jeepnuts311 said:
dont run the coolant half full..
go to the dealer, spend $9 and get a new OEM cap.
-Tim
Quote: from the owners manual, Engine must be off and cool. 6 cylinder and turbo diesel engines. Fill slowly at the coolant bottle until the coolant level is at the top of the *post* located inside the bottle which indicates full.
The top of the post is actually closer to the surge tank being 1/4 to 1/3 or so full.
Half a quart of expansion isn't uncommon, if the bottle is full, where is the coolant going? Probably spewing out the pressure relief valve in the cap. It's likely going to spew as soon as the motor heats up some.
The cap has a pressure release valve in it, it lets air out under pressure (I think it's 16 PSI), holds what is has and lets air in easily. The system pressurizes from expansion.
Normally when the caps fail, it is because they have been over tightened and the threads are stripped or the pressure release valve is plugged with calcuim and the system builds too much pressure. Stuck closed and the bottle is likely to blow up like a ballon and split. Not sealing and building pressure and the coolant is subject to boil (with no pressure at around 225 F) and make steam, which will cause the coolant to spew out the cap. With 16 PSI of pressure it boils at a round 270 F. The temperature sender isn't at the hottest point in the motor in the Renix.
It could be the cap loosing pressure, but it's likely it would boil over and spew or overheat at other times than right after shutdown. But heck anything is possible.
Coolant mix is also a factor, but less so than pressure.
The next time you shut the motor down, wait a couple fo minutes and then turn the key to run, it's likely the temp will be well above normal. Right after shutdown, the motor gets hotter, before it gets cooler.
If the cap isn't sealing, you can often see a stain on the top of the bottle. Wash the top of the bottle off and check it the next time you drive. You can pick out a leak at the cap fairly easy.