Coolant flow?

[micro57]

Can anyone tell me the direction of coolant flow on a 2008 ktm 450sx-f? Does the pump push coolant thru or does it come in the head then out the pump? Thanks for any input.

[Tabasco Beast]

Old topic but I'm interested as well for 250 SXF 2008. If someone can clarify, please. 

If I presume correctly; the pump pumps coolant into the bottom of the right radiator, it comes out on the top where it goes to a T. From T one hose goes down to cylinder head and a second one goes left to the top of the left radiator. From the bottom of it it goes to the cylinder. 

 

Someone please confirm this! 

[darby11]

9 hours ago, Tabasco Beast said:

Old topic but I'm interested as well for 250 SXF 2008. If someone can clarify, please. 

If I presume correctly; the pump pumps coolant into the bottom of the right radiator, it comes out on the top where it goes to a T. From T one hose goes down to cylinder head and a second one goes left to the top of the left radiator. From the bottom of it it goes to the cylinder. 

 

Someone please confirm this! 

It seems to be a well kept secret, as I’ve never seen a coolant flow diagram in any KTM manuals.  In your case looking at parts diagram, I would think hot coolant come out of the head into the the bottom of the pipe, then travels up, hits the tee, then branches off to the top of each side radiator then travels down through the radiators, and the cooled liquid exits the bottom of each radiator and goes into the cylinder.

[Tabasco Beast]

11 hours ago, darby11 said:

It seems to be a well kept secret, as I’ve never seen a coolant flow diagram in any KTM manuals.  In your case looking at parts diagram, I would think hot coolant come out of the head into the the bottom of the pipe, then travels up, hits the tee, then branches off to the top of each side radiator then travels down through the radiators, and the cooled liquid exits the bottom of each radiator and goes into the cylinder.

Not sure as the pump is on the bottom right side and I'm 99% positive it pushes the coolant from engine into the radiator block. 🤷🏼‍♂️

[Swappa]

17 hours ago, Tabasco Beast said:

Not sure as the pump is on the bottom right side and I'm 99% positive it pushes the coolant from engine into the radiator block. 🤷🏼‍♂️

Radiator block or engine block? 

Typical a KTM water-pump impeller turns clockwise and pushed coolant through the engine (block!!) first and up to the radiators, secondly. 

[Tabasco Beast]

5 hours ago, Swappa said:

Radiator block or engine block? 

Typical a KTM water-pump impeller turns clockwise and pushed coolant through the engine (block!!) first and up to the radiators, secondly. 

I see! For some reason I was convinced the pump "pulls" coolant out of the block instead of "pushes" the coolant through it. It makes sense what you said actually.

If that's so then is the new explanation below correct? 

BTW I checked a schematic diagram of cooling system and I was wrong: cylinder and cylinder head are on the same "coolant line". 

 

So, for confirmation:

1. Pump turns clockwise, pumps coolant into engine block. In there it divides into a) cylinder/cylinder head and b) the rest of the block. 

2. From a) the coolant exits to a T

3. From b) the coolant goes to the bottom of the left radiator, from the top left radiator it exits to a T

4. Both coolant lines (2. and 3.) go from a T into the top of the right radiator, exit at the bottom of the right radiator and into the pump. 

5. Repeat. 

[darby11]

8 hours ago, Swappa said:

Typical a KTM water-pump impeller turns clockwise and pushed coolant through the engine (block!!) first and up to the radiators, secondly. 

On RFS motors, impeller spins CCW.  
 

 

[Tabasco Beast]

On 6/18/2024 at 9:48 AM, darby11 said:

On RFS motors, impeller spins CCW.  
 

 

Ok! 

Except for that, is my understanding from previous post correct? 

[300lbsgorilla]

My understanding is that in all cases for all engines the coolant flows out the bottom of the radiator through the motor and back to the top.  Otherwise if the coolant was low, it could be below the top hoses and starve the motor of coolant (below the level of the feed hose if on top). On my 2009 505 XCF it for sure feeds from the bottom of the rads, to the pump, pushed up the engine cylinder, out the head, back to the top of the  the rads through the tee in the frame. 

