Problem with 8kva NL Generator

[Palarran]

I'm having a problem with my Northern Lights 8KVA generator overheating. It started with an over temp cut out at about 210 degrees on the panel. After a frantic call to a friend, I ordered almost everything that involves water on the raw and system side. While waiting for the parts though, I became pretty convinced that it was the thermostat. The temp would go up, drop a bit, go up, drop again, until it went off on the high temp limit. There was plenty of sea water coming out of my exhaust.

Anyway, after receiving the parts, I replaced the coolant pump, thermostat, sea water pump, and all the parts involved with the sea water pump. We started the generator and ran it for 8 hours straight in fairly hot conditions and under a pretty full load with it maintaining a 190 to 195 degree temp. Then the temp crept up to 200, and would vascelate between 200 and 205. It's hotter than blazes in the generator compartment.

I turned the unit off, waited a few hours, restarted, and it now goes right to the 200 to 205 temp and wavers between those. Up and down.

Attached are a few photos of some gunk that was in the coolant pump. I'd appreciate any suggestions of what to check next.

[a64pilot]

That is the fresh water pump?
It looks to me like Dex Cool that was mixed with another coolant, Dex Cool is GM’s brand name but many engines have used it, Yanmar for instance I believe does. Anyway Dexcool is fine really if it’s maintained and if the engine isn’t run with the level low and what will really make it Gel up is contaminating it with a different coolant, which has happened often.
Just Google Dex cool problems to see what I mean, most of the orange coolant are I believe without looking it up organic acid coolants which is DexCool I’m pretty sure.

What you have certainly looks like the gel that forms when Dex cool is mixed with another type of coolant.
If so flush it to death, and disassemble and clean your heat exchanger, the fresh water side may be gelled up.

How did you get parts delivered to the Bahamas and so quickly?

I’d be tempted to run without a thermostat, I believe the dexcool Gel is clogging something and breaking loose and that is why your seeing varying temps, if I’m right then flushing out the gunk and cleaning the heat ex or anywhere else you could get a clog is what I would do.

Now of your thermostat is a simple thermostat then you can run without one, but if it’s a complex one then you can’t, cause it also blocks off the bypass as it opens and without it the bypass isn’t blocked.

Thai explains bypass thermostats and has a picture too, if your thermostat has that washer looking valve under it, it need it stay installed.
http://www.stant.com/files/4814/0979...tructions1.pdf

[Auspicious]

@a64pilot may well be correct. I don't think it matters - if the coolant pump looks like that the heat exchanger tubes will be a problem also. They need to be inspected. At that point you'll probably find they need to be cleaned.

[Palarran]

I agree the heat exchanger will need to be cleaned, my problem is what to do without making matters worse right now based on not having any cleaning products or spare parts/gaskets.

If I flush it with clean water, do I run it until it gets up to a certain temp, let it cool, drain, repeat, then put new coolant in? Is there anything I could add that would help the cleaning process?

This is a photo of the thermostat. In order to take it out I have to remove the whole coolant pump assembly, which would hopefully not ruin the gaskets as I don't have another set.

[a64pilot]

You can always cut your own gaskets out of thin cardboard, it’s easy to do.
I like a thin coat of grease on paper gaskets, it does seem to help it seal but also greatly helps it from sticking and tearing on removal.
If your gasket tears and you don’t want to cut your own 99% of the time if you use a sealer on the old one it will work fine. Just leave all the form pieces in place if you go the sealer route. I normally don’t like sealers myself as in my opinion they aren’t needed and they make a mess to clean up next time.
Yes I would run it until it got hot and drain it. To flush one that is bad like yours is, I like to have a thermostat out and ideally plumb in a “flush kit” but if you don’t have one of those, open every drain and or maybe pull a lower hose off and put the hose in where the radiator caps goes and flush away, maybe put a rag on the hose to try to hold some pressure, pressure helps blow any junk out.

I don’t know of any special stuff the may help dissolve Dexcool Gel, but I can’t see how maybe putting in some vinegar and running it until it get hot would hurt, but I wouldn’t leave vinegar in long term, and it may not help, I was just thinking vinegar is a decent household cleaner is all really.

I would run it every day for a week or so, draining out the water at the end of each run before I went back in with coolant, try to get it as clean as possible before you use coolant as I assume it’s in limited supply too.

The idea of removing the thermostat is primarily to keep its hole open when you flush, with it in its closed and you can’t get water flow through that passage, it’s difficult to actually flush with a thermostat in, you can only really drain and refill.
Short term running it without a thermostat isn’t going to kill it, and the increased flow without the thermostat in the hole may help it blow the junk through and may help it run cooler.

However I’d still like to hear if you don’t mind how you got parts so quick.

Also did you google DexCool problems or maybe how to flush a Dexcool Gel or similar, there may be some kind of cleaner or something that dissolves the Gel. I’ve never had to deal with Dexcool Gel, just have read about it over the years.

[tkeithlu]

A64 pilot is correct on cutting your own gaskets, but did not include how.

First, gasket paper is superior to plain cardboard. Get a sheet and carry it with you. Then, carry a small ball peen hammer. You place the gasket pape over the surface you want to gasket, and tap the paper around all the sharp edges of that surface with the rounded end of the hammer. That cuts the paper to become your gasket. You separate the new gasket from the sheet of paper, and you've got it.

General comment on this thread: If I saw that gunk in part of the cooling system, I would disassemble the entire system and clean it out. The heat exchanger in particular cannot do its job as is.

