Over heating

[IG 30]

Hi All,
My name is Steve and I have just purchased an Island Gypsy 30, on my first trip and only an hour from the mooring the temperature started to climb up to 200f and after knocking out of gear got down to 180f before shutting her down.
I have been through everything, new impeller, checked the water flow, the heat exchanger and all good, this is the problem the motor will slowly climb in temperature until it starts to push the coolant out around the header tank cap, I removed the thermostat but the problem is still there.
Could it be the exhaust manifold leaking exhaust into the cooling side of the manifold causing pressure and heating the coolant.

 

[Solly]

With it running look for bubbles in the coolant. Maybe it's just burping the coolant, getting any air out of the cooling system.
200 isn't terribly hot for a diesel. They like to run hot. If it goes much over that you should be worried.
Might get some more specific help if you ID the motor.
Good luck !!

 

[mvweebles]

Any other symptoms? Hard starting? Excessive smoke? When you say you've checked impellor and heat exchanger and water flow, did you check the tubes in heat exchanger, both ends?

Not a product endorsement (if be interested in views for best product from others - I've used dilute muratic acid but not sure that's a good choice), but here's a video at top of Google search on using Barnacle Buster to flush heat exchanger. Your description sounds like classic symptoms for an occluded heat exchanger.

Peter

 

[mvweebles]

BTW - hard for me to imagine this is a blocked exhaust or something on that end, though you may want to check your elbow as part of regular maintenance. I assume you have good raw water flow out the exhaust?

 

[mvweebles]

With it running look for bubbles in the coolant. Maybe it's just burping the coolant, getting any air out of the cooling system.
200 isn't terribly hot for a diesel. They like to run hot. If it goes much over that you should be worried.
Might get some more specific help if you ID the motor.
Good luck !!

OP states he is getting blow-out at radiator cap. A coolant recovery tank may be in order - this could be simple thermal expansion as this response suggests. But would also consider thorough cleaning of tubes in heat exchanger and a good check of exhaust components as they are maintenance items. Assuming the engine is otherwise healthy, these suggestions will very likely solve the problem.

 

[Codger2]

To me it sounds like a heat exchanger is blocked and should be removed, inspected, and rodded out. An almost exact situation like this happened to me on a trip from Newport Beach to San Diego years ago. It turned out to be the tubes in the heat exchanger were partially blocked with salt water deposits. The OP mentioned that he checked the heat exchanger and I am wondering how he did that. You have to remove the end caps to look for blocked tubes.

 

[bluebyu]

Even if caps have been off and tubes clear, a build up of salts and calcium like materials will insulate the tubes from the sea water.

Once this happens, the ability to transfer heat from the copper tubes to the sea water is greatly reduced.

Hope this helps.

 

[Giggitoni]

I’m almost embarrassed to post this photo! I was having slight over heating and removed the heat exchangers after checking exhaust elbows, impellers, etc. The photo speaks for itself

 

[IG 30]

Hi Guys, Thanks for the reply, the heat exchanger is clean with absolutely no blockages, I have plenty of salt water coming out the side but only a poor amount coming out of the exhaust. I have taken every hose off and followed the salt water flow and it is good.
If the exhaust manifold is leaking hot exhaust into the coolant side of the manifold would this heat the coolant up and pressurise the coolant side...?

 

[IG 30]

I did think it could be a blown head gasket but with the header tank cap off the water is flowing and there is no bubbling, the motor is running fine and sounds goo, I do believe if I keep driving the temp would just keep climbing

 

[firehoser75]

