Advice needed on over heating engine

[Michael Quelch]

Hi all,

 

I am having issues with my engine over heating which has happened on a couple of occasions and I really need to get to the bottom of the issue.

 

we bought our boat about 1.5 years ago and when we did it came with a brand new Isuzu 38 which had been put in the engine room but had never been fitted as the previous owners never moved the boat so never got round to having it plumbed in.

 

So when we bought her the engine room was empty apart from the engine just sitting on its new mounts. 

 

The boat was built in 2004 and I installed the engine myself I following the installation instructions that came in the engine manual and it runs fine apart from on a couple of occasions it has over heated and I’m wondering if it’s something I’ve done wrong. 

 

Having read the previous posts on a similar issue with another Isuzu I have removed the thermostat and checked it in hot water and it’s opening fine. I am going to be taking her out for a short holiday in a weeks time so wanted to gain any insights that people can offer. To make thing easier I will be posting some pictures so you can see how she is installed and spot any obvious issues visually. 

 

Our boat is a 72 foot narrow boat with a trad back and we believe the shell was built by measham boats, now called star line I think? We have fitted the colarifier to the engine but the first time she over heated was before this was connected up so not sure this is the issue. 

 

I will I’ll also be measuring the skin tank size later and post that to rule out an undersized cooling tank issue

 

she first over heated when we moved her down from the Ashby canal to where we are now at billing aquadrom on the river nene, we had the guy from RCR come out and he disconnected the buzzer saying it was the temperature sender that was the issue? But he did no tests on it and the engine is def running hot when pushed. The last time we went out all was fine for 2 hours then it spat a hose off and emptied Everything into the engine bilge.

 

ive reattached the hose and refilled her but have not moved her since.

 

really don’t fancy braking down on the river so any advice is very welcome

 

as soon as the wife’s up I will get in the engine bay and post some pictures 

 

[Tony Brooks]

I suspect " running hot when pushed" is the clue. Lets have the skin tank size, you need about 1 sq ft per 4 HP. The Ashby tends to be shallow and it is easy for new boaters to drive their boat too hard in an attempt to speed up so ta may have played a part.

 

Simply checking the thermostat opens after an overheat may not be good enough, you need to measure the temperature at which it starts to open. Modern Waxstats can loose wax when badly overheated so they then open at too high a temperature.

 

Please reconnect the buzzer, a faulty sender is not so likely on an new engine, however long it has been stood in the boat.

 

If driving the engine less hard seems to cure the problem then it points to skin tank size BUT are you sure its properly blead?

 

I expect the water pump (fan) belt is still tight enough but best t check, if you have two its the narrow one.

[Michael Quelch]

Skin tank measures 55cm by 102cm by 3cm I also built the steel frame and boarding 

 

[matty40s]

My first though when you said spat a hose off is that you have an airlock somewhere.

I have moved many boats that have sat doing nothing for years - and the most common problem I have come across on boats like these - and the first thing I check if running hot - is the skin tank valve .

You can see it in picture one just above the top skin tank hose connection. Loosen it off carefully - you will often hear a rush of air before liquid appears - this sometimes small bubble of air just gets bigger and stops the skin tank circulation thus leading to overheating and pressure build up as the water turns to steam. If your boat is trimmed so it sits stern down - you may need to try to level it with ballast at the front when bleeding - or get a new bleed valve installed at the forward (higher)_end of the skin tank.

Edited August 11, 2018 by matty40s

[blackrose]

16 minutes ago, Michael Quelch said:

Skin tank measures 55cm by 102cm by 3cm I also built the steel frame and boarding 

 

 

So it's about 6ft sq which is too small. Using the 1 sq ft for every 4hp rule of thumb that would only cope with a 24hp engine.

 

Fine on a canal but not pushing against the current on some rivers.

Edited August 11, 2018 by blackrose

[Neil2]

Your skin tank is way too small - as a comparison the tank on one of my boats is about the same as yours in square feet but that's an 32' aluminium boat with a 21 hp engine.

 

 

 

[Michael Quelch]

I for got to mention that it was stood for 12 years and the skin tank and engine had no fluid  in the ports were all capped off I.e as it was delivered from the manufacturer. 

 

Blackrose, I was hoping that was not going to be the case as not sure what I can do in a week to rectify the size of the skin tank

Edited August 11, 2018 by Michael Quelch

[blackrose]

Ultimately an additional 4ft sq skin tank (probably welded onto the outside of the swim) would be the best solution. However, there are some other threads on the forum with ideas including a series of pipes instead of a tank or additional raw water cooling with a heat exchanger.  

 

Just wondering if you could plumb in a car radiator with a 12v fan as a temporary measure if you're on a schedule to get somewhere? The only trouble is that once the air in the engine space gets hot it will be come less efficient. Unless you use a bilge blower as your fan pumping fresh air in from outside through one of the vents? 

Edited August 11, 2018 by blackrose

[TheBiscuits]

I agree that you need more skin tank as a long term fix.

 

As an emergency workaround try constantly running a hot tap when the engine gets hot.  The calorifier will then be helping to cool the engine.

