Running Hotter Now

[Nibor]

Hi all. I just ran up my engine yesterday and it ran at 190. It has always run at 160. I opened up the engine bay and it seemed as always. I could put my hand on it for a short time and the coolant reservoir was cool. I think it is just the gauge. Lots of water out the back as well. A little background. It is in a sailboat and is a Universal MB20 22 HP. The gauges , except for the tach , work on and off. I am trying to figure that one out. Also , we just went through two months of below zero weather. I had a heater on the boat but did not open the engine compartment. I did not think it necessary. Maybe the thermostat or temp sender got damaged in the cold? Any thoughts? Thank you in advance.

[rbk]

First what are your engine specs for operating temps? 190 should be within those, have you checked your intake/strainer/impeller in that order. Its possible you lost part of your impeller or lost part of the seal/flow and now its being inadequately cooled or possible blockage on your heat exchange or sings of immanent failure of the impeller. BUT most likely you just sucked something up/have growth and have a partial blockage of your intake and/or strainer.

[nhschneider]

Hand-held infrared thermometers are relatively inexpensive and have lots of usefulness aboard a boat. They can be particularly helpful in checking the accuracy of gauges plus establishing a baseline of normal operating temperatures for various components, especially those on an engine. My wife often uses ours to check the water temperatures before she dives in.

Fair winds and calm seas.

[sailorboy1]

the temperature gauge on my instrument panel fails on a fairly regular basis (every 5 years or so)

you can test if the sender is running by measuring the resistance from the wire to ground at cold and hot conditions

[Captain Graham]

Originally Posted by rbk

First what are your engine specs for operating temps? 190 should be within those, have you checked your intake/strainer/impeller in that order. Its possible you lost part of your impeller or lost part of the seal/flow and now its being inadequately cooled or possible blockage on your heat exchange or sings of immanent failure of the impeller. BUT most likely you just sucked something up/have growth and have a partial blockage of your intake and/or strainer.

I am thinking the same thing.
I would do the following in this order
1. Check the raw water intake thu hull and make sure it is clear.
Sometime it will suck in a plastic bag and get stuck in the intake hose.
2. Check the raw water strainer and clean.
3. Start the motor and see if the normal amount of water is coming out.
4. If a normal amount of water is coming out then the raw water system is OK and it would be in the engine coolant system. (see notes below)
5. If there is a smaller amount to water coming out then something is wrong with the raw water system.
6. Continuing with the raw water system.
At the raw water strainer use a hose and flush out the intake hose.
Or uses other methods to check the intake hose for a blockage.
7. Now all the easy things are checked I would check the impeller.
8. If the impeller is missing pieces find them.
Look in the hose and the heat exchanger, they can block raw water flow.

If you think the problem is in the engine coolant system do the following
1. Check coolant level.
2. Check the thermostat is opening.
The thermostat is just a heat activated valve.
When the engine coolant is cold it is closed allowing the engine to warm up faster.
When the coolant gets warm the thermostat should open and allow the coolant to circulate thru the engine and heat exchanger.
Many times if you do not change the coolant the thermostat will get old and rust closed.
If would also be a good idea to change your coolant if it looks dirty compared to new coolant.

[rbk]

Ya its rarely the freshwater side(if there is one) outside forgetting to check coolant levels and if thermostats failed in Vancouver temperatures every vehicle in the rest of Canada and upper US would need new ones every couple weeks in the winter months (they are very reliable)

[sailah]

When my Westerbeke started getting hot it was due to the salt precipitating right at the inlet of the heat exchanger. I have a 1" hose going from RW pump to heat exchanger. This was reduced down by 75% due to the salt. Removed HX, cleaned it out along with any impeller bits and problem went away. Also soaked HX in a mild acid solution to clean out the tubes.

My boat was pumping a normal amount of water to my eyes.

The salt was the consistency of clay and scraped right out using a screwdriver.

Check the other things listed too, I'm in agreement it's on the RW side.

[Captain Graham]

Originally Posted by sailah

When my Westerbeke started getting hot it was due to the salt precipitating right at the inlet of the heat exchanger. I have a 1" hose going from RW pump to heat exchanger. This was reduced down by 75% due to the salt. Removed HX, cleaned it out along with any impeller bits and problem went away. Also soaked HX in a mild acid solution to clean out the tubes.

