Update: 5.7L MC Bluewater FWC temp creeping high on plane, read tons of posts.

[rothfm]

Yep Skippy. That will be coming soon too. Wanted to go thru the system fully today for piece of mind.

Gotta return with exchanger end seals (hand-made my gaskets today), so will get one of these to try.

Thanks again

 

[rothfm]

Dont know much about Thru-Hull pickups.....I havent been back to try the Hi Flow Stat recommended, BUT......

HOWEVER, with goggles, a underwater view of the thru-hull intake strainers showed they were "convex"-shaped inwards, not Convex. I didnt view this myself ( a family members boat). But I do remember making a mental note of this when it was delivered from out of state in the Spring.

****Could these pickup thru-hull strainers be of the wrong type (concave vs Convex?) or simpily the vanes just bent inward? MORE IMPORTANTLY CAN THIS SHAPE AFFECT ENGINE TEMP?

Even the good engine runs possibly a tad high, but it also has the long run up the boat to the hot water heater, maybe that run reduces the heat a bit to acceptable levels. Its strainer is similar to the Engine in question (temp)

I relate it to my boats Live well drain (in floor livewell). If I take out the plug that leads to the bottom of the boat, on Plane no water comes in, or goes out due to the way water flows under the hull!

So if these pickups are convex or crushed in, what impact is that having on proper volume in, on Plane? Low speeds Temps are fine.

Thanks

 

[rothfm]

mistyped...meant the pickups are concave ( slots inward shaped) not Convex (slots outwardly shaped).

 

[rothfm]

Any thoughts on this "concave" shaped theu hull water pickup? Could this be my heat on plane issue?

 

[rothfm]

May have heat issue id'd. Intakes have barnicles in them.

Took boat out of water. Not only are the thru hulls bent inward, they seem semi-clogged inside.

Going to take theu hulls and seacoks out for cleaning/replacement

 

[rothfm]

Well, We had boat hauled out. thru hull intakes were partially blocked with Barnicles, and were bent inwards/concaved, so took them out-put new ones in, sealing it all back up.

Really thought that was it....Test run yielded the same results. Climbs to 195/200. Going to Test with No stat, then put in the HI-Flow that was recommended. If this still climbs with no stat--Obviously something is awry. If nominal temps will put in the Hi-Flow 160 I have, or even move to a 140 for testing.

The saga continues.

 

[rothfm]

Rrrggg, Looking for further input on this issue, if anyone can lend their thoughts.

Took out the Staboard engine stat totally. It warmed up slower-BUT still went to about 170 at idle at dock, with NO stat! Took it for a ride, and same result--about 180-190 on guage. (guages already swapped).

I then put in new 140 stats in Both engines....But only idled at dock this time(no speed run), and surprisingly both idled at 170 maybe a tad higher. If we did a speed run, I bet stdbd would still run at 180-190 and I'm feeling the Port would run the same at 170-180. The Port is the side that has a run up the boat to the hot water heater and I'm thinking that drops it 10+degrees. So both seem to be running about the same, but too hot in my opinion. Shouldnt I expect lower(lots lower) Temps with no stats and seawater at 65-70????

To Sum up....I'm thinking Both Port and Starboard have heat issues. Tested Stbrd with no Stat=HOT. 140 Stats in Both idle at 170+ degrees.

Up to now I have only been working on the Starboard engine methodically, working the process of elimination approach. See above posts for what was done/tried. I have some thoughts but looking for other input to "Hash" around.

Big Thanks if you can lend further advice

 

[Fun Times]

And I couldn’t use the Cork as it would sit up high and the housing would not seal. Is this correct?

No your closed cooling thermostat housing design doesn't utilize any additional gaskets or O-rings inside the housing like a standard cooling system uses.

The parts counter guy suggested I get the plastic sleeve and brass type ring also in case needed. It didnt have either of these in the housing. It was just the stat sitting on the lower housing, gasket over that, then the top housing/cover and bolts. Very simple.

He was either looking at or thinking of the standard cooling system vs the closed system. Easy mix up to do as standard is a bit more common practice. The following link will be your cooling/thermostat system, Notice no gaskets or sleeves inside the T/housing. http://www.mercruiserparts.com/Show...nbr=2047&bnbr=170&bdesc=CLOSED+COOLING+SYSTEM

Also keep in mind that you may have a transmission oil cooler that could be clogged as well. Item #13 for example, http://www.mercruiserparts.com/Show...ION+AND+RELATED+PARTS+(V-DRIVE)+(BORG+WARNER)

Here's all your parts if needed, http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=809645+93

A few good reads for you,
https://www.perfprotech.com/blog/articles/fresh-water-cooling-trouble-shooting
https://www.perfprotech.com/blog/articles/cooling-system-tips
Start with FreeBeeTony's topic date of June 26th, 2015, 06:39 AM and work your way up for other ideas.
http://forums.iboats.com/search?sea..."vBForum_PrivateMessage"],"starter_only":"1"}

Typically closed cooling runs a little hotter so seeing right around 180 degrees isn't to big of a concern... Anything over say a true 186* would be of concern.

Can't rule out the circulating pump/s until at the very least the brass impeller is inspected with the removal of the SS backing plate. The impellers do wear out eventually.

