Mystery to be solved - reward to whoever gets it!

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KWG

Seaman Apprentice
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Aug 11, 2010
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Hello guys, I am new to this forum.

Here is what I have:
1999 Bayliner 2655 with 5.0L V8 (carb) , Alpha 1 gen. 2 drive

I have a problem that has developed over the past couple years that I can't seem to figure out ... most of you will probably think: "here we go again...we have covered this before" ... as I have seen these symptoms on other forums and thought the same thing....please read ALL the post before giving the standard answer please, thanks. :)

My starboard side manifolds and risers are WAY hotter than port AND at the oulet at the transom it pours out the port side and just sort of spits out the starboard.

Before I get the "its a clogged manifold, riser, elbow" stuff let me tell you they are new ... so that's not it. :D

I can take a C-clamp and clamp off the port supply hose at the Tstat housing and the water will then pour out the starboard side and spit at the port. The starboard manifolds, risers and elbows then run cooler than the port! All the while the engine temp. stays rock solid at 165! AND when I then remove the C-clamp (with the engine still running) the heavy stream REMAINS on the starboard side!!?!
(you would think it would go back to the other side like it was before the test began)
If I shut the engine off and let it sit a while then restart it then again starts with full flow out of port.

I have posted about this before on another forum but could never seem to get an answer other than "the starboard side always runs a little hotter" ...well my port side is cool enough to leave your hand on while the starboard side gets so hot you can't leave your hand on it for more than 2 seconds (will get IR gun readings later) and I know that is TOO MUCH of a temperature variant.
When it was new, yes the starboard side was a LITTLE hotter but not this much.

I can't understand why the water isn't being split equally going to the manifolds from the Thermostat housing.

The Tstat housing is clear as a bell, I cleaned it real good while I had it off anyway (it was clean to start with though) and the plastic diverter is in there correctly and the Tsat is operating perfect. This is the most puzzling thing I have ever run across in all the engines I have ever worked on.

My Tstat housing doesn't have the rod and ball setup to equalize the pressure it has an inlet from the leg, a large hose to the water pump (circulating) and then 2 hoses going to the bottom of the (nice and clear) manifolds.

Here is a list of everything that has been replaced/checked so far -
(and it did it before any of these were replaced also)

- Water pump impeller/plate (leg)
- Circulating water pump
- All hoses checked and clear
- New hose from drive to engine (flow checked to be unobstructed)
(this done during bellows replacement earlier this year)
- Manifolds new/ risers and elbows clear as a bell
- Flapper valves checked and OK
- No obstructions in exhaust Y pipe
- Tstat housing checked clear and clean
- New Tstat working properly
- Checked power steering cooler tube to be clear (in line with hose from leg)

So there you have all the pieces of this puzzle that I have ... now if I can somehow get this puzzle to work out then my life can get back to normal

A case of your favorite brew to whoever puts me on the answer to this mystery.

Thanks for letting me bend your ear.

Kirk
 

JustJason

Vice Admiral
Joined
Aug 27, 2007
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Re: Mystery to be solved - reward to whoever gets it!

are you measuring your temperatures on a garden hose or with the boat in the water?
Exhaust is going to run hot on the garden hose, that's part of the reason you don't run the motor over idle speeds.
If you haven't already, put the boat in a pond, warm it up, then take the manifolds/risers temp with an IR gun and report back.
 

FreeBeeTony

Captain
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3,991
Re: Mystery to be solved - reward to whoever gets it!

I am confused.......

I assume this is a single engine.......how can you tell the difference in the flow of water from 1 manifold to the other if both manifolds are feeding the y pipe?
 

KWG

Seaman Apprentice
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Messages
46
Re: Mystery to be solved - reward to whoever gets it!

Thanks guys,

Yes it also does the same thing on the water.

There are 2 outlets at the transom where water comes out right up forward of the drive ... it also comes out through the prop.

Thanks ...I left those parts out!

Kirk
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
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10,083
Re: Mystery to be solved - reward to whoever gets it!

Before I get the "its a clogged manifold, riser, elbow" stuff let me tell you they are new ... so that's not it. :D
Howdy,


Before I tell you it's a clogged (new) riser....did you swap them and see if it's still "hot" on the same side? Those things are cast. The casting process is not exactly a hard science!!


Cheers,

Rick
 

frank246

Petty Officer 1st Class
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Messages
293
Re: Mystery to be solved - reward to whoever gets it!

You might do need the termostat house with the TEE valve/checkball assy on the 5.0 as these equalize the flow out
Good luck!
 

KWG

Seaman Apprentice
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Messages
46
Re: Mystery to be solved - reward to whoever gets it!

Thanks Rick,

No I didn't swap the manifolds but I did swap hoses at the Tstat housing (had to use 2 extensions) and the flow/temps did switch sides. Thats why I think it has something to do with the Tstat housing ... but there's not much that can go wrong in there unless something has worn away in a manner that it still looks normal or something.
I tried to find a cutaway picture or diagram on the net of a tstat housing to compare mine with but no luck.
If anybody here knows where I can find one or even pics of a new one )internal pics) that would help me to completely eliminate the tstat housing.

Thanks
Kirk
 

Cuyose

Petty Officer 3rd Class
Joined
Jan 19, 2006
Messages
90
Re: Mystery to be solved - reward to whoever gets it!

Doing a quick search on google, this is a common issue among people with the T-stat housing that do not contain the diverter ball assembly. I haven't actually found any indications its causing any damage, but like you it is definitely a concern. If you can find a housing with the diverter ball assembly I would try that.
 

