Generator oil change and filter replacement
The smallest job we do on a generator set, and the one that decides how many of the large ones you will ever need. Everything that eventually puts a crankshaft on our grinder arrives through oil left in too long, the wrong filters, or dirt past an air cleaner nobody checked.
The interval is a calendar, not an hour meter
Most standby sets in this country will never reach their engine maker's hour-based interval. They run a few minutes a month on test and a few hours a year in earnest, and their owners then — reasonably enough — do not change the oil. That is the most expensive routine mistake in the standby power business. Oil degrades whether the engine runs or not. In a hot, humid climate a crankcase breathes: warm air is drawn in as the engine cools, moisture condenses on cold metal, and the water sits in the sump with the oil. Additive packages settle and deplete on the calendar. Acidic products of the last run stay in the oil and keep attacking bearing surfaces for the whole of the following year. A set that has done twelve running hours since its last service can have oil in worse condition than a prime-rated engine that has done a thousand.
So a standby set needs a calendar-based oil and filter schedule with an annual backstop, whatever the hour meter says. The governing document is the maintenance schedule in your engine manual — the hour figures are the engine maker's, not ours, and the calendar backstop is the part most schedules already contain and most owners have never read. Send us the engine model and we will service to that schedule rather than to a generic one. How it fits the wider regime: preventive maintenance.
Automatic starting is inhibited for the duration of the work, with the site's permission, and restored and proven before we leave — a set left inhibited after a service is worse than one that was never serviced. And the engine is warm when it is drained, so the oil carries its contamination out with it: hot oil, manifolds, turbochargers and exhausts are all part of that job, and it is not a walk-up task for someone passing through the plant room.
Why "it still looks clean" is not a reason
What is actually wrong with the old oil
Chemistry — invisible, and the part that does the damage
- Water and condensation. The Gulf's standing enemy. Water in oil corrodes bearing surfaces, attacks additives and, when the engine is finally run hard, forms an emulsion that does not lubricate.
- Acid. Combustion produces acids, and the oil's additive package exists to neutralise them. That capacity is consumed as the oil is used and it does not come back. Once it is gone, the acids go to work on the bearings — which is why a set with clean-looking oil can be quietly destroying its own bottom end.
- Fuel dilution. Unburnt diesel washing past the rings into the sump, from leaking injectors, poor combustion or long periods of light-load running. It thins the oil and reduces film thickness at exactly the bearings that can least afford it. Common on standby sets, and it points at the fuel system rather than the oil — see injector repair and calibration and generator fuel system service.
Contamination — what is physically in it
- Soot. Fine carbon from combustion. It is what makes diesel oil go black almost immediately, which is normal. What is not normal is soot at a level where the particles agglomerate — at that point they behave as an abrasive and they thicken the oil.
- Dirt. Silica and abrasive dust drawn in past a loaded or badly seated air filter, or through an induction leak downstream of it. This is the wear mechanism that ends in a rebore, and the air filter is the only thing standing in its way.
- Coolant. Glycol in the oil is never a maintenance finding. It is a fault finding, and it means something is leaking internally.
Ask every supplier this
Oil grade comes from the manual, at this ambient
The grade and specification come from the engine manufacturer's manual for that engine, at the temperature it actually works in — not from whatever is on the van.
- Viscosity is chosen for the temperature the engine actually works in. A 45–50 °C ambient plant room is not the condition most engine manuals were written around, and the grade selected has to account for it
- The service category matters as much as the viscosity. Modern oils are formulated for specific engine designs and emissions equipment, and newer is not automatically better for an older engine. What the engine maker specifies is what goes in
- A longer-life oil is not permission for a longer interval. Extended-drain formulations earn their extension against measured conditions, not against optimism
So you can check it rather than take it on trust. Where an oil or a filter is available in more than one grade, we tell you the options and what the difference is, and the choice is written on the quotation rather than made quietly on your behalf. A service that looks cheaper is frequently one where that decision was taken for you.
Half a job without them
The filters, and why the cheap ones are expensive
A convincing fake oil filter with the wrong media, a missing anti-drain-back valve or a bypass valve that is simply a hole will destroy an engine you have just paid to have serviced. Naming the source is the only protection there is, and we would rather you asked us about it than did not.
The visit
The operations we perform
- Confirm the set's historyDuty, hours and last service, and read the controller's event and alarm log.
- Inhibit automatic startingWhere the site requires it, and with the site's permission.
- Warm the engine before drainingSo the oil carries its contamination out with it.
- Drain the sump, and inspect what comes outThe drain is a diagnostic step, not just a disposal step.
- Cut open and inspect the old elementWhere the engine's history warrants it. The filter is a record of what the engine has been shedding.
- Renew the full-flow oil filterAnd bypass filtration where it is fitted.
- Renew fuel filters and the water separator elementDrain and check the separator bowl, and look at what comes out of it.
- Check or renew the air filterAnd inspect the induction ducting for leaks downstream of it.
- Renew the coolant filter or conditionerWhere fitted.
- Refill to the engine maker's grade and specificationFor this ambient, not a generic one.
- Check the oil cooler and external oil linesFor leaks and restriction.
