clogged Volvo MD2B manifold.

[Akestor]

I was about cranking her today for first time after refitting, but then i read in a post that the engine inlet for cooling is that T under the manifold ...Unfortunately i missed that because the manual states that the water goes to the thermostat housing and distributes from there...

Anyway i uninstalled the manifold and unfortunately this is blocked with hard black salt mix of dirt...all paths are clear ( i am testing blowing in them) , but the T input is totaly clogged. I removed and cleaned the brass T fitting ( thats ok) and I removed deeper any dirt i could with cicels but there is no tool i can dig in there much deeper.. I even connect it with a hose to get help from the pressure of water but nothing comes out from the holes..

I assume the T should distribute water to the 2 upper inlet holes as shown on picture...(from manifold to head holes)

The 2 inlet holes communicate with each other (air pass when blow).

Is there a possibility that the inlet is not from the T but from thermostat housing?

Otherwise any ideas of how this thig can be unblocked?

Thanks

 

[stu9000]

I had this problem earlier this month. Soaking it in brick cleaner dissolved the inaccessible areas beautifully. I also ran brick cleaner and water mix through the engine on a loop for half an hour which brought water flow back to what it should be. Lots of good advice on the thread.
http://www.ybw.com/forums/showthread.php?498654-no-water!-it-isnt-the-impeller&.

 

[Akestor]

I had this problem earlier this month. Soaking it in brick cleaner dissolved the inaccessible areas beautifully. I also ran brick cleaner and water mix through the engine on a loop for half an hour which brought water flow back to what it should be. Lots of good advice on the thread.
http://www.ybw.com/forums/showthread.php?498654-no-water!-it-isnt-the-impeller&.

Thanks that was a very informative thread. So by brick cleaner i asume you mean Hydrochlroric acid? I have filled the blocked holes since Tuesday with this stuff . I spill it and apply fresh acid every morning. Crud gets out so its a matter of patience i suppose!

 

[VicS]

Thanks that was a very informative thread. So by brick cleaner i asume you mean Hydrochlroric acid? I have filled the blocked holes since Tuesday with this stuff . I spill it and apply fresh acid every morning. Crud gets out so its a matter of patience i suppose!

Not all brick cleaners are hydrochloric acid based so its important to read the label to be sure what you are buying is HCl

Regarding your query in # 1 about the water inlet to the exhaust manifold . I can confirm that its is via the Tee piece on an MD11C. The MD2B uses the same manifold according to the parts lists . The thermostat cover appears to have a connection to the manifold below the thermostat but it is not used on these engines.

 

[Akestor]

Not all brick cleaners are hydrochloric acid based so its important to read the label to be sure what you are buying is HCl

Regarding your query in # 1 about the water inlet to the exhaust manifold . I can confirm that its is via the Tee piece on an MD11C. The MD2B uses the same manifold according to the parts lists . The thermostat cover appears to have a connection to the manifold below the thermostat but it is not used on these engines.

Thanks Vic, its was in one of your posts that i learned about the Tee inlet. It can't be otherwise because when i connected the water hose to the T, 2 holes bleeded slightly after half an hour of high pressure ( unless its corroded inside and bleeding is wrong) . The cleaner is 15% hydrochloric acid for general purpose use. ( they sell it here in Greece moslty for cleaning crud in the bottom of toilet bowl).

I was cunfused with what looked like blocked hole at the thermostat side, but then read its a pending hole for fresh water cooling. I had a leak there ( blew the tube and heard the hiiisss from there). Manifold is slightly corroded at the point, and the O ring was too thin for sealing the distance between . I cut a thick 5mm rubber disk instead and now seals ok.

 

[Akestor]

After 3-4 days trying with Hydrochloric acid, i am stoping because i see that this stuff will melt the manifold at the end. It has dissolved badly the threads for the T fitting, lyckily still holding it.
I tried again connecting it to the home faucet, but it only bleeds a little bit from the 2 inlet holes for the head.

I guess something in there can't be removed with the acid- or the manifold was in purpose blocked for some reason.
The previous owner run it without a thermostat. Unfortunately never met him and he is dead long time now, so i cant ask him!

- I am thinking of going to a machine shop gor glassblasting
- Or run it like this and hope that the first time the air in the engine will open the thermostat and let the water flow in. But then will there be a circilation of hot-cold water?

 

[VicS]

After 3-4 days trying with Hydrochloric acid, i am stoping because i see that this stuff will melt the manifold at the end. It has dissolved badly the threads for the T fitting, lyckily still holding it.
I tried again connecting it to the home faucet, but it only bleeds a little bit from the 2 inlet holes for the head.

I guess something in there can't be removed with the acid- or the manifold was in purpose blocked for some reason.
The previous owner run it without a thermostat. Unfortunately never met him and he is dead long time now, so i cant ask him!

- I am thinking of going to a machine shop gor glassblasting
- Or run it like this and hope that the first time the air in the engine will open the thermostat and let the water flow in. But then will there be a circilation of hot-cold water?

You have to get the passages from the Tee to the heads clear because that is the route for cooling water to enter the engine. While they are blocked there will be no flow and the engine will overheat.