Your water temp switch to sound the alarm is Merc part number 87-86080 which means the alarm won't sound until 220 degrees (FWC**)

If you by chance have a velvet tranny then, http://bpi.ebasicpower.com/mm5/merc...roduct_Code=ALT99329A&Category_Code=CRUSENDER

 

[rothfm]

Thanks FunTimes

I will go thru the links you sent. Stats and housings I now know are pretty basic, they drop in and thats about it.

Just seems odd that with 140's installed for testing, both engines still go 170+ at idle and up to 180-190 on plane, particularly the starboard.

I wanted to see if the cooling system was able to be regulated at any lower temps at all. I have to believe the new 160's and now new 140's are fully opening, yet im running the same high temps.

Even took out the stdbd stat and on planesatill went to 190+.

I opened the trans cooler, no blades or any debris(at least on the input end). I didnt remove it to clean fully, as i did with the Exchanger, so that could still be suspect as is the raw water impeller done in 2013.

Im under the assumption the coolant side is ok due to its maint history and mani's and risers are within 5yrs, and risers run cool. I wouldnt expect mani blockages with that age, and running coolant thru them(no salt water)

Can someone confirm that testing with no therm, then 140"s- I should see an obvious difference in temps at least? Seems no reason I'd be that high with an open channel of raw water. Surrounding seawater is 65deg. And with 140's I should see something around that range idle and on Plane, Right?

Thanks again. Will read the attached links.

 

[rothfm]

Read all the links above...Brings up a simple question I have....

IF my risers are 100-120 (pretty cool) even on Plane...Isnt that an indication of proper FLOW thru the entire Raw side? Raw water "to and through" those risers is needed to keep them from getting crazy hot from Exhaust gas. That is the last flow area in the Raw water path as it exits to the mufflers.

So, Is it a correct statement to say, given my risers are cool at all temps---The Raw side had no flow or restriction issues?

Important question in my mind...Allows me to concentrate elsewhere!

 

[FreeBeeTony]

Is it possible to remove the rubber boots from the risers?

Might be worth taking a l​ook.
My risers were only 3 1/2​ yrs old and they were shot.

 

[rothfm]

Thanks Tony.

Will take a look next time at the boat...But given the Mani's and Risers have seperate water sources(fresh/raw), and dont interact..If Risers were shot and/or I had reduced raw water flow thru them, wouldnt I see heat there? They run cool.

Looking at the diagram now...I supposed a blockage in that area, could slow the raw-flow enough where the Exchanger is not efficient at transfer of Coolant heat, But again my risers are cool at all RPM's.

Or are you saying Risers could have an actual exhaust gas passage problem thru the Risers(vs water flow), backing up the release of exhaust, creating higher manifold temps??? Would I see that scenerio as a strange running engine?

I guess its plausible, as the Mani's do run warm 180-200+ on Plane...If the Mani's are running too warm, maybe this elevates the overall Coolant Temp thru them, and the rest of the coolant side of the system??

 

[rothfm]

Tony, Your risers at 3.5yrs "SHOT"....shot meaning water passages? Were they running hot specifically?

Thanks

 

[FreeBeeTony]

Not sure if they were running hot.....never checked the temps.

But after I replaced them the temp was steady @~160*.

 

[rothfm]

Ok Thanks for that.

If anyone has any further input.

.If My risers are cool at all RPM's, can I deduct that the Raw water side of this system is running fine?

Or Can risers run Raw water thru ok, keeping them cool--But still have a problem where its increasing the coolant temp flowing separately in the Manifolds, Elevating the entire Cloosed loop tempatures??

 

[rothfm]

Tony,

Can i ask if your setup was Full FWC, Meaning Coolant in the mani's and Raw flowing thru those risers?
Will help me relate to our issue knowing that.

thanks

 

[FreeBeeTony]

Full FWC'd.
Maybe the raw water flow is enough to cool the risers and not the heat exchanger?

 

[rothfm]

Thanks Tony

Those risers are surrounded by very hot exhaust gas.

We called Mercruiser support today, he said if risers are that cool, raw side is good.

Going to plug on a mechanical temp guage direct to sender port... Sort of back to square one and verify the actual water temp by measuring the water itself coming out of the block.

Maybe the work that has been done has improved the systems, and we got bad 20yr old guages and senders.

Ongoing! Will update when we do this.

 

[FreeBeeTony]

Did you inspect the risers anyway?
Just curious.......

I went out last night.
I can actually watch my thermostat open, temp rises to ~170-180* and when the thermostat opens drops to~160* and holds there.

On my may back the boat cooled down to the point where the thermo and opened while I was running kinda hard.
When it did open, it still cooled down to 160*, just took a little longer.

My point is that before I replaced the risers the temp continued to rise close to~190* or so. That's when I began suspecting my risers.
I believe as a rule of thumb: overheating at idle = impeller problem; overheating at speed = restriction problem.

 

[biggjimm]

Rothfm, my first step would be what you just hit on in your last post. Put a mechanical gauge in place of the current gauge sender to verify actual temp of each engine & go from there. I don't know a lot about these cooling systems, but I have learned a lot about them by reading this thread. One thing I would point out is two identical engines can have very different characteristics, one could just transfer heat from the block, heads & manifolds better than the other one. It is odd the only difference your finding is in the stat-housings though. Has this always been an issue with this boat or did it just start? What does previous owner say about has it was when he had it? Sorry if you stated that earlier, if so, I don't remember.