Descaling Volvo D9s

[Driver]

Hello, much has been written on this subject already, geneally in favour of Rydline, etc. However, my very experienced Volvo man tells me that after 10 years and 800 hours without cleaning the heat exchangers and charge air coolers, they will definately have to come off and be mechanically cleaned as descaling will only be effective for a few months at best. He is not looking for the work as its very tight in my Pearl 50. Any comments, please?

 

[Mr Googler]

I would say not if you use a pump to circulate it for a few hours. Can’t see the logic as to why removal is more effective unless you have a complete blockage / over heat symptoms

Effective for a few months is rubbish in my view….if the scale is gone it’s gone by whatever means.

Removal however is better in some ways as you can inspect the coolers/ housings etc….

 

[jrudge]

The acid ( use brick acid cheaper then Rydlyme) dissolves the limescale .

The only time it cant - or will do so very slowly - is if the tubes are complexity blocked so it cant circulate.

In that case it can only dissolve from the ends and given the tubs are 12 inches or so long this will take time.

More likely if there is a blockage it will be at the end where the water sits at the bottom and is unlikely to go though the while pipe.

As above when it gone its gone. It wont just come back BUT if it was not fully removed than it will only take a small amount to block it up again.

 

[Portofino]

Techs get nervous about seals + gaskets .
These deteriorate with time and obviously are not replaced if you don’t strip it down .

Seawater in your sump oil or any water in your cylinders and not good bedfellows.

Aside the rinse with acid route doesn’t remove the oil film ( if any ) on the airside of the charge air cooler .Arguably any crud deposits on the closed cooling side of the main coolers …..but the amount of crud film depends on the closed cooling maintenance regime…..ie how ancient it is .

So there’s a bit more to this than a quick acid flush + run ……to deliberate.

 

[kashurst]

Are you experiencing any temperature or performance issues, or is this just a recommendation because the boat is ten years old?

 

[Driver]

Yes. In the summer, with water temp about 25 degrees C at 2200, port engine ran at 97 degrees and the alarm sounded. Stbd ran at 95 degrees.

 

[kashurst]

That sounds abit warm from memory. You could strip them all down or you couldacid flush them which if done properly works well. Wheni was moored in the med the locals just ran supermarket aqua fuerte around the system for twenty minutes with the engine idling. Pretty easy to rig up a 25 litre tank and some plastic hoses from the seawater inlet on the engine back to where the sea water goes into the exhaust. I did my kamds like this and a lot of crud came put and temps dropped back to normal. 5 years later everything was still ok. It cost little so if you are not happy later on go for the full strip or acid flush again. If you do decide to acid flysh rinse out the system with clean water first

 

[volvopaul]

That sounds abit warm from memory. You could strip them all down or you couldacid flush them which if done properly works well. Wheni was moored in the med the locals just ran supermarket aqua fuerte around the system for twenty minutes with the engine idling. Pretty easy to rig up a 25 litre tank and some plastic hoses from the seawater inlet on the engine back to where the sea water goes into the exhaust. I did my kamds like this and a lot of crud came put and temps dropped back to normal. 5 years later everything was still ok. It cost little so if you are not happy later on go for the full strip or acid flush again. If you do decide to acid flysh rinse out the system with clean water first

If they flushed it that way how did they cool the rubber exhaust pipe if no water was travelling around the system?

 

[kashurst]

If they flushed it that way how did they cool the rubber exhaust pipe if no water was travelling around the system?

You won't lke this solution at all, but it's what they do - even the official Volvo people.
With the engine just idling and using the engine sea water pump to circulate the acid mixture for 15 - 20 minutes the exhaust pipe doesn't get especially hot.
I guess if people were worried about cooking teh exhaust they could run for ten minutes and stop the engine. Leave it for say 10 minutes and do another ten minutes.

 

[volvopaul]

You won't lke this solution at all, but it's what they do - even the official Volvo people.
With the engine just idling and using the engine sea water pump to circulate the acid mixture for 15 - 20 minutes the exhaust pipe doesn't get especially hot.
I guess if people were worried about cooking teh exhaust they could run for ten minutes and stop the engine. Leave it for say 10 minutes and do another ten minutes.

Jesus .

 

[Mr Googler]

Makes no sense….just need a bilge pump in a barrel!

