Cooling System Blocked

Interesting thread this. Guess what, the port engine on my Prestige 34 has also been running hot!! Not overheating hot but at 91C with starboard only at 85C or a bit less. Temp stays at that from 2800-3400 rpm. It's erratic though, some trips it's fine some not. Last time out it was running hot to the anchorage. After I took a dip and cleaned the lower leg water inlets with a stiff brush the run home was at normal temps. I would not be surprised to see the problem again next time out. I have a suspicion though that the gauge could be playing up as I have seen it flick a few times and I also plan to change the thermostats if I can't find a gauge problem.
However I have KAD300s not D4s so my ramblings probably not that relevant. A bit of a coincidence though...
 
AdeOlly said:
Interesting thread this. Guess what, the port engine on my Prestige 34 has also been running hot!! Not overheating hot but at 91C with starboard only at 85C or a bit less. Temp stays at that from 2800-3400 rpm. It's erratic though, some trips it's fine some not. Last time out it was running hot to the anchorage. After I took a dip and cleaned the lower leg water inlets with a stiff brush the run home was at normal temps. I would not be surprised to see the problem again next time out. I have a suspicion though that the gauge could be playing up as I have seen it flick a few times and I also plan to change the thermostats if I can't find a gauge problem.
However I have KAD300s not D4s so my ramblings probably not that relevant. A bit of a coincidence though...
Click to expand...

Adrian, my engines have for the last year (90 hours) run consistently at 85 degrees, never more. Recently they went to 91 and I knew that was wrong and the following trip to 93, so I knew there was a problem. However, only at WOT. At 26 knots seemed happy at 85 degrees. Your P 34 = Same boat, different engines, same problem... Hard to fathom!

I'm only really interested in solving the problem, so hopefully, blocked coolers is it and we may be sorted by the wk end, but it is interesting that P 34s seem to be suffering in this way...???
Andrew
 
Chaps -pop into Maplins and come out with a £10-20 pounds worth of infer-red digital thermometer .
Take the plastic covers off the engines .
Bear in mind the thermal guard " alarms" trip out at ( from memory ) 94 degrees .
Run @ 3000 or WOT check the REAL temp with gadget placed on top of the thermostate housing and cross refference this to the gauge .
You may find a huge discrepancy -ie gauge says 110 ( dispite no alarm) but REAL temp is actually 88 .
Stop engines -now safe to climb in engine compartment and test temps of the two coolers they will be the same -quite cool from memory 60 degrees ish .
Prob is not faulty gauge ( you can swop the harness at the back of the black box on a Kad300 ) or fit a new gauge .
It's not the sender swooping this make no diff
It's the actual insulation in the wiring work hardening with time and heat over the years sending a duff signal ( some sort of change in resistance? ) = a false high reading on the temp gauge .
You really need a Digital inferred thermometer ,before anything else to find out the REAL temps
My Starboard engine after a 6 week period of under activity show 250 degrees off the scale @ 3000 rpm -no alarms!
REAL temp was 88 .As the days passed ( 2wk hol) it came down to 110 on the gauge ,but REAL temp
88-90 same as port engine -which the gauge reads true
 
If you really think this is a specific P34 issue I suggest you look at the calorifier as its the only installation that is specific to the P34 and the difference between the port and starboard engines, it is connected to the port engine. Perhaps we have a chemist on the forum who can comment if this potentially could explain why you are getting that stuff in your heat exchangers.

Incidentally my port engine KAD43 is also running a few degrees higher however it does not go over 90c at WOT so I have not considered it as an issue.
On my boat every item in the cooling system is Volvo Penta standard installation stuff, except of course the calorifier on the port engine if you want to include that into the system. I assume it's the same for the the D4 installation.

I also think the same calorifier is used on pretty much all prestige boats so if an issue it should be an issue for others as well.
 
I posess an IR thermometer and will take it with me next time.
A calorifier that was already hot from electric should in theory speed warming of the port engine, but in reality it seems to make little difference and I can't see how it can make the engine run hotter.
 
