Vinegar Flush Help

I've posted this on a couple of other forums however word on the street is that THIS is where the REAL mechanics roam. 😉 True story.

My issue? Well last summer I had an overheating problem that plagued me all season.
Last season's threads:
http://www.mbboatown...lp-overheating/

http://www.mbboatown...emp/#entry60382

2004 330hp Excalibur 5.7L

I've narrowed the cause down to the exhaust manifold/risers. I'd like to try doing a full vinegar flush to see if that solves my issues before taking the whole exhaust manifold apart and dealing with that potential chaos. (I'm NOT a mechanic... also not an idiot... but not a mechanic)

Side note: my mechanic cannot figure out the issue either... he's top shelf. Unfortunately he charges top shelf prices as well. $$$ He and I checked/replaced everything up to the exhaust last season so I know there are no issues with wrong/faulty parts up to the exhaust.

My question... cuz I'm crazy paranoid... is how exactly, step by itty bitty step, do I do it? I'll be doing it myself with no help so the more info you guys can lend the better my odds of success. I'd also like to post a detailed thread complete with video/photos after (unless it already exists) for others like myself so they don't need to go through what I'm currently going through at the moment.

so...
-what holes do I open...
-what holes do I close...
-what holes do i pour into...
-particular type of vinegar...
-how much vinegar, how much water...
-fake a lake or no fake a lake...
-what parts do I remove...
-what parts do I replace...
-how long do i do it...
-how will i know if it works...
-warning signs, things to watch out for...
-run engine, don't run engine...
-warn the neighbors of potential stink cloud...
-etc.

These are the questions that keep me up at night.

Please help with advice, wisdom, links, photos, videos, wise cracks/comments etc... I'll take anything cuz my family's happiness this summer depends on it! My boy, only 9yrs old is counting on his father to come through. My teenage daughter is counting on her father to be the "coolest" dad ever. My wife, well, I fear that no boat for the summer may be a deal breaker for her. No pressure, but a warning that I'll be blame shifting onto everyone else but me if I can't get this solved for my wife and kids. Just sayin'.

Thanks in advance.

Dave

Hey Dave, welcome!!

Before you Massengil that poor engine let's look at a few things:

I read the other threads and we should probably just start over here.
Did you replace the original strainer (hopefully not with the one that was posted)?

Checklist of things to do:
Check impeller condition, if OK leave it in.
Clean strainer screen and be sure you still have the rubber gasket at cup
Tighten every hose clamp, use a 5/16 nut driver not a screw driver
Remove the large brass plugs from the exhaust manifolds and clean out any debris you can


Then report back

Corrected Links:
http://www.mbboatowners.com/index.php/topic/4688-help-overheating/
http://www.mbboatowners.com/index.php/topic/4813-2004-pcm-57l-excalibur-330-mfi-running-temp/#entry60382

I'm not familiar with that engine but is it possible that he routed the serpentine belt incorrectly? Also, what caused it to get so chewed up in the first place?

I read both threads quickly, it sounded like a comedy of errors with several different failure modes happening at different times- giving the appearance that they were related by a common cause... but I suspect you have/had MULTIPLE issues that you were trying to troubleshoot concurrently, leading you down wrong paths. Here are a few things to remember:

-160 stat will have you running a fairly steady 170-180 if all is well.

- an overhead at idle (normal temps at speed) is likely due to an air leak between the rwp and through hull. Hose condition, hose connections, strainer bowl are all things to look at here.

- an overheat at speed (normal temps at idle) is going to be due to lack of flow. Impeller condition, rwp installed/spinning backwards, bad rwp seals, or a blockage in the system will cause this failure mode.

With all the attention given to the cooling system I *think* you moved from one failure mode to the other, i.e., you solved one problem and caused another. Describe for us the exact nature of your overheating situation NOW, ignoring what you saw in the past.

Consider me very skeptical that the exhaust manifolds are to blame.

How you douching on this

Well the idea of cleaning out the manifolds has some merit, maybe only to me because i did just that.

I used 'The works' toilet cleaner. I closed off all ports & sloshed it around, let it work for an hour. The manifold was off the engine, of course (I had them off for valve seal work).. A lot of crud came out when I dumped it.

I don't think doing this with vinegar, while manifold is still on the engine will accomplish much.

If you think the manifolds are clogged, maybe just hook a garden hose up to the raw water port & see if they flow OK.

Edit - Just occurred to me this problem sounds similar to a friend's. He has a 'toon with mercruiser GM V6 not very old. It was overheating.   I got involved because his mechanic gave up on it (PIA to work on)

I took 1 riser off & clean as a whistle inside. I then hooked up garden hose to hose that connects to manifold & back flushed.

Now instead of pegging, it goes a little hot then stettles down. I think sand was /still is in the thermostat housing passages.

Gary, or anyone else here.... has anyone made stainless steel manifolds for saltwater applications? Alternatively has anyone tried metallic barrier coatings for manifolds (the oil patch uses high phosphorus electroless nickel plating for brine applications to prevent corrosion from seawater.)?

There are several Pete,Commander made them, Stainless Marine is another and of course Hi Tek. I am in the process of testing out a pair on my Shamrock    For what they cost I could have bought 3 sets of PCM ones but that would only give me about 15 years of service. So far after 2 years the Hi Teks don't even have a mark on them. A great advantage with them is that they fit exactly the same as the PCM ones. If I had found a set of Commanders my battery tray would have needed to be removed and something to do with them figured out. I would love to have them for the Nautique just for the looks but due to fitment it makes plugs hard to get at.

tryathlete wrote: Gary--any issues with hose/manifold fretting corrosion?

I can say no since it occurs between metal surfaces and the hose is rubber!

The common place for it is at the prop shaft to the trans coupling when the alignment is off. The interference between the two is under load and constantly flexing.

tryathlete wrote: Rubber hose and stainless are known to be bad together in terms of corrosion. From an bold "yacht survey" blog

Pete,
You need to remove the word "fretting"! BTW, rubber on 400 series isn't the greatest but on 300, it's fine. Your yacht survey people must be using inferior "muffler" stainless!!

It's crevice corrosion I was recalling. It's described here;

Maybe better defined here;

https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/25077/SGNO78.pdf?sequence=1

No that stuff is for old people 😂

Gary S wrote: You need crack cream

tryathlete wrote: No that stuff is for old people 😂

Careful with the old people reference.

Another question: replacement exhaust hose... best prices/place/brand to get them?

LiquidObsession wrote: Another question: replacement exhaust hose... best prices/place/brand to get them?

David, weren't you going to post details of the overheating problem later on? As people have mentioned, it's likely a cooling system issue that can be diagnosed once you explain more about when it overheats.