 

It's a waste of water, but makes quite a difference if you are pushing hard against a current - and it's why CRT suggest you have a full water tank before setting off on the Ribble Link.

 

 

[Iain_S]

Our old share boat had a similar problem, although that turned out to be a lack of baffles rather than lack of area.

 

This was a real problem when we did the Ribble link, and we resorted to filling buckets of water from the river and pouring them over the inside of the skin tank, into the bilge. We just made it into Savick Brook before the tide dropped too far.

 

On the way back, we connected a hose to a basin tap and directed a fine spray onto the skin tank. This was very effective, and the engine temperature stayed within the normal range for the trip, despite being run harder than it had been on the outward journey.

 

One of the owners rigged up a bilge pump pumping from the bilge to a pipe with a row of holes in it which was laid on the top of the skin tank. I'm not sure how effective this was, as we never used it, but there is no reason why it wouldn't have worked.

 

 

[Alan de Enfield]

Did you ever ask why there was a new engine waiting to be installed ?

Had the old engine overheated and seized ?

 

As more and more NBs take to the rivers to avoid the 'collapsing canal system' I fear these problems are going to become more frequent.

The boat builders are building 'to a budget' (and using designs from many years ago before big engines became the norm) and are not building 'river boats' but canal boats.

 

Due to the lack of rain there is little flow in the rivers at the moment - if we get some 'weather' in the next few weeks you will have a serious problem - the river at Billing Aquadrome is not particularly friendly and has flooded the moorings quite frequently, it does get a fair bit of flow on it.

 

It can be 'sorted' but I think you are unlikely to get a reliable 'fix' to allow you to have your holiday in a week's time.

 

Billing with the river in flood

Edited August 11, 2018 by Alan de Enfield

[Neil2]

I agree with Alan - taking this boat out on the river is asking for trouble.  Yes there are things you could do to mitigate the risk of overheating but is that really what you want on a holiday?  If it was strictly a canal boat then ok you could live with it but for river work you need to be sensible and address the cause of the problem then you can go out without the stress of wondering if the boat's going to let you down.  

 

There doesn't seem to be a lot of room in that engine bay so any additional cooling is probably going to have to be outside the hull.  One way to do it is a pipe running around the swim - Streethay Wharf use this method and I'm told it's very effective.

[matty40s]

Another place is where Martin Trnecka off the forum went as his boat was struggling on the Nene, Ouse and Lark. He used Foxboats yard over there who use the same system on most of their hire boats. 

This is what they do.

As far as I am aware he hasn't had a problem since fitting.

 

[system 4-50]

I am no expert but I would suggest feeling the skin tank inner side when starting up from cold  to try and detect if the skin tank has baffles.  Why would anyone omit baffles? But then why would anyone put a small skin tank on a 72ft-er?  This would help determine whether you have a bigger problem than just a 6sq ft skin tank.

[TheBiscuits]

What % mix did you use for antifreeze, and did you premix it before adding to the cooling system?

 

Does bleeding the air out as @matty40s suggested help?

 

[alan_fincher]

 

35 minutes ago, system 4-50 said:

I am no expert but I would suggest feeling the skin tank inner side when starting up from cold  to try and detect if the skin tank has baffles.  Why would anyone omit baffles? But then why would anyone put a small skin tank on a 72ft-er?  This would help determine whether you have a bigger problem than just a 6sq ft skin tank.

We had an Evans and Son boat (50 feet with approx 30HP engine)

Not only was the skin tank only about 2 feet by 2 feet, (so nly 4 square feet), it was also about 3" "thick" and completely unbaffled.

Otherwise Evans & Sons boats were pretty good, but Mike Heywood clearly wasn't interested in proper skin tank design.

EDITED TO ADD:

I agree with the diagnosis here.  Even if the tank is well baffled, 6 square feet is just too marginal in a boat of that size, with than engine and used on rivers.  On canals you will probably survive if not rushing, but not when pushed hard on rivers.

Edited August 11, 2018 by alan_fincher

[Neil2]

25 minutes ago, system 4-50 said:

I am no expert but I would suggest feeling the skin tank inner side when starting up from cold  to try and detect if the skin tank has baffles.  Why would anyone omit baffles? But then why would anyone put a small skin tank on a 72ft-er?  This would help determine whether you have a bigger problem than just a 6sq ft skin tank.

 

6 minutes ago, alan_fincher said:

 

We had an Evans and Son boat (50 feet with approx 30HP engine)

Not only was the skin tank only about 2 feet by 2 feet, (so nly 4 square feet), it was also about 3" "thick" and completely unbaffled.

Otherwise Evans & Sons boats were pretty good, but Mike Heywood clearly wasn't interested in proper skin tank design.

If you want to give the builder the benefit of the doubt it's possible they worked to a brief which suggested the owner didn't intend moving the boat about much,, if at all.  Looking at the number of boats on our marina that never, ever, go out, I think a lot of narrowboat owners could do away with the engine altogether.

 

Given the nature of the market for narrowboats these days I think you might forgive a lot of the shortcomings you see in boat design as builders continue to maximise living space at the expense of good design/efficiency.    

