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Vicki Kanninchen

How can I DIY clean my oil cooler?

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Hi, my BMC 1.5 has been overheating regularly and I think it's due to a blockage in my oil cooler. Is there a way I can clear this safely myself?

 

I've read a lot of conflicting advice about various descalers, acids, or steam and I just want to make sure I don't inadvertantly damage anything in in my efforts to get it clear. 

 

Thanks 

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 Remove and back flush it with a hose, just use your hand to make a seal and run the water in the opposite direction to normal flow. If you run it into a bucket you can see what washes out. If you can see the individual tubes you could poke a pipe cleaner down them to make sure they are clear. Do not use wire ect as you could damage the tubes. Good luck.

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Could try a descaler designed for boilers/dishwashers. 

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2 minutes ago, BWM said:

Could try a descaler designed for boilers/dishwashers. 

I think I would be wary of this. I am no chemical expert but, as I understand it, many boilers/dish washers are made of stainless steel and any descaler designed for that may be too strong for copper/brass type oil cooler tubes and cause damage. Back flushing with water would be safer.

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4 minutes ago, hovrin said:

I think I would be wary of this. I am no chemical expert but, as I understand it, many boilers/dish washers are made of stainless steel and any descaler designed for that may be too strong for copper/brass type oil cooler tubes and cause damage. Back flushing with water would be safer.

The ones i've seen have comprised of a mixture of materials including rubber, plastic and others but it would be sensible to try a low concentration at first. Brass and copper are not particularly vulnerable to chemicals, nor aluminium, with many being treated in industry with caustic materials as part of the manufacturing process. 

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10 hours ago, Vicki Kanninchen said:

Hi, my BMC 1.5 has been overheating regularly and I think it's due to a blockage in my oil cooler.

 

Frankly, I think you are quite likely to be barking up a blind alley or something like that.

 

Thing is, if the trivial cooling power of your oil cooler is all that is preventing the engine from overheating, your engine has bigger problems than a blocked up oil cooler in my opinion. Others may be along shortly to quibble about this but it needs suggesting.

 

Have you checked the basics, like is there enough coolant in the engine and cooling system? Is the vee belt suitably tight? Does it only overheat when giving it some beans for a long period or does it do it regardless of engine load? How long does it take to start overheating? How do you know it is overheating? What are the symptoms you are seeing? What is making you focus on the oil cooler as the culprit? Is this a recent problem or has it always done it?

 

 

 

 

 

 

 

 

Edited by Mike the Boilerman
Add a couple more questions
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A blocked oil cooler will normally only be an issue on a direct or indirect raw water cooled engine. If it is then the most likely cause is a build up of crud on the inlet side of the tube stack and simple back flushing usually shifts it but if it has rubber end caps then taking them off is often easier. If its a dry exhaust skin tank or keel cooled boat then the cause is likely to be something else so we ned to know exactly what type of cooling system you have and wet or dry exhaust.

 

If its indirect raw water cooled (heat exchanger) then a blocked heat exchanger core on the inlet side is also possible as is raw water pump impeller wings being detached and blocking pipe elbows etc.

 

We can't help much without more information as to type of cooling and e3xhaust system, age of boat and a bit of previous history. Maybe photos will help us identify the type of cooling system.

 

 

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30 minutes ago, Mike the Boilerman said:

 

Frankly, I think you are quite likely to be barking up a blind alley or something like that.

 

Thing is, if the trivial cooling power of your oil cooler is all that is preventing the engine from overheating, your engine has bigger problems than a blocked up oil cooler in my opinion. Others may be along shortly to quibble about this but it needs suggesting.

 

Have you checked the basics, like is there enough coolant in the engine and cooling system? Is the vee belt suitably tight? Does it only overheat when giving it some beans for a long period or does it do it regardless of engine load? How long does it take to start overheating? How do you know it is overheating? What are the symptoms you are seeing? What is making you focus on the oil cooler as the culprit? Is this a recent problem or has it always done it?

 

 

 

 

 

 

 

 

Has symptoms of air in the skin tank, an easy starting point. 

Edited by BWM

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Just now, BWM said:

Has the symptoms of air in the skin tank.

 

Indeed, but a series of ifs, if the oil cooler is blocked on the water side and the cooler is in series with the skin tank, this would easily cause restricted cooling by the skin tank leading to overheating. 

 

So Tony's request for details of the cooling system and photos if poss, is all the more significant, as always. 

 

 

 

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28 minutes ago, Taslim said:

Deleted.  Agreeing with MtB when TB came along.  I'll leave it to the experts.

Members' input should always be welcomed because you might have thought of something others have overlooked or not come across before. I suspect BMW may be correct but there is too much we don't know about the OP's system to be sure.

