Inboard Perkins 30HP Diesel Overheating

[damoses1]

Hello everyone. My name is David and I'm fairly new to sailing. My wife and I have owned our boat for 3 years now, and I could use some of this forum's expertise!

Last week we took our Cal 29 out for the first time this season and after motoring for about 15 minutes, I smelled something funny, and noticed that the engine temp was pegged to the right. We shut off the engine, put up the sails, and sailed it in. I turned on the engine for about 2 minutes- just long enough to get us safely back to our well. This is my first big engine problem, and I was hoping some experts out there could help me figure out how to troubleshoot this before I have to shell out tons of cash on for a mechanic.

Here's what I know:

-Impeller is brand new, and water (not smoke or steam) is coming out of the exhaust pipe.
-When the engine was hot, I thought I may have heard a hissing sound, but am not sure.
-Engine was properly winterized and has just had an oil change.
-After the engine cooled, I took off the radiator cap and noticed rust.
-The engine still starts up without any problems.

I've never worked on boat engines, and don't even know where the thermostat or internal water pump is located on my engine. Any helpful comments would be much-appreciated!

 

[Merlin Clark]

Hi David,
First off, Perkins are tough and it will probably be fine.
In case you don't have one, here is the shop manual for that series engine, check out section 7, troubleshooting, par. D "overheating. I'd suspect the heat exchanger (they call radiator) or a clogged exhaust elbow.
http://l-36.com/read_pdf.php?file=manuals/Perkins-100-Series-Workshop-Manual&title='Perkins 100 Series Workshop Manual'
Please let us know how it goes.

 

[Merlin Clark]

Here is the parent page that link came from, bunch of very handy info that some wonderful person put together and shared.
http://l-36.com/manuals.php

 

[damoses1]

Thanks for the link merlinuxo!

This will definitely be helpful!

 

[Merlin Clark]

You're welcome David.
Welcome to SBO, great bunch of people and lot's of good info.

 

[dparilla]

The tech manuals are awesome and make troubleshooting much easier. I personally recommend nigel calder's book "Marine Diesel Engines". He goes into great detail on almost every project you can think of, and his troubleshooting charts are excellent. I have actually created laminated copies of his charts to put onboard for easy reference.

In short, your circ pump (fresh water/antifreeze) is the top pulley on the engine front. The thermostat is often just above it (with the painted hose running into it). There should be hoses going in and a wire coming out of it. Your picture did not show antifreeze in the resevoir so you may have an air bubble in the system, which I would take as the most likely and also easiest fix.

Oh, I noticed on your picture that the raw water pump is missing a screw off the cover plate, it won't cause overheating, but could slowly weep or seep and cause corrosion.

Good luck, and welcome aboard.

-Dan

 

[Stu Jackson]

David, sorry to hear about your issues, and hope you've resolved them. Just a question, you mentioned the coolant was empty. Did you find evidence of a leak? Had you checked it at the beginning of the season/before your first trip? We had a persistent leak which I eventually traced to a broken heat exchanger mount which had created a tiny hole in the heat exchanger (this after changing all the hoses, which I needed to do anyway).

One of our "Critical Upgrades" suggestions has been this:

http://c34.org/bbs/index.php/topic,5078.msg31458.html#msg31458

You might want to click on the links in that post. And also wander around the rest of that topic, since the concepts apply to many engines and boats.

We bought our boat in 1998, it was 12 years old. I knew nothing about diesel engines back then. Experience makes us stronger, or something like that.

Good luck.

 

[damoses1]

Update:

I finally got to work on the boat for a bit today. I took apart the hose past the impeller, and was shocked at what I found- tons of impeller pieces! (See photo below). Since I've never had a broken impeller, the owner before me must have blown up an impeller and just left it clogging the water intake port. Gee, thanks! Anyway, I cleared all of the pieces out, and fired it up. Wow! About 3x the amount of water flowing out of the exhaust!

Only problem is that the engine still is overheating. I turned it off after running it at 2000 rpms for 7 minutes- when it hit about 225 degrees Fahrenheit. The next thing I am going to check out is the thermostat. I know where it is, but didn't have the right size socket, so I am going to remove that on Tuesday when I can get out to my boat again.

Could anyone provide me with a quick way of testing the thermostat to see if it is indeed broken? Also, dparilla mentioned something about an "air bubble in the system." What is this, and how can I fix it? I've posted another picture showing the heat exchanger, but I have no idea what the two tubes coming out of the top portion are. The rise up into a tan thing. Could anyone please help me in determining what this is, and what it is for?

