Dangerous Overheat?

[brianontheroad]

So I already fried my engine or maybe I did -- but I know it dangerously overheated.

I was motoring back in from a great sail when I saw a faint bit of steam/smoke coming up from the engine area and immediately turned off the engine, the steam/smoke immediately got much worse, I'm glad I turned it off immediately but I'm worried I might have run done some damage, it smelled like burning coolant I think and today in my troubleshooting/investigating I found:

1. Impeller was totally eaten (could have been the cause of the overheat, or the result)
2. Sea cock was open, I tested it today and waters come out of it, though I'm not sure if enough is coming out -- it was like a garden hose without any sort of end on it (and this is after the strainer) a steady stream but not exactly powerful
3. I can't get my strainer open? I've never opened it before (only had the boat for 8 weeks, and had the engine checked out before I sailed it the 80 miles from Hilton Head up to Charleston) it looks like a standard old style strainer, like the top should twist off and then the strainer lift out? I must be missing something
4. The zinc on the heat exchange was totally eaten, but it also looks like the zinc is still in the heat exchanger? I'm not sure if it's corroded -- picture to follow, how do I get the zinc out to put a new one in?
5. I couldn't get the end of the heat exchange off to check for clogs, I was able to get the bolt off the end but not the cap -- do I just need to dig into it and give it some force or ?
6. The top of the coolant recovery tank was blown off (eek...bad sign) how did that happen? The coolant burning up?

The motor was only running for a few minutes total, but I know a few minutes can be a few minutes too long -- I'm going to replace the impeller with another Johnson 810, check the strainer (once I get the damn thing open) and the zinc.

What kind of coolant should I use? Do I need to flush the cooling system? Once I replace the impeller/zinc/coolant/check heat exchanger should I start it and see how it runs or are there other things I should check after a dangerous overheat? Any tips for a newbie to tell just how bad he f'ed up?

Thanks for all your help and advice.......

Brian

[brianontheroad]

more info:

Engine is a Westerbeke 27, heat gauge says last temperature was above 200/below 240

picture of the heat exchange with zinc stuck down in it is located at

Picasa Web Albums - Brian - Boat Stuff

[Chief Engineer]

Take a deep breath. Don't Panic. Relax

Then calmly approacj the problem

Replace the impeller....make sure you get all the broken pieces out.

Check the hoses to and from the pump for any debris.

Fill up the coolant side and start the engine.

Report back here what you observe

[Alan Wheeler]

As Chief said.
Sometimes it is not the best idea to stop an engine when they are overheating. The core of the engine can boil what water is in there and you can do more damage. It is often best to allow the engine to idle and slowly pour water in allowing it to cool slowly. Don't pour cold water in quickly and if you have the luxury of Hot water on tap, pouring hot water in can be the best idea. Once you have some water in there and the temp comes back a bit, then you can shut down the engine.
For Diesels with cast iron heads, they can handle being hot like that. I have had Diesels actually seize and once cooled down, start back up and be just fine. So as Chief said, don't panic....yet.
The Zinc has probably corroded and thus the residue has got stuck. A careful push with screw driver wil most likely push the crud through. It will wash on through the system...with a little luck....but the parts you need to watch are the impeller blades. You need to account for each one. Count the blades and then ensure you pull the same number out of the exchanger. Blades will block exchangers and cause issues.
The other part you need to check is the exhaust. If it has plastic components anywhere, they most likely will be doing Picaso imitation.
Impeller blades can break if you don't have good water supply. If the impeller doesn't have to suck, it will last a long time. But once you have a restriction, you can chew the blades off quickly.

[boris]

"Impeller blades can break if you don't have good water supply". Is this why you are suppose to change impellers annually ?

[never monday]

Originally Posted by brianontheroad

1. Impeller was totally eaten (could have been the cause of the overheat, or the result) That happens they are designed to fail. Get accostomed to how it works and be prepared to drop a hook and change one on a moments notice

2. Sea cock was open, I tested it today and waters come out of it, though I'm not sure if enough is coming out -- it was like a garden hose without any sort of end on it (and this is after the strainer) a steady stream but not exactly powerful normal

3. I can't get my strainer open? I've never opened it before (only had the boat for 8 weeks, and had the engine checked out before I sailed it the 80 miles from Hilton Head up to Charleston) it looks like a standard old style strainer, like the top should twist off and then the strainer lift out? I must be missing something I'll need a picture to see how it works

4. The zinc on the heat exchange was totally eaten, but it also looks like the zinc is still in the heat exchanger? I'm not sure if it's corroded -- picture to follow, how do I get the zinc out to put a new one in? push, pry, scrape and dig it out.

