Running hot in Caribbean

[jr_spyder]

My engine is starting to show hotter than usual temps. I usually cruise at 180° in cool New England waters which crept up to 185°F in tropics, but I’ve seen 190° lately, and this morning 200. I was fighting into a strong wind and the engine was working harder than usual. I slowed down and turned out of the wind into a quiet anchorage. In the short easy mile the temp dropped to 190 but seemed to bump up and down 5° like I’ve never seen before.

Once the engine cooled I did a bunch of checks.

- Strainer clear
- opened impeller housing. Impeller perfect, but replaced it anyway
- opened heat exchanger. Very clean inside with open tubes
- water flow out of exhaust pipe is robust. Doesn’t seem a problem.
- fan belt on coolant pump fine
- coolant level correct

So overall the raw water side seems fine. That makes me suspicious of the engine thermostat, which is far more difficult to access, naturally. I do have a spare on board, but not a spare gasket (doh!).

Before I do thermostat job I’m wondering if there is other advice here.

Also, what’s the likelihood I can take the thermostat housing apart and reuse the old gasket? I have some gasket sealer goop. I’ve seen both extremes of gaskets being completely reusable to completely destroyed. I really don’t want to risk taking it apart in a remote place and not being able to seal it back up.

The engine is a Westerbeke 82B with unknown total hours but 1600 hrs since major overhaul according to previous owner. Runs fantastically well. Maintained obsessively by me, but I might be missing something.

Thanks,

JR

[Stu Jackson]

While you may have "opened" up the HX, this most likely means you took off the end cap. Is that right? Often the inlet port of a traditional shell & tube HX gets gunked up with salt deposits, leading to your issue. I suggest considering removing the HX and checking the ports.

[jr_spyder]

Thanks Stu, but that’s not it. Today I opened both ends of the HX tube and both were clean inside. A couple months ago I ran a full flush using Barnacle Buster to clean out marine growth and buildup. I used the input and output hoses of the HX connected to a pump and bucket to circulate the flush. A fair amount of gunk was in the bucket at the end of the process, and the hoses and HX were definitely clean.

I ran that flush because the running temp was slowly climbing from 180 to 185. After the flush there was no difference, which was a disappointment. It was also an early clue that something is failing in
my cooling system. But what?

[boatman61]

In my experience thermostats don't warn.. they just go.
Maybe you've got build up of crap in the block.. assuming that the cooling systems in engines today are similar to the Volvo MD2B.. did everything you did but in the end found the problem when I took the side off the engine and all the little side ports that channel the raw water/coolant were blocked solid.
Not an engineer so don't know all the terminology.. but cleaning them all out had the engine running sweeter than ever before.

[a64pilot]

A thermostat gasket is real easy to cut out or cut the proper way with a baby ballpeen, but you can trace it out and cut with a razor blade or scissors, and or use silicone. I would stay away from anything hard to remove.
I would change the thermostat, and or check it first with an IR thermometer, sometimes gauges go bad. Point the IR thermometer right at the thermostat housing

[boatpoker]

I've recently had the same issue with a Westerbeke 55A. Exhaust water flow is fine but changed the impeller (tho' it appeared fine), changed the thermostat, changed my heat exchanger pressure cap, installed a new temperature sender and a new gauge. My oil changer and heat exchanger tubes are clean as is my exhaust manifold.

Through all of this I've monitored engine temperature at the sender unit housing with an IR gun which shows 190F but my gauge is still showing 200F.

Sometime this week I'm going to bypass the engine harness and run a wire straight from my sender to the gauge and see what happens.

Love to here if you find a solution.

[jr_spyder]

Wow, boatpoker, you’ve done all the things I would do. Sorry to hear there is no joy. Do you continue to run the engine even tho the gauge shows 200°? I’m very uncomfortable doing that. I have an ir thermometer on board and will start checking with that.

The input from bostman61 is quite interesting and plausible with an old engine, but I don’t want it to be true. Too big a project it seems while I’m cruising the Caribbean with my wife.

Keep the ideas coming mates!

I’ll be in a civilized place tomorrow (regretfully?) and will be able to get gasket material, etc, if that’s the right next step.

