KAD 43 - Mystery overheating

[foxgoose]

Lovely this morning - good forecast, so we set of from Dartmouth towards Yealm for lunch.

Boat running well but down to 22k (from 30) 'cos it's been in all winter and badly needs a scrub/antifoul.

Running nicely at normal cruising revs of 3200 rpm, just round Prawle point slowed down for a bit of chop and then - catastrophe! - overheating alarm (200degF+).

Major panic 'cos the last time this happened to me was on it's delivery trip last year when all the belts came off the engine.

Anyway this wasn't serious, slowed down and temp came back down to normal 180-190F.

Anchored off Hallsands for lunch and checked coolant, sea water strainer etc. - all OK.

Gave up on Yealm due to general nervousness and decided to gun back up to Dartmouth at full throttle to replicate prob.

Temp stayed spot on normal so kept going flat out up to Brixham - still no heating, likewise on way back.

I don't think it can be the weedy bottom as I went out for some heavy weather experience with my instructor in F5/6 for most of last Friday . running in nasty lumpy seas ar full throttle for several hours without any probs.

Can any of you more experienced folk suggest what caused the engine to get hot?

Any

<hr width=100% size=1>

 

[DavidJ]

I can only think to check the impellor. It's a simple task and might just be the problem if you're lucky.
David

<hr width=100% size=1>

 

[longjohnsilver]

Probably something blocking the raw water intake, when you slowed down less pressure so maybe bag or whatever dropped off. Just a guess. Expect you'll never find out.

<hr width=100% size=1>

 

[hlb]

Suspect Mr underpants might be right. Happend to me once. Two engines overheated in Plymouth. so course I stopped dead. Never did find out the reason. Probably some big placy bag stuck over intakes.

<hr width=100% size=1>

Haydn

 

[Happy1]

As the others say most probably a plastic bag. What you did was right and others should take note, if a plastic bag covers the intakes it will cause the temp to rise dramiticaly due to the suction of the bag onto the intakes, when you stop it is very easy for the bag to just float away unnoticed as the suction stops, and the problem never really found. If you don't stop the overheating continues, the impeller will disintegrate and much further damage can be done.

It would do no harm to check the impeller to see if any damage was caused, but seems you got away with this one by being vigilent and taking the proper action.

I only know about this after hours of talks with Volvo UK due to my alarms going off.

<hr width=100% size=1><font color=purple> "You only see what you recognise, and you only recognise what you know" <font color=purple>

 

[hlb]

Oh No. Happys become an expert!! Will we ever here the last of it. Wheres me hat!!.........../forums/images/icons/laugh.gif

<hr width=100% size=1>

Haydn

 

[Happy1]

Cheeky monkey!! I explained where I got my info from, just impressed that others on the forum seem to have been on the right track /forums/images/icons/wink.gif especially after I was told most of you talk nonsense /forums/images/icons/laugh.gif

<hr width=100% size=1><font color=purple> "You only see what you recognise, and you only recognise what you know" <font color=purple>

 

[TRH]

Maybe just Maybe: your Thermostat is sticking, it may need a new one, happened to me recently, If like me your worried about overheating, do as I do and carry a heat sensor laser gun to answer any overheating problems.You just point at any part of your cooling system and find the hot spots. Regards Trevor

<hr width=100% size=1>

 

[DavidJ]

Thats a possibility and reminds me that one of mine on a KAD43 stuck open during trials so equally they could stick closed.
David

<hr width=100% size=1>

 

[adarcy]

Re: KAD 43 sticky thermostats

Well they shouldn't stcik closed.
Unless I'm very much mistaken, all thermostats should fail open so overcooled rather than fail shut and overheat. At least it's been that way with cars for 40+ years. Maybe the marine scene hasn't caught up or still manages to use non-standard parts!

<hr width=100% size=1>

 

[foxgoose]

Re: KAD 43 sticky thermostats

Thanks to all for various advice.

Ran down to Salcombe & back Sunday with no probs so passing placcy bag seems most likely.

FG

<hr width=100% size=1>