Volvo Penta D2 55 Yr (2000-02) hear Exchanger leaking

[Shariff]

Dear All - I am new to this, Please Help!
I have a small fracture inside the filler cap(where the coolant is poured ) on the hear exchanger where small amount of coolant has been leaking, initially i thought it was the inside black round washer or the over fill clips both has been changed, but leaked continued.

I discovered this yesterday when i decided to clean the green stuff built up around the filler cap and noticed that i was able to move the round filler cap slightly with the screw driver and fracture become clearly visible. I cant find a parts numbers, which make me bit worried. Has anyone had similar problem. how do i fix it.

Furthermore, checking below the heat exchanger I have notice water marks, (small amount of water on below the engine) this is must have happened recently as i check my engine regularly, the engine has been running okay, no overheating signal, although i hardly go over 1200 rev during normal cursing and tend to use sails as much as possible. so this probable means the gasket is also blown, and have to take the whole things apart.

Last week in a Strong winds i did had to use full throttle for a short awhile to get out of a tricky situation, i am guessing this is what might have caused the blow.

I engine has a expansion tank fitted.

I am fairly technically minded but haven't tackled anything as complex as this, please advice things I need to look out for,

Regards
Shariff

 

[RichardS]

Welcome to the forum.

I think you are saying that the neck of the coolant filler tube is moving around in the top of the heat exchanger. It sounds as if the neck is a short tube welded onto the heat exchanger and that the weld has now fractured. The ideal fix would be to remove the heat exchanger and get the neck re-welded. Alternatively you could reseal the weld with epoxy (Araldite or similar) but you will need to get it clean using meths or similar and dry and then build up a fillet of epoxy around the seam. If you have access you could also do this on the inside but I suspect that you will not have access.

The water stain below the heat exchanger might be just water which has run down from this leak but as you ideally need to drain the coolant and remove the heat exchanger anyway you can examine the gaskets and seals for any leaks and replace them as appropriate when you re-assemble.

Richard

 

[Shariff]

RichardS, Thank you. I think it might have been previously repaired with epoxy or something because I can see outside the neck there are white dry out sealants. Is it fairly easy to weld, does it need any special type of welding or just normal.

 

[RichardS]

RichardS, Thank you. I think it might have been previously repaired with epoxy or something because I can see outside the neck there are white dry out sealants. Is it fairly easy to weld, does it need any special type of welding or just normal.

Unfortunately I'm not a welder so I've no idea what might be required. If you say where you are the forumites on here might be able to recommend a local welding shop.

Richard

 

[Tranona]

It is aluminium and you may find it difficult to repair. A new one is extremely expensive and you you will probably have to find a specialist industrial heat exchanger specialist to repair it. at the age of the engine it is probable that the heat exchanger needs cleaning and the exhaust outlet where the cooling water is injected removed and cleaned as it will almost certainly be partially blocked with deposits.

BTW not a good idea to run at that low rpm. The engine should run between 2000-3000 rpm and from time to time run at maximum for short periods. Regular low speed light load running is not good for diesel engines and among other things leads to coking up of the exhaust.

 

[ytd]

You may get away with expoy but it will not be a permanent repair. I would take the heat exchanger off and take it to a welding shop. Welding cast aluminium is difficult because the casting usually distorts but I have seen cracked inlet manifolds repaired with an oxy torch and filler rod like silver solder. The filler's melting point should be high enough to deal with a heat exchanger.

 

[RichardS]

You may get away with expoy but it will not be a permanent repair. I would take the heat exchanger off and take it to a welding shop. Welding cast aluminium is difficult because the casting usually distorts but I have seen cracked inlet manifolds repaired with an oxy torch and filler rod like silver solder. The filler's melting point should be high enough to deal with a heat exchanger.

You're going to have to remove the exchanger so it's worth seeing if you can find a repair shop which is prepared to guarantee a good weld like that suggested by YTD. However, I think you would be able to make a permanent repair with a two part epoxy but you will need a high temperature epoxy like JB Weld or Chemical Metal as you do not want any softening. The main issue is going to be preparation. It must be spotlessly clean, grease-free, dry and keyed with 60/80 grit so that any paint is removed and bare aluminium is exposed. Also apply the expoxy as soon as the sanding and degreasing is finished and before the oxide layer can start to build up.

If you can do the preparation properly and apply a thick fillet 5mm across it should be as strong as the original and will last the life of the engine.

Richard

 

[Shariff]

Hi Richard Thanks, I had a look at JB Weld website and there are many different related products, can you recommend which one would be best suited. I have not had experience of the product. Rgds

 

[RichardS]

Hi Richard Thanks, I had a look at JB Weld website and there are many different related products, can you recommend which one would be best suited. I have not had experience of the product. Rgds

No problem.

I didn't know there were so many JB products! The JB Weld Original Epoxy Adhesive is the traditional treacle-thick high temp epoxy which would be fine although you need to build it up around the joint as thickly as you can before it sets as you are using it as a filler rather than an adhesive. You may find it useful for many jobs around the boat and house.

However, for your specific problem, you might find one of the epoxy puttys easier to apply although probably not as useful generally around the boat. The JB Weld Steelstik looks good. It's designed more for re-building up thickness on metal and can be used up to 150 degrees C. It's not a strong as the traditional stuff but what you are doing is not load bearing so that's not an issue. Depending upon how much metal surface you have to work with, the putty would allow you to roll out a sausage of the right thickness and length to cover a large area of abraded aluminum and be sure of getting a really good seal.

Which will be easiest to apply depends on how much metal surface is available and how easy it is to get at. These two products above are both under the metal repair section.

Richard