[Tabasco Beast]

On 6/29/2024 at 9:55 PM, 300lbsgorilla said:

My understanding is that in all cases for all engines the coolant flows out the bottom of the radiator through the motor and back to the top.  Otherwise if the coolant was low, it could be below the top hoses and starve the motor of coolant (below the level of the feed hose if on top). On my 2009 505 XCF it for sure feeds from the bottom of the rads, to the pump, pushed up the engine cylinder, out the head, back to the top of the  the rads through the tee in the frame. 

Hey! Sorry, somehow I ignored this post 🤷🏼‍♂️

Are you saying the pump pushes the coolant from two bottom pipes from rads into a T on top? 

If so, makes sense also since the warmer fluid will rise above the colder one. 

 

EDIT: if I put the thermostat probe on the center pipe I'll probably have higher and more realistic readings. 30ish degrees Celsius during normal ride doesn't seem very realistic. 

Edited December 16, 2024 by Tabasco Beast

[300lbsgorilla]

9 hours ago, Tabasco Beast said:

Hey! Sorry, somehow I ignored this post 🤷🏼‍♂️

Are you saying the pump pushes the coolant from two bottom pipes from rads into a T on top? 

If so, makes sense also since the warmer fluid will rise above the colder one. 

 

EDIT: if I put the thermostat probe on the center pipe I'll probably have higher and more realistic readings. 30ish degrees Celsius during normal ride doesn't seem very realistic. 

30C is not realistic.  on slow technical single track hill climb rides I am at 230F (110C) as read by now broken tusk temp gauge cap. This is part of the reason why I put on oversized radiators, silicone hoses (the tee part specifically for more flow), a high volume water pump, and a manual switched fan. Before those things I would boil over soon if I wasn't moving at a good clip.  I haven't boiled in a few years now. 

[Tabasco Beast]

2 hours ago, 300lbsgorilla said:

30C is not realistic.  on slow technical single track hill climb rides I am at 230F (110C) as read by now broken tusk temp gauge cap. This is part of the reason why I put on oversized radiators, silicone hoses (the tee part specifically for more flow), a high volume water pump, and a manual switched fan. Before those things I would boil over soon if I wasn't moving at a good clip.  I haven't boiled in a few years now. 

4 stroke normal operating temp is  around 80-90 degrees Celsius, right?

I'm planning to put manually switched fans also. The last thing I want to think about is will it overheat if I'm stuck in mud in the middle of nowhere. 

[Swappa]

10 hours ago, Tabasco Beast said:

4 stroke normal operating temp is  around 80-90 degrees Celsius, right?

I'm planning to put manually switched fans also. The last thing I want to think about is will it overheat if I'm stuck in mud in the middle of nowhere. 

 

[Tabasco Beast]

20 hours ago, Swappa said:

 

Thanks! Informative and helpful! 

[300lbsgorilla]

On 12/16/2024 at 10:47 PM, Tabasco Beast said:

4 stroke normal operating temp is  around 80-90 degrees Celsius, right?

I'm planning to put manually switched fans also. The last thing I want to think about is will it overheat if I'm stuck in mud in the middle of nowhere. 

If you are going to put a fan on the bike make sure you use a manual switch not an automatic one.  This generation of SXF only has 35 watt electrical output and much of that is used for the ignition system until you get to higher revs. Running a fan will drain the battery. so you only want to run it only when actually needed.  Trust me,  been there. that is why I put a 90W aftermarket on mine because I also needed a light.  During the day it works great with the fan but I can't run the LED headlight and the Fan at the same time and still charge the battery.    

[Tabasco Beast]

On 12/22/2024 at 4:36 PM, 300lbsgorilla said:

If you are going to put a fan on the bike make sure you use a manual switch not an automatic one.  This generation of SXF only has 35 watt electrical output and much of that is used for the ignition system until you get to higher revs. Running a fan will drain the battery. so you only want to run it only when actually needed.  Trust me,  been there. that is why I put a 90W aftermarket on mine because I also needed a light.  During the day it works great with the fan but I can't run the LED headlight and the Fan at the same time and still charge the battery.    

No worries! I'm not going to and I don't want to touch existing electrical installation. I'll put a battery pack just for the fans, fuses, two switches and two IP68 80mm fans. If I get stuck with slow riding I can turn them on. Come home, charge the batteries when needed, repeat 🙂