Volvo 2003 Engine anode

[AntarcticPilot]

Dear All,

I have a problem replacing the engine anode on my Volvo Penta 2003. The anode is mounted in a brass plug that screws into the engine block immediately behind the oil filter, and below the alternator. The brass plug SHOULD have a half-inch square on it, but this has been badly mangled (prior to my owning her!) so it is no longer even approximately square, and it is impossible to get a spanner or other tool to grip on it. The brass plug has obviously not been moved for a long time, but what I can see of the thread looks OK. There is very little clearance to the side of the engine, and no possibility of making more access on the side - there is a solid bulkhead less than a foot from the engine.

Any ideas how I might get this to unscrew? Things tried so far include mole grips and using a punch to try and drive the plug round. Stilsons have been suggested, but space will be a problem for a large tool like that. I have applied penetrating oil as well.

I don't mind if the brass plug is destroyed; I have a replacement ready to fit.

Thanks!

 

[Pete7]

Think you are going to have to take the alternator off to get in there. I did mine over the Christmas hols (same yacht) and was fortunate that an open ended spanner was able to get the plug moving. Also if you remove the upper steps could you then attack it from the top?

I seem to easily get 2 years from the anode and then its only half wasted. I only changed it because I don't want it breaking up inside the block.

Pete

 

[DavidGrieves]

remove anode

Hi

Just a couple of ideas...

Can you get to it with a file and file some flat side back on, then get an open end spanner on to it?

Or have you considered using a stud extractor? A bit savage I know, as it will destroy the stud. But if you can buy a new one it might be worth a go. First you drill a hole into the stud, then screw the extractor into the hole. The extractor has a left hand thread and is tapered, so it tightens up into the hole and eventually turns the stud.

David

 

[AntarcticPilot]

I've already tried filing flats on the remains of the head, with little success; the problem seems to be that the brass is quite soft and needs a reasonably large bearing area to get a spanner or whatever to grip without the metal deforming.

I have removed the alternator - the next step will be to take off the companionway steps. But the problem is really getting something to grip the remains of the stud; the limited access is not such a problem, except that it narrows the range of options.

Drilling the stud and using a stud extractor is not a good option, not because it wouldn't work but because short of taking the engine out of the boat, there isn't room to drill the stud - there is less than a foot between the head of the stud and the adjacent bulkhead, which is not removable. I suppose a flexible drive might do the trick.

There is no rush; I am unlikely to get back aboard before March!

 

[pvb]

Just a thought - your engine is seawater cooled is it? I ask because the freshwater cooled engine doesn't have an anode, even though it has a brass plug, and this isn't clear in the Volvo literature (guess how I found out!).

 

[MoodySabre]

A mechanic friend of mine has sockets that are eliptical (well almost - odd shaped anyway) and diagonal grooves inside. They are made for gripping rounded nuts. Could be these.

 

[bigwow]

Drilling the stud and using a stud extractor is not a good option, not because it wouldn't work but because short of taking the engine out of the boat, there isn't room to drill the stud - there is less than a foot between the head of the stud and the adjacent bulkhead, which is not removable. I suppose a flexible drive might do the trick.

There is no rush; I am unlikely to get back aboard before March!

http://www.machinemart.co.uk/shop/product/details/rad-1-right-angle-drill-attachment

 

[Gwylan]

Anode or not?

Just a thought - your engine is seawater cooled is it? I ask because the freshwater cooled engine doesn't have an anode, even though it has a brass plug, and this isn't clear in the Volvo literature (guess how I found out!).

We have fresh water with coolant circulating in the engines and cooled by sea water via the heat exchanger. Therefore I had assumed that I did not need an anode - that I couldn't find on the engine anyway.

Therefore I was disturbed by the original post and then reassured by this post that I was doing the right thing in not doing anything - if you see what I mean.

Now I'd like to be sure who is right.

 

[Skysail]

Most M31s with a 2003 are raw water cooled.

How about the wrench here:

http://www.machinemart.co.uk/shop/p...rench-set/path/screw-bolt-and-stud-extractors

 

[VicS]

Now I'd like to be sure who is right.

A fresh water cooled engine does not need an anode, particularly if it is filled with an antifreeze solution as that contains inhibitors to combat corrosion.

Some heat exchangers have an anode in the seawater circuit, it depends on the materials used in their construction. The Volvo ones don't.

It is a good idea to read the engine users manual!

