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Tamd40a overheating question

G

glen_adolph

Regular Contributor
I ran my boat for a few minutes today only to discover the port engine was overheating. I was running the engine without the thermostats. I removed them to flush the engine and just figured I would not reinstall them in our warm climate. However I know that a high flow in the system somtimes will not cool an engine. Does anyone know if this is the case with the TAMD40a?
 
How long was it actually running. A few minutes does not seem to be long enough to over heat that engine, especially if the AF was filled. Assuming it is fresh water cooled.
 
I cranked it at the dock and then I idled it for 10 minutes. Left the dock at full throttle for 3-5 min. I smelled something and lifted the cover. Gauge was hot. I shut it down and returned to the dock on starboard engine. I did not have a thermometer with me, but it could have been a gauge malfunction. I also had a leak on the transmission cooler. Af was full.
 
Did you check the water flow after the trans cooler and through the heat exchanger? The trans cooler can get blocked up with debris and restrict the flow of water to the heat exchanger.
 
I went through the engine last summer and cleaned the exchanger. I will flush the engine again and take a few temps with the IR gun. I think there may be crud in the water jacket around the cylinders. I need to fix the hole in the transmission cooler first.
 
I did remove and clean the aftercooler. I will recheck the seawater pump. I will also reinstall the thermostats after another engine flush.
 
Ran the boat again today. Same problem. New thermostats, new water tank cap, clean tank, clean tubes, clean exhaust elbow. The small water line from the turbo was blocked. I cleared it. Next suspect is the rear cover for the heat exchanger. Did anyone have trouble with this before? Could the water be bypassing the tubes?
 
yes on my 41a there are three plates on rear cover one broke off had it brazed back on also had cooler cleaned
 
Get an IR gun and check temps in the raw water circuit.
If temp climbs with engine temp at exchanger outlet -you have a raw water capacity problem. If water stays cold out from echanger, you have most likely a circulation problem in the exchanger (rear cover/gasket).
 
I have narrowed the problem down to a dirty heat exchanger on the tank or shell side. When I was trying to get the boat running, I thought I had pulled the bundle and cleaned it. I did not. I removed the tank and could see white crud on the shell side when I looked into the drain plug hole. The engine flush cannot remove the crud. I tried to remove the bundle, but it refuses to budge. I am afraid I will break it. Does anyone have a suggestion of a chemical that will disolve the white crud (lime, calcium, salt?) I was thinking phosphoric or critric acid? All questions, comments and lewd remarks accepted.
 
Thanks Chris. I will try vinegar. I also read wood bleach(oxalic acid), cascade detergent and Barkeepers friend detergent. The trick is not disolve the Aluminum, steel or copper.
 
The safest is just to pull the element and hand it to a radiator shop. Must likely you have the same build-up on seals and O-rings and you may end up with a creeping leak. At least pressure test the unit after cleaning.
 
Haffiman37, do you mean tank and all? I cannot get the bundle or tubes to move. I will pressure test it after I use vinegar and then flush with baking soda.
 
I tried 2 gallons of vinegar followed by a baking soda flush. Ran the vinegar for about 2 hours. I removed the tank and inspected. It helped some, but I would need to do it a few more times. I also tried to press the bundle out again to no avail. I will talk to a radatior shop and try to find oxalic acid. If not, I will run it on vinegar again a few more times. Maybe I will read up on electrolisis. Wish me luck.
 
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