Cooling System Blocked

[Quest]

When I was hoping to purchase Endeavour (Prestige 34) a year ago a problem with the port side engine came to light that caused me to pull out of the sale. However, some time later things seemed to have been sorted by an acid clean of the heat exchangers and cooling system and the boat subsequently passed sea trial etc For a year things have run beautifully but just recently the same port engine has begun to overheat at full revs AAAGGGHHH! So, the engineer has pulled things apart and this is what he found. So, it's off to the acid baths for a clean up!

For you mechanics out there, I would appreciate a little more background - how often does this occur with marine engines (VP D4 260's)?, what causes this build up? Is the build up salt or limescale? Should I be concerned about the starboard engine? etc etc

The boat is a Prestige 34 2007 with approx. 300 hours, though when I purchased a year ago, only 210 hours then.





Thanks,
Andrew

 

[omega2]

They do not look too bad considering, but it is good practice to open them up at least once a year, the crud you see is built up because of dissimilar metals and salt water, chip the deposits off and poke through the reeds, make sure that the mating surfaces are good, the rubber rings may need replacing. To remove them from the casings can be off putting, but we stand ours on wooden blocks supporting the case, then remove the rubber rings, then with a mallet tap the matrix out, if it is reluctant to move then upturn it and try the other way, once you get movement they do come out, do not force the issue though they are expensive to replace. We do all ours, i.e. header tank, charge air, engine oil and gearbox coolers yearly. as any one of them will cause overheating if blocked. Have a set of rubber seals handy in case you tear one or more of them. Not convinced with introducing cleaning agents into the system much better to see what you are looking at. Get the matrix steam cleaned when it is out, you will be amazed to how much crud lies between the reeds. Cannot see from the pictures but if there are drain plugs in the end caps leave them be as moving them will no doubt shear the nut head off.

 

[[2068]]

How was the boat winterised?
Was the seawater side flushed through with antifreeze and fresh water?

 

[Quest]

How was the boat winterised?
Was the seawater side flushed through with antifreeze and fresh water?

In short, No! We use the boat regularly through the winter so didn't prepare for lay-up.

 

[Quest]

They do not look too bad considering, but it is good practice to open them up at least once a year, the crud you see is built up because of dissimilar metals and salt water...

So is this simply salt deposit?

 

[Bandit]

You can treat the engine x1 or x2 together in situ by running Rydlyme through them.

Did this with my 2x 63's two lots plumbed in in series takes about 2 hours plus pump hoses bin etc.

Rydlyme. Does not damage copper alloys or aluminium any metal etc.

Do not use acid it damages coper alloys and other metals its aggresive.

 

[Mr Googler]

+1 for rydlyme. Once every couple of years and all will stay clear. I reverse flushed my engine and the **** that came out was amazing. Wasn't overheating or anything just preventative

 

[andy59]

Hi Quest , am I right in thinking that you dry stack your boat ? , if so maybe when the bulk of the water drains out the residue left evaporates and leaves behind dried salts etc that build up after each launch ?

 

[Quest]

Hi Quest , am I right in thinking that you dry stack your boat ? , if so maybe when the bulk of the water drains out the residue left evaporates and leaves behind dried salts etc that build up after each launch ?

I'd been wondering this myself as the images seem to show a tide mark about half way up don't they? However, the boat has only been dry stacked for a year and the problem first occurred after the boat was 5 yrs old and kept on the water. You could still be correct though, just that it may not be linked to the dry stack in particular. If this is the case with the port engine, I can't help but wonder about the starboard side though that one has run well to date.

I'm not able to do the job myself, but the ME seems to indicate it's a pretty big job to expose all this lot and even more to reassemble. Seems fairly major work as preventative. He also seems to feel that flushing with cleaner might help some but doesn't properly clean the inner parts of the system.

Will certainly be talking to him about Rydlyme though.

Thanks gents.

 

[Bandit]

Try Rydlyme first to clear the deposits, they will not wash out with fresh water.

The cooler stacks when new are a golden brass colour a yellow, if you dip them in brick cleaner they go a red copper colour indicating it is loosing the zinc? Personally I would not use acid on my stacks!

If you squeeze your hoses do they crunch indicating limescale in the hoses and the rest of the engine? Mine now appear to run cooler and hoses have no crunch.

If you are dry stack, After you have cleaned with rydlyme what about putting a valve and a hose tail so each time you lift you can rinse through engine with fresh water?

 

[lynall]

Would neutra salt kit help?


Lynall

 

[cryan]

Rydlyme is an acid. You need an acid to dissolve the alkali deposits caused by salt and limescale. There are other safe acids available commercially for the job. The real trick is being able to properly circulate the solution through the system, preferably backwards. This will probably require a little bit of modification to the pipework to allow you to attach a small pump and bucket to allow circulation. You generally want to circulate until the acid is neutralised and stops being effective.
Removing the cooler tube nest and dipping it is an effective means of cleaning, especially if badly fouled but it does not clean the pipe work.

 

[Bandit]

Perhaps it is an acid but it is not strong you can put your hands in it, brick cleaner is aggressive and nasty stuff.

 

[longjohnsilver]

Another vote for Rydlyme. Does exactly what it says on the tin.