- Take an oil sampleWhere analysis is being run.
- Start, run to temperature, check pressure and check for leaksA service that ends with the engine cold is not finished.
- Recheck the level hot, and again after standingBoth readings, not one.
- Record readings, parts fitted by number, and anything foundIncluding anything that needs attention.
- Remove and account for the used oil and filtersOff your site, on your report.
Nothing found gets acted on without your agreement
Anything we find is reported, photographed where it helps, and quoted. Nothing is done until you say yes.
The small job that reads the whole engine
Oil analysis
A sample taken at the change is the cheapest diagnostic tool available on a generator set. It works because everything wearing inside the engine leaves traces in the oil, and the traces are specific.
- Iron, chrome, aluminium, copper, lead and tin in combination point at which parts are wearing — liners and rings, bearings, bushes or the valve train — rather than merely that something is
- Silicon means dirt is getting in: an air filter, a seating face or an induction leak. The single most actionable result on the sheet
- Glycol means coolant is entering the oil — a head gasket, a liner seal or a cracked casting
- Fuel dilution points at the injection equipment, or at chronic light-load running
- Soot, viscosity and remaining acid-neutralising capacity tell you whether the interval you are running is right for this set in this location, or whether it should be shortened
The value is not in one sample. It is in the trend across services, which is why results are kept with the set's history rather than handed over and forgotten. A slow rise in iron over three services is a conversation about a top or major overhaul held early and cheaply, instead of a failure.
It is exactly the conversation a workshop with its own crankshaft grinding capability would rather have with you early — because at that stage the parts are still recoverable.
- One sample
A snapshot. Useful, but it cannot tell you which direction anything is moving.
- Three samples
A trend. This is where wear becomes visible before it becomes a failure.
- Kept with the set
Results filed against the machine's history, so the next engineer starts where the last one finished.
The deliverable
What you get afterwards
The report is a deliverable, not a courtesy. If a supplier leaves nothing behind, there is no way for you or your client to know what was done, and no baseline for the next visit to be measured against.
- A service record listing readings taken, work done, and parts fitted by part number and grade
- The condition of what came out — oil, filters, and anything found in either
- Oil analysis results where analysis was run, kept against the set's history so the trend is visible
- Photographs of anything we are recommending you act on
- A dated record you can hand to an FM client, an insurer or an auditor
Standby cover
Doing it without leaving the building exposed
An oil change means the set is unavailable for a period, and on a building with a life-safety obligation that period has to be agreed rather than assumed.
Tell us what the site can tolerate
If the set cannot be out of service at all during working hours, the visit is scheduled around that.
Auto start inhibited, then proven
Inhibited during the work, restored and proven before we leave. A set left inhibited after a service is worse than one that was never serviced.
Run and proven before the visit closes
Started, brought to temperature, pressure checked, level rechecked hot, and — where the site allows — put on load.
Or put it on a schedule
Scheduled servicing scoped against your equipment and your site, with priority when something fails between visits: AMC and annual maintenance contracts. Scoped per site rather than sold as a package.
Common questions
Oil and filters, answered
How often should a diesel generator's oil be changed?
To the engine maker's schedule for your engine, which sets an hour interval and a calendar backstop — and on a standby set it is almost always the calendar that falls due first. Send the engine model and we will tell you what its schedule says rather than quoting a generic figure.
My generator has done almost no hours. Does it still need an oil change?
Yes, and this is the most common expensive misunderstanding in standby power. Oil absorbs moisture, loses its acid-neutralising capacity and settles out on the calendar regardless of running hours. Low-hour sets are the ones that fail on the day they are needed.
What oil grade should I use?
The grade and specification in your engine manual, chosen for the ambient this set actually works in. It goes on the report by grade and part number so you can verify it.
Do you use genuine filters?
We quote genuine parts where you want them or your policy requires them, and quality aftermarket where that is the sensible choice — and the quotation and the report state which is which and where they came from. On filters this matters more than on almost anything else, because a counterfeit filter can destroy the engine it was fitted to protect.
Is oil analysis worth paying for?
On any set whose failure would cost you real money, yes. It is the only routine way to see wear developing rather than discover it. Its value is in the trend across services, so it is worth starting before you have a problem, not after.
Can you do the oil change without shutting the site down?
The set is unavailable while the work is done, and that window is agreed with you in advance rather than assumed. Tell us what the site can tolerate and the visit is planned around it.
What happens to the used oil?
It is removed from your site and accounted for on the report. If your site's own procedures require the used oil to be handed to a nominated waste contractor instead, tell us at booking and we will work to that.
Booking
What to send when you book
Call +971 50 767 9050 or email jacob@abradiesel.com. If you do not know when it was last serviced, say so — that is useful information in itself, and it usually means an oil sample is worth taking on the first visit.
- Generator make and model
- Engine model
- Running hours
- The date of the last service
Servicing across the UAE from the workshop behind Yerevan Steel Factory, Industrial Area 15, Sharjah. The full routine is on the generator maintenance checklist, and the wider repair capability on generator repair and service.
Book an oil and filter service
Send the generator make and model, the engine model, the running hours and the date of the last service. Open 7 days, 07:00–20:00.