Steve,
I recommend a complete off engine servicing of your raw water cooling system components if for no other reason than it is a new to you boat. That means removing heat exchanger, gear oil cooler, aftercooler (probably don't have one, but you didn't specify your engine), etc. If you are not comfortable acid cleaning them your self, take them to a radiator shop. They will clean them, conduct minor repairs as needed, and importantly pressure test them to ensure products don't mix when they shouldn't (identify leaks). You will then have a starting point to work from for future maintenance.
I would also suggest the installation of an exhaust over temp alarm (like the ones from Borel or Aqualarm) and a raw water flow alarm like the one from Aqualarm.
The flow alarm could prevent you from ruining an impeller should you forget to open the thru hull or your intake gets blocked (plastic bag?), and most engine overheats will first show up at the exhaust hose, giving you an early warning thus avoiding the potential of engine damage (could happen by the time coolant overheats). Just another layer of protection and they are not expensive (as boat costs go).
I just noticed you say you are from Lake M. Does that mean this boat is in freshwater? If so, the need for raw water side servicing is obviously less of an issue, but maybe still not a bad idea.

 

[PM]

For about $20.00 you can replace your temp sending unit, then another $20.00 might replace the gauge. Start simple

pete

 

[Island Cessna]

These symptoms sound eerily like a head gasket leak I had. Everything ran fine except after a few hours it started to blow the coolant out of the expansion tank.
The leak only existed with the engine hot, defied detection by pressure testing and looking for bubbles in the expansion tank, and defied cure by new pressure caps, thermostats, etc. I did not suspect heat exchanger because the coolant returning from the exchanger was very cool. Easy check with IR gun, or in this case was cool enough to check with hand. Raw water flow was huge, and cool coming out of HE.
Finally talked to an old time tractor mechanic who asked “do you have brown scum in the antifreeze?” I did. He explained that the combustion gas from the head gasket leaks into the anti freeze, bringing unburned fuel and oil, which forms a scum on the coolant surface.
Took the head off, and sure enough found a minuscule leakage track on the gasket on top of one liner. New head gasket, end of problem.

Look for scum in expansion tank or overflow bottle.

 

[IG 30]

Hi Tom, Thanks for the response and your suggestions, I will be going over everything now and replacing or adding new alarm sensors. I have the heat exchanger off at the moment and need to have the end sealed back on.. Im in Australia and Lake Macquarie is a large salt water lake..

 

[Lepke]

Don't forget, there's 2 sides to cooling. I've fixed a lot of engines for overheating that someone else couldn't and the engine only needed a good coolant flush. Old coolant will allow rust to build on the water jackets and passages, hurting heat transfer.

The coolant with the cap on should have a higher pressure than the exhaust. By your comments, I assume you send some of the exhaust water over the side and not thru the exhaust. So that should indicate you have enough flow but not necessarily adjusted right. But you have a partially plugged exhaust elbow.
A completely filled coolant system should eject some coolant from the cap as the engine heats. Normally an overflow tank catches this and feeds it back to the engine as it cools.

It could be you're over propped for the rpm or a lot of bottom/prop growth. Black smoke would indicate you're working the engine too hard.

 

[firehoser75]

Steve,
Good luck tracking down this issue. You have had some good suggestions so far. I never thought of a "salt water" lake. There is one in California called the Salton Sea. You are not far from Sydney I see. I really liked my time in Australia (couple of months) back in 2009. Started in Melbourne in January at the Aussie Open, about 10 days in Sydney, and ended in Brisbane, with a trip up to Townsville and back down the coast. Tassie as well for a week.
Anyway, enjoy your new boat, and here's hoping you get it all "sorted out" without too much pain.

 

[rgano]

I have seen overheating as a result of biofouling of the through-hull. The cooling water out the stack looked OK, but it was not enough.

 

[READY]

I had a similar issue with my NL genset when I first purchased my previous boat. It had great flow on the exhaust so it was not the impeller. Heat exchanger was clean. Turned out to be the engine coolant water pump. Have you checked the temp of your water flowing out the back?it should start at ambient and warm up as your temp gauge increases. If it is not rising then it is not getting the heat out of the motor. That pretty much points to either heat exchanger (which you ruled out) or the engine coolant pump.

 

[mvweebles]

So OP states raw water flow is diminished. This is not caused by a blown head gasket though he may have one now.

Have you checked sea strainer and intake thru hull for occlusion?

 

[Began]

You said specifically it is pushing "coolant out around the header tank cap" meaning "the cap" as opposed to out the overflow hose- correct? Is there an overflow hose, is there a recover tank? What is the exact engine?