 

[pampas]

+1 again for Rldlyme, Many folks think its "Snake Oil" the only metal to remove are any anodes as it eats Zink, opened up 1 cooler on BMC Commander after circulating for 12 hours, bright and shiny, now see the F/Water temp gauge moving slightly when warmed up, worth every penny, remove pump impellor on both engines, with a few bits of hose connected in series, small bildge pump in a bucket exhaust injection from last engine back to bucket, fill up 25% -50% start circulating and forget, Jog done.

 

[Bubblegtt]

Andrew - I have exactly the same issue with my Prestige 34, the port engine overheats on WOT, it is fine cruising @ 25 knots, but after a couple of minutes flat out, the port engine temps rise to 95 deg. The starboard engine doesn't rise above 85 deg.

I spoke to the Volvo guys at the Southampton boat show and they reckoned that they had never heard of the issue of blocked heat exchangers. Instead they said that the pick-up elbow on the leg cracks and as the boat rises higher onto the plane on WOT it then sucks in air. They blamed mechanics over tightening the hose clips and cracking the elbow. They also said that there is a modified elbow to stop this.

When my boat was out of the water this winter, I had the legs serviced, with new bellows etc. and asked them to check the elbows, which turned out to be fine and they had never heard of this, but the water inlet of the legs were blocked with barnacles. So I was more than a bit dissapointed to find that the port engine still overheats on relaunch

I read about Rydlyme last year and bought some directly from them. I have built a kit consisting of a plastic barrel, high flow water pump and hoses etc. I now just need to run the Rydlyme through the system. I need to be 100% sure on where to connect it all up first though.........

 

[Quest]

Andrew - I have exactly the same issue with my Prestige 34, the port engine overheats on WOT, it is fine cruising @ 25 knots, but after a couple of minutes flat out, the port engine temps rise to 95 deg. The starboard engine doesn't rise above 85 deg.

I spoke to the Volvo guys at the Southampton boat show and they reckoned that they had never heard of the issue of blocked heat exchangers. Instead they said that the pick-up elbow on the leg cracks and as the boat rises higher onto the plane on WOT it then sucks in air. They blamed mechanics over tightening the hose clips and cracking the elbow. They also said that there is a modified elbow to stop this.

When my boat was out of the water this winter, I had the legs serviced, with new bellows etc. and asked them to check the elbows, which turned out to be fine and they had never heard of this, but the water inlet of the legs were blocked with barnacles. So I was more than a bit dissapointed to find that the port engine still overheats on relaunch

I read about Rydlyme last year and bought some directly from them. I have built a kit consisting of a plastic barrel, high flow water pump and hoses etc. I now just need to run the Rydlyme through the system. I need to be 100% sure on where to connect it all up first though.........

Bubblegtt, that's exactly how mine presents also. I guess you may find your cooling system in similar shape to mine then? Currently, the ME has the relevant bits away for acid cleaning and the plan is to reassemble before this coming wk end, all being well. I am hopeful that it will sort the problem as a year ago, two flush through s with acid sorted things for a year, but we shall have to see...

I will obviously be interested to see how you get on with your Rydlyme approach, let me know please.

Andrew

 

[Quest]

Andrew - I have exactly the same issue with my Prestige 34, the port engine overheats on WOT, it is fine cruising @ 25 knots, but after a couple of minutes flat out, the port engine temps rise to 95 deg. The starboard engine doesn't rise above 85 deg.

I spoke to the Volvo guys at the Southampton boat show and they reckoned that they had never heard of the issue of blocked heat exchangers. Instead they said that the pick-up elbow on the leg cracks and as the boat rises higher onto the plane on WOT it then sucks in air. They blamed mechanics over tightening the hose clips and cracking the elbow. They also said that there is a modified elbow to stop this.

When my boat was out of the water this winter, I had the legs serviced, with new bellows etc. and asked them to check the elbows, which turned out to be fine and they had never heard of this, but the water inlet of the legs were blocked with barnacles. So I was more than a bit dissapointed to find that the port engine still overheats on relaunch

I read about Rydlyme last year and bought some directly from them. I have built a kit consisting of a plastic barrel, high flow water pump and hoses etc. I now just need to run the Rydlyme through the system. I need to be 100% sure on where to connect it all up first though.........

For us both to have identical issues, can't help wondering if it's something to do with Prestige 34s or VP D4s (assuming yours are D4s?)...

 

[Bubblegtt]

For us both to have identical issues, can't help wondering if it's something to do with Prestige 34s or VP D4s (assuming yours are D4s?)...

There is another identical boat in our yard that has had the exact same problems too. But the engineers firstly changed the raw water pump, thermostat etc. before finely cleaning the heat exchangers. I was told this by the previous boat yard that he and I were in, but I haven't spoken to the owner yet about it. His boat is currently out of the water with the drives off. He has D4s like us.......

 

[pampas]

Bubbleggt

If I had legs, I would remove prop, lower leg into barrel with minimum water (enough to cool engine) pour in the Rydlyme , run engine at min revs and run intermittently until the solution is spent. Test is to put a small piece of shell or barnies into a sample and if fizess it still active. Again remove any anodes both led and engine.

ps assume your exhaust will need ducting back to the barrel .