Volvo d4-260 heat exchanger/cooler question

J

julians

Well-Known Member
Joined
11 Jun 2006
Messages
2,679
Visit site
Hi all,

A couple of questions regarding the various heat exchangers/coolers installed on this engine, I'm hoping that these should be easy for those in the know:-

- am I right in thinking there are 3 heat exchangers/coolers than typically need to be cleaned out? Theres the main heat exchange, the oil cooler, and the aftercooler? are there any more.
- Does a labour estimate of around 15 hours sound about right to do these?


Cheers
 
Yes these three are fitted to a D4/6, the time sounds about right depending on engine access, its more tricky to remove the combined heat exchanger/oil cooler on the D4 as the block is shorter so they come up tight to the aftercooler and starter motor.
 
Volvo Penta suggest cleaning by chemical leaving all "in situ". There is a service bulletin somewhere recommending the use of Oxalic Acid and a Nuetralising chemical. These can be nasty products so very careful following of instructions required. Supposed to be very effective.
 
Springer - Thats interesting. Do you happen to have a link to the service bulletin explaining how to do this? Presume this is a significantly less labour intensive way of cleaning these out?
 
You can clean them with rydelime but most of the ones I've done still retain some marine growth that really need manual removal afte stripping down. Also the end cap o ring leak on the rear of the heat exchanger and intercooler which drip sea water on to the starter motor and relay. Best to do a proper job and renew the o rings as descaling the deposits can allow water past the o rings.
 
volvopaul said:
You can clean them with rydelime but most of the ones I've done still retain some marine growth that really need manual removal afte stripping down. Also the end cap o ring leak on the rear of the heat exchanger and intercooler which drip sea water on to the starter motor and relay. Best to do a proper job and renew the o rings as descaling the deposits can allow water past the o rings.
Click to expand...

Thanks paul, the estimate i have includes renewing all the o rings and seals.

My fathers boat (same engines) had the problem you describe regarding the heat exchanger dripping salt water onto the starter motor, its surprising how much a starter motor costs these days.
 
The SB relating to the oxalic acid and neutralising chemical is for use on the fresh water (coolant/antifreeze) side of the system if changing from Volvo Green coolant to the new Yellow VCS coolant. The correct product to use for flushing the raw water side of the system is Rydlyme marine, as mentioned by Volvopaul.
Using a descaler in situ is advisable on the D4/D6 engines annually/every 24 months as part of preventative maintenance, but I would not advise its use to clean a blocked or leaking cooler in place. If your coolers are showing signs of needing service (salt deposits or leaking from the end caps) then they need to be removed, stripped, professionally cleaned and inspected.
There are 3 coolers in total, a combined heat exchanger/oil cooler which is split apart once removed and the charge air cooler. to remove all of these involves draining the coolant, removed almost everything from the LH side of the engine, including raw water pump and starter motor and then obviously the reverse to refit. Depending on the exact vessel and access to the engine, 15hrs could be reasonable and on certain installations we have had to charge even more. As the oil filters need to come off, the coolant/antifreeze will be drained and the oil will need topping up it is well worth combining this with the 24 month/200hr service at the same time.
Depending on how bad it is, if the coolers have already leaked sea water, I would take the time to clean and paint the engine block whilst everything is off, and maybe even have the starter sent in for service to prevent any future problems (spend a small amount now to prevent a larger bill in the future) - this is entirely dependant on the individual case.
 
GAMPortsmouth said:
The SB relating to the oxalic acid and neutralising chemical is for use on the fresh water (coolant/antifreeze) side of the system if changing from Volvo Green coolant to the new Yellow VCS coolant. The correct product to use for flushing the raw water side of the system is Rydlyme marine, as mentioned by Volvopaul.
Using a descaler in situ is advisable on the D4/D6 engines annually/every 24 months as part of preventative maintenance, but I would not advise its use to clean a blocked or leaking cooler in place. If your coolers are showing signs of needing service (salt deposits or leaking from the end caps) then they need to be removed, stripped, professionally cleaned and inspected.
There are 3 coolers in total, a combined heat exchanger/oil cooler which is split apart once removed and the charge air cooler. to remove all of these involves draining the coolant, removed almost everything from the LH side of the engine, including raw water pump and starter motor and then obviously the reverse to refit. Depending on the exact vessel and access to the engine, 15hrs could be reasonable and on certain installations we have had to charge even more. As the oil filters need to come off, the coolant/antifreeze will be drained and the oil will need topping up it is well worth combining this with the 24 month/200hr service at the same time.
Depending on how bad it is, if the coolers have already leaked sea water, I would take the time to clean and paint the engine block whilst everything is off, and maybe even have the starter sent in for service to prevent any future problems (spend a small amount now to prevent a larger bill in the future) - this is entirely dependant on the individual case.
Click to expand...

Thanks for the comprehensive reply, i appreciate it.

Yep , the estimate includes switching to the new yellow coolant. Access the the engine is pretty good, its a single engined boat, a windy 25 for those who are familiar with it. None of these are leaking at present, im just trying to resolve an overheat problem at >3200rpm. All this will be carried out as part of the yearly service along with the usual service items, oil, filters etc etc.

My fathers boat , a windy 37, was not so lucky and had a leaking heat exchanger,which had corroded too much to be reused, which also took the starter motor with it. It was all quite costly to repair.
 
julians said:
Thanks for the comprehensive reply, i appreciate it.