 

[Xsbank]

“If you hear hoof beats, don’t expect zebras.”

Go for the easiest first. Test your coolant. Over 5 years old and it will not be effective in a diesel. Most motor places have test strips.

Sounds like you’ve done the rest. My clam-crusher overheated and puked out coolant at wot. I tested everything and it turns out the coolant was about 10 years old, or older. I replaced it, no more overheat nor discharge.

If you have A coolant filter, they contain an additive package so if you change the filter you will recharge the additives in the coolant.

What engine?

I get everyone annoyed when I talk about coolant cavitation in diesels but it really is a thing.

 

[BruceK]

You said specifically it is pushing "coolant out around the header tank cap" meaning "the cap" as opposed to out the overflow hose- correct? Is there an overflow hose, is there a recover tank? What is the exact engine?

You sparked a memory. If(as is likely) this is a Ford Lehman,the expansion tank on which the "radiator" cap sits,has an internal tube to the overflow. The tube blocks up,sometimes needs drilling to clear it. Some dismantling involved but I think Steve is up for that. If that tube is blocked the cap is the next easiest way out for the expanded coolant.
May be worth checking the cap seal too. Very low psi, about 4psi if memory serves. If it`s not been done, adding a coolant recovery bottle after the expansion tank is a good idea.

 

[IG 30]

Hi to you all, I really do appreciate all the feed back, to clear things up a little.
I have had the boat out of the water a few weeks before this started water blasted a new vinyl barrier coat was placed and 3 coats of Altex antifoul, the intake through the hull for the motor was all clear the sea cock was pulled apart and serviced, the strainer has plenty enough water flowing, in fact the salt water side does not seem to have any flow problem except there is only a trickle coming from the exhaust, a new impeller has been fitted.
The coolant side seems to be just the same except for the header tank where the coolant is coming from around the cap, I had noticed and cleared the relief hose for the header tank which was totally blocked.
I have decided that I am going to spend the time and go through the sea water system again the coolant side again, replace all the oil coolers and I will be removing the head and replacing the head gasket, I plan to spend a lot of the time out in open water so no time for break downs and in doing so will get to know the motor and how it cools.....

 

[IG 30]

Hi, I noticed your in Sydney do you know where I can get a head gasket set from...?

 

[crashley]

200 is not too hot for a diesel, When you say there is plenty of salt water flow out of the boat but no much out of the exhaust how is the plumbing system set up to split the water flow between the exhaust and other outlet, was the engine staying cool and plenty of exhaust water flow before the boat was slipped, You can buy test kits that will tell you if the head gasket is leaking or the head is cracked

 

[FF]

The raw water side has the hardest life , so gets more attention , but the fresh side frequently has never seen a 2 part cleaner and fresh antifreeze.

Unless you live in hard freezing areas 35% antifreeze and distilled water is s good mix.

Antifreeze only carries 3/5 the heat load of pure water , so less is better , although the other stuff, anti rust ect is needed by the circ system.

 

[Xsbank]

That’s nonsense, FF, except the first paragraph; simply follow the owner’s manual for the correct mix.

Water instead of coolant may give you the same symptoms as a bad head gasket, particularly in “later” diesels.

No sort of engine that we run in boats needs any other coolant than what the owner’s manual states.

 

[Began]

What!? The main benefit in our cooling systems is "anti-boil" and at 50/50 it raises the boiling point to 265 degrees (I just read that). A lower solution as you suggest lowers the boiling point and gets one closer to spontaneous boiling of the solution in contact with the very hot combustion chamber walls. Poof- instant overheat. Keep it from turning to steam to circulate and cool.

 

[Trawler Sandpiper]

Might be a collapsing coolant hose on the suction side of the circulation pump. Check condition of the wire inside the hoses. Although reduced raw water flow out of the exhaust is the most telling symptom and some sort is blockage likely.

 

[C lectric]

Lots of good suggestions above. Regardless I will offer my tome below.