Oops, another Volvo overheating question . . .

[gravygraham]

We've had an overheat message appear in the lcd window in tacho (no buzzers sounding though), so I checked the engine temp and it read 95 degrees. We throttled back and after just a minute or so the temp dropped back to it's usual 85 degrees. All was ok for a while but when we went WOT again the issue recurred. The strainer basket's clear, we're full of antifreeze mix coolant, the impeller is fine (we put a new one in anyway). What else can I check? I suspect it's a 'real' problem, rather than a 'virtual' problem, e.g. faulty sensors.

Any advice gratefully received.

 

[targa31]

are you on outdrives?

Lots of weed and barnacles around at the moment. Are the inlets clear on the legs?

 

[Designo]

If you have the big Volvo Penta strainer, make sure the insert is really down to the lowest position it can fit, or else the lid is leaking air. A common problem...

 

[gravygraham]

No, we're on shafts. I'd say the inlets are nice and clear because when I take the top off the strainer housings to look at the mesh, the water falls away very quickly out of the bottom of the housing, through the seacock and into the briny.

 

[symondo]

No, we're on shafts. I'd say the inlets are nice and clear because when I take the top off the strainer housings to look at the mesh, the water falls away very quickly out of the bottom of the housing, through the seacock and into the briny.

sounds familiar - check my thread on overheating about checking exhaust elbows - may help you out

 

[superheat6k]

What engine ?

My TAMD60C has a vent plug on the turbo that sits higher than the header tank, so this has to be bled with the engine running. An air lock here might not shift itself.

Another one for the magical IR thermometer I fear, but a damn good tool to keep aboard.

I would pay close attention to the outlet temp downstream of the injection elbow. Mine run at 41 oC WOT in 22 oC seawater. If the elbow is blocking I would expect this to rise significantly.

 

[gravygraham]

What engine ?

D4 300 - sorry I should have said.

 

[julians]

D4 300 - sorry I should have said.

I have a d4 260 that was overheating last year, it turned out that the three coolers were becoming blocked up and needed cleaning, so thats the air intercooler, oil cooler and the heat exchanger.

We removed them to clean them out, but people do say you can flush them in situ with some sort of acid to acheive the same result.

Once this was done all was well again.

 

[CHI]

You can flush the system through with Rydlyme. I think this can be done whilst still in the water but not sure of how. Another forumite may know..

 

[GAMPortsmouth]

Hi,
Given the symptoms you have described, I would suggest that the heat exchange and/or charge air coolers are scaled up or blocked slightly. A good dose of Rydlyme should do the trick without having to strip the coolers. If you are inboard (which I would assume you are given you have remote strainers and a thru-hull water intake) then this should be easy to do in situ. Sterndrives are a little more difficult and I normally recommend that the coolers are removed for cleaning on these.
Caveat: If the engine is more than 4/5 yrs old and the coolers have never been done, I would suggest paying to have them removed, stripped, re-sealed and cleaned at this time. Then run through some Rydylme every year or two as preventative maintenance.
P.S don't forget to remove the anodes before you de-scale the coolers!