My boat was pumping a normal amount of water to my eyes.

The salt was the consistency of clay and scraped right out using a screwdriver.

Check the other things listed too, I'm in agreement it's on the RW side.

Good point.
If the heat exchanger is dirty, the dirt will work like insulation preventing the heat from transferring for the engine coolant to the raw water.
A good chemical flush (like Barnacle Buster) of the heat exchanger will remove the dirt.

[shakey doug]

Raw or fresh water cooled??

[Lepke]

In salt water, the raw side need a chemical flush every couple years. The coolant side does, too, just not as often.

[a64pilot]

I don’t like chemical flushes, to begin with I don’t think they are necessarily all that effective.
If I take the Heat ex apart, remove the tube stack and physically clean the tubes, I know they are all clear, because I can inspect them.

[Jim Cate]

Hmm... your engine is apparently FWC,being that there is a coolant tank, etc. Diesel engines like to run fairly hot, 180-190 F being a common range. So, I'd say that your previous operating temp was either lower than optimum or the gage was then inaccurate... and is now correctly reporting. So, I don't think there is any new fault in the cooling system to track down. I'd just check the actual temperature, and check what the nominal thermostat temp is... and if in agreement, enjoy a better running engine!

Jim

[Stu Jackson]

Originally Posted by sailah

When my Westerbeke started getting hot it was due to the salt precipitating right at the inlet of the heat exchanger. I have a 1" hose going from RW pump to heat exchanger. This was reduced down by 75% due to the salt. Removed HX, cleaned it out along with any impeller bits and problem went away. Also soaked HX in a mild acid solution to clean out the tubes.

My boat was pumping a normal amount of water to my eyes.

The salt was the consistency of clay and scraped right out using a screwdriver.

Check the other things listed too, I'm in agreement it's on the RW side.

I've been promoting this issue for years. It "normally" is "met" with the "clean the tubes out" crowd. In 20 years I've never had tube problems, but this salt precipitation is a reality. I remove the HX every two or three years and check it out.
It happened first when we bought the boat, the PO "admitted" slight overheating. When I got the boat I knew diddly about diesel engines, so dove in by learning, removed the old HX, found the blockage, and the overheating disappeared.
Thanks, sailah

[Nibor]

Quick update. I have had no time to do anything anyone suggested. I do appreciate all the replies. I went do to the boat for another reason and ran up the engine again for a half hour. This time the tach and oil pressure were not working both all the way to the right. No way that is a true reading when at idle. The temp stays at about 175 degrees but rose a bit when I picked up the revs. I really think it is an instrument problems so I am going to start there by cleaning all the terminals at both ends and then moving to the sensors. I will probably change out the coolant as well as I have no idea how old it is. In the meantime I had the frame for my new dodger built and I installed it so I could learn all the things not to do when drilling holes in gelcoat. And of course there was a lot of dropping tool and stuff over the side......but that is another story.

[sailah]

Originally Posted by Stu Jackson

I've been promoting this issue for years. It "normally" is "met" with the "clean the tubes out" crowd. In 20 years I've never had tube problems, but this salt precipitation is a reality. I remove the HX every two or three years and check it out.
It happened first when we bought the boat, the PO "admitted" slight overheating. When I got the boat I knew diddly about diesel engines, so dove in by learning, removed the old HX, found the blockage, and the overheating disappeared.
Thanks, sailah

Yeah i was pretty surprised at how choked down the inlet was. I've also never had a blocked tube but once you have HX out, it's simple to clean.

What was more surprising to me, was 2 years later after cleaning, the inlet was starting to get choked up again. I'm in MA, do about 100 hrs a season on my diesel. I can't imagine that it's specific to just my boat because the salt water hasn't even made it to my engine really.

Now i remove every 2 years as i dont want to go through a bad head gasket sutuation again. That had me chasing my tail for years and was supremely annoying in the amount of work.

I trace it all back to PO who likely didnt even know where engine was and probably overheated it so i inherited his issues as engine was running 195-200 on our maiden voyage after closing.