The thermostat controls the flow of ( hot) water leaving the engine in order to regulate the engine temperature.

When we had trouble with the ( identical ) manifold on an MD11C we had no option but to poke away at the blockages with some stiff wire until we cleared them. We had a length of stainless steel wire on board which was useful for unblocking things, although its most important use was to wire the coffee pot onto the cooker.

I dont like the idea of using uninhibited hydrochloric acid very much because of the damage it can do. 15% is quite a high concentration if you are using it undiluted. Rydlyme may be a safer alternative.

 

[colind3782]

15% is quite a high concentration if you are using it undiluted. Rydlyme may be a safer alternative.

I've been thinking of using agua fuerte, mainly because I have a couple of bottles on the boat. It's 16% hydrochloric apparently. I wonder how much I would need to dilute it to make it safe but still effective? Not sure where I would be able to acquire Rydlime or similar in Spain.

 

[Akestor]

You have to get the passages from the Tee to the heads clear because that is the route for cooling water to enter the engine. While they are blocked there will be no flow and the engine will overheat.

The thermostat controls the flow of ( hot) water leaving the engine in order to regulate the engine temperature.

When we had trouble with the ( identical ) manifold on an MD11C we had no option but to poke away at the blockages with some stiff wire until we cleared them. We had a length of stainless steel wire on board which was useful for unblocking things, although its most important use was to wire the coffee pot onto the cooker.

I dont like the idea of using uninhibited hydrochloric acid very much because of the damage it can do. 15% is quite a high concentration if you are using it undiluted. Rydlyme may be a safer alternative.

For sake of 1 in a million md2b has different paths than md11c, I removed again the thermostat housing and put a hose in the manifold- just in case i see water coming out from the 2 bottom holes of the manifold( inlets to heads), but no, water was coming out only from the 2 upper holes (exits of hot water). So for sure lower holes communicate only with T inlet and head inlet holes. Additionally 2 lower holes communicate nicely with each other, so the damn T hole is blocked to both directions.

I am going to find a hard steel wire and hope to open it! (hope this is still a manifold and not emental cheese :sorrow
Thanks for your feedback

 

[Akestor]

I've been thinking of using agua fuerte, mainly because I have a couple of bottles on the boat. It's 16% hydrochloric apparently. I wonder how much I would need to dilute it to make it safe but still effective? Not sure where I would be able to acquire Rydlime or similar in Spain.

I used the 15% directly(no water) for 3 days, ( just filled the holes didnt bath the manifold). I hope i stopped before damage because the iron dissolves to a black thing. Use some water to make the stuff less aggressive.

 

[VicS]

I've been thinking of using agua fuerte, mainly because I have a couple of bottles on the boat. It's 16% hydrochloric apparently. I wonder how much I would need to dilute it to make it safe but still effective? Not sure where I would be able to acquire Rydlime or similar in Spain.

I'd dilute it to something around 5 to 7.5 % but although that will slow down the attack on the metal it will also slow down the attack on what is blocking it. Industrially an inhibitor would be added which would reduce or prevent the attack on the cleaned metal.

For sake of 1 in a million md2b has different paths than md11c,

The exhaust manifolds are the same though! I checked the part numbers before calling it "identical"

 

[Akestor]

Job done finally!!

I used a hard wire as VicS proposed. I tried unblocking from the T hole (A) to both directions but seems like the T hole sends to the hole towards the stern( head 1) only (B). From there there is a path to the fore hole that spils to head 2 (C). I connected again the hose at T and now flows nice to both holes. The detail is that you only have to go one direction with the wire ( towards the stern) and this is not hard getting through the crud. Fore hole cannot communicate directly with the T because of limited space inside the manifold. I have drawn on the picture the paths. If i would do it again i d go directly with the wire and no acid at all.
In the future i might wash the cooling system with something like Azax for salts ( wc cleaning faucets etc..) but never acid again...

 

[Bilgediver]

While you are digging and poking there are other important wee holes that are easily overlooked.
Check the head gasket surface close to the manifold side and find the small depression on the cylinder centerline. There is a hole in the base which can become invisible when filled with crud. This hole/port ensures the cooling of the lower block areas. Also ensure all drain cocks show water flow.If not remove the centre valve and poke clear.

 

[Akestor]

While you are digging and poking there are other important wee holes that are easily overlooked.
Check the head gasket surface close to the manifold side and find the small depression on the cylinder centerline. There is a hole in the base which can become invisible when filled with crud. This hole/port ensures the cooling of the lower block areas. Also ensure all drain cocks show water flow.If not remove the centre valve and poke clear.

Hi!
You are refering to the upper left hole at the pic correct? (googled pic)

Fortunatelly i had cylinders and heads glassblasted at the machine shop that left them clean shine metal inside out.( I checked the hole and looks ok in both cylinders)

The draincocks holes for somereason are totally blocked. Not by crud, its more like someone weld them. Maybe electrolysis between iron and bronze? A hard wire wouldnt do and to be honest i didnt have the gut to drill there blindly. Dont know how deep i should go and neither the direction of the path inside so i left it as it is. I will not be able to empty the water though.