kad300 heat exchanger and coolant flush

[jon and michie]

Hi - Just been looking at my maintenance book and wondering how much coolant is required for the change out/flushing.
I am thinking of getting a ready mixed 20ltr tub.
as a side note the instructions seem straight forward - is this the case or is there anything I should be aware of?
Many thanks for any opinions
Jon

 

[oldgit]

I used 5 litres of Barnycule Buster which appeared to do the job on a 41B.
Chum used 5L of Rydlyme with some success
In my case , merely marinated the raw water system for few hours , he rigged up a little pump to set up flow in the system.
Dilute as recommended.
Might be worth checking that it actually needs doing.Sometimes be possible to remove an heat exchanger/oil cooler end plate and peek inside.
Any obvious temp increase is good sign of clogging.

https://www.ebay.co.uk/itm/Barnacle...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
https://www.ebay.co.uk/itm/Rydlyme-...785869&hash=item2ef87e781c:g:TE0AAOSwjOxazJVB

 

[jon and michie]

Thank you oldgit - I am just doing its 2 year change out of the coolant.
Jon

 

[Bandit]

If your KAD 300 has not been flushed recently, I would remove all coolers and Inspect, the oil coolers have a habit of leaking/dripping after about 10 years past the seal and bi metallic corrosion forms on the outside of the cooler between the aluminium casing and the brass components, this can cause the rubber seal to pop out under the oil pressure and dump all the lube oil, this can kill your engine. Any signs off corrosion to the Aluminium casing replace it do not dick around with chemical metal etc. Cleaning cooler stacks use Rydlyme.

 

[Mr Googler]

I used 5 litres of Barnycule Buster which appeared to do the job on a 41B.
Chum used 5L of Rydlyme with some success
In my case , merely marinated the raw water system for few hours , he rigged up a little pump to set up flow in the system.
Dilute as recommended.
Might be worth checking that it actually needs doing.Sometimes be possible to remove an heat exchanger/oil cooler end plate and peek inside.
Any obvious temp increase is good sign of clogging.

https://www.ebay.co.uk/itm/Barnacle...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
https://www.ebay.co.uk/itm/Rydlyme-...785869&hash=item2ef87e781c:g:TE0AAOSwjOxazJVB

So is barnacle buster the same stuff as rydlyme? Look....smell the same?

It’s much cheaper that’s for sure

 

[oldgit]

So is barnacle buster the same stuff as rydlyme? Look....smell the same?

It’s much cheaper that’s for sure

Unable to confirm the exact chemical composition of Barnacle Buster, suspect it is a industrial solution used commercially elsewhere and merely lacking the required fancy container and a distinct lack of the price gouging linked with anything Marine.
One of my engines displayed a distinct rise of temperature,perhaps 5 degrees or so at displacement and perhaps 10 at fast cruise,with a distinct delay in temp dropping when coming off the plane.
Disconnected raw water pipes at pump and at riser and poured in solution. Left oil cooler/heat exchanger to soak in the solution for a morning , reconnected and flushed by starting engine.
Both engines now running again at indentical temps and both temps drop quickly again after fast cruise.
It did the job for me and P & P is free as well,arrived within 24 hours of ordering.

 

[jrudge]

The op is saying heat exchangers and coolant - they are different sides of the system

The exchangers - yes rydlyme ( or just order hydrocloric acid of eBay for 5% of the price.
Coolant is the fresh water side. Coolant on my volvos is every 2 years I think. If changing from green to yellow you flush with oxalic acid. If the same as far as I know you just fresh water flush it and refill.

 

[Portofino]

The op is saying heat exchangers and coolant - they are different sides of the system

The exchangers - yes rydlyme ( or just order hydrocloric acid of eBay for 5% of the price.
Coolant is the fresh water side. Coolant on my volvos is every 2 years I think. If changing from green to yellow you flush with oxalic acid. If the same as far as I know you just fresh water flush it and refill.

Yes there’s two surfaces in the heat exchanger coolers and charge air coolers ( where applicable) .

“ different sides of the system “

Rydlyme and brick cleaner or other acids pumped round or pickled in situ through accessing the raw water will remove salt scale and is obviously anecdotally beneficial, it does indeed work there’s no doubt .

But there’s only so many times that can be done before the system needs a thorough strip down imho .
This is because on the closed cooling side there is also a film of crud building up .No where near as detrimental compared to the raw side but nether the less it remains untouched by rydlyme et al systems .

Then with charge air coolers a smear of oil films develops on the air side fins , not a lot but nether the less it’s impedes the heat exchanger efficiency.Elevated EGT,s is not to be encouraged.

Thirdly there’s the old bimetallic galvanic corrosion issue .Often inhibited by gaskets and seals . Just a rubber ring keeping fluids that shouldn’t mix from mixing .
With a rydlyme job theses are basically neglected .

They often sit deep in flanges out of sight out of mind I guess .Gaskets age harden , weep and the alloys deep inside the flanges distort .Sometimes needing a whole new part as the flange now visible once the things on the bench can’t accept just a new gasket .

So with a manufacturers recommended strip down and dunk with pipes or fin plates you get both sides cleaned AND importantly if the boats a keeper fresh gaskets , the gaskets hopefully keeping the metals from attacking each other .

Just want to add balance to someone reading this thread thinking there’s no need for a total strip down .
It’s all about an informed choice .

 

[Bandit]

If your KAD 300 has not been flushed recently, I would remove all coolers and Inspect, the oil coolers have a habit of leaking/dripping after about 10 years past the seal and bi metallic corrosion forms on the outside of the cooler between the aluminium casing and the brass components, this can cause the rubber seal to pop out under the oil pressure and dump all the lube oil, this can kill your engine. Any signs off corrosion to the Aluminium casing replace it do not dick around with chemical metal etc. Cleaning cooler stacks use Rydlyme.

