How to analyse your oil leaks.
A vessel operator called us the other day, with some worrying news…
Their bilge was filling with oil and their propulsion engine was down on power.
The good news was that they were due in port soon, so we made sure we were there as soon as they arrived.
Initially, our plan was to inspect the following common leak areas:
(As it turned out, it wasn’t one of these issues, but we’ll get to that…)
- Damper crankshaft seal
- Damper
- Sump and sump joints
- High-pressure fuel pump
- Cylinder head gaskets and cylinder head fittings
- Alternator drive shaft seals
- Oil cooler
- Header tank contents (lubrication oil leaking into the cooling system)
- All oil pipework including the oil drain lines
Before we started the investigation, we inspected the bilge and found that the oil present was not as extensive as reported.
In fact, it was a thin layer on top of a significant quantity of water, but because of the limited access to the bilge, this was all that could be seen by the crew.
Knowing it was only a minor oil leak, the focus shifted to the cause of the water leak.
By running the engine at 100% load for 45 minutes, a borescope test could be carried out when the engine was at operating temperature. This allowed a more thorough inspection of the engine for the minor oil leak and cause of the water leak.
This is what we saw:
The remedy of both of these leaks was straightforward, by tightening the sump bolts and replacing an o-ring
The operator was absolutely right to raise this as a concern and give us a call, but if you find yourself in a similar situation, you could limit downtime by:
- Checking the extent/quantities of oil in any leak
- Run through the common leak areas to see if you can locate any leaks and take pictures
This then gives us a useful starting point to attend the engine with parts and tooling to make a quick rectification.
