Mucky coolant

[laika]

When I put the boat back in the water after 9 months ashore the coolant in the expansion tank had vanished. I refilled it expecting to find it gone again ( evaporation didn't seem like a good explanation) but the level didn't drop. However, after a couple of trips out the pink coolant was rather murky. I put this down to pollution from the old blue coolant lurking round the calorifier when the coolant was last changed. Today I was checking the level and noticed the colour really didn't look right. It's almost black. No other symptoms: no white smoke in the exhaust, everything looking fine. The coolant doesn't smell of oil but I thought it did feel a bit oily on my fingers. Interestingly I only recently changed the oil and it is nowhere near as black as the coolant.

Ideas of anything this might be that isn't hideously expensive sounding? And given that my mechanical skills aren't worthy of my shiny new (less than 200 hours) engine can anyone recommend an honest yanmar mechanic in Cherbourg or Alderney?

 

[VicS]

When I put the boat back in the water after 9 months ashore the coolant in the expansion tank had vanished. I refilled it expecting to find it gone again ( evaporation didn't seem like a good explanation) but the level didn't drop. However, after a couple of trips out the pink coolant was rather murky. I put this down to pollution from the old blue coolant lurking round the calorifier when the coolant was last changed. Today I was checking the level and noticed the colour really didn't look right. It's almost black. No other symptoms: no white smoke in the exhaust, everything looking fine. The coolant doesn't smell of oil but I thought it did feel a bit oily on my fingers. Interestingly I only recently changed the oil and it is nowhere near as black as the coolant.

Ideas of anything this might be that isn't hideously expensive sounding? And given that my mechanical skills aren't worthy of my shiny new (less than 200 hours) engine can anyone recommend an honest yanmar mechanic in Cherbourg or Alderney?

Id drain it out and give the system a flush with something like Holts Speed flush http://www.halfords.com/motoring/auto-parts/head-gasket-exhaust-repairs/holts-speedflush-250ml before refilling with the correct coolant

Not mixed conventional and longlife OAT antifreezes have you? Use the correct type for the engine. OAT for many modern Yanmars IIRC

 

[stevd]

The blue and pink coolant really shouldnt be mixed together. That will be why it has turned a murky muddy brown. Change it as soon as you can, as it could, afaik, cause blockages.

 

[CJU]

Mixing the two different longlife antifreezes together by a previous owner certainly caused a blockage in the heat exchanger on my boat. So I would flush it out as thoroughly as you can.

 

[Spirit of Glenans]

If you've just changed the oil then that won't be black, but a nice amber colour.

 

[Bobc]

You might find that the coolant in the engine was dis-colored (maybe a bit of rust), and then because the header tank was empty, when the pressure built, it pushed coolant from within the engine up to the header tank (you see this a lot on older cars).

If it's dis-coloured, it's probably worth draining it and putting new in anyway.

 

[laika]

Thanks for all the replies. The engine shouldn't be rusty: it's only 4 years old: I am its first owner. Besides, the coolant is now pretty black rather than murky. When it was originally installed it was filled with blue volvo coolant. After a bit over 2 years my manual said it was time to change the coolant. I was happy with the normal drain down procedure but couldn't find information on draining the calorifier other than warnings about getting airlocks. As I've never owned a boat engine before I decided to pay a main yanmar dealer to do it while I watched. Unfortunately the guy told me it wasn't necessary. I pointed out that the old coolant was blue volvo stuff (I still had a container of it to show him and it was obviously blue), the new one was pink (yanmar) and I'd read you shouldn't mix them. He assured me a little wouldn't harm and I deferred my book learning' to his professional experience.

If the wisdom here is that they were wrong I shall go back and challenge them.

 

[knuterikt]

Thanks for all the replies. The engine shouldn't be rusty: it's only 4 years old: I am its first owner. Besides, the coolant is now pretty black rather than murky. When it was originally installed it was filled with blue volvo coolant. After a bit over 2 years my manual said it was time to change the coolant. I was happy with the normal drain down procedure but couldn't find information on draining the calorifier other than warnings about getting airlocks. As I've never owned a boat engine before I decided to pay a main yanmar dealer to do it while I watched. Unfortunately the guy told me it wasn't necessary. I pointed out that the old coolant was blue volvo stuff (I still had a container of it to show him and it was obviously blue), the new one was pink (yanmar) and I'd read you shouldn't mix them. He assured me a little wouldn't harm and I deferred my book learning' to his professional experience.

If the wisdom here is that they were wrong I shall go back and challenge them.

The authorized Yanmar service guys I know told me that they have to use a system cleaner when replacing the blue with Yanmar longife.
It's hard to understand that the boat builders can save much money on using the wrong coolant...

 

[VicS]

Thanks for all the replies. ..........
......
If the wisdom here is that they were wrong I shall go back and challenge them.

One cannot be sure that what they did is the cause of your problems but it seems quite likely.

In view of what you have said about the mucky nature of your system it makes sense to drain it, clean it and refill it with the type of antifreeze recommended for the engine.

 

[laika]

Interesting. Mailed the company and outlined what I thought might be the problem and asking them to look at it. They sent me a short reply back saying it would be nothing to do with the "egg cup full" which would have been left in the system but would be a consequence of age and use. They know it's been in there less than 2 years. I've pointed out that the engine has done about 50 hours since then and it's black. The original system had 5.5l of blue stuff in. They put 4l of pink stuff in and the expansion tank was at the same level.

Am I correct in assuming that the coolant goes off round the calorifier which, being slightly below the level of the engine at its lowest point, would require a separate drain-down? i.e., draining coolant from the engine only gets what's in the engine, not the rest of the cooling system?