I repeat, ignore the condition of the oil cooler at your peril, if it fails you could very probably trash an engine. It is almost impossible to see without removing the oil cooler, especially with tight engine room access and especially if you don’t know what to look for.

 

[jon and michie]

thank you for the replies - interesting read and will clean/inspect at the winter period when she's on the hard.
as jrudge has mentioned I am doing the 2 yearly coolant change and flush out - so is it as easy as the manual says and does anyone know how much coolant is required - I am thinking of getting the premixed volvo green coolant.

thanks again
Jon

 

[petem]

20 litres I believe. Many people find that filling above the minimum mark results in the engines spitting the coolant out via the caps. In fact, the engine manual says that the level should be checked when the engine is at normal operating temperature. There's a seam on the expansion tank between min/max that seems to work will as a filling point for me.

 

[jrudge]

I replaced with Volvo Green. Total waste of money but I wanted green! If you google hard enough you can find an equivalent.

I would fill it right up. It will " burp" when you first get it upto temp and the air comes out and fall down. Worst case you have a small bit of green mess to clean up - but you are likely to spill some anyway!

 

[petem]

I replaced with Volvo Green. Total waste of money but I wanted green! If you google hard enough you can find an equivalent.

Why was it a waste of money?

 

[jrudge]

As Volvo stuff is many times more expensive than unbranded antifreeze ( with other additives etc)

 

[Michael Inkster]

I repeat, ignore the condition of the oil cooler at your peril, if it fails you could very probably trash an engine. It is almost impossible to see without removing the oil cooler, especially with tight engine room access and especially if you don’t know what to look for.

Good advice - I was out in my 2004 Merry Fisher 925 (Volvo KAMD 300) with my wife and daughter last summer. Without warning the engine ground to a halt and stalled. Opened the engine hatches and she‘d dumped most of her oil in the bilges. It was a hot steaming mess. The culprit was the oil cooler which was replaced at a cost of around £1,200 but much cheaper than a new engine. I wonder if the engine switched off due to a pressure sensor or perhaps an oil level sensor? If I owned a similar engine I’d immediately replace the oil cooler irrespective of any problems. Any thoughts about the automatic switch off?

 

[stelican]

Hi - Just been looking at my maintenance book and wondering how much coolant is required for the change out/flushing.
I am thinking of getting a ready mixed 20ltr tub.
as a side note the instructions seem straight forward - is this the case or is there anything I should be aware of?
Many thanks for any opinions
Jon

Might need to bleed the turbo return line.

 

[oldgit]

Might need to bleed the turbo return line.

Failure ensure coolant to turbo could result in the turbo overheating and casing getting hot enough to cause surrounding surfaces to smoulder.

 

[hmallett]

Thinking I'll replace my heat exchanger and oil cooler on KAD300A and looking for aftermarket solutions to avoid VP prices. Came across a heat exchanger replacement, and was serviceable (end caps removeable!), but cannot find now. Any idea where reasonable after-market coolers can be found? Hard to believe that VP would make their units unserviceable..... Thanks for the above information; a 'Salt Away' flush is at least something I will try....
H

 

[hmallett]

I used 5 litres of Barnycule Buster which appeared to do the job on a 41B.
Chum used 5L of Rydlyme with some success
In my case , merely marinated the raw water system for few hours , he rigged up a little pump to set up flow in the system.
Dilute as recommended.
Might be worth checking that it actually needs doing.Sometimes be possible to remove an heat exchanger/oil cooler end plate and peek inside.
Any obvious temp increase is good sign of clogging.

https://www.ebay.co.uk/itm/Barnacle-Bust-Safe-Non-Toxic-Biodegradable-Marine-Growth-Remover-Cleaning-5L/123299544241?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
https://www.ebay.co.uk/itm/Rydlyme-...785869&hash=item2ef87e781c:g:TE0AAOSwjOxazJVB

Hi oldgit; wonder if you know of an aftermarket heat exchanger and/or oil cooler that will fit my KAD300A for far less $ than VP parts? I've been through every other possible heat situation, and coolant runs cool, but gauges read hot, so suspect oil cooler as temps climb rather slowly at plane, and cool (rather) slowly when speed/rpm reduced. Have had all coolant areas checked by IR heat gun and coolant temp is totally normal. However, I doubt the previous owner(s) replaced heat exchanger and oil cooler, so will at least run some 'salt away' through heat exchanger and re/re oil cooler with fingers crossed. Thanks for any assistance/advice! New to forum but it looks good! hmallett

 

[A_8]

Good advice - I was out in my 2004 Merry Fisher 925 (Volvo KAMD 300) with my wife and daughter last summer. Without warning the engine ground to a halt and stalled. Opened the engine hatches and she‘d dumped most of her oil in the bilges. It was a hot steaming mess. The culprit was the oil cooler which was replaced at a cost of around £1,200 but much cheaper than a new engine. I wonder if the engine switched off due to a pressure sensor or perhaps an oil level sensor? If I owned a similar engine I’d immediately replace the oil cooler irrespective of any problems. Any thoughts about the automatic switch off?

I don't know why it switched off but to echo the sentiment and expand it to all KAD engines, the oil cooler need a refurb or change of o'rings at around 10 years and if you don't they will need replacing a few years later and if you don't, they will fail in another few years. This is a pic of one untouched for 16 years and notice the coolant drain broken, it just disintegrated when getting the hose off .