RC8D rebuild/don't rebuild question

Alctel · Jan 11, 2016

Changing over the hoses may help for sure. it'd explain both the diesel smell and the water under the engine. I'd try that first.

centerline · Jan 11, 2016

StephenD said:
........... I've gotten it bone dry and put an absorbent pad to try to see where it's coming from but haven't been able to stay around long enough to tell..

...........So would pulling and re-gasketing everything help? Replacing all the supply lines?

we understand all the good points of the engine, and we hear your complaint, but I have cut your message to the two points that need to be dealt with first....

if one doesnt have the time needed to dianose the problem, it may never get fixed properly....and if it is diagnosed properly, it may be a relatively inexpensive repair.

and to the last point, it certainly wouldnt hurt it, but it may not be necessary, but we will never know without a good diagnosis.... someone, if not you, needs to take the time to find out where the leaks are coming from.

it may be something as simple as a loose or corroded/broken hose clamp, or an issue with the engine water pump.... these are much less hassle and money to repair than a a complete engine re-seal....

Or... you could blindly throw everything in your arsenal at it, and hope that something makes a difference

centerline · Jan 11, 2016

StephenD said:
Makes so much sense. Hoses are relatively easy to swap and cheap, and if I pulled the motor I'd do them anyway.
I appreciate the input- I'm a black or white, all or nothing kind of thinking person especially when I'm tired or a little frustrated. Not to humbly mention that this is my first ever diesel.
Therefore it helps to consult others with a more balanced and experienced view, like you guys. Thank You!!!

there are two main reasons people prefer diesels engines in boats, they are a safer engine due to lack of gas fumes, and they are simpler to maintain which makes them more dependable.... there are many other benefits also, but these are the top two

so with it being your first diesel you may find the problem with it is NOT because its a diesel, but because its a marine engine.... swapping hoses should be a task that can be done in an hour or two without removing the engine from is bed....

black or white.. all or nothing..... im kinda the same way, maybe too much. but Im also frugal and have never seen the reasoning behind spending any more than necessary to achieve the desired results (but also willing to spend what is needed to achieve the desired results).... so short of your engine having 4-5000 hours on it, I doubt it could benefit by having new gaskets and seals installed throughout, as most gaskets and seals can last the life of the motor....

hoses are a different matter, they could use changing every 6-8 years just for general principals of safety and peace of mind....

when I bought my boat, it had a terrible oil leak..the bilge had oil in it, and not just a little.... but it looked like the exxon valdez had ran aground in there... the engine was dirty and stinky and I knew it needed some major work on it, and the seller was looking for someone to dump the boat on... I had the skills and didnt delve into it too deep before the sale, because I knew I was buying a project boat and we negotiated accordingly..... before the deal was final, I was actually looking forward to pulling the little diesel out and giving it an overhaul.....
but I never got to do it.... upon closer inspection, down in behind the heat exchanger is where the stub for the mechanical tach is located.... when running at a low rpm it never leaked, but when running at WOT, it spewed oil out.... I capped it and pressure washed the engine, the engine compartment and the bilge using a strong degreaser, and the whole boat had a complete personality change within a four hour period.... the 39 year old engine has not leaked a drop since then.
I found out later after talking with dock neighbors who were familier with the boat, that this problem plagued at least the last three owners of the boat before me, which covers almost a 22 year span... (I am the 5th owner of it)..... its hard to imagine why someone never took the time to find out where and why it leaked....
other than upgrading the sanitation system, that is all I have had to do to make what I thought was a project boat, a happy boat....

the point of my (true) story is,... one must be willing to do whatever it takes, and it must be inspected fully before moving forward, and when this is done it may be found that its a simple repair and there is no reason to go any further.

Benny17441 · Jan 12, 2016

If the engine starts right away and runs fine I would not think about a rebuild. The Renault engine is no longer in production and parts may be hard to find in the US. As the engine was widely used in Europe for marine and other applications parts are still quite available over there. Check in the UK for parts suppliers. It is hard to gauge smell descriptions but "pretty awful" sounds to me like overbearing which usually is a result of fuel spillage inside the hull. A most common reason is overfilling the tank. Fuel and water can get trapped in the hull stringers and as long as it remains there the smell will linger. Do replace the hoses as a preventive measure but if the smells remain I would do some flushing of the interior hull. Dump a few bucketful of soapy water in the stern and the bow compartments with access to the bilge and take the boat out and get it moving, rolling and yawing; the washing machine action will dislodge some of that trapped contaminated water and clean out some of the oil before discharging it by the bilge pump. If everything fails check for a ruptured tank or a leaky fuel pump. The only good news is that if you stay on the boat for a few days usually after the second day the smell wont bother you anymore.