AQ 271C w/ AQ 290DP Leaking water from flywheel cover

[208Cuddy]

My boat is leaking water out the round hole at the bottom of the flywheel cover. First thought was a bad driveshaft bellows.... I can't inspect the bellows well while its in the water and since its a houseboat it's not a simple thing to take it out of the water. But I noticed that it varied from a small stream to drips and that it entirely stops when the engine is started.

To try to isolate the engine from the bellows, I drained the water out of it by disconnecting the big water intake hose to the outdrive (breaking any siphon action) and removed the big hose on the engines circulating pump to drain most of the water from the engine. I came back 24hrs later and the leak had stopped. So this seems to indicate it's coming from the engine, right?

Has anyone heard of such a problem? I am at at a loss, never having the pleasure of taking a Volvo apart. The AQ271 is a 1988ish Chevy 350. Is there a hose or freeze plug or something on the rear of the engine that could be leaking inside there?

I am going to try dumping anti-freeze in the intake hose and see if it starts dripping pink. It starts, idles and runs well and has about 10hrs on it this season before this started. Last fall water was drained out the same way and AF was poured into intake hose while running and then into the thermostat housing and manifold feeder hoses... so I doubt its a cracked block- Am I missing something? What do I do next?

Thanks to the experts for running this board and everyone else who reads and contributes.

 

[Don S]

Re: AQ 271C w/ AQ 290DP Leaking water from flywheel cover

To try to isolate the engine from the bellows, I drained the water out of it by disconnecting the big water intake hose to the outdrive (breaking any siphon action) and removed the big hose on the engines circulating pump to drain most of the water from the engine.

To make absolutely sure, mix up some green antifreeze and water (just to make it green so you can see the difference)> Then adapt a hose from the intake side of your raw water pump into the bucket and start the engine. See if the water turns green coming out of the engine. If it turns green, you may have lost the core plug on the back of the engine block.

 

[208Cuddy]

Re: AQ 271C w/ AQ 290DP Leaking water from flywheel cover

Thanks a bunch Don. I put antifreeze in there and it started leaking again- clear water. I didn't have the hose necessary to rig up and run it on antifreeze. Planning to do that later today. How difficult a job is it to replace a core plug? The engines in the cabin on this boat and I probably could slide it forward a foot or so.

 

[Don S]

Re: AQ 271C w/ AQ 290DP Leaking water from flywheel cover

How difficult a job is it to replace a core plug?

The core plug is easy to replace, it's getting to it thats the problem. I'm guessing since the engine is in the cabin that it's a jackshaft model? The flywheel cover and flywheel have to come off to get to it.

 

[208Cuddy]

Re: AQ 271C w/ AQ 290DP Leaking water from flywheel cover

I don't know what a jackshaft model is.. this is what I've got

That's a negative on the antifreeze experiment. I tried everything more than once even removing the thermostat and dumping the circ pump hose to see if I could see the color in the water... It was easy to see, but tried again anyways, piping in several gallons of af while running the engine, stopping the engine and checking periodically for color over several hours. So I guess it's back to bellows? or What else could be leaking?
I am truly baffled as to why the dripping eventually stops if, and only if, I disconnect the water intake from the engine. I am going to reverify this over the next few days.... I may also try to put a few lbs of air pressure into the flywheel hole and swim for bubbles.
This model looks like it has at least 2 sets of bearings and a u-joint between the bellows and the flywheel housing that have water on them now. Can you change all this stuff from outside the boat? Can I dry and regrease the ujoints if they're not sloppy? What else should be done besides bellows. Thanks again!

 

[208Cuddy]

Re: AQ 271C w/ AQ 290DP Leaking water from flywheel cover

Turns out I've finally and conclusively found a leaking driveshaft bellows... I'd expect to see a lot more water to be coming in from the size of the crack in it. From what I've been able to find there's nothing else to stop it besides those 2 sets of "intermediate" bearings and oddly enough those must be stopping the water. So mystery's over but I still need a lot of help.

I've located and ordered both bellows the u-joint and the hose, 4 hrs on the internet and I cannot find the 2 sets of bearings ANYWHERE. The VP parts reference I have gives me 183247 and a "best" part# of 19247 for the outer... and all of the following numbers 3850852, 853949,183668, suspiciously 183247 again for the inner w/ a "best" of 19949. 183247 for both. Hmm so they're both the same? for real? Does anyone have a source for these?

Also please tell me that the engine doesn't have to come out to do the bearings- and that's it's possible to do by just sliding it forward...or better yet whats the chance I can avoid engine moving and just dry them out and reuse. Thanks again for your help!!

 

[Don S]

Re: AQ 271C w/ AQ 290DP Leaking water from flywheel cover

4 hrs on the internet and I cannot find the 2 sets of bearings ANYWHERE.

Scroll up and look just above your original post. Click on the Volvo parts icon look up the OEM parts and order them from here at iboats.
Connecting Components Aq Drive Unit 290a, Dp290a AQ271A, AQ271C - 7743470 - Volvo Penta

Also please tell me that the engine doesn't have to come out to do the bearings- and that's it's possible to do by just sliding it forward...or

If you can move the engine forward enough, go for it. Personally never tried it. I would guess you will have to move forward a minimum of a foot, probably more.

...or better yet whats the chance I can avoid engine moving and just dry them out and reuse.

Not a snowballs chance in ....., well, you know.