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Discussion Starter · #1 ·
Hi All,

Let me preface the following question first. My Universal 5424 runs GREAT! :) Aside from getting in and out of the marina, I run it at 2300 rpm, (it's top rpm is 2800). I put a new temp sender, a new thermostat and replaced the anti-freeze last spring. The only "not new" item in the mix is the temp gauge. The operating temp for this engeine (from the manufacturer) is supposed to be 170-185F. It has never indicated more than 160 or so.

I have hoses that leave the engine for a hot water heater (6 gal) and to an automotive style heater (about 8 more feet of hose).

Can these two items cause the water temp not to go over 160? What else could cause this besides a gauge? I am replacing that this winter when I completely refit the engine control panel

Dave
 

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Dave,
Is the 5424 raw water or fresh water cooled, where is the water temp being taken, and for what portion of the engine was Universal's spec written? As you know, I'm not an engine expert by any stretch of the imagination. However, I could see how the operating temperature of the engine would be different from the temp of the water. The water shouldn't be in the engine long enough to get close to the engine temperature; that's kind of the whole point in the cooling circuit, isn't it? So if you're measuring the water temp, you aren't actually measuring the operating temperature of the engine. Now, granted, on a FWC engine, you're cycling that cooling water in a closed loop, but that's the whole point of the heat exchanger - to get the heat out of the fresh water before it gets back to the engine. The run from the engine to the hot water heater and then back to the heat exchanger also cools that water in the hose. Maybe not 20-30 degrees, but it's still going to give the water a way to radiate off some of the energy.

In the end, I think Ian is right - test the water temp and see how it compares to the reading on the thermometer.
 

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As mentioned, most likely you've got a 160 deg thermostat. That's what determines the stable coolant temperature...

Once your hot water is heated it should have no further effect, but on start up a cold HW tank will delay reaching normal running temp since the cold water absorbs a lot of heat to begin with.
 

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Discussion Starter · #8 ·
I think your boat is trying to tell you it wants to go south lol.
Brother wouldn't I like to! I used to live in Jacksonville, did some Navy time in Key West. This Florida built boat would love to go back... via the Panama Canal. :) However... there's no way the wife will take that adventure, or move to Florida. So I'll just have to suffer with all the good sailing I have here in the PNW. ;)
 

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Discussion Starter · #9 ·
Thanks for all the feedback! I will stick the laser on it tomorrow and then give the thermostat the hot water test. It must be the thermostat... I relied on Thorsend (Toad I think they're call now) when I ordered it. The 5416 engine does run at 160 (raw water cooled). Let you know what I find.
 

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Discussion Starter · #12 ·
Hey,

There are two common thermostats: the 160 and the 180. Make sure you have the 180!

Barry
Hi Barry,

I looked at the thermostat today and you're correct... There is a 160 degree installed. I went to the local parts store and they looked it up... It was a 160. I looked it up on the TOAD site... again a 160. So where do I get a 180?

This thing has been running forever at 160, what has this done or doing to the engine?
 

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Where to get it depends on the type of t-stat. My 5411 uses a Dole type unit thats smaller diameter and available only in the marine market. $82 at Moyer and $145 from TOAD.
If yours is the larger "automotive" type you can get it from an auto parts place probably less than $10. Antifreeze is antifreeze, marine or not doesn't matter. If it fits the hole and the right temp its the right one.
 

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Dave...

If you have been changing the engine oil regularly, it will have been OK.
Put the new 180 F thermostat in there and carry on.
The 20 F will not have made much difference.
You will have been running a bit cool for some time but that is better than the chagrin of an overheat from a jammed thermostat. They tend to be pretty awful.

If your motor overheats in future, and you suspect that the thermostat is sticking shut, take it out quickly either beat the centre mechanism out of it such that it is always open, or tear out the spring, or cut the spring out of there, or hacksaw the whole mechanism off it, or otherwise put a big hole down the centre of it, or just take the whole unit out and put a pre-cut gasket in there for a seal.....

https://www.google.co.uk/search?q=v...xonomy%3Dproduct_type%26term%3Dsimple;640;427

You will over-cool for a while, but when you get home, fit another thermostat.
.
 

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Hi Barry,

I looked at the thermostat today and you're correct... There is a 160 degree installed. I went to the local parts store and they looked it up... It was a 160. I looked it up on the TOAD site... again a 160. So where do I get a 180?

This thing has been running forever at 160, what has this done or doing to the engine?
Hey,

I believe the 180 stat is kubota part number 15321-73010. It should be cheap, like $15 or so. My o'day had the Universal M25 and I used to buy parts from the local kubota dealer at WAY less than TOAD et al.

Just google kubota 15321-73010

Lastly I don't think you've done any damage to your engine by running cool. You will get worse fuel economy and your hot water (if heated by the heat exchanger) won't get very hot but the engine should be fine. Raw water cooled engines need to run at 160 because the salt will precipitate out at 180.

Barry
 

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If this engine is a RAW WATER COOLED engine (NO HEAT EXCHANGER) you dont want to use a 180° T-stat. Using a 160° instead of a 180° T-stat will keep the cooling water in the range of BELOW about 155°F - necessary to prevent and retard the formation of Calcium Carbonates 'inside' the engine (scale). A 150° T-stat is even better for RAW WATER COOLED engines.

If you boil sea water, WHEN that temperature of that water increases above about ~153-155° the carbonates dissolved in the seawater will 'precipitate out' of the water and form 'rocks' on most of the internal engine surfaces.

;-)
 

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Discussion Starter · #17 ·
Fresh water cooled... sorry, forgot to mention that. Got a 180 stat from Carquest, putting it in tonight and check it this weekend. Will let you know the outcome.

Dave
 

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Rich...

It builds up as a biscuit-like, brown, heavily staining material. It tends to build up at the narrow orifices in the motor. On my old Volvo MD17C it just about scaled-off the coolant entry port to the forward cylinder. The result was a consistent overheat. Indeed, you could hear the seawater boiling in there on shut-down. A stiff wire or screwdriver will remove it readily. I cleared the problem in a morning with a coat-hanger wire and a water hose. A mild acid would help remove it also?

Presumably it is the same stuff that builds up on the heating element of a water kettle? Vinegar removes that readily.
.
 
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