The Hammer

Petty Officer 2nd Class
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Re: Mystery to be solved - reward to whoever gets it!

I would bench test the thermostats, just because there new dosn't mean they work right. Just guessing for the prize!:)
 

John_S

Rear Admiral
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Messages
4,269
Re: Mystery to be solved - reward to whoever gets it!

I experienced some heating/cooling issues this spring, so have a little idea of the fustration you are going through. I was surprised to learn that because of all the drive and cooling system variations, there is not a comprehensive diagnostic path. There seems to be a delicate balance between water volume and pressure/restrictions.

Like Jason, wondering how you are running and doing the testing. If on muffs, take a plastic garbage can and cut it down to use as a tub to feed the drive.

Does the temp diff go away if you increase rpms to 1K? Does it go away if you rev it and then drop back to idle? Have you pulled plugs on starboard side to make sure your riser gaskets are not leaking? Starboard manifold hose not crimped, especially at bends?
 

scoflaw

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Re: Mystery to be solved - reward to whoever gets it!

The water is taking the path of least resistence. So one side is tighter than the other. I'd say disconnect the 2 manifold lines at the T stat and blow thru them ,to see if you notice a difference. Could be a casting flaw. If they feel equal, must be in the T stat housing.
 

John_S

Rear Admiral
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Re: Mystery to be solved - reward to whoever gets it!

If you can find a housing with the diverter ball assembly I would try that.

Was there a 2 hose output with balance balls? I know the 4 hose did, when there was a seperate hose to riser and bottom of exhaust manifold.
 

John_S

Rear Admiral
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Re: Mystery to be solved - reward to whoever gets it!

No I didn't swap the manifolds but I did swap hoses at the Tstat housing (had to use 2 extensions) and the flow/temps did switch sides. Thats why I think it has something to do with the Tstat housing ...

Interesting additional input.

Any air bubbles in the output water?
 

KWG

Seaman Apprentice
Joined
Aug 11, 2010
Messages
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Re: Mystery to be solved - reward to whoever gets it!

Wow,
Thanks for the replies guys,

Yes it does the same thing in the water or on the muffs ...starboard side always WAAY hotter.
Did the blowing into the manifold hoses thing before ... no restrictons/resistance at all. Hoses are clear & no kinks.

Thermostat was tested out of the engine ...working perfect.

My housing doesn't have the diverter balls, and although a different housing WITH diverter balls may (or may not) solve this problem I am wondering what has happened to cause it to be like this ... there HAS to ba an answer to this.
I have tried everything I can think of.
I am going back out to the boat now to ponder on this some more.

Thanks for all the responses ... I know it sounds as if I am just saying I have tried all of these things you are suggesting but I really have tried them all (so far) and that is why I am at my wits end with this thing.

I won't let it beat me though ...there HAS to be an answer. :confused:

Thanks
Kirk
 

Outsider

Lieutenant Junior Grade
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Apr 24, 2007
Messages
1,022
Re: Mystery to be solved - reward to whoever gets it!

After carefully evaluating the information you've supplied, I've determined you have no actual problem.

If everything is new and/or correctly installed - and you have no overheat problem - then you have only a perceived problem. The solution I see is to tinker with the diverter vane, which smacks of fixing something that may not be broken. Your choice, your call.

No prize needed, just a hearty thank you, thank you, thank you ... ;)
 

John_S

Rear Admiral
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Re: Mystery to be solved - reward to whoever gets it!

Does the temp diff go away if you increase rpms to 1K? Does it go away if you rev it and then drop back to idle?

???

I am guessing that at least one of the above does clear it up, or you have been docked a long time working on this :( . ie, I assume you have been still boating and haven't melted any exhaust hoses yet.

Your comment that this has been an evolving problem, like it has gotten worse over time, might map to a corrosion issue, possibly in the housing. I assume you are raw water cooled and boat in slat or brackish water.
 

JustJason

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Re: Mystery to be solved - reward to whoever gets it!

salt boat or freshwater?
 

KWG

Seaman Apprentice
Joined
Aug 11, 2010
Messages
46
Re: Mystery to be solved - reward to whoever gets it!

Thanks,
Outsider, yes there is a problem which isn't just percieved ...it is real.
When new I could keep both my hands on the elbows no problem, yes the starboard was a little hotter but no problem.
Now the port stays cool and you can fry eggs on the starboard ... on the muffs or running in the lake. But it hasn't got to the point of burning any hoses or anything so SOME cooling is going through the starboard.
The water out the transom flows a solid (no air bubbles) stream on port side and just spits and sputters out of starboard. Unless I do the C-clamp thing like I described or swap hoses at tstat housing then everything swaps sides.

This has to be something with the tstat housing ... I really need to see a cutaway diagram or an internal look at a new or known good housing and compare mine with it. That will give more clues as about what is going on.

Mystery still not solved.
But thank you, thank you, thank you anyway. :D

Kirk
 

KWG

Seaman Apprentice
Joined
Aug 11, 2010
Messages
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Re: Mystery to be solved - reward to whoever gets it!

It is used in both salt and fresh.

Manifolds, risers and elbows are new. (I change every 5 years)
And you really wouldn't believe me if I told you how much I flush it out after running in salt ...you really wouldn't...I really go to an extreme...so it's not a matter of me not flushing after salt usage.

I am going to pull the tstat housing and take & post pics of it to see what you guys think.

Be back later.

Thanks
Kirk
 

scoflaw

Ensign
Joined
Jun 2, 2010
Messages
962
Re: Mystery to be solved - reward to whoever gets it!

Put a restrictor of some sort in your free flowing side to balance things off.
 
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