Oh, and for those that were asking about leaks- I did not find any.

Thanks again for all the help!

Dave

 

[Merlin Clark]

Good to hear your making progress.
I'd check the thermostat and the heat exchanger. The hose you mention looks to go to a vented loop (brown thing, and on to the exhaust elbow) which serves to avoid syphoning.
In case you don't know the heat exchanger has a core with small tubes that clog and periodically have to be cleaned out.
You can do it yourself (read up on this) or take it to a shop to have it done. I've never cleaned one myself so can't advise on this.
Might check any other hoses that could trap pieces.

 

[Stu Jackson]

1. Heat exchanger (HX) - it is rarely the tubes that get clogged because the water passes through them quite quickly. However, in your case with the blockage you described, it could well be an issue. You could take it off and bring it to an auto shop and have them "clean your tubes out" or you could just run some Ridlyme through it. If you're in salt water, deposits drop out where the cool water meets the hot water and one of the ports of the HX may/does get clogged up. I continue to recommend that skippers take the HX OFF, disconnect all four hoses and LOOK at what ya got and clean it up. Many times folks forget to change the zincs and they clog the tubes (if you have a zinc on your HX).

2. Thermostat - it will have a # stamped on it, usually it's in degrees C, not F, so do the conversion, boil some water in a pot, get a thermometer and see if the thermostat opens. Even easier: by the time you take the old one off you'll need a new gasket, so just break down and buy a new gasket and thermostat and be done with it. Then check the old one. If it works, keep it as a backup. They last forever.

3. Burping your engine - air bubbles. If you have a hot water heater for your drinking water, there's a "branch" of hose that goes to and through the heater. Sometimes/usually, this is where the air is trapped and a slug of air leads to overheating. Either you can use the petcock on the top of the thermostat housing, or do this: Engine Overheating 101 - How to Burp Your Engine (Reply #6) http://c34.org/bbs/index.php/topic,4518.msg26462.html#msg26462

4. You might want to buy a book on diesel engines, Calder's written a good one. Do you have the shop manual for your engine? I don't know if Torreson does your engine, www.marinedieseldirect.com, or Google around for your engine information.

Good luck, none of us was "born" a diesel mechanic, we all had to learn the hard way. Like this!

Enjoy.

 

[kloudie1]

DaMoses, Another quick check would be to remove the black cap over the front of the heat exchanger and take out the rest of the impeller blades.. That is the cap that the water hose goes to from the seawater pump. Take off the back cover (black cap with hose going to anti-siphon valve) too and you should be able to see clear trough the tubes.. you may have to take something like a rifle cleaner and rod out the tubes to get all of the impeller parts out. Check the hose through the anti-siphon vent and down to the fitting on the exhaust pipe.. I am surprised to see a plastic fitting on your exhaust mixing elbow! This should be replaced today with stainless or bronze.. Be careful to get the gaskets on the front and back of the heat exchanger back in exactly the correct locations. Get a mechanic (or a capable gear-head friend) to guide you if you don't feel comfortable doing that work..
Ohhh don't pull those covers until the antifreeze/coolant is drained. You may want to have the coolant side vigorously flushed while the coolant is out.. The "rust" may be hard deposits from letting old anti-freeze sit in the engine too long.. If that is the case, pull the heatex tube "bundle" and get as much of the deposits out of the heatex shell as you can reach..

 

[damoses1]

Thanks again everyone for the helpful comments!

I have a couple more questions:

1. My West Marine told me they don't carry parts for Perkins engines. Do I need to buy a Perkins gasket and thermostat, or will a generic one work? Any recommendations on where to buy one?

2. Kloudie1 mentioned draining antifreeze. This is something I am unsure about, and am even embarrassed to ask; does my engine use antifreeze? I know it has a radiator cap, but I assumed that since there is no overflow radiator fluid container (like cars have) that my engine only used the lake water to cool itself. Even if my engine did use antifreeze, how would I know when it is full? If someone could please take a look at the pictures I provided and help explain this, I would greatly appreciate it!

Oh, and by the way Kloudie1, I actually found all of the impeller parts inside the black cap on the front of the heat exchanger as you described. At this point, I'm really hoping the problem is just a faulty thermostat. Does anyone know if I have to take off the water pump on this engine in order to get the thermostat out?