Yep , the estimate includes switching to the new yellow coolant. Access the the engine is pretty good, its a single engined boat, a windy 25 for those who are familiar with it. None of these are leaking at present, im just trying to resolve an overheat problem at >3200rpm. All this will be carried out as part of the yearly service along with the usual service items, oil, filters etc etc.

My fathers boat , a windy 37, was not so lucky and had a leaking heat exchanger,which had corroded too much to be reused, which also took the starter motor with it. It was all quite costly to repair.
Click to expand...


It sounds quite comprehensive which is good. Not quite sure why you are going through the considerable hassle and added cost of changing from green to yellow coolant. The green coolant is not expensive and you would have to go through about 10 years (5 changes green vs 2 yellow) before you start to see any of your money back from the switch over. I'm all for making money like a business should, but not unnecessarily. If it is your choice and you are going into it will full knowledge then fine and go for it.
Once you have had this done, as mentioned before - to minimise the chance of having to do this again (and prevent an incident similar to your fathers Windy), it would be prudent to adopt a maintenance plan of flushing with Ryldyme every 12months (24 months at latest) on the raw water side moving forward.
Good luck
 
The change to yellow coolant is a recommendation from the people that service the boat for me, it seemed to be an obvious thing to do given that we have to drain the fresh water side down anyway to clean the various heat exchanger/coolers fully. Volvo seem to think the yellow coolant does a better job at corrosion prevention than the green, so my thinking was I may as well use it.

Can you elaborate on why it might not be worth changing to the yellow stuff?

Cheers again, this is all useful stuff to know.
 
julians said:
The change to yellow coolant is a recommendation from the people that service the boat for me, it seemed to be an obvious thing to do given that we have to drain the fresh water side down anyway to clean the various heat exchanger/coolers fully. Volvo seem to think the yellow coolant does a better job at corrosion prevention than the green, so my thinking was I may as well use it.

Can you elaborate on why it might not be worth changing to the yellow stuff?

Cheers again, this is all useful stuff to know.
Click to expand...

Just in the interest of honesty, I should make sure you know that I speak on behalf of a Volvo Penta Centre. However, I have no ulterior motive here, either for or against the VCS coolant.
Volvo Penta have tested and found that the new coolant offers better corrosion protection when compared to the green coolant, however we do not see corrosion on the internal (fresh water side) as an issue on the D4/D6 engines, even in the cases of stray current corrosion - we do see issues on the external (raw water) side after leaks, usually because maintenance hasn't been done properly (remember to change your charge air cooler anode).

The two types of coolant cannot be mixed even slightly, and the instructions for changing the coolant are quite detailed. Add to that the fact that oxalic acid as just downright dangerous - to the environment and to humans I can't see the benefit of changing on your type of engine.
My concerns are that if your engine has run for several years on green coolant, then if this is not removed properly and cleaned thoroughly you could be opening yourself up for further issues which will get very costly, very fast. The cost of changing is going to be in the region of at least 4hrs + materials to do it properly (£200-£260ish minimum), and given that the price differential between VCS and green coolant is about £3/5ltr, your cost over 10 years would be an additional £100-£150ish for keeping the green coolant (3 extra changes) - and the green coolant works just fine in your engine.
I'm not going to take anything away from your maintenance people, or try to convince you to do something you don't want to do. However, if you were my customer I'd be advising you to stick with what you got and not take unnecessary chances - KISS theory!
 
Last edited:
Thanks, thats interesting.

Presumably the consequence of not cleaning out the old green stuff sufficiently, is that the new yellow stuff is ineffective in terms of corrosion prevention if even just a small amount of green stuff remains? is that correct?

Is it really that hard to sufficiently flush the old green stuff out of the engine?
 
If the two types of coolant mix, then the inhibitors will not work - i'm not sure of the exact nature of the problems, but suffice to say it cant be good. VP are usually very politically correct and stereotypically nice in their instructions, but took the time to write the text "may not be mixed chemically with other coolants such as Volvo Penta Coolant (green)" in bold text in the SB. I have heard rumours of the two types forming a gel, but I have no way to prove this - and i'm not going to risk finding out!

Having seen first hand the internal condition of an engine once it has run for a few hundred hours, and also knowing the coolant layout of modern marine diesels I can comfortably say that yes - it will be very difficult to remove all coolant, and almost impossible to remove all traces of it. The only way I would be comfortable undertaking this task would be to drain the coolant, flush with fresh water, run briefly and repeat. I would then run it up until the thermostat opens, and drain again. I would do this until no evidence of coolant residue is present. Then the oxalic acid mix needs to go in and then engine would need to be run to full operating temperature (nearly impossible running alongside in January) to leach all the residue out of the metal components and remove any scale/deposits from the coolers. Then this needs to be drained and flushed 100% before finally draining again and VCS adding.

In your instance, as you are having the coolers removed for professional cleaning, I'm not sure when your service agent is planning on carrying out the above. If even a bit of green coolant remains, then the cleaning has been for nothing - to me the risk is too high to attempt at this stage in your engines life - especially as the recommendation from Volvo is not for safety or defect reasons, but only due to development of new coolant as a result of having to develop new engines and use different materials within them.
 
Thanks.

You've certainly given me food for thought, I will discuss it with the chap that will be performing the work and see what he thinks.

Thanks again for all the input.
 
GAMPortsmouth. It's not my thread but as an interested bystander, this information is outstanding and very useful for D4/D6 owners.

I will be checking my service invoices ;)
 
You must log in or register to reply here.

Share this page

Top