5. I couldn't get the end of the heat exchange off to check for clogs, I was able to get the bolt off the end but not the cap -- do I just need to dig into it and give it some force or ? yes you'll need to pry it off. Be careful of the rubber gasket and o-ring

6. The top of the coolant recovery tank was blown off (eek...bad sign) how did that happen? The coolant burning up?

The motor was only running for a few minutes total, but I know a few minutes can be a few minutes too long -- I'm going to replace the impeller with another Johnson 810, check the strainer (once I get the damn thing open) and the zinc.

What kind of coolant should I use? Do I need to flush the cooling system? Once I replace the impeller/zinc/coolant/check heat exchanger should I start it and see how it runs or are there other things I should check after a dangerous overheat? Any tips for a newbie to tell just how bad he f'ed up?

Thanks for all your help and advice.......

Brian

comments in red

Originally Posted by brianontheroad

more info:

Engine is a Westerbeke 27, heat gauge says last temperature was above 200/below 240

picture of the heat exchange with zinc stuck down in it is located at

Picasa Web Albums - Brian - Boat Stuff

200-240 is not a critical overheat.

[brianontheroad]

So I've replaced the impeller, removed the heat exchanger and cleaned it with vinegar to remove any deposits, cleaned the raw filter, changed my oil filter and oil and refilled my fresh water/coolant. Once I crank it, it's about 5 minutes until it starts running at about 230 Fahrenheit, I get plenty of water out of the exhaust, I suspect it's the thermostat or an airlock in the fresh water system -- but I don't know where the thermostat is nor how to detect an airlock in the FWS, I've posted pictures of the engine, can anyone advise me on the thermostat's location??

Thanks!

[Chief Engineer]

Your center picture shows the theromostat housing.

On your heat exchanger is there a petcock?

If there is. Start the engine open the petcock (that being the high point of the cooling system)

On some weterbeke/kubotas there is a petcock on the top of the thermostat.
Yours doesn't appear to have that.

Do you have a hot water heater plumbed into your engine?

[brianontheroad]

No hot water heater -- pardon my ignorance but what's a petcock? Are they the bolt looking things that have like a butterfly top?

There's one of those on the expansion chamber (I believe that's what the top part where I pour the coolant in is called??) and one on the bottom of the heat exchanger (that looks like I turned it, it would crumble so I better get a spare)

What will opening the petcock tell me? If freshwater/coolant is going through the system?

[Chief Engineer]

Originally Posted by brianontheroad

No hot water heater -- pardon my ignorance but what's a petcock? Are they the bolt looking things that have like a butterfly top?Yes

There's one of those on the expansion chamber (I believe that's what the top part where I pour the coolant in is called??) and one on the bottom of the heat exchanger (that looks like I turned it, it would crumble so I better get a spare) The one on the bottom is a drain

What will opening the petcock tell me? If freshwater/coolant is going through the system?

This situation is this....you have a closed system with air in it.
In order for the engine to cool properly there cannot be any air in it.
As the water heats up and expands...the air compresses...it will not come out of the radiator cap.....by opening the petcock as the engine is running, you allow this trapped air to escape and ensure that there is only coolant in the engine.

Taking the heat exchanger cap off will not always do this.

Buy two petcocks while you are at it....they are notorious for corroding and breaking when you try to loosen them.

Keep us posted

[brianontheroad]

I'm also going to remove the thermostat -- the hex bolts on it seem pretty frozen - is PB penatrent ok to use on an engine? any advice for getting hex bolts off if they strip with the allen wrench?

[Chief Engineer]

PB is ok.

Now for a secret taught to me by My Port Engineer many moons ago.

As the tugs I was working on were 50+ years old...there were some nuts/bolts that had not been loosened in that time ever.

Warning: If you share this with anyone else there will be dire consequences.

After you put the PB on and before you attempt to loosen....give each screw a sharp tap or two directly on the top of the head. If you have a piece of brass shaft you can use that between the head and the face of the hammer to prevent distortion.
Or you can use a small ball-peen hammer resting on the head while you sharply rap with the other. Make sure you use the proper allen wrench. Personnally, I like to use the drivers that are like a 3/8 socket with the apportiate sized allen hex on the other end.

Above all...be patient.....take your time

[Alan Wheeler]

Chief, I do the same and also do the same with screws. I use the all metal driver bits and will give the head a good crack with a hammer and the frozen screw is loose enough to screw out. If it doesn't budge, use a bigger hammer.

[boris]

[If it doesn't budge, use a bigger hammer.[/quote]

I use work for a builder, when I was ayoung fellow, who worked on the same principal!