MD2030 Heat Exchanger Clean and Coolant Drain Tap

Volvo MD2030D 2002 Engine Hours 800.
Hi All.
To add to the Volvo manual, which is your guide, here are some notes on my 2-month project to clean the heat exchanger, which may assist you. With the tools and knowledge I have now it would be a job for two day with 72 hours in between for sealant to cure. Sorry for the disjointed style of posting but my PC is very old.

The Need to Clean the Heat Exchanger.
Summer 09, I noticed the saloon felt hotter than usual with the engine running. After 6 hours at 2600 rpm we had to increase revs to 3200 rpm, 5 mins later the engine over temperature alarm sounded, I reduced the revs to 2000 and the alarm quickly cleared.

Reduced Heat Exchanger Efficiency.
The postings on the Internet refer to scale building up saltwater side (inside) of the tubes being the main cause of reduced efficiency. In my case the insides of the tubes were OK, with 5 of the 34 tubes being partially blocked, the cause of the reduced efficiency was sludge on the coolant (antifreeze/fresh water mix) side of the tubes. There was a 1mm coating over the tubes with solid sludge at the ends and within the tube matrix. Unfortunately this does not show up well on the attached photo. I removed this sludge with a paint brush, running water and a soak in a mild mix of limescale remover and again lots of running water to flush it clean.



and

Draining the Coolant.
On my engine Volvo did not fit a coolant drain tap but fitted a plug with a 17mm square head that needs a 17mm 8 point socket to remove it using a long lever. The rounding you can see on the square head is due to an unsuccessful attempt to undo the nut by hammering on a 12 point socket (as used on normal 6 sided nuts). Upon removing the plug the coolant gushes out and I used a washing machine grey hose (correct size and flexibility), with some tape wound around the end to improve sealing, to drain it into a 5 litre container, lifting the floor boards in front of the engine meant gravity assisted me.





and

Removing The Heat Exchanger Matrix.
The most important thing is to close the seawater intake valve on the saildrive leg !!!!
With the Coolant drained from the engine block, undo the 4 clamps, plus a fifth on the exhaust elbow, pull the 2 boots off carefully and carefully pull the heat exchanger matrix forward. Be ready to catch some seawater and coolant.


Exhaust Elbow.
Check the hole is not blocked or restricted by scale.

Reinstalling the Heat Exchanger Matrix.
It is very important to check fore and aft position of the matrix to ensure that the clamps are positioned on the solid ends of the matrix.

Mike,

Thanks for this, it is very helpful and great job in providing a step by step.

 

Hi

We got the same two hoses on our md2020.

They are bi-turbocharged perfomance enhancers....

No really - they are for heating the hotwater tank.


Edited by H8jer - 30 July 2014 at 18:09