2005 Mercruiser 5.0L MPI (Bravo 3) - Question about changing Mainfolds/Elbows

[searay250]

Hello,

I have a 2005 Mercruiser 5.0L MPI engine. It's for a Bravo 3 so it has the integrated water pump. I am changing the manifolds and elbows (and I also have spacers) and have two quick questions.

One, I bought new sierra manifolds. The directions say to use red threadlocker on the bolts, but everything I've read online says to use anti-seize. What's the best practice here?

Two, I bought the same manifold part number. They came with a little drain:


But, my current manifolds don't have this drain. Instead, on the only port that seems like it would fit the drain, they have a little Y-connector piece:


What is this piece? Does anyone know what part number it is? It seems like I should replace it since they're quite old and rusty. It ties back into my water system if that helps identify it. Or is there some reason I should switch over to the drain? The piece in my current manifold is not a drain, I don't think... one side of the Y threads into the manifold, another outlet is tied into my thermostat housing, and the one pointing down goes into a tube that seems directly tied into my water recirculating system. So I don't think it's designed to drain.

Or, am I completely missing something and my manifolds actually have both parts and I'm just not seeing the drain on my old manifold?

Any guidance would be greatly appreciated, thanks!

 

[Jmunk]

As far as the thread locker/anti-seize if your referring to the riser to manifold bolts, I used aviation sealant. Not saying it’s recommended or the best, it’s just what I’ve used in the past.

Do your motor have the single point drain system? If so that may account for the difference in the fittings on the manifold. If so, reuse the old.

 

[Fun Times]

Red thread locker = Merc part number 92-809822,
Mercury / Quicksilver SEALANT-50ML TUBE 92-809822
Thread Sealant 809822 is a universal thread sealant. It is for use on thread fittings, hoses, sensors, connectors, fuel lines, etc., on boats, cars, trucks, RV’s, ATV’s, etc.. Has a wide temperature use range of -65F through +450F degrees. Follow instructions on the package for best results. See your owner’s manual or service manual for specific application and instructions. Product is and package is marked at Loctite 567.

Mercury-Mercruiser 92-809822 Loctite 567 PST Thread Sealant

Mercury-Mercruiser 92-809822 Loctite 567 PST Thread Sealant genuine factory part not aftermarket. Fast shipping - Click here to see live inventory status

www.mercruiserparts.com

There is a check ball inside the old fitting to your engine model that is part of the drain system and could also affect engine temperature if not working properly.
Item number 8 - 11, https://www.mercruiserparts.com/bam/subassemblydetail/43949053/28193893

Mercury-Mercruiser 22-863786A1 FITTING ASSEMBLY

Mercury-Mercruiser 22-863786A1 FITTING ASSEMBLY genuine factory part not aftermarket. Fast shipping - Click here to see live inventory status

www.mercruiserparts.com

Genuine Mercury Marine parts, large inventory, fast shipping. 5.0L MPI ALPHA/BRAVO 0W310000 THRU 0W649999

5.0L MPI ALPHA/BRAVO 0W310000 THRU 0W649999

www.mercruiserparts.com

 

[searay250]

As far as the thread locker/anti-seize if your referring to the riser to manifold bolts, I used aviation sealant. Not saying it’s recommended or the best, it’s just what I’ve used in the past.

Do your motor have the single point drain system? If so that may account for the difference in the fittings on the manifold. If so, reuse the old.

Thank you. Yes, it looks like I have the single-point drain system. I was not aware there was a difference. Appreciate the insight!

Red thread locker = Merc part number 92-809822,
Mercury / Quicksilver SEALANT-50ML TUBE 92-809822
Thread Sealant 809822 is a universal thread sealant. It is for use on thread fittings, hoses, sensors, connectors, fuel lines, etc., on boats, cars, trucks, RV’s, ATV’s, etc.. Has a wide temperature use range of -65F through +450F degrees. Follow instructions on the package for best results. See your owner’s manual or service manual for specific application and instructions. Product is and package is marked at Loctite 567.

There is a check ball inside the old fitting to your engine model that is part of the drain system and could also affect engine temperature if not working properly.
Item number 8 - 11, https://www.mercruiserparts.com/bam/subassemblydetail/43949053/28193893

Thank you! Yes, I didn't realize it was a check. I think I'll buy new ones in that case just to be safe. Thank you. I will also pick up some locktite.

 

[Fun Times]

Thank you. Yes, it looks like I have the single-point drain system. I was not aware there was a difference. Appreciate the insight!



Thank you! Yes, I didn't realize it was a check. I think I'll buy new ones in that case just to be safe. Thank you. I will also pick up some locktite.

New fittings should already come with 92-809822 Loctite 567 PST Thread Sealant put on, sort of like what appears the other drain fitting has on it that you showed that came with the new kit....

https://www.ebay.com/sch/i.html?_nkw=22-863786A1+&_sacat=0&_from=R40&_trksid=p2332490.m570.l1313

 

[searay250]

Thank you all. One more quick question.

I bought a sierra manifold kit, the 18-1843. I bought two and both of them were the same... they came with four brass freeze plugs loose in the box, and a sealed bag of 6 other freeze plugs.

On both manifolds, there are five spots for plugs. Two large ones on the bottom, two large ones on the top, and one smaller one on the top. The plugs don't seem to fit right. The little one screwed in fine (by which I mean, it went in a good distance, pretty smoothly, but didn't get flush, which I think is normal for these plugs).

The plugs that were loose in the box don't seem to fit any hole well. They start in the bottom holes, but only go maybe 1 full turn before it feels like they bind up. I don't think they can even fit in the top holes. When I put the large ones from the bag in the top holes, they go in okay, but not great. I couldn't get the large ones from the bag to fit into the bottom holes at all. All of the large plugs LOOK the same, but seem to be slightly different sizes. A 9/16 hex key fits into the ones that were loose in the box, but is BARELY too big for any of the ones that were in the bag. I think those must be metric or something?

This was the case on both manifolds. Same plugs in the bag, same plugs loose in the box... same weird sizing differences... same trouble getting any of the plugs to fit in the bottom holes. Same easy time getting the top smaller plug in.

Also, it seems like the drain plug hole is a weird size, too. I bought a replacement drain (for the single point drain system! That was it!) and it doesn't want to screw in. It starts and goes smoothly for about 1 turn and then binds. On my old manifolds, they went in a bunch of turns. But these new ones don't want to go in, and even the old ones off of my old manifolds don't want to go in, either (they bind up at the same point). The plastic drain that came in the kit goes in nicely, but none of these metal single-point drain systems appear to work.

Am I just dumb? Has anyone else experienced this? The directions didn't give plug placement or dimensions or anything, so one would think that all of the ones that look the same are, in fact, the same. But something is definitely feeling... off.

Any thoughts would be appreciated! Thanks!