How much antifreeze does a mercruiser 3.7 hold

[insjim]

I was preparing the boat for taking the family to Bull Shoals Lake this weekend and have a pre-cautionary question for you guys before I strand them at the lake, I hope you can help...I have a 1986 3.7 Mercruiser 170hp with 4" heat exchanger with 130 hrs. This year when de-winterizing the boat I did thoural inspections and flushed the cooling system to begin the season. When I added the new antifreeze 50/50 premix it held a little over a gallon , I then ran the engine approx 10 min. on muffs and re-checked and added about another 1/5 of a gallon....after that I enjoyed the day tubing etc. and everything was fine "Great day in fact" Today I am doing pre inspections and noticed the resevoir was low and added another 1/2 gallon. I see no leaks and temp was running the prior trip all day at 160 degree's. So my question is this...How much fluid does the system hold and do you think I just was low from the initial fill up after the flush. Any suggestion is appreciated:redface:

 

[EddiePetty]

Re: How much antifreeze does a mercruiser 3.7 hold

.......by the book, 11 quarts!!!

....but I only see where you installed +/- 7 quarts.

It takes a while to purge all the air from the system, especially with the thermostat installed AND on muffs.

 

[insjim]

Re: How much antifreeze does a mercruiser 3.7 hold

Perfect....Thanks for the help. I feel better now Knowing the problems with these motors.

 

[Don S]

Re: How much antifreeze does a mercruiser 3.7 hold

When you put antifreeze in, make sure the engine is either level or the front of the engine high, or it will get an air bubble in the back of the block and overheat on you.

 

[hooks1]

Re: How much antifreeze does a mercruiser 3.7 hold

A question to Don S and others: since he didn't overheat do you think there was flush water in the engine when he initially filled it and he was in fact only two quarts low?

 

[Eric 3.7LX Alpha 1]

Re: How much antifreeze does a mercruiser 3.7 hold

When you winterized the engine, did you drain the water out of the sea water side of the exchanger?

If you continue to loose coolant, it might be a crack in one of the tubes of the heat exchanger which can happen if it is not drained early enough before freezing temps. It would be draining out the water inlet in the outdrive if so. Just keep an eye on it for greenish water.