 

[VicS]

Interesting. Mailed the company and outlined what I thought might be the problem and asking them to look at it. They sent me a short reply back saying it would be nothing to do with the "egg cup full" which would have been left in the system but would be a consequence of age and use. They know it's been in there less than 2 years. I've pointed out that the engine has done about 50 hours since then and it's black. The original system had 5.5l of blue stuff in. They put 4l of pink stuff in and the expansion tank was at the same level.

Am I correct in assuming that the coolant goes off round the calorifier which, being slightly below the level of the engine at its lowest point, would require a separate drain-down? i.e., draining coolant from the engine only gets what's in the engine, not the rest of the cooling system?

If the calorifier is lower than the engine then it will need to be drained in addition to draining the engine.

Even if it were not there is no guarantee that draining the engine would also completely drain the calorifier . It depends on the design and layout of the hoses .

 

[laika]

Any advice on how to approach this? Obviously I don't know for sure that this is actually the problem but if it *is* I think it's the company's responsibility to properly flush and clean the system and re-fill, especially as that's why I employed them in the first place. Obviously I will attempt it myself rather than pay them (if it is indeed they that caused it). Any top tips on avoiding airlocks in the calorifier?

If someone identifies a problem with my work my first inclination is always to jump on investigating it and, if it *is* down to me to fix it before my reputation is harmed. My concern is that these guys have jumped to denying before even looking at the problem.

 

[parbuckle]

The disappearance of the coolant as mentioned in OP would be more of a concern to me , on refilling the thermostat will be closed so a problem in the heat exchanger may not be evident. Has sea water got into the fresh water galleries of the heat exchanger and caused corrosion ? This may be discolouring the coolant any leak in could also cause the coolant to leak out when the thermostat is opened..... all supposition and you may not have a heat exchanger.

Also check that dastardly elbow.

 

[knuterikt]

Any advice on how to approach this? Obviously I don't know for sure that this is actually the problem but if it *is* I think it's the company's responsibility to properly flush and clean the system and re-fill, especially as that's why I employed them in the first place. Obviously I will attempt it myself rather than pay them (if it is indeed they that caused it). Any top tips on avoiding airlocks in the calorifier?

If someone identifies a problem with my work my first inclination is always to jump on investigating it and, if it *is* down to me to fix it before my reputation is harmed. My concern is that these guys have jumped to denying before even looking at the problem.

contact Yanmar and ask them what the correct procedure for replacing blue (wrong coolant) with proper red is.
Tell them that you have a calorifier installed at the lowest point.

Compare this with what was done on your engine and see if you have a case.

 

[laika]

So. Conversation with the company. Flat denial that mixing coolant could cause it to turn black. Will most likely be down to age and use. they say ??? it's 2 years old and given that I was out of the water all last year, only a handful of hours. No necessity to drain the clarifier. No necessity to flush before refill. OTOH here's what Yanmar said:

The cooling system needs to be drained and flushed to remove traces of the blue coolant.

The coolant from calorifier needs to be drained and flushed also

 

[robmcg]

So. Conversation with the company. Flat denial that mixing coolant could cause it to turn black. Will most likely be down to age and use. they say ??? it's 2 years old and given that I was out of the water all last year, only a handful of hours. No necessity to drain the clarifier. No necessity to flush before refill. OTOH here's what Yanmar said:

Sorry but the company's view is carp! Google mixing coolants and it will return loads of hits on motoring forums where mixing the two types of coolant causes them to go black and produce a level of precipitate.
When I bought coolant from Unipart in Plymouth, they were careful to ask me what was already in there and stated that the two types of coolant should never be mixed.

 

[knuterikt]

So. Conversation with the company. Flat denial that mixing coolant could cause it to turn black. Will most likely be down to age and use. they say ??? it's 2 years old and given that I was out of the water all last year, only a handful of hours. No necessity to drain the clarifier. No necessity to flush before refill. OTOH here's what Yanmar said:

The cooling system needs to be drained and flushed to remove traces of the blue coolant.

The coolant from calorifier needs to be drained and flushed also

I asked my Yanmar mechanic friend about this today.
He said that in worst case the mix can lead to a gel like substance forming and clogging the cooling system.

Wonder why Yanmar said "remove traces of the blue coolant"

 

[laika]

To conclude, after forwarding Yanmar's response, the company agreed to flush the system with me paying only for materials. They still maintain that 2 years (recommended lifespan) and less than 20 engine hours after them changing yanmar pink lowlife coolant it's perfectly normal for it to be black, think and gloomy:
View attachment 45004

I now also realise that I shouldn't have just been concerned about the calorifier: The 3m of hose below the engine drain plug level would also have contained quite a lot of liquid.

They said that a flushing agent was unnecessary and used tap water. I was rather concerned that only the 5l coolant container I had left for them seemed to have been used which would have meant that at least another couple of litres must be water, but the company's proprietor assures me that all the water was drained form the system before refilling and they simply haven't charged me for the 1.5l of their own coolant they added.

It all concluded rather unsatisfactorily. One of the calorifier hoses split when they were disconnecting it. My friend who let them in (and took the picture above but couldn't stay the whole time: I had couldn't get time off work) gave them approval to change the hoses. The bill I ended up with apparently included 1.5 hours labour sourcing the replacement hoses and 2 hours labour to fit them (despite the fact that they had to be removed at one end anyway to completely drain the system). OTOH if you ever need a system flush, the central south coast's main yanmar dealer reckons the part that they'd agreed to do for free (drain system, disconnect hoses, drain down calorifier, reconnect, flush and drain twice with water, drain, disconnect hoses, drain calorifier, reconnect, re-fill) only took 1 or at max 1.5 hours of the 5 they originally sent me a bill for.