Originally Posted By: timeau
Originally Posted By: OVERKILL
HTO-06 is a high heat deposit control spec co-developed by Honda and ExxonMobil. The first oil to carry it was Mobil 1 5w-30.
Exactly! Exactly "high heat deposits", you hit the nail. Remember that these are key words of the whole theory.
Originally Posted By: OVERKILL
Is your theory here that once an engine hits 80K on conventional the oil drainback holes in the piston plug up and/or the oil control ring sticks?
Completely opposite. High heat deposits don't come from conventional oil. They comes from
some synthetic oil.
HTO-06 has a number of standarts, and high heat deposits (HHD) is just one from many. So not all Mobil1 oils are compliant by viscosity or some other parameters, but 5W30 is compliant. It would be logical to expect that all M1 oils have more or less same properties in terms of high heat deposits. I.e. 5W20, 5W30, 10W30, etc from this point of view are same.
Same thing we could say about Pennzoil Platinum and Ultra: if they use more or less equal base oil for all their products and at least one oil has good HHD propetries, they are fine.
If no one one in a product line has HTO-06 certification, this makes me think that HHD
could be an issue.
Hope I was clear. "Spoon test" is very, very rough way to check the oil. Just a very simple and inacurate way to separate trash.
Talking about Saturn. Yes, these cars had a problem of small oil drenage. But this means that other car with bigger holes will hit the problem later, but could not avoid it. Based on my experience most of the cars start feels it at about 80k+. Oil passages got clogged step by step: now car consumps a half of quart, next time 3/4 of the quart, next time 1 quart, etc.
Last, but not the least, and the most important, IMO. Please, read this citation, this is VERY good point:
Originally Posted By: sicko
There have been too many reports from people trying a new brand of oil and experiencing consumption to jump to the conclusion that next time the vehicle will consume more.
There has never been an explanation as to why it happens, and at least half the site doesn't believe it really happens, but too many people have reported it happening to them for it to just be made up. For whatever reason it tends to happen more with Mobil 1 than any other oil, but people have reported it with a wide variety of oils.
My explanation is the next.
1. People used to use any synthetic oil that produced high heat deposits on their piston and oil drenages. Problem did not show up yet, but oil rings already lost SOME their ability to move.
2. M1 has excellent ability to reach the most far corners of the engine (I just don't know correct English term here, but you definitely understand what am I talking about). So M1 could not be properly cleaned from cylinders by partially stuck oil rings. We have some oil consumption.
3. Mobil1 does not create new deposits and starts cleaning engine. Few OCI later rings and drenages are free of deposits and do their job as they should. No oil consumption anymore.
Hope this helps.
Also I would like to thank you for a proper and technical arguing. Please, ask again if you see any logic gap here.
I believe I understand what you are saying now. Keep in mind though that HTO-06 isn't the only high heat deposit control test. Most of the Euro marques have that component to their testing regimes as well, as they produce turbocharged engines with similar characteristics as the Honda example. Think VW, Mercedes and BMW, who all now have a great number of turbocharged engines in their fleets
That said, those Euro lubricants (like M1 0w-40, PU 5w-40....etc) are not energy conserving oils and so wouldn't align well with Honda. Thus, Honda went out of their way to work with a lubricant manufacturer (in this case, ExxonMobil) to develop their own high heat deposit control test so that they could be guaranteed as to a lubricant's performance in this engine, hence the HTO-06 certification, which indicates an oil has passed the requisite testing.
I've seen some rather nasty engines apart and the nastiness doesn't seem to be exclusive to one part of an engine. For example, I often get chastised on here for my view that varnish isn't harmless. A good friend of mine had a 302 with similar mileage on it to my own. Mine had an unknown oil change history before I bought the car but I religiously ran Mobil 1 in it at 8-12,000Km intervals from the day I got it. Shortly after that changeover my valve cover gaskets began to leak (common on a 302, they are cork and get hard) so I replaced them. The engine looked decent inside. I continued my maintenance regimen and eventually tore into the engine to do heads/cam/intake. The engine was spotless inside, the valley was clean, the heads looked like new....etc. It had 280,000Km on it at that point. My buddy who ran nitrous on his stock engine with similar mileage then burned a valve at the track when an injector harness was chewed on by a mouse and one cylinder got not much fuel and a whole pile of nitrous. Instead of getting the head rebuilt I just gave him one of mine. The difference between the two heads, from the same vintage of engine with similar mileage was staggering. My head was spotless, whilst his had some rather significant varnish accumulation. We joked that his engine would be lopsided now
Anyway, he had run the car on Castrol GTX in various flavours changed at 5,000Km intervals (roughly) since he got the car, which had been many, many years prior. Ultimately the engine started losing oil pressure (the bottom-end wasn't overly healthy after all the spray) and he stepped it up to 20w-50 just to keep his oil pressure above 10psi at idle. A few months later he committed to building a new engine so we tore into that one. The rings were stuck on all of the cylinders with the oil control rings varnished into their lands and the drain holes plugged solid. We knew it was down on compression, now we knew why. It also was burning some oil, and this explained that too. Not exactly sure on the consumption rate, as he never told me.
