the % is way easier and you end up with the same results.

Good for changing the cooling system fluid. So many people neglect it. It's critical to keep the coolant changed out.

 

[Chewwy]

I’ve never used anything but local supplied fresh water from my garden hose for any engine I’ve owned. Never seen an auto dealer, auto service center, or tractor dealer use distilled water either as coolant.

An internet search indicates using distilled water as coolant is either good, bad, or makes no difference.

 

[Snobdds]

I’ve never used anything but local supplied fresh water from my garden hose for any engine I’ve owned. Never seen an auto dealer, auto service center, or tractor dealer use distilled water either as coolant.

An internet search indicates using distilled water as coolant is either good, bad, or makes no difference.

Well...do what you wish.

 

[LouNY]

It depends on your local water supply if naturally soft with no minerals it will be fine. I've seen radiators almost completely plugged with hard water calcium build up. I use distilled water, but to each his own. I would never recommend tap water.
Depending on how good of a flush you are doing I like to remove the thermostat when doing a radiator flush and clean and I will use an air hose to blow most of the water out of the block and it often brings out a bit or more of rust and or corrosion or mud from the block.

 

[big bubba]

I’ve never used anything but local supplied fresh water from my garden hose for any engine I’ve owned. Never seen an auto dealer, auto service center, or tractor dealer use distilled water either as coolant.

An internet search indicates using distilled water as coolant is either good, bad, or makes no difference.

distilled water is my only choice. better yet, why not get 50% premix? there are too many variables in local water supply imho on an expensive diesel engine. all it takes is one overheating event. regards

 

[number two]

If you have a well maintained cooling system,I have found draining and refilling with 50/50 coolant and distiller water is quite adequate and keeps the freeze point correct.
YMMV!