 

[All U Get]

I did a quick search and found this,
http://www.perkinspartsdirect.com/category/1898-4236-engines.aspx

All U Get

 

[Chris Patterson]

Yes it takes antifreeze. I see in one of your pictures that the cap is off, it should be full to the rim. With a 50/50 mix.
No the pump does not have to come off. you can see the thermostat housing just to the right of the water pump pulley as you're looking at it. You may have to remove the pulley, and if so, very simple.
You can make the gasket out of a Michelob carton. Do not use Milwaukees Best, as it will not work. Maybe a Corona carton.

 

[kloudie1]

Chris is right on.. The heat exchanger bundle, the little bunch of tubes that looks like a strainer to catch the parts, probably have impeller parts inside them as well. Pull the back cap and rod out the tubes.The coolant is on the outside of those tubes inside the housing and the seawater goes through the tubes and out the exhaust. The seawater cools the antifreeze which is circulating in tthe block. Again, careful with the gaskets/seals. You will surely have to take off the belt to get the t'stat housing off and as Chris says, maybe the pulley as well. If you were that low on antifreeze/coolant, that alone would cause overheating.

 

[damoses1]

Chris is right on.. The heat exchanger bundle, the little bunch of tubes that looks like a strainer to catch the parts, probably have impeller parts inside them as well. Pull the back cap and rod out the tubes.The coolant is on the outside of those tubes inside the housing and the seawater goes through the tubes and out the exhaust. The seawater cools the antifreeze which is circulating in tthe block. Again, careful with the gaskets/seals. You will surely have to take off the belt to get the t'stat housing off and as Chris says, maybe the pulley as well. If you were that low on antifreeze/coolant, that alone would cause overheating.

Wow! Thanks Chris and Kloudie1! I didn't know it took antifreeze as well. Would you recommend that I just fill the heat exchanger with 50/50 antifreeze to the rim of the top cap and give it another try to see if it still overheats? Also, where is the drain plug located for the coolant?

 

[kloudie1]

Coolant is pretty cheap, so yes, I would try that after making sure the tubes of the exchanger do not have impeller pieces i them. I am not familiar with that engine, so I don't know where the drains are. Usually, there is a "petcock" (might be a small valve) on the bottom of the heat exchanger housing and another on the engine block .. That appears to be an engine that was put into the boat by a previous owner since I think it was manufactured later than the boat was built.

 

[dparilla]

Follow the blue plastic hose that runs from below the antifreeze cap. It should end at your expansion tank. Just make sure it doesn't end in the bilge with nothing to collect the antifreeze. Let us know where it terminates.

Fill the reservoir with a 50/50 blend of antifreeze and distilled water to the top and put the cap back on. Then run the motor until it warms up. Either the temp will stabilize usually around 170 or so, or it will over heat. If it stabilizes, you are all set, let it cool down, check the antifreeze level and the go sailing. If it overheats, shut it down, let it cool and CAREFULLY open the reservoir cap. I use a towel and gloves just in case. Check the coolant level, you will probably need to add more antifreeze. If the level is low, you had an air bubble so just add coolant and try again. If the coolant level is still full, and your raw water path is clear (no impeller blades), then you can suspect the thermostat. I would personally bet it was low coolant and not the thermostat, but only testing will tell.

 

[kloudie1]

Quick note.. Some engines have an air space where the radiator cap is and have the overflow line going to the bilge. I worked on a couple of Universals that were set up that way.. We did add an overflow tank but that requires a different radiator cap with a better seal to not let it pull air back into the Heatex housing. I think that model of Perkins has a designed in air pocket .. I don't like the idea of air in the coolant .. but I think that engine/heatex was designed to be that way.

 

[Stu Jackson]

Based on the picture in the first OP, it appears that the coolant tank has an overflow hose. If you don't have an overflow tank, it so easy to make one. Go to a dollar store and buy a small Rubbermaid plastic bottle. The hole in the top for pouring liquids is perfect for that hose size. Mount the bottle on a wall in the engine room level or a little below the top of the coolant tank on the engine, run the hose into the bottle, fill it halfway with antifreeze, cut the hose at a 45 degree angle and you're done. I did this 15 years ago on our M25 Universal based on an idea from another one of our C34 skippers, and have never had overflow antifreeze in our engine compartment and never lost coolant.