square drive manifold drain plug seized on

[Whidbey]

This is probably stupid, but...winterizing and can't get back drain plug off on one side, so I did the front of the stuck manifold instead (take hose loose and point fitting down). Am I good to go for that side. The other side was piece of cake...different fitting too. Weird because both manifolds look new.

Thanks!!

 

[Don S]

Re: square drive manifold drain plug seized on

They don't have square drive pipe plugs for drains. Those are just plugs to unused ports.
What model and engine are you working on.

 

[Whidbey]

Re: square drive manifold drain plug seized on

91 VP 570. It does have a brass square plug on one side (port). The other (starboard) is a standard plug that came off easily. So, I drained the port side from the front after taking of the raw water hose. I just did my dads aq271 and his has allan drives...so I certain I'm draining the right plug. Just wanted to see if you agree that by drain the port side from the front of the manifold in good enough or should I get more aggressive on the square plug?

 

[Maclin]

Re: square drive manifold drain plug seized on

If those are stock then there should be a large plug on the end aiming at the exhaust pipe, just enough clearance to unscrew it.

As far as draining it out the front, I think the bottom of the plug on the back end may be lower than the bottom of the fitting on the front. But if you can get the boat angled forward some, say towing it down a steep hill slowly then stopping a couple of times, and with the hose off you may be able to get enough water to drain and slosh out to be safe from freezing.

 

[Maclin]

Re: square drive manifold drain plug seized on

For reference, the exhaust plugs on my 1991 570/DP are large brass plugs with 7/8" hex end. They are on the back ends, not the sides.

 

[Whidbey]

Re: square drive manifold drain plug seized on

As always, thanks Maclin for all your help! Crazy boat of mine, one side has the standard hex plug, don't know why the re-builder put that square head in the other side, but it sure seems to be stuck. I'll do as you suggested, didn't think it was baffled like a septic tank but wanted to make sure. The front drained well, but I'll pull it down my steep driveway and put some angle to it. I wonder if heat would help it give? I put a lot of leverage and tapped the wrench well good, but to no avail, it almost seems cross threaded. Everything is to new to be corroded that much....crazy!!

 

[Don S]

Re: square drive manifold drain plug seized on

Item 13 in the picture below is the drain plug. Usually a 7/8 or 15/16 wrench needed. (Don't remember exactly which). The rebuilder may have lost the original and used a different plug. The ones with a square hole in them are used a lot in Mercruiser manifolds for blocking unused ports. I would suggest you head to the hardware store and get a matching set of BRASS pipe plugs. Makes it a lot easier to deal with each year than having different sizes in them.

 

[Whidbey]

Re: square drive manifold drain plug seized on

Will do Don. I think I'll inject some antifreeze in the front of the one side for a little insurance while I work on getting the square head plug off. Thanks!

 

[Don S]

Re: square drive manifold drain plug seized on

Putting antifreeze into a manifold that has water in it isn't going to do anything. Fill a glass FULL of water, and then try to put some antifreeze in it without spilling any.

 

[Whidbey]

Re: square drive manifold drain plug seized on

I took the raw water hose off the 90 at the front of the manifold and then rotated the 90 fitting counterclockwise until it pointed down, it drained well. Also, I lowered the trailer so that gravity favored the front (temporarily) and then hauled it at a steep angle stopping a few times as Maclin suggested. So how about if I re-attach the hose, undo the other end from the heat exchanger (which has both ends off) and pour antifreeze thru a funnel. I get ya on the glass full point. Thanks for being concerned re-freeze damage, I appreciate your experience and input.

 

[Whidbey]

Re: square drive manifold drain plug seized on

Hey Maclin, on the power steering pump cooler on our motors. What do you do there? I not understanding this system.

 

[Maclin]

Re: square drive manifold drain plug seized on

Whidbey,

I was hesitant to post back on this because I am certain my system does not have the power steering cooler, so I will not be able to give specifics on draining one. It would be inline on the inlet hose between the drive and the raw water pump, right about at the front engine mount. My system just has a straight hose, no cooling unit and I am pretty sure it has not been messed with prior. The PS lines on mine run straight back to the steering rack. This has always confused me because the 570 manual calls out to drain the power steering cooler. The manual for the AQ271C which is the immediate predecessor to the 570 calls out just draining the exhaust, block and removing the raw water pump cover. That is all I have ever done and been fine, but please do not necessarily take that as the corrrect procedure for yours.

I have the owner's manual for the 570 and also for the AQ271, separate manuals. The gauge call-outs from the AQ271 book look more like my system than the ones in the 570 even though the top cover on my engine says 570. The 1990-1991 years were transition years maybe, Volvo seemed to have a hard time with that regarding documentation.

If you do have the power steering cooler then it should be drained separately because just removing the front cover of the raw water pump may not drain that as the hose goes up then back down to the pump after the cooler. There would be a drain plug in the bottom of the cooling unit. Should be a pint or more of water maybe?