Has anyone checked the plastic elbow on the drives for cracks as its above the waterline when on the plane, if its cracked the sw pump will suck air not water causing an overheat. Any vp engineer should look at this first before spending your hard earned on ripping your coolers apart . Most d 4/6 motors need the coolers off after 4 years now in my experience .
 
volvopaul said:
Has anyone checked the plastic elbow on the drives for cracks as its above the waterline when on the plane, if its cracked the sw pump will suck air not water causing an overheat. Any vp engineer should look at this first before spending your hard earned on ripping your coolers apart . Most d 4/6 motors need the coolers off after 4 years now in my experience .
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That's what the Volvo guys told me at SIBS, so I got French Marine to take mine off and thoroughly check them, but they were fine. I was hoping for an easy fix while the drives were being serviced, but alas not :(
 
volvopaul said:
Has anyone checked the plastic elbow on the drives for cracks as its above the waterline when on the plane, if its cracked the sw pump will suck air not water causing an overheat. Any vp engineer should look at this first before spending your hard earned on ripping your coolers apart . Most d 4/6 motors need the coolers off after 4 years now in my experience .
Click to expand...

Paul,
Can you suggest any reason why these symptoms should affect the port side engine rather than starboard, as seems to be everyone's experience here at least?
Andrew
 
Groot T said:
Hi Andrew, sorry for chipping in at a late date.

As a sanity check, if it is a salt deposit can you chip it off and dissolve it in boiling water?
Click to expand...

Truth is, I'm not really sure. I'm not a techy, so have a MarineEngineer dealing. I'm genuinely impressed with him, he seems to be a smart guy. His conviction all along has been to get in and have a proper look rather than just flush through with acid or similar as that was done a year ago and was only a temporary solution clearly. His suggestion was to get the affected parts to an acid bath or similar and I'm going with him. I don't have sufficient knowledge to bring alternative suggestions, though I have a few suggestions from the forum now to bear in mind - Rydlyme etc.

All being well, boat may be back on the water this wk end so I will then be able to report further...
Andrew
 
Update from Dan, the Marine Engineer - things nearly reassembled and back together. All parts now nicely cleaned up. Sea trial probably Saturday.

A year ago when this problem first appeared, before I took possession the VP dealers used Rydlyme as a treatment and did it twice. It obviously worked to a degree but only for a year. My guess is it simply didn't shift enough scale and so only lasted a year.

He thinks the dry stack could be a contributory factor, with things more prone to drying out than they are on the water.

Anyway, next step is the sea trial...

Andrew
 
Fingers crossed that this work lasts for more than a couple of seasons at the least and I look forward to hearing the outcome. Last year French Marine showed me the stacks out of a fishing boat with a single D4 and they were in quite a state too. I will be treating mine with Rydlyme in a couple of months when I get the time to do it. I'm wondering if it is a good idea to do this as part of the annual maintenance, rather than the pain and man hours of stripping it all apart to clean it manually.

Would you be so kind as to pm me a figure of what the final bill is, so that I can weigh up my options for the future?

Geoff
 
Bubblegtt said:
Fingers crossed that this work lasts for more than a couple of seasons at the least and I look forward to hearing the outcome. Last year French Marine showed me the stacks out of a fishing boat with a single D4 and they were in quite a state too. I will be treating mine with Rydlyme in a couple of months when I get the time to do it. I'm wondering if it is a good idea to do this as part of the annual maintenance, rather than the pain and man hours of stripping it all apart to clean it manually.

Would you be so kind as to pm me a figure of what the final bill is, so that I can weigh up my options for the future?

Geoff
Click to expand...

Of course, no probs.
Andrew
 
Tel call from Marine Engineer to say sea trial went well - no problems at WOT, engine temp stayed consistent at 85 degrees. Sounds good. I will be on the boat for a couple of nights early on this week so can check things out myself.
Andrew
 
Quest said:
Tel call from Marine Engineer to say sea trial went well - no problems at WOT, engine temp stayed consistent at 85 degrees. Sounds good. I will be on the boat for a couple of nights early on this week so can check things out myself.
Andrew
Click to expand...

Well that sounds like great news and hopefully no further overheating :)
 
Good blast from Plymouth to Falmouth and back, incl times of flat out use to check things out. All behaved beautifully. Well done Dan Lewis of Lewis Marine. Have yet to have the invoice of course!!! Will have to decide what to do about the starboard engine over the winter. Think a couple of flushes with Rydlyme will be the way to go for starters, as a preventative.

Dan made the point that doing this job on the port engine of a P34 is a pig due to restricted access. Starboard engine would be easier.

Andrew
 
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