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Universal Diesel M25 overheating

Joe M

Member I
The seller transferred Chiquita from Dana Point to King Harbor on Friday. After 12 hours or so under power, just off Palos Verdes, the engine overheated and was shut down. Vessel Assist took her in from there. Today I checked the raw water through hull valves, sea strainer and hoses. Next step is the raw water pump and impeller. Any tips or suggestions would be appreciated. Happy Holiday!
Joe
 

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Rocinante33

Contributing Partner
Joe,

Was the water continuing to spurt out of the exit port down near the waterline? If not, you have a clog in the system.
If so start by closing the thru-hull to the engine intake. You may not have to, but better to be safe.

Take the cover off the pump in your picture. Check out the impeller. Any missing blades? If so, it probably got sucked down the hose to the heat exchanger. You hafta find the broken piece and get it outta there, if so. While you're in there, put a new impeller on. most chandleries would have a replacement impeller. You may need ring clip pliers to get the ring clip off. You may need a new gasket, too, or maybe you can save the old one.

If a broken off impeller vane went though the hose you need to find it. Most likely, it is in the heat exchanger (HE). You will have to climb in there to disconnect it. It could be in a hose or fitting where there is a bend. I f you have to remove the HE, you can unbolt the end plates to look inside for blockage.

Marine Diesel Direct (Torreson Marine) has some on-line diagrams. Look there to get an idea of what you are looking at.

If it is not the stuff described above, you have to delve into it a bit more. I just outlined the most likely scenario.
 

Joe M

Member I
tomorrow the raw water pump then the heat exchanger

Hi Keith

The water was definetly nor "spurting" and was more like a dribble. Tomorrow I inspect the raw water pump (RWP) then the HE. The seller states that upon over heating occured he checked the RWP and it was fine, but I will check it regardless. Did not consider that I would have to hunt down any missing impellar blades so your advice is appreciated. Removing and cleaning the HE looks straight forward enough although access very tight. I'm gettin a crash course in cooling systems which I guess is better on land than at sea.

Thanks
Joe
 

Mort Fligelman

Member III
Raw Water Pump-Heat Exchanger

Joe:

To add to Kieth's excellent advice......

I decided to have the H/E chemically boiled out, and replace the raw water pump as I saw signs of salt water corrosion, and leaking, and was taking the boat to fresh water.......

The P/O never had a raw water strainer on the boat.....the crud in the hoses was not to be believed.....also, one of the connections, I the out side of the R/W pump was a 90 degree fitting.....

Long and short.....there was a piece of an old impeller in the 90, and in looking at the old pump everything was worn and wiggled....the goo that was in the H/E was not a thing of beauty either .....

So....all being said.....considering the cost of boating.....and the safety factor of a dependable engine.....it was time and money well spent....

Good Luck
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
"Filtered, not Stirred"

The factory had not installed a strainer in our '88 boat, so I put in a Groco brand over a decade ago.
(At the time I was updating the routing for the intake hoses and thruhull anyway, so it was good to bring that whole system up to standard.)

It's easy to check the basket every season.
The install will be different for every boat, but the need is the same.

I found a picture of our model (from the looks of it...) on line and will post.

For more info do a site search on the word "groco", and here is a thread with an installed photo.
http://www.ericsonyachts.org/infoexchange/showthread.php?551-New-Strainer-amp-Thruhull&referrerid=28
Loren

ps: Keith and Mort's advice is really good; I am just tuck-pointing a wee bit of mortar around their bricks of wisdom!
 

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Sven

Seglare
Hi Loren,

The factory had not installed a strainer in our '88 boat, so I put in a Groco brand over a decade ago.

Did you install it above the waterline ? I've been struggling with the desirability of having an intake strainer for our freshwater cooled Perkins but haven't yet figured out where in the engine compartment to easily mount it above the waterline due to the plastic bowl.



-Sven
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Hi Loren,

Did you install it above the waterline ? I've been struggling with the desirability of having an intake strainer for our freshwater cooled Perkins but haven't yet figured out where in the engine compartment to easily mount it above the waterline due to the plastic bowl.

-Sven

Due to luck rather than planning... our installation put the screw-out top of the Groco right at the loaded waterline. It will barely run a bit of water over when opened. In any case, I just close the thruhull when I pull the strainer basket out.
Loren
 

Joe M

Member I
Mort/KeithThe impeller is in good shape and all hoses clear into and out of the HE. Also good water flow into the HE but minimal outflow. I opened both ends of the HE and they appeared fre of any debree. Basically the raw water goes in but does not come out. Any suggestions on how to flush out the HE with out having to remove it? Or is that inevitable?Thanks for your support.Joe
 

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Rocinante33

Contributing Partner
Joe,

It sounds like you do have to remove it now. Drain coolant & sea water, remove the hoses, followed by those big hose clamps seen in your picture will let you pull it out. When you have it out of there and take the end caps off it should be more apparent what is going on inside. Then it is probably time to take it to a radiator shop, as Mort suggested. Ask around your marina on the docks & usually somebody knows a good local radiator shop to do an acid flush-out for you.

Inspect the ends of the hoses while you have them off.

If you decide to add a strainer, I've seen cheaper ones on the Catalina Direct website, too. I think they are plastic instead of bronze (with a plastic bowl) as is the Groco.

Don't forget to put a new pencil zinc inside. Cut off about 3/8 to 1/2" from the zinc before installation so it will fit.

P.S. If the strainer is mounted above the waterline, does the pump have any problem pulling the water up and over the high point after the strainer has been emptied? It might run dry for a minute, right?
 

cruis-n

Member II
Check the closed loop system as well

Another possibility is that the closed loop cooling system had lost coolant and developed an air bubble in the thermostat housing (where the sensor is). I know, this happened to me. I got an air bubble in the circuit and the engine temp climbed quickly. Turns out the expansion tank was dry because all the coolant was in the overflow tank (another story). I refilled the expansion tank and had to 'bleed' the engine closed circuit to get rid if the air bubble.

There is a bleed valve on top of the thermostat housing. Crack it open when the engine is running to let the air/steam out (be careful it is extremely hot!!!). The engine will cool down until the next bubble is let through. Repeat until no more air/steam is coming out. Took about 3-4 minutes to get rid of the air in the system.

If your M25 does not have a closed loop cooling system, never mind. :)

Paul
 

Mort Fligelman

Member III
More On the Heat Exchnger

Joe:

crus-in has a very valid point......check for an airlock

I can't tell from your photo, but my H/E has end caps, and gaskets which were a mess.......SenDure is the manufacturer of my H/E and I was able to get new ones through a supplier in Florida.......

Also....Keith mentioned the pencil zincs.......there were many pieces of old ones in mine......I did not see them, but I was told they were in there

Just one more thing to add to the trauma of boat ownership.....

Good Luck
 

mherrcat

Contributing Partner
Don't forget to put a new pencil zinc inside. Cut off about 3/8 to 1/2" from the zinc before installation so it will fit.

I used to think I had to do this to make the zinc fit, but discovered that the 2"x1/4"x1/8"NPT (I believe they are also noted as size "00") fit the heat exchanger on my M18 engine fine without cutting. Your mileage may vary, as they say...
 

Joe M

Member I
going with a larger HE

Guys, your advice and wisdom are very much appreciated!

Upon discussing the matter with the seller he confirmed that the HE was serviced within the past few weeks (the picture is before then). So before pulling it again I decided to consult with a local mechanic. His advice is to replace the 2" x 16" HE with a newer larger 3" x 13" HE. Apparently, the M25 with the smaller HE has a history of overheating which is probably why the larger unit is now available. The attached link describes the overheating issues of a catalina 36 with the same engine, that were resolved with the larger HE.
http://realitycheck.me/wp/2009/07/motoring-without-overheating-the-heat-exchanger-upgrade/

Thanks
Joe
 

cruis-n

Member II
Larger heat exchanger

I had the problem where the temp would rise when powering into 20+ kn and large waves. Backing off on the throttle would drop the temp but would not make much headway. If the heat drops when you back off the throttle, it's likely a heat exchanger size issue.

I replaced the heat exchanger with a larger model serveral years ago. It fixed the heating problem but resulted in other issues. The mount needed longer bolts. Several years later, the mount broke where it was mounted to the engine. Had to get it welded. The HE length interferes with the transmission dipstick, so it's tough to check/change the tranny fluid. I unbolt the exchanger from the engine to move it out of the way during service.


Paul
 

Joe M

Member I
Problem solved ?

On July 9th had a new larger HE installed with a 3" diameter which seems to be working well and perhaps the solution to the overheating concern. Unfortunately I left the floowing day on a two week vacation (inclluding some fishing off of Cape Cod MA) and was not able to put the HE through it's paces with a sea trial. Will report back if the problem persists. Thank you all again for your support.
Best
Joe
 

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Stu Jackson

C34IA Secretary
We, too, installed the larger 3 inch HX. When you get back to your boat, loosen the HX and put a cushion between the bracket and the HX. A rubber bicycle tire will do. It avoids the metal to metal rubbing and a possible puncture of your brand new HX. You could also bend the bracket down to give more clearance to the transmission dip stick.
 
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