MAN 1200hp engines

As the old saying goes, every day is a school day. Thanks for enlightening me!

I'm not sure to see the point of it, considering that there's a cap just above the HE box and it's very easy to check the level from there - not to mention that there's also a low level alarm.
But I guess Viking thought an additional instrument couldn't hurt.
Assuming it's a factory installation, that is - could as well have been retrofitted.
Pretty sure it doesn't come standard with MAN engines, anyway!

I appreciate the convenience, but I suppose that instrument can only provide a meaningful reading on a cold engine, since the coolant closed circuit gets pressurized while running.
And when the engine is cold, opening the cap and checking the level in flesh (so to speak) ain't such a big deal - not to mention that you're sure to have a perfect reading that doesn't depend on any instrument.
Then again, I also have the habit to trust only tank sight gauges for fuel checks...

R U asking because you expect it to be fitted together with that Murphy thing?
I never came across any kind of coolant recovery on MANs.

From that listing, these seem to be key:

Man Engines Fully Serviced Including All Coolers, Aftercoolers, Manifolds in 2022,

20Kw Onan Generator Full Service Including New Heat Exchanger,

Verifying against actual service records -- including complete MAN history if possible -- would be a good thing, but I'd say promising... especially given pics (verify those, too) suggest decent care.

-Chris

If installed and calibrated correctly, the Murphy will read the level in the actual expansion/heat exchanger tank when running at temp. As it's possible to drop coolant level without a similar level decline in an overflow/expansion tank, it's reassuring to see that the level is correct while running for extended periods of time, especially if the same type are fitted for oil level. I ran an 82' yacht with MTU 6V396 engines that consumed oil. The liquid level gauges were a great comfort when steaming for 3-4 days non-stop.
The Murphy's also function as gauge senders for remote reading.

i have them on 820's as well and actually i find them pretty convenient. Easy to see level during engine room checks. When I had 1000-hour service over winter the only hoses mechanics changed were the hoses to the murphy gauges. I do have the expansion tanks A well.

Well, IF you happen to look at the pictures posted. The heat exchanger cap is 2" from the engine room ceiling. So the gauges make life a whole lot easier on this boat and most SF, so you're not constantly putting your arm across the heat exchanger and sticking your finger in the heat exchanger opening because you cannot see into it, and hoping the tip of your finger touches coolant. Especially nice if it's the next morning after you've run all day and the coolant isn't 110-120F.

As for the boat, they do run nice and cruise at 26.5 knots. Visibility of the stern is difficult as the aft deck hard top blocks a lot of your view and you have to bend down to look underneath it, but still cannot see the transom. They do have a lot of steps.

Very interesting technique.
In my boat, whose e/r ceiling is maybe a little bit higher but nowhere near enough to look into the HE box, I made a very simple marked stick, which gives me a reading accurate to the millimiter.
But if you prefer to stick your finger inside it, who am I to argue?

Look at the pictures. The engine room ceiling is 2" (51mm)above the heat exchanger cap, you're not getting a stick in there. This is very common on a lot of Sportfish boats.

CJ, have you ever heard the expression "when in a hole, stop digging"?
I didn't want to stress how silly your previous suggestion that without the gauge you must stick a finger in the heat exchanger to check the coolant level is, but since you insist, here goes.

Firstly, I don't need to look at any picture, and it's funny that you suggest me to look at it when I'm the one who posted it, but... hey-ho!
In fact, I know exactly how the HE is built and how the internal core is placed vs. the filler neck.
Now, as long as you can grab the cap with one hand to open it (and you don't even need a 2" clearance, for that purpose alone), you can also put a stick much longer than 2" inside it, inserting it diagonally and then straightening it vertically to check the level. No rocket science involved.

OTOH, if the clearance would be restricted to the point of struggling to open the filler neck cap, then it's the builder that should be blamed for not complying with the minimum installation clearances given by the engine manufacturer.
Not something I would expect from Viking actually, but if you are sure that the ceiling really is only 2" above the engine, then the HE cap and the coolant check would be the last of my concerns.
It's rather the CAC removal for cleaning (and re-installation!), that is bound to be a big PITA.
Christ, even reaching manually the stop solenoid in an emergency is bound to burn your hand.
Not to mention using the manual fuel pump for priming the circuit if some air should find its way inside it, possibly while drifting in open sea, heaven forbid!

But I'm digressing.
Back to the point, the next time you'll need to check the coolant level in a MAN powered SF with 2" of clearance and no external gauge, try using a plain vanilla plastic ruler instead of your finger.
It will work much better, and your finger will be grateful.

Try measuring it when the motor is still 140F from last night, hence the gauge and no need to keep taking the cap off on a multiday delivery. Give it a rest already.

Clutching at straws by moving goalposts now?
What will you tell us next, after suggesting to use the finger, that you managed thousands of boats with that gauge?