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TAMD73 overheating

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KalaKai

New member
I have 2 1998 TAMD73 Engines in a Navigator 53. They have about 2,000 hours.

* both surveyed by Volvo tech 18 months ago @ purchase

- port temps 170-175

- stb temps 170-180

- no issues of any kind

* I´ve put about 400 hours on the engines in last 18 months, 90% at low (1400) rpm

* I replaced both impellers, themostats, and coolant 3 months ago as a preventative measure

* both run at 170 degrees while when at 1400 rpm, my usual cruising speed of 9kts

I took trip this weekend (100 miles) and as usual ran up to 22-2300 rpm at end of 7 hour run to get engine up to temp for 15 minutes or so. Port engine fine, but starboard temp ran up to 190 degrees or so. On reducing rpm back to 1400, temp quickly reduced back to 170.

on stb (overheating) engine:

* seawater strainer clean

* checked impeller, it was fine

* some wear on the seawater pump plate at the cam, but port engine was same

* coolant level good

* impossible to really determine water flow, but at idle, seems fine

Any guidance appreciated!
 
At that age and hours when were the aftercoolers, heat exchangers and gearbox oil coolers stripped and cleaned? Also when were the exhaust elbows last inspected? If these things haven't been ever inspected/cleaned then you are possibly running on borrowed time as they will all be overdue. Around 2000hrs over a bunch of years is about when you might expect to start having issues with coolers and elbows etc.
 
Thanks for the info. I just bought the boat a year ago, so don't know if the mentioned items have ever been stripped/cleaned, but would guess not. I bought the boat iwth 1,600 hours or so. I'm guessing I could take all of those things off and take them somewhere to have acid dipped, or whatever they do. Is there any reason an amateur couldn't do that? I do basic things (oil, impellers, belts, etc), but don't mess with injectors, cylinders etc.
 
Pulling the coolers and elbows is normally easy stuff (sometimes awkward though) using standard tools. Breaking them apart, cleaning then pressure testing is best left to a shop unless you know what you are doing.
 
It is often possible to easily remove an end cap off a cooler to check how clogged up it is. The blockages usually occur at the ends of the tube bundles just under the end caps. The exhaust elbow can get blockages in the spray holes where the water is injected and this slows down the water flow. Again this can be quite easily inspected once removed from the engine or even by taking the rubber connector hose off the elbow and looking back up the elbow from that end with a light etc.
 
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