LPG OCIs?

Status
Not open for further replies.
Joined
Jun 29, 2014
Messages
16
Location
Melbourne, Australia
Have a 1998 Toyota Landcruiser which was converted to LPG a few years back prior to my ownership, changed the oil the moment I got it. It has been about 20k km already, and I can still see through the oil to the gratings on the dipstick, and possibly just ever so slightly darker. In my experience, this would be the point where I would change the oil in the petrol car, where the oil a dark brown and definitely not see through. There is no consumption whatsoever.

Do I leave the oil in or replace?
 
LPG is clean, which is easy on oil and helps TBN retention.

But there will still be wear metals accumulating through normal use.

My guess is you could probably go further on a change, but eventually wear metals will accumulate to the point of condemnation before TBN bottoms out.

If you really want to know how far you can go, an oil analysis is the only way to know for sure.

Or for roughly the same cost, you could change the oil.

It's up to you.
 
My experience tells me propane runs super hot, and valves take a beating. Seen many engines without hardened valves and valve seats burn the vavles. If it was my vehicle, change it often every 8000 kms and go with something like a T6 5W-40.
The oil always looked almost like new with no change in colour.
 
Given the age of your engine, in that it's well into the unleaded gasoline era, I wouldn't worry much. Run a UOA to be sure, but 10,000 km should be a breeze on any ordinary conventional.
 
[censored] if I changed my oil when it looked too dark, I'd be doing it fortnightly.

As others have said, try get a UOA done. Then you know what the oil's condition is.
 
Best to have a UOA done to analyse the condition of the oil. Even though LPG is a clean fuel, I'd stick to whatever Toyota recommended for that engine. My understanding is its just an EFI version of the old I6 Petrol they'd used for years (1FZ-F), and so is a relatively "old" engine for the 1990s, much like the Rover V8.

The good news is that the Diesel or Petrol motors made in that time are very solid.

Since LPG is a fairly "wet burning" fuel, I suspect the cylinders, pistons etc will be somewhat steam-cleaned, so the main concern then goes onto wear metals more than carbon deposits.

Depending on what a UOA would say, you could very well spin on a new filter and keep going. Although it is best to get things checked before getting too carried away.
 
What does a UOA even cost in Oz? As much as an oil change? If it were me, I'd just throw new oil and filter at it every 10,000km or so and live happily ever after. I'm not even convinced you actually "need" an LPG specific oil, the taxis I serviced back in the 90's just used the standard workshop bulk "whatever" oil and literally did over a million k's on the original engines. And trust me, the drivers weren't having the oil changed anywhere near as often as every 10,000km...
 
Don't change your oil (or not change your oil) just based on color.

Start by running a full OCI at the factory interval then test it with a UOA. You may be able to stretch it way further but you won't know that until you test it. Color means nothing.
 
Originally Posted By: fj610
I've talked to penrite about this and LPG is actually quite hard on oil. The danger is from oil nitration which will corrode your big end bearings. Extended drains just because the oil looks clean is a very bad idea.

I'd still go by UOA. The taxis went 10,000 km back in the 5,000 km OCI days, and lasted hundreds of thousands of kilometres. Bearings were never touched on any of the taxis. Valves had issues if they were from before the unleaded fuel days. Also, Chevy small blocks ate cams, and the fuel and oil choices were irrelevant. Certainly the colour on the dipstick isn't a great indicator, but a couple UOAs are always a good idea when extending intervals.

While there certainly are CNG and LPG specific oils out there, one has to be cognizant of costs, too. In the taxis, LPG specific oils were never used, despite them being available, given the price premium over regular PCMOs. A few dollars over dozens upon dozens of oil changes can add up.
 
Going through Blackstone here in AU works out to the usual price, plus exchange. So about $40-$45 with TBN analysis, and that's not even counting postage.

I understand there are some local firms dealing in the UOA market. An example I found with a simple google search E-Monitor.

Once again, I'd be wary of "LPG Specific oils," without looking at spec-sheets, my assumption is likely to be something of the following from the MFG:
- LPG runs hotter, therefore you "need" a thicker oil
- Charging a higher price for an oil that's "watered down" (additive-wise) due to the lower contamination with LPG
- (Much smaller chance), the MFG actually makes a legitimate product formulated correctly for this alternative fuel.

I don't see why any normal PCMO can't be used in a LPG-fueled vehicle, much like using a dual-rated Diesel oil in a normal petrol won't harm anything, and may actually benefit.
 
Some of the LPG specific oils, at least the ones I've seen here, were of PCMO type viscosity, with a lower TBN, given lower expected TBN depletion with an LPG engine over a gasoline engine, particularly in the carb days. Some of them were by the majors. Other major oil companies stayed out of that market altogether. A local LPG service shop, that also happened to run a fleet of LPG taxis, also stuck with normal PCMOs of the day.
 
Look at my Blackstone report after 28,000 miles. very good. OK, CNG which is cleaner stiil but bears out the taxi anecdote.

30,000 OCI
 
Last edited:
any update here ?
smile.gif
 
Status
Not open for further replies.
Back
Top