In contrast, another friend of mine with a boosted 302, also similar mileage, but oil religiously changed with either Mobil 1 or Syntec blew an intake gasket at the track and filled the engine with coolant. he towed it home and tore into it expecting the worst. The engine was spotless, the rings were all free in the lands, the bearings looked fantastic, the oil control holes were clean. In fact he reused most of the parts when he put the engine back together and they are still in service now.
This is one of the reasons I have a very hard time accepting varnish as "harmless". Because if you see it, then it is elsewhere in the engine, and if it is in the piston/ring-land area, it has the potential to affect compression, oil drain-back and generally lead to poorer performance and possibly consumption.
The thing is, my friend who had the mess of an engine didn't run synthetic in it, only conventional. But I don't think that was the problem. It is easy to point to that but varnish is a product of a number of different things happening. The 302 in car applications has the PCV valve nestled in a grommet on the back of the intake manifold. Below the grommet is a screen to prevent oil from being sucked into the valve. What happens is that over time the screen will plug up and then the engine start drinking oil through the PCV valve. This can also result in excessive blow-by, as the PCV is no longer functioning. I ran into this issue on my Town Car, which, after replacing the PCV screen, took quite a while to reduce its blow-by to acceptable levels. Most people, even if they change the valve, never change the screen, which is the root of the problem. My buddy was probably in that camp. Same thing with running colder thermostats, which he also did. IIRC, he was running a 160 and had run no thermostat at one point. Common stuff for folks "hot rodding", and you hear of a lot of "old timers" doing it, which is where he would have learned it from. Not getting up to proper operating temperature leads to varnish, sludge...etc.
I've never torn down, or been involved in the tear-down/witnessed the tear-down of an engine that was clean and also had stuck rings or plugged oil return holes. But all the ones that HAVE had that problem had one thing in common: varnish. And sometimes sludge. Since my one friend's dad was really into SBC's, I saw quite a few of those with varnish, sometimes sludge, burning oil and having stuck rings. The bad ones also having low compression from the compression rings sticking too. He was big into picking up vehicles for their engines looking for 4-bolt mains or a certain set of cylinder heads, so we saw quite a few of them. Those engines would all have been neglected in some way or another, which lead to the varnish, then ultimately, if left long enough, the sludge. Some of them had baffed thermostats and ran too cold. Some of them didn't get their oil changed regularly, whatever the neglect was, this was the end result.
Where I am going with this is I think of varnish as a symptom, one of a problem that may have a host of sources. If its rate of progression is slow perhaps its effect will never be significant enough to impact the engine in a way noticeable by the end user. On the other hand, if it is due to something like a plugged PCV, its formation can be rapid and could potentially lead to much larger issues, ones we've already touched-on. I also think some engine designs are FAR more forgiving than others, and this needs to be factored in here as well.
On top of that, consumption can also be tied to design and my not be representative of a problem. The early S62 engines drank 10w-60 like it was beer. 1L/1000Km, and sometimes higher wasn't uncommon. Yet the engines stayed clean inside. The ring design was low tension for maximum power and this translated into unacceptable consumption rates for a street engine. BMW revised the rings and the post 03/00 cars had a fraction of the consumption, mine uses about 1L/8000Km or so, some use nothing noticeable between changes. I test drove a pre 03/00 car that looked fantastic under the valve cover but the owner outright stated that it used about 1L/1000Km.
I guess this is a long way of saying that we cannot just point to one thing and say "this is it!". I think it is a number of things that work together to create the problem when it happens. I think varnish is a key sign, but as I already noted, varnish doesn't just "happen", it is the result of a process itself. I DO believe there is a correlation between varnish formation and ring sticking; I don't think, barring mechanical issues, that you can have the latter without the former.
This is a great diagram that illustrates the formation of varnish, and the subsequent evolution into sludge: