kohler 5e overheating argh!

G

gyrospiro

Member
Oct 3, 2006
307
Minnesota
Boat Info
1998 370 DA
Engines
T-7.4 310hp V-drives
My generator runs for 7 minutes and then shuts down then runs for 3 minutes, I've checked everything I can think of. There seems to plenty of water flowing.

Things I have tried.
Impeller replaced even though it looked fine.
Heat exchanger back-flushed. Air bled out of exchanger
Spark plugs changed
Sea strainer Cleaned out
Oil new and level fine
Siphon break checked and cleaned
Anybody have any suggestions to try before I call repair guy?
 
Close your Seacock, Take the strainer cap off - open the valve and if water is coming in fast - you know there is not a clog. If slow - something is caught in the lines or seacock.
 
skolbe said:
Close your Seacock, Take the strainer cap off - open the valve and if water is coming in fast - you know there is not a clog. If slow - something is caught in the lines or seacock.
Click to expand...

I second that. Just had this happen with mine and there was a good bit of kelp in there from being out the previous weekend. There was water flow, but not the normal amount.
 
skolbe said:
Close your Seacock, Take the strainer cap off - open the valve and if water is coming in fast - you know there is not a clog. If slow - something is caught in the lines or seacock.
Click to expand...

There is plenty of water coming in and going out of the boat. I checked when I cleaned the strainer any other ideas?
 
Does your boat have a water pressure sensor on the heat exchanger?
 
Coolant bottle full & coolant pressure cap tight? I serviced mine today, and shot the top of the heatexchanger where the coolant pressure cap is, with a Raytek I/R thermometer, mine was running at 190 degrees F. I'm not sure at what temp the sensor shuts them down though....
 
I have Kohler 5ecd - and it runs about 190 as well.
 
Are you getting an error code? You are not sure it is overhearing. It is just shutting down?
 
No error codes, Yes overheating, I think it may be the thermostat. Anybody know where the stat is located?
 
I hope this link works...I'm not 100% certain, but it looks like there could possibly be (2) T stats. One located in the raw water circuit for the heat exchanger, the other on the closed cooled AF system....I downloaded the parts manual from this link. Pg 18 points out a T stat housing but no reference to a T stat part number....on a seperate page, they point it out as item 11 near the heat exchanger.

http://search-manual-online.com/dow...vbS9NYXJpbmVfZG9jdW1lbnRhdGlvbi90cDU5ODcucGRm
 
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Well I changed the thermostat it was quite easy

All you need is a 1/2 wrench, 7/16 wrench, 5/16 socket for clamps.

the round tube is the heat exchanger, which is attached to the exhaust manifold the thermostat is between the two on the right.


you need to remove the 4 1/2 bolts. first remove the hoses connected to the exchanger and drain antifreeze.



I flushed the heat exchanger to make sure there were no pieces of impeller in there.



once everything is together you need to bleed the systems as these models have a tendency to air lock mine had a 7/16 plug which I used to bleed system.


The bad news is it still overheats......:smt089

Anybody know how to check if the new thermostat is opening while still installed in generator?
 
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They are easy to test. Put it in a pan of water and heat it up. When the water reaches the right temp, it should open. Monitor with a thermometer so you note the open temp. Probably in the 160-190 range.
 
Check your oil level. It's the only reason mine has ever shut down. Screw the dip stick all the way in, then pull back out to check.
 
While I wouldn't do this for normal operations, when you remove your thermostat for testing as Chumbley suggested, button it back up and try running it without the thermostat. If it is still overheating, then you need to get into the water pump as shown on page 20 of the service manual.

How many hours do you have on it? I just can't believe that a water pump would go out on an '02 though. Shoot it with a laser temp gun as well. I haven't shot mine, but as a couple have suggested, 190° sounds like a good number - you certainly shouldn't see anything above 195°...
 
Odd that you are not getting a fault code. Mine is doing something similar (runs for a bit, then shuts down, then runs, then is hard to start, etc.) I'm getting an EC69 code and Kohler has replaced the wiring harness, the O2 sensor, and a couple of other things. The new theory is the ECM is bad...we'll see.
 
Kohler, model 5E-BBG, serial #0739218. 652 hours, Excellent water flow. spent 2 hours today making sure all air is out of system. When I installed the new thermostat I back flushed the system and the heat exchanger all seemed clear. also checked zinc in good shape replaced last year(fresh water) strainer checked and clean, good water flow. Impeller replaced old one was in good shape no pieces.

Infrared temp reading when The gen shuts down is 220 deg on the exhaust manifold by radiator cap. Am starting to think new thermostat is defective. Has anybody temp the heat exchanger when running?

oh Its still overheating!
 
Mine was doing the same exact thing and I did the same thing you did, inspect thermostat and try and bleed the air out of the system using the pipe plug opposite of the cap. What I found out is that even though you bled the system using the pipe plug and the radiator cap there is still air trapped someplace near the coolant circulation pump. I went to another site and someone suggested (as he has the same problem and the fix he used) to bleed system using pipe plug and cap method. Make sure full to the top as much as possible. Then fill the overflow bottle with coolant to the top. What will happen (it happened to his and mine as well) is when the coolant heats up and expands it will force coolant to the area that is vapor locked thereby removing the air pocket and the vapor lock. When the system cools down you will notice that the overflow bottle is not full anymore and you will need to add coolant to bring it up to the correct level.

This method worked for me. My gen was shutting down after 5 minutes and I could not figure it out. Once I did this, it has worked since then, no problems at all....knock on wood.

Hope this helps.

Let us know if this worked for you as well.
 
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