[boatpoker]

Originally Posted by jr_spyder

Wow, boatpoker, you’ve done all the things I would do. Sorry to hear there is no joy. Do you continue to run the engine even tho the gauge shows 200°? I’m very uncomfortable doing that. I have an ir thermometer on board and will start checking with that.

The input from bostman61 is quite interesting and plausible with an old engine, but I don’t want it to be true. Too big a project it seems while I’m cruising the Caribbean with my wife.

Keep the ideas coming mates!

I’ll be in a civilized place tomorrow (regretfully?) and will be able to get gasket material, etc, if that’s the right next step.

I'm still running, it is a little worrisome but i'm checking with my IR gun every half hour and I'm comfortable with what I'm seeing on that although I'd really like to see the same temp on the gauge.

[Cheechako]

A boat I owned had this problem nearly half the way back from Trini up the island chain. Finally a smart mechanic changed the temperature sender! So think about that.

[FlyingScot]

https://www.westerbeke.com/operator'...erator_man.pdf

Shows normal operating temperature as 170F-190F. Alarm set at 210F.
Shut down if the oil is hotter than 230F.

Warmer intake temps make cooling harder.

I would attempt to bleed air out of the system.
I would check 50/50 ratio of antifreeze. Too high and makes cooling more difficult.
Also check for 15GPM raw water flow (measured before discharging into exhaust elbow).

-Chris

[Locquatious]

For us it was impeller bits blocking the transmission fluid and oil heat exchanger. We have a Perkins engine and this is the first constriction point after the raw water pump. It could be that impeller sections are blocking the hose right where the hose connects to the heat exchanger "barb". One might take the hose off and inspect the exchanger but not look in the other direction up the hose.

[stormalong]

Originally Posted by jr_spyder

Thanks Stu, but that’s not it. Today I opened both ends of the HX tube and both were clean inside. A couple months ago I ran a full flush using Barnacle Buster to clean out marine growth and buildup. I used the input and output hoses of the HX connected to a pump and bucket to circulate the flush. A fair amount of gunk was in the bucket at the end of the process, and the hoses and HX were definitely clean.

I ran that flush because the running temp was slowly climbing from 180 to 185. After the flush there was no difference, which was a disappointment. It was also an early clue that something is failing in
my cooling system. But what?

I am not familiar with barnacle buster. Even the slightest buildup in the tube stack will reduce cooling. The best results I have had was to soak the tube stack in white vinegar for at least 24 hours. It is amazing how much crud comes out from the soak. Get a piece of PVC pipe wide enough and long enough to hold the tube stack. Glue on one end cap and you are ready to go. Worst case you get nothing out but you have eliminated that as a possible cause. I have done this twice on two different engines with excellent results both times, Engines were 5,000 and 4,000 hour engines.

[boatman61]

Originally Posted by jr_spyder

Wow, boatpoker, you’ve done all the things I would do. Sorry to hear there is no joy. Do you continue to run the engine even tho the gauge shows 200°? I’m very uncomfortable doing that. I have an ir thermometer on board and will start checking with that.

The input from bostman61 is quite interesting and plausible with an old engine, but I don’t want it to be true. Too big a project it seems while I’m cruising the Caribbean with my wife.

Keep the ideas coming mates!

I’ll be in a civilized place tomorrow (regretfully?) and will be able to get gasket material, etc, if that’s the right next step.

Downloaded the schematic and my problem was not the fresh water/coolant side.. it was the raw water side.. the holes in the block and exhaust block that caused the over heating.

[Ip485]

My engine started to run hotter at the top end of the revs.

I decided to run Rydlyme through the raw water circuit. I was amazed how effective this was and the instant return to normal operations. It didnt fizz for more than about 40 minutes so it clearly was not that bad but the difference was impressive.

Engine has about 1,800 hours and never been done beofre.

[stormalong]

Originally Posted by boatman61

Downloaded the schematic and my problem was not the fresh water/coolant side.. it was the raw water side.. the holes in the block and exhaust block that caused the over heating.

Huh? Do you mean the tube stack in the heat exchanger?