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15 minutes ago, Tony Brooks said:

Members' input should always be welcomed because you might have thought of something others have overlooked or not come across before. I suspect BMW may be correct but there is too much we don't know about the OP's system to be sure.

Thankyou but between MtB, BWM and Yourself I had nothing to add.   And still don't.  Good luck to the OP with finding a solution.

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Thanks for all the very helpful advice! The engine has a wet exhaust, although there's barely any water coming out- lots of steam though! The cooling circuit also runs through a calorifier and my boat's hydraulic drive unit. 

 

The engine generally starts to overheat after about 30-60 minutes depending on how hard the engine's working. The reason I thought it might be a blockage in the oil cooler is that this turned out to be the cuprit when I had the same problem last year. 

 

The other reason I thought this might be the issue is that the oil cooler's intake hose gets hot while the outlet side is barely warm. I've also been getting oil aspirating from somewhere lower down on the engine but I'm not sure if that's related...

 

I've checked the filters, the coolant tank, the belt, and the impeller, and I've repeatedly run the engine with the heat exchanger cap off in case it's an airlock. 

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9 hours ago, Vicki Kanninchen said:

 

Thanks for all the very helpful advice! The engine has a wet exhaust, although there's barely any water coming out- lots of steam though! The cooling circuit also runs through a calorifier and my boat's hydraulic drive unit. 

 

The engine generally starts to overheat after about 30-60 minutes depending on how hard the engine's working. The reason I thought it might be a blockage in the oil cooler is that this turned out to be the cuprit when I had the same problem last year. 

 

The other reason I thought this might be the issue is that the oil cooler's intake hose gets hot while the outlet side is barely warm. I've also been getting oil aspirating from somewhere lower down on the engine but I'm not sure if that's related...

 

I've checked the filters, the coolant tank, the belt, and the impeller, and I've repeatedly run the engine with the heat exchanger cap off in case it's an airlock. 

 

Almost certainly you have virtually no idea how your cooling system works. I suggest you start by studying this website http://www.tb-training.co.uk/15cool.htm#bmn53

 

Although by no means certain you probably have a heat exchanger system that has two water pumps (different types) and two water circuits. One in the engine that is not discharged overboard but is pumped around a heat exchanger while the other pump moves canal/river water through any oil coolers and the tubes in the heat exchanger before discharging it via the exhaust.

 

The canal water (known as raw water) passes through any oil coolers into the raw water pump and then via the heat exchanger, exhaust manifold water jacket if not part of the heat exchanger and the into the exhaust. The engine coolant (the stuff under what you can the heat exchanger cap) not only circulates around the engine but also flows through the calorifier coil. All this is typical for most boats but yours could very easily be a little different - hence the request for photos.

 

Its seems that you have localised the problem to the raw water circuit but you can not extrapolate that to a blocked oil cooler just because it was last time. You should have a raw water intake strainer somewhere so  the first thing to check is that it is clean and nothing has been sucked over  the intake hole in the hull.

 

Any air leak into the circuit between the raw water inlet (like via its cap often) and the raw water pump will reduce the volume of raw water pumped because the pump will rather suck air so check all the connections on this circuit.

 

I suspect this is an old boat and if so the raw water pumps can wear so that air is sucked down the shaft or the pumping chamber gets scored so the pump sucks air or can not eject enough water. With a slack raw water pump belt (if your engine has one) try to move the shaft up and down, side to side in the pump body. If it has more then a just perceptible amount of play it needs repairting. How I can't say unless I know the pump. Some pumps have oil seals in them that wear. If the pump is direct mounted on the engine then take the impeller out and then test the play in the pump shaft.

 

It is very common for raw water pump impeller wings to snap off and jamb in the pipework or in the end of the heat exchanger so that needs checking as well as the inlet end of the oil cooler(s) so you need to check that. While you are at it I would be less concerned about damaging the pipes in the oil cooler(s) and heat exchanger than others on here as long as you use a length of this steel wire. I use thin welding rod GENTLY push through the tubes but usually once the end cap was off the muck was easy to wash off.  L length of domestic type or multi-strand single conductor (wire) will also do.

 

Once you are sure all that is OK then you need to consider the exhaust. If it is partially blocked  it will create back pressure on the raw water pump impeller wings and fold them back so it can't pump. Sometimes the exhaust mixing elbow furs up until it only ash  small hole in it or I have known the exhaust hose to delaminate and suffer internal splits so the gasses force the lining across the pipe. In both cases the faster you run the engine the less water is ejected.

 

An oil cooler or heat exchanger that is working should have a hot inlet side and a cold or cooler outlet side, the water should have carried all the heat away. Your oil cooler could be a hydraulic cooler as part of the hydraulic drive system or an engine oil cooler or you may have both.

 

 

 

 

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