[a64pilot]

That’s graduate level gasket making, many will glue one side to whatever is being cut to hold the material. You use the face of the hammer for the straight sections, and the ball end for cutting holes, cause your not getting that flat face into a hole

However many people trace out a gasket and cut it with scissors which works, but not as precise as a hammer. I’ve use a Manila folder and a cereal box before when gasket material wasn’t available, both worked fine.
On edit your not cutting a head gasket obviously, but water pump ones are fine.

[Chotu]

Having just gone through the same thing with a northern lights generator this summer, I highly suggest what has already been suggested. Take out that heat exchanger and clean it. It’s very easy to do. Just loosen the hose clamps around the black rubber and pieces. Slide the heat exchanger out and use a pipe cleaner type of thing to clean it out.

Make sure the belt is tight that spins the water pump also.

I was out on some islands and had no access to a gasket. Are used that crappy gasket seal stuff you can buy in a hardware store. It has held up just fine actually. If you can’t get the real gasket and are not cutting one out of the gasket paper, that’s another route to take.

Just go through the whole thing in detail from the water coming in to the boat all the way to the water mixing into the elbow. You will eventually get it solved.

And with the elbow, keep an ion it. The original elbow rests through easily. If it starts spring water out it ruins the electrical components. So if you see any signs of that, replace it with the new stainless elbows they have aftermarket.

[tkeithlu]

Wonderful post, a64 pilot. I'm graduate somethings (PhD Duke experimental psychology) but purely self taught when it comes to gaskets. That said, an additional point on using gasket goo from the hardware store:

The best procedure, rarely used, is clean both surfaces with an alcohol rag, spread the stuff on both surfaces thinly, mate to just gripping, WAIT 24 hours for it to gell, and THEN tighten. Tightening while it's still sticky means that your gasket has no clamping pressure whatever, and you are depending on the stuff having stuck all the way around for your seal.

Let's hear it for creative gasket making. Being able to do everything short of head gaskets (actually, I could discourse on anealing copper gaskets for re-use) frees you from ridiculous delays and expenses trying to find the right gasket on the internet.

[Auspicious]

Vinegar was the first thing I thought of. Cheap and readily available including in disaster relief shipments.

Take the heat exchanger off and soak it in vinegar (you can cut it 50/50). Look inside as best you can. Mechanical cleaners with bottle cleaners helps. Soak for a couple of hours, empty, flush, repeat four or five times and see what happens. Best if you heat the vinegar before you pour it in. Once you have the heat exchanger clean you'll want to clean the engine as well. Barnacle Buster works well but vinegar will do.

It sure sounds like a heat transfer problem.

[Cadence]

Originally Posted by a64pilot

That’s graduate level gasket making, many will glue one side to whatever is being cut to hold the material. You use the face of the hammer for the straight sections, and the ball end for cutting holes, cause your not getting that flat face into a hole

However many people trace out a gasket and cut it with scissors which works, but not as precise as a hammer. I’ve use a Manila folder and a cereal box before when gasket material wasn’t available, both worked fine.
On edit your not cutting a head gasket obviously, but water pump ones are fine.

If there is access to the surface a gasket can be peened. What? Maybe google it. May be old school.

[a64pilot]

Watch this video, you will see when to use the flat side of the hammer and the ball peen. Usually a gasket cutting hammer is a small ball peen, never seen a body hammer used.
https://youtu.be/U-YJo99OCu8

[Cadence]

Originally Posted by a64pilot

Watch this video, you will see when to use the flat side of the hammer and the ball peen. Usually a gasket cutting hammer is a small ball peen, never seen a body hammer used.
https://youtu.be/U-YJo99OCu8

A ball peen that looks like it came with a child tool set.

[Palarran]

Thanks for the advice. I have vinegar on board and two gallons of coolant. Chotu, I don't think my heat exchanger is one that slides out but will check for sure. The heat exchanger design is where the sea water goes through little holes and the coolant surrounds the whole thing. The sea water side is clean (very).

Since the generator runs right now, but just hot, I'm going to try flushing without removing all the parts. The risk of losing the generator and not being able to make H2O is too high. When we filled up earlier from another ship the PPM was 800. I'll go with straight water and do it twice and then see what happens. With 7 on board, showers every day (we need them, period), and everything involved, we are using about 100 gpd.

A64. We found the generator running hot and going off on safety Friday morning, right after we arrived. I had been planning on offering to supply water if needed as we make 1000 gpd. I brought extra membranes and of course many pre-filters. Anyway, I called a buddy in Michigan on Whatsapp and essentially said the generator is overheating, call Hatton Marine in Seattle, tell them the problem, they knew my model number, and have them Fed-Ex overnight any parts that is could be to my friend who was leaving LA at 6am on Monday. After spending a full BOAT unit, he received a box of parts on Saturday, and I had them by Tuesday at 9:00am. Thank you for your help.

[transmitterdan]

I would be worried about clogged small water passages in the engine especially the heads. If there is gunk in the pump then there is probably gunk in the block and heads too. You may need to flush and clean the engine in addition to the heat exchanger. There are products available but their effectiveness is not always what you would like.

Prestone AS105-6PK Radiator Flush and Cleaner - 22 oz, (Pack of 6) https://www.amazon.com/dp/B00B99U074..._Ho38DbV5WDBAZ

The lesson is to always pay attention to the manufacturer’s specification on coolants. There are very bad combinations.