Engine coolant system (Volvo MD11c)

[Swanrad2]

Systematically working on a cooling problem with my engine, job number 3 is to defur the cooling chambers of the engine. Is there a chemical/supplier for this? Draining down the system will not be too tough but any suggestions as to how to refill with the defuring chemical?
Thanks

 

[VicS]

The most important thing to look at on this engine are the small passages in the exhaust manifold that take the cooling water from the inlet on the under side to the two heads. Unblock them with a stout wire.

The water jackets in the blocks are likely to be pretty well "clagged up" with sand and silt and corrosion products. Maybe some limescale but they should not get hot enough to deposit much. The heads are more likely to contain limescale.

Consider pumping a fairly concentrated and hot solution of a central heating boiler descaler such as Fernox DS 1 or DS 3 in via the cylinder drain cocks. DS3 is sulphamic acid based and will be the best bet on a limescale but DS1 is based on organic acids which may be more effective on iron oxide deposits. It will be a slow process though.

Maybe you could fill via the inlet hose to the manifold after disconnecting from the pump and draining the engine completely and removing the thermostat.

Hydrochloric acid (dilute some brick cleaner) will be quicker but much more aggressive.

Drain, flush and neutralise with washing soda when you are done.

 

[pampas]

Use Ryhdle (Think its spelt right) but you must remove any anodes,, sea suction removed and a circulating pump temp, installed , suction from bucket and exhaust return to same bucket , start pump add enough fresh water to give a good flow, tip in 1 lte and leave to circulate for at least 6 hours, return to normal start engine and blow out the crud. Most effective de-salter I have ever come across.

 

[VicS]

[ QUOTE ]
and leave to circulate for at least 6 hours

[/ QUOTE ] The trouble with your suggestion is that it won't circulate around the cylinder blocks, just the heads, as the blocks are normally cooled by convection. If the thermostat is not removed it will not even circulate round the heads, just the bypass.

I cannot find "Ryhdle" by Google so probably incorrect spelling. Any idea what it is based on?

BTW there are no anodes in the MD11C

 

[Spuddy]

Rydlime still not right, but closer

 

[VicS]

[ QUOTE ]
Rydlime still not right

[/ QUOTE ] It's Rydlyme web page I've no idea what it is but it is said to contain <10% HCl and to have a pH <3.
So it is an acid descaler

 

[pampas]

RYDLYME RICO Ltd, 4 Henry Edwards Ind, Est. Boraston Lane, Tenbury Lane Wells Worcestershire, WR15 8 LE. Bought mine from a local chand. for £7.50/ltr American product Only metal known to destroy is Zinc, improved raw water circulation by 100%.. the out board just dribbled took head off completely blocked. reasembled and ran in my test tank with this stuff for 4 hours on tick over. plenty of water out of tell tale. stripped and found ALL of the salt gone. does what its says on the can. safe to skin, in fact to test if the mix is spent they say put some in the palm and drop a sea shell in if if bubbles there is more life, I have used it every winter since it was available.

 

[Swanrad2]

Thanks all a weekend of fun and frollics for me (again) then.

 

[VicS]

Have you read Cliff's method described in this thread He has got a good system for his engine. I would remove the thermostst and block the bypass though.

Also because of the cooling system design of the MD11 I would periodically drain some of the cleaning solution out though the drain cocks and return to the bucket.

You could also manage without a extra pump by having three buckets. One to supply the solution to the engine and two used alternately to catch it coming out of the exhaust and return to the top one.