 

[AntarcticPilot]

Just a thought - your engine is seawater cooled is it? I ask because the freshwater cooled engine doesn't have an anode, even though it has a brass plug, and this isn't clear in the Volvo literature (guess how I found out!).

We have fresh water with coolant circulating in the engines and cooled by sea water via the heat exchanger. Therefore I had assumed that I did not need an anode - that I couldn't find on the engine anyway.

Therefore I was disturbed by the original post and then reassured by this post that I was doing the right thing in not doing anything - if you see what I mean.

Now I'd like to be sure who is right.

To reassure people - yes, I have seawater cooling!

 

[prv]

Drilling the stud and using a stud extractor is not a good option, not because it wouldn't work but because short of taking the engine out of the boat, there isn't room to drill the stud - there is less than a foot between the head of the stud and the adjacent bulkhead

You can get right-angle drills which are only three inches or so deep. Easier than taking the engine out! Not sure of the price of such things (I've only ever seen pro Makita etc ones) but if there's room for a bit more depth you can get right-angle adaptors for an existing drill.

Pete

 

[pvb]

It is a good idea to read the engine users manual!

Strangely, Vic, the VP2003 Operator's Manual does show the zinc anode location on the engine, but doesn't say anything else about it, or mention that it's not fitted on a freshwater cooled engine.

 

[AntarcticPilot]

Many thanks for all the useful suggestions!

 

[VicS]

Strangely, Vic, the VP2003 Operator's Manual does show the zinc anode location on the engine, but doesn't say anything else about it, or mention that it's not fitted on a freshwater cooled engine.

Typical.

Always a good idea to read the manual before posting ... especially when you already have it downloaded!

the workshop manual shows it too on the diagram that shows the indirect cooling but you remove it to fit a hot water outlet for a calorifier

 

[pvb]

the workshop manual shows it too on the diagram that shows the indirect cooling but you remove it to fit a hot water outlet for a calorifier

Just to compound the confusion which Volvo Penta literature can create, the zinc anode shown on that diagram is the position used on the 2001 and 2002 engines - the 2003 engine has the anode in a different position, hidden behind the alternator!

 

[AntarcticPilot]

Just to compound the confusion which Volvo Penta literature can create, the zinc anode shown on that diagram is the position used on the 2001 and 2002 engines - the 2003 engine has the anode in a different position, hidden behind the alternator!

Yes; the Volvo agent where I bought the replacement anode and anode holder warned me about that!

 

[AntarcticPilot]

Many thanks to all who posted suggestions!

I was doing pre-season work on Capricious last week, and finally shifted the recalcitrant engine anode. The successful solution was the Irwin Bolt-Grips; they worked simply and VERY efficiently. Coupled with a long bar and a bit of penetrating oil, they gripped the old anode bolt firmly and allowed it to be unscrewed.

I should say that the thread turned out to be in good condition, and once the holder started turning, it was easy to unscrew - no problem with the thread having corroded or anything.

I am now a fan of Irwin Bolt-Grips - they do what they say on the packet. The only caveat would be not to use them on a bolt you want to re-use - they make a mess of the head. However, I can't imagine using them in any circumstances where you'd want to re-use the bolt.

I tried the following, none of which worked.

1) Filing flats on the mangled square and using a spanner - failed, because the brass was too soft and deformed easily; filing enough metal off to get good flats would have left too little metal.
2) Mole grip (I couldn't damage the head any more!) - slipped off.
3) Tap spanner - would not grip the head.

I did not try:

1) Stilsons - might have worked, but the experience with the tap spanner which uses a similar principle wasn't encouraging.
2) Drilling a hole through the mangled stub and putting a bolt through it to provide a grip - might have worked.
3) Using an "Easy Out" tool - might have worked.

The latter two were very much the "nuclear option" as far as I was concerned, but I suspect either would have worked.

I will now check the engine anode on a more regular basis! The old one was completely gone.

 

[ditchcrawler]

I use a half inch socket extension bar.This fits on the end of the brass plug( I know yours was deformed) and extends out far enough to get a spanner on the other end.If I could find a socket adapter with holes in both ends I could use my socket arm as well.

 

[Sans Bateau]

A fresh water cooled engine does not need an anode, particularly if it is filled with an antifreeze solution as that contains inhibitors to combat corrosion.

Some heat exchangers have an anode in the seawater circuit, it depends on the materials used in their construction. The Volvo ones don't.

It is a good idea to read the engine users manual!

100 % correct.