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Author Topic: Coolant level in engine is below Regulator housing (with engine off) normal?  (Read 214 times)

Mike Shumack

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I changed my Temperature Sender Unit (for Dash Gauge) which is located in the Regulator Housing (Thermostat housing) on my C13.

I thought it odd that no coolant came out when I pulled the Sender Unit out. I was prepared to do a fast swap.
After looking/thinking about it, I see that the coolant level in the engine is below the Regulator housing when the engine is shut off.

The way the Surge tank is mounted, the cold fill line for the Surge Tank is below the engine upper hose and regulator housing - and the top of radiator is below the top of engine - so there is no coolant in the upper radiator hose. I could add more coolant to the surge tank (near max line) to have coolant in the Regulator housing (and then Sender Unit would be submerged) when engines is off.

I guess it's not a problem as my engine does not overheat. 

Is this typical on Beavers (motor coaches)? Now that I think about it, I don't recall ever seeing any cars or trucks with the radiator or surge tank lower than the top of engine.

« Last Edit: October 03, 2019, 03:26:55 PM by Mike Shumack »
- Mike

'05 Beaver Patriot Thunder 525, Vicksburg, CAT C13, Allison 4000MH, HydraLift
Orlando, FL

Gerald Farris

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Mike,
The thermostat housing and sending unit are normally full of coolant, but when you pulled the sending unit out, you opened an air vent that allowed the coolant to drain down into the surge tank. This air pocket will purge into the surge tank and be replaced with coolant when the engine is running at operating temperature. What you experienced is a normal condition.

Gerald
2002 Solitaire (2017 -  )
2000 Marquis, C12 (2004 - 2017)
1993 Patriot  (2000-2004)

Mike Shumack

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But no coolant came out of the Regulator housing when I pulled out the Sender Unit. I was expecting coolant to gush out.
I think I could have pulled off the upper radiator hose and no coolant would be lost.

Of course if the engine was running, that would have been a mess.
- Mike

'05 Beaver Patriot Thunder 525, Vicksburg, CAT C13, Allison 4000MH, HydraLift
Orlando, FL

Gerald Farris

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Mike,
Coolant does not run uphill. You opened the high point in a non-pressurized system, that allowed the coolant to drain down to the lower elevation surge tank. If the engine was warm enough to still have pressure in the system, coolant would have been forced out of the opening that you created.

Gerald
2002 Solitaire (2017 -  )
2000 Marquis, C12 (2004 - 2017)
1993 Patriot  (2000-2004)