[Alan de Enfield]

1 minute ago, Neil2 said:

Given the nature of the market for floating flats these days I think you might forgive a lot of the shortcomings you see in floating flat design as builders continue to maximise living space at the expense of good design/efficiency.   

Slight amendment.

[Sea Dog]

I agree with the concensus here that your 6 Sq ft skin tank is too small for your Isuzu 38 HP engine.  Beta would recommend a minimum of 9.5 Sq ft for their 38 HP engine, agreeing with Tony's 1 sq ft per 4 hp. With that as a given, I'd also suggest that your issue is exacerbated by your (modern type, as opposed to vintage which are rather different) 38 HP engine being rather on the small side for your 72 ft boat, hence it's also working at the upper end of its ability and being under cooled at the same time. 

 

You're clearly not going to resolve this issue by next week, so I'd be staying off all but the most benign of rivers until such time as your cooling is of sufficient capacity to cope with your engine being heavily loaded.  It's raining very heavily in the west the moment, so watch the weather over your side.  In the longer term, I'd also be considering upping the capacity beyond the 9.5 Sq ft to a size able to cope with a larger engine.  Firstly, this will be better able to cope with your present 38 HP Isuzu when being pressed harder than it ought and, secondly, it will also cope with a more comfortably sized replacement should that ever be required.

[Michael Quelch]

Thanks for your help chaps, the boat was designed not to be moved a lot and we sort of expected it to have issues seeing as it was never designed for rivers and it was built on a budget, but saying that the fit out is good and perfect for our needs with me the wife and our twin 10 year old daughters. We only shelled out £20k for her and have been told by everyone that it was a bargain so bound to be some short falls, I will be getting the welder out when she’s next out of the water and look at the solutions you have surgested above.

 

i am thinking I might be able to get enough temporary cooling with an additional rad like thishttps://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F302644208149 

 

i understand it certainly not a perfect solution but the engine did run for 2 - 3 hours before over heating.

 

Anyone on here able to work out the addition cooling requirements needed if using this type of additional rad?

[Alan de Enfield]

19 minutes ago, Michael Quelch said:

30-Thanks for your help chaps, the boat was designed not to be moved a lot and we sort of expected it to have issues seeing as it was never designed for rivers and it was built on a budget, but saying that the fit out is good and perfect for our needs with me the wife and our twin 10 year old daughters. We only shelled out £20k for her and have been told by everyone that it was a bargain so bound to be some short falls, I will be getting the welder out when she’s next out of the water and look at the solutions you have surgested above.

 

i am thinking I might be able to get enough temporary cooling with an additional rad like thishttps://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F302644208149 

 

i understand it certainly not a perfect solution but the engine did run for 2 - 3 hours before over heating.

 

Anyone on here able to work out the addition cooling requirements needed if using this type of additional rad?

The question is how are you going to get cool air into the engine room for the fans to suck thru' the radiator.

Unless you can source sufficient 'outside' air all you will do is heat up the engine compartment. 

A car has cold air being forced thru' the radiator by a 30mph - 50mph - 70mph wind blowing thru the engine compartment.

Edited August 11, 2018 by Alan de Enfield

[Robbo]

41 minutes ago, Michael Quelch said:

 

i am thinking I might be able to get enough temporary cooling with an additional rad like thishttps://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F302644208149 

 

i understand it certainly not a perfect solution but the engine did run for 2 - 3 hours before over heating.

 

Anyone on here able to work out the addition cooling requirements needed if using this type of additional rad?

Instead of a radiator, just get a heat exchanger, pump, filter and some hose.   It will be more effective.

Edited August 11, 2018 by Robbo

[Stilllearning]

If there is an existing central heating system on the boat, you could connect it up to the engine cooling system. You will curse it on warm days, but it should do the job.

[David Mack]

1 hour ago, Michael Quelch said:

 

i am thinking I might be able to get enough temporary cooling with an additional rad like thishttps://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F302644208149 

 

i understand it certainly not a perfect solution but the engine did run for 2 - 3 hours before over heating

 

I suspect this might do the trick provided you mount the radiator and fans outside the boat where they will get plenty of air. With a trad stern boat that probably means putting the whole caboodle on the roof. I would plumb it in series with the skin tank for maximum cooling, so that the water flows from engine to radiator to skin tank and back to the engine. You could even plumb it with long flexible hoses so you just put it out when you need it, and stow it away (still plumbed in) when you don't. 

But something of an impractical workaround I think.

[Tony Brooks]

Remember that your skin tank is good for about 24 HP so about half throttle BUT if you load the engine like with something around the prop then, despite being set at half throttle, the way diesels work the fuel delivered might be close to that at full throttle so the engine is delivering close to maximum power. In that case it will overheat. However if we tuck the last bit into the back of our minds you can probably cruise safely as long as you restrict ourself to no more than half throttle PROVIDING the river flow makes that safe.

 

I think it will be best if you accept that you will be the slowest on the river and just pootle along while it is safe to do so and tie up while it is not.