Idiot Guide to AD41b heat exchanger unblocking please

robyonfrome

robyonfrome

Well-Known Member
Joined
12 Jun 2008
Messages
280
Location
Wareham river Frome
Visit site
overheating problem possibly from sand from my shallow river mooring or impeller shredding recently. Have a diagram of the exchanger from past posts, trying to get the ends off to have a look inside any hints how to get the ends off greatly appreciated. Sorry in advance I would ask my usual mechanic but have just paid nearly 2K for another problem and cant afford him just now
 
Rather than taking it apart you could consider Rydlyme

http://rydlymemarine.co.uk/

I used it and it was fantastic. All you need is a small pump, bit of tubing and a bucket. As you run it through the other way to the normal flow, any bits may well come out. After a few hours of circulating, all kinds of stuff came out and overheat was sorted.

Cheaper than a exchanger overall.
 
Rydelime or take the 2 hoses off,mark where the end cap is,13mm bolt in the middle of end cap, 2 screwdrivers carefully prise off end cap, before you do it order new o ring for end cap.

Clean out scale from ends of tubes carefully with either a small wire brush or gentle scraper, make sure the rubber dividers dont fall off.

Chances are though its the oil cooler thats blocked as its the first cooler from the sw pump that gets the weed andold impeller bits stuck in it, and there is little you can strip off it to clean it out other than through the hose apperture, rydelime is the one of the oil cooler.
 
Thanks paul are you saying to get the end cap off, you take the two short hoses at the stern end off and unscrew the 13 m bolt then you can prise off the end cap without removing anything else, what about the other end can that be taken off also and how. Sorry I did say idiot guide !!

Thanks also Farsco but explanation in more depth please again the above applies, where do you put the stuff, which way is the flow, any diagrams available on all this. Many thanks for your patience guys.
 
FARSCO said:
Rather than taking it apart you could consider Rydlyme

http://rydlymemarine.co.uk/

I used it and it was fantastic. All you need is a small pump, bit of tubing and a bucket. As you run it through the other way to the normal flow, any bits may well come out. After a few hours of circulating, all kinds of stuff came out and overheat was sorted.

Cheaper than a exchanger overall.
Click to expand...

Also a big fan of Rydlyme, has worked well for me and a mate.

Usual way is to suck it up through the raw water intake and just leave it for a few hours and then flush it out. Very simple. Very effective.
 
http://www.rydlymemarine.com/pdfs/MARINE ENGINE RAW.pdf

Instructions from rydlyme are above but I ran it backwards through the system instead.

Basically, fill a bucket with rydlyme and put it next to the engine low down.
Take the water inlet pipe off your oil cooler and stick it in the bucket. (The rydlyme will be coming from the oil cooler into the bucket)
Disconnect your outlet pipe (the one going into the exhaust elbow I would think)
Get a bilge pump with a long tube and stick the tube into your outlet pipe and the pump in the bucket.
Let it rip and you will see the flow coming back into the bucket. Let in run for 2 hours.

I assume you are on outdrives so be careful taking the inlet pipe off as you have no seacock I assume and the bucket needs to be lower than the oil cooler obviously. I did mine on land just to be safe.

If you think you have big bits like impeller vanes in there, may well be worth a look as per Mr Volvopaul. The flow rate mayn not be enough to dislodge big bits of rubber. It will destroy the scale in there though :) :)

Hope it helps
 
Last edited:
robyonfrome said:
Thanks paul are you saying to get the end cap off, you take the two short hoses at the stern end off and unscrew the 13 m bolt then you can prise off the end cap without removing anything else, what about the other end can that be taken off also and how. Sorry I did say idiot guide !!

Thanks also Farsco but explanation in more depth please again the above applies, where do you put the stuff, which way is the flow, any diagrams available on all this. Many thanks for your patience guys.
Click to expand...

The heat exchanger only has 1 end that can be opened up to clean out the dirt, the tubestack is part of the assembly, though no doubt it was made with an inner stack then soldered around the front to form the structure, it may also be that the tubes on the outside are blocked, not allowing the internal coolant to pass through over the tubes to cool the water.
 
I use a central heating pump to circulate the Rydlyme and have had excellent results.
12062010402.jpg
 
we have had overheating probs with twin volvo D12 s. The heat exchangers were blocked with tiny bits of twig, plus other *** from the estuary. The "twiglets" were stuck end on into many of the holes and had to be pulled out forcibly with long nose pliers. We do work from a particularly mucky bit of the estuary where all the flotsam collects. I suspect our probs also stem from bad practise in taking the strainers out to empty leaving a bit of low pressure behind, allowing water from the intakes upstream of the strainer to flow in and past where the strainer basket lives. Now we use the wet/dry vac to hoover out the bits from the strainer basket.
 
You must log in or register to reply here.

Share this page

Top