interOctave

I have a 2002 31SS with twin 496 HOs and am planning on changing the coolant. I've read Raylar's post regarding location and size of the drain plug. I've also seen a post suggesting the need to unbolt the autodrain pumps to make room for accessing the drain plugs. My initial inspection of where these drain plugs are make it seem like an impossible job with these motors in the boat. There is little to no room on either side of these motors.

Is this job feasible with unbolting the autodrain pumps? I can't imagine people are having to pull motors on these just to change the coolant. I plan to go back out to the boat this weekend to take a closer look at unbolting these to gain access.

Sydwayz

iTrader: (1)

Try laying over the top of the engines, with your arms down. They are not easy to get to, period. The motor mounts get in the way as well. I had much better access in my 37AT than your boat, and it was very, very difficult; and I have pretty long and thin arms. Good luck.

BUP

iTrader: (9)

drain your heat exchanger and then pull off the water circ pump hose completely (front of engine). It will surprise you how much anti freeze will drain. It can make a mess so however to capture most of it would wise. All but 1 to 2 qts max should drain out doing that way. Had to do many 496's that way for draining because of no side access. Baja outlaws especially. Very hard to none side access, plus 99.9 % customers do not want to pay for engine pulls changing anti freeze.

interOctave

BUP,

So you are able to get 17-18 quarts put back in after draining by the hoses alone? Most reasearch I've done seemed to indicate much more would be stuck in the block if draining by hose removal alone. These hold 19 quarts I believe.

BUP

iTrader: (9)

you jack up the boat in the rear and lower the front. very easy to do on trailer. and of course take off the coolant hoses that are related to the anti freeze side of things before doing the jacking. haha

Knot 4 Me

You will also be surprised how much AF you can suck out of the block with a shop vac. Pull the circ water pump hose off at the heat exchanger and angle it downward to drain the majority of the AF. Then stick a shop vac hose into the water pump hose and close it off best you can and let it rip.

interOctave

Well, I tried like hell to feel around the bottom of the engine for those plugs but with the very limited reach I had no success. Also tried sticking my phone down there with video recording but could not find them. I like the idea of using a shop vac to suck it out. If suction works with oil through the dip stick I don't see why this wouldn't get most of the fluid out as well. Thanks for the suggestions. I'll give the shop vac a try this weekend.

interOctave

Finally had time to get to the coolant issue after replacing sea water pump. I pulled the hose from the heat exchanger and after some spillage into the bilge I hooked up the shop vac. The vacuum hose and the coolant hose were the same diameter to the connection formed a perfect seal. I think it worked fairly well. One engine filled up the shop vac to the point of leaking back out the hose which was enough to almost fill up a 5 gallon bucket. The second engine didn't get as much out but that is because I lost a lot of coolant into the bilge the day before when I was swapping out the heat exchanger to cross-over seals. Didn't follow the order of operations on that one. Thanks again for the suggestions. I recommend the shop vac method if you cannot reach the drain plugs.