The oil change message came on at 4500 since the last one. No oil used during the 4500, but I probably could have added about 6oz (+/-) judging by the dipstick, which I have watched religiously after reading some posts here about oil usage.
When I drained the RX Catch Can I installed at the last oil change, I was pretty shocked.
There was a little over 4oz of oil mixed with condensation that drained from the can.
This would have been ingested into the intake plenum, coating it and the intake valves.
It cannot be cleaned with additives since the DI engine does NOT pass fuel over the intake valves. Just air.
I would assume that would depend on your dealer and service writers. I spoke to mine and they didn't see that as a problem at all. The service writer I deal with is a nice guy and knows a lot about these engines and understands how the valves get coked with oil. Once the weather warms up, I'll be getting and installing a can and cleaning the top of the engine.
With hundreds of thousands Cadillac CTS DI sold, not to mention other DI brands/models, and now many thousands driven >100Kmi, I can't help but wonder how few of those vehicles actually have catch-can(s) installed? So how perilous is oil ingestion, anyway? How many miles/km driven before DI engine performance and/or fuel economy degrade to the point of owner awareness? Or, is excessive oil consumption the only discernable symptom?
BTW, my DI engne was rebuilt and later replaced by a brand new LLT engine due to excessive oil consumption caused by factory defective out-of-round cylinder bores - GM, my Cadillac dealer, and GMPP agreed. Was my original engine a one-off? Not likely, in my opinion; thus many reports of excessive oil consumption for 2008-09 CTS, both DI and PFI engines.
Also, driving longer miles where your engine gets good and hot may make a difference, too. Driving fewer miles and just a couple of miles to the store, for instance, the moisture in your engine won't be removed by the heat.
I must be very lucky as I have a 3.6DI that uses virtually no oil between changes and gets 19.8mpg combined. I don't drive it like I stole it, but I don't baby it either.
I have a 43 yr old Corvette and a Harley that I do all my own wrench-turning on.
After seeing this, a catch can of whatever brand is a no-brainer. The non-DI engine doesn't have this problem because an occasional bottle of cleaner or top-tier fuel makes it a moot point.
I can't help but think that these contaminants come out during an oil change. I think if you want an oil catch can , you should be able to buy one and put it on. But if you don't have one, just like the millions of cars on the road, you will be fine.
I can't help but think that these contaminants come out during an oil change. I think if you want an oil catch can , you should be able to buy one and put it on. But if you don't have one, just like the millions of cars on the road, you will be fine.
Couldn't agree more. I don't know if they come out during an oil change, but they can't be that important given the number of people that don't have them.
Two completely different systems. Induction and Lubrication.
Any oil or vapor that makes it into the PCV system will never enter the oil flow again. Ever.
It gets sucked into the intake plenum and then the combustion chambers via the intake valves, coating everything in its path since the fuel and its cleaning properties are injected directly into the combustion chamber and doesn't flow over the valves like in a normally injected engine, thus cleaning them.
Get one or don't. I have no skin in this game. Just showing that the cans DO work as designed.
Going back to the original theme: 'look at this'; well, if you didn't have a catch can, and depending on your driving cycle (short trips, long trips), 99 plus percent of that fluid caught (plus or minus) would harmlessly be burnt (through combustion) through the PCV system. It doesn't stay in your oil crankcase contaminating your oil, and yes some of that oil (vapor) might aggregate to the intake valves (and that's where the "bone of contention" lies, whether in your determination you think you need a catch can or not (I'm in the camp of not).
Direct fuel injection is a fuel-delivery technology that allows gasoline engines to burn fuel more efficiently, resulting in more power, cleaner emissions, and increased fuel economy.
How direct fuel injection works.
Gasoline engines work by sucking a mixture of gasoline and air into a cylinder, compressing it with a piston, and igniting it with a spark; the resulting explosion drives the piston downwards, producing power. Traditional (indirect) fuel injection systems pre-mix the gasoline and air in a chamber just outside the cylinder called the intake manifold. In a direct-injection system, the air and gasoline are not pre-mixed; air comes in via the intake manifold, while the gasoline is injected directly into the cylinder.
I don't have a dog in this fight. I am just a little anal about my toys and have been doing all my major/minor repairs since 1976.
Without top tier fuels and their cleaning agents bathing the intake valve stems, DI engines are going to build up carbon on them. If the intake valves were open at all while the injectors were pressurized, the fuel would be shooting up into the intake plenum as the path of least resistance.
The biggest concern with direct-injection technology is with carbon buildup. In a direct injection engine, oil droplets tend to get ‘baked’ on the valve. Carbon buildup can create a lot of headaches in the long-term, with build-up being bad enough to make extra noise during operation and damage the engine. At the very least it can reduce fuel mileage, and affect performance.
This issue can affect other components in your car’s engine, like turbochargers or catalytic converters. Some automakers have filtering systems in place to catch droplets and debris.
I think the point is, there hasn't been an over whelming number of reports by forum members, citing the need for valve jobs. If it was epidemic I'm sure we would have seen a ton of posts about it.
I'm definitely a DIYer and I just installed a catch can Friday. I also removed the intake manifold and cleaned it. It was well coated in oil but very little pooling. There was even a small puddle in the rubber intake hose between the throttle body and the MAF. The head ports were coated and the backs of the intake valves had a fair amount of carbon deposits. This was on an engine with 80k miles. I can't say cleaning it up helped power any at least not noticeably. Fuel economy appears to be unaffected as well but it may be too early to tell.
I have a long daily commute so very few short trips in this car. I also drive more aggressively than most particularly when it comes to the application of the go pedal.
I chose to add the catch can because while there are arguments against it's necessity, I've yet to hear any good reason not to add it. In other words, it does no harm even if the benefits turn out to be limited.
I've got an 08 DI with 50K, picked up a couple months ago. I'd read about the catch can and coking issues, but before installing a can, I decided to try Seafoam through the intake first and see what effects it produced. My mileage went up over the next month from 20mpg to 22mpg on average. Can't say I felt a noticeable pickup in power but the mpg gains are true. I've now run nearly a dozen tankfuls and the 22mpg is holding, so that's nice.
I may still install a can, but the Seafoam treatment is incredibly easy since the intake hose is right on top. Juts my .02.
I did the seafoam as well and will probably do it again now that the can is installed because I was not able to clean up the intake valves to my satisfaction while I had it apart. Now that I have the catch can, it should stay relatively clean once I do that. I may still do the seafoam again at some point in the future as well. As good as the catch can appears to be, it's not 100% so future cleaning will likely be beneficial.
Someone posted a video showing the "blow-by" a while back. Yes it was substantial BUT only when revving the engine to high RPM. It seems to me that when not driven like you are hell bent to get somewhere it should be ok. Of course I suppose it is fun to put your foot in it once in a while.
Especially when at those RPM's is when our engines produce the most fun. Hard for me to do though, I've always hated winding out the engine.
Question on the topic for those who know more than me: Even though the stuff being diverted is nasty looking stuff, is there anything on the intake side that relies at least partially on that gunk for lubrication? Seems to me that running that part dry may cause an issue if so. Maybe the best strategy is a good top end cleaning (like sea foam) once in a while. For all the proponents, I am not arguing against, only asking for some knowledge that I don't have.
No, there is NO benefit to the engine from contaminants from the PCV.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Cadillac Owners Forum
4.8M posts
369.7K members
Since 2002
Cadillac Forums is the perfect place to go to talk about your favorite Caddys including the ATS, CTS, SRX, Escalade, LYRIQ, Vistiq, concept and future Cadillac models.