 

[Billy Blue]

Same question, different engine.
I have a VP D4 260. 2010 so now 13 years old. No issues with the temp, remains steady at 85 degrees. It is just coming up to 2000 hours. It has had a lot of use, 200 to 250 hours per annum since my 8 years of ownership, don't know whether that makes any difference. Rydline or a proper strip down, clean & new O rings, etc.?
Anything else should be carried out considering the hours in addition to the annual servicing?

 

[wofff]

I had similar issues with my D9's. Did the acid wash as described and it got me through the season - dropped the temperature enough to get by. Then had them removed and cleaned properly at the end of the season. The result was a great improvement, and five seasons without worry. Last season they started to creep up again and I'll have them cleaned before next. Why wouldn't you ? I see it as a regular service issue.

 

[Bandit]

Be very careful with strong acids like brick cleaner. D9's are no longer in production, if you screw one of a pair it is an expensive re power job.

Rydlyme is fairly mild but also tried and tested.

I agree eventually a cooler strip and clean is a good and thorough thing.

If you have overheating a chemical clean will put back the cooler dismantle and clean but both have their place.

 

[Driver]

Thanks everybody for your replies.

I finally bit the bullet and in order to clean the port heat exchanger, we cut a panel from the saloon floor over the engine and in between the steel support framework. It was a simple enough job compared to the mammoth task of lifting the whole floor which is the designed above engine access for a Pearl 50. There is easy access to the inboard heat exchanger and CAC. The opening measures about 60 by 70cm. My engineer is not a small man but was able to get in and do the job. It also gives better access to the raw water pump. Next is the starboard side and the outboard CAC, which will be a little more complicated as the seat has to come out.
Attached is photo of the heat exchanger. I rather doubt Rydlyme would have fixed that!

 

[harvey38]

Thanks everybody for your replies.

I finally bit the bullet and in order to clean the port heat exchanger, we cut a panel from the saloon floor over the engine and in between the steel support framework. It was a simple enough job compared to the mammoth task of lifting the whole floor which is the designed above engine access for a Pearl 50. There is easy access to the inboard heat exchanger and CAC. The opening measures about 60 by 70cm. My engineer is not a small man but was able to get in and do the job. It also gives better access to the raw water pump. Next is the starboard side and the outboard CAC, which will be a little more complicated as the seat has to come out.
Attached is photo of the heat exchanger. I rather doubt Rydlyme would have fixed that!View attachment 170251

Jeeeeez, it must have lost 70% of it's cooling capacity

 

[jrudge]

It likely would fix it. The only time it won't is if the tubes are blocked all the way through but that does not tend to happen. It mostly blocks the ends.

 

[DavidJ]

It likely would fix it. The only time it won't is if the tubes are blocked all the way through but that does not tend to happen. It mostly blocks the ends.

I see the wisdom in the recommendation to pump the Radlyme in the reverse direction (which is what I did)

 

[Jerbro]

Thanks everybody for your replies.

I finally bit the bullet and in order to clean the port heat exchanger, we cut a panel from the saloon floor over the engine and in between the steel support framework. It was a simple enough job compared to the mammoth task of lifting the whole floor which is the designed above engine access for a Pearl 50. There is easy access to the inboard heat exchanger and CAC. The opening measures about 60 by 70cm. My engineer is not a small man but was able to get in and do the job. It also gives better access to the raw water pump. Next is the starboard side and the outboard CAC, which will be a little more complicated as the seat has to come out.
Attached is photo of the heat exchanger. I rather doubt Rydlyme would have fixed that!View attachment 170251

I’ve fitted a fresh water flush valve after the sea water strainer to ensure the heat exchangers are not sat in salt water for long periods..I’m hoping this will give me a bit more time before a major descaling is required.. this is on a Cummins QSB though.. not a volvo D9…

 

[Driver]

You won't lke this solution at all, but it's what they do - even the official Volvo people.
With the engine just idling and using the engine sea water pump to circulate the acid mixture for 15 - 20 minutes the exhaust pipe doesn't get especially hot.
I guess if people were worried about cooking teh exhaust they could run for ten minutes and stop the engine. Leave it for say 10 minutes and do another ten minutes.

If doing this, why not just put a hose from the shore supply into the exhaust?