With all the recent posts about draining cooling systems and the repeated reports of boaters only draining and never having a problem I thought some might find my experience from last winter helpful.
Last fall was my first with an I/O set up. I warmed the engine up on muffs for 20 minutes. The engine was of course not under load but the temp guage said it was at op temp. I switched the cooling water to a bucket of antifreeze and pumped five gallons of antifreeze thru. Thought that was it. Luckily I read a post here by Don warning to drain first along with probing. So I opened the petcocks and out came crystal clean pure water!! from the block and the manifolds. (Thanks Don for saving my bacon) Next I removed the thermostat housing and poured two gallons of pink Rv AF in.
Now the mystery; This spring I opened the same drains and instead of pink AF, dark water came out. An antifreeze tester showed my engine was only protected to +10'F. Where did the AF go? The boat was inside an unheated enclosed storage building.
Now the miracle; despite whatever I did wrong the engine had no freeze damage. From now on, I will always add AF after draining.
Last fall was my first with an I/O set up. I warmed the engine up on muffs for 20 minutes. The engine was of course not under load but the temp guage said it was at op temp. I switched the cooling water to a bucket of antifreeze and pumped five gallons of antifreeze thru. Thought that was it. Luckily I read a post here by Don warning to drain first along with probing. So I opened the petcocks and out came crystal clean pure water!! from the block and the manifolds. (Thanks Don for saving my bacon) Next I removed the thermostat housing and poured two gallons of pink Rv AF in.
Now the mystery; This spring I opened the same drains and instead of pink AF, dark water came out. An antifreeze tester showed my engine was only protected to +10'F. Where did the AF go? The boat was inside an unheated enclosed storage building.
Now the miracle; despite whatever I did wrong the engine had no freeze damage. From now on, I will always add AF after draining.