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So about a month ago I noticed some oil consumption on my FWD TL. At first it was relatively minor; I noticed it was about a half quart low when I changed it. However, it's gotten worse over the last month. Last week alone it consumed 1qt (about 500 miles of driving). It also began pinging a bit on full acceleration when the RPM's were low - presumable due to carbon buildup. I pulled the plugs to see if any were fouled and sure enough, the plug on cylinder 5 was all fouled up. It also had oil on the interior threads and none in the spark plug well, so it's not the valve cover. I replaced the oil with 5w30 which vastly reduced the consumption but that's really just a band-aid. I know using thicker oil is sometimes the norm when engines get higher mileage but in this case, I knew that it was more than normal wear and tear. I figured (hoped....) it was the valve guide seals and not piston rings. Took it to my mechanic which has worked on a few of my cars in the past to confirm and sure enough, bad valve guide seal. I'm having him replace it since removal of springs and that type of stuff is beyond my pay grade. Maybe I'll fiddle around with it someday but not yet....
The good news is it's just the one. I'm not bothering having them all done since I believe it's an isolated incident. However, if anyone observes oil consumption on their 3.5L, try pulling the plugs first to see if it's just one cylinder having trouble rather than a more widespread issue like the 3.7L.
Question for those with the SH-AWD with oil consumption problems - do you ever notice any fouling on your plugs? If all cylinders are consuming oil equally rather than just one, and it's not excessive, I'd expect there wouldn't be much, especially if it's occasionally pushed hard to burn off some of the carbon. Curious on that though.
It's not often that I ask for help from the AZ community but I need a bit of advice.
So I had the valve seal replaced on cylinder 5 but it hasn't solved the problem. I took it back to my mechanic and he did another leak down test and this time he told me that it's the piston ring. I'm not sure if it was both the valve seal and the piston ring, or if the piston ring issue may have been caused by carbon buildup. Either way, he had me come back to the shop and confirm it was the piston ring by feeling the flow from the PCV valve, which indicates blow by from the piston ring into the crank case. I think he felt pretty bad for the faulty diagnosis. He offered to apply the cost of the valve seal replacement to whatever engine repair/replacement will be necessary and didn't charge me for the 2nd leak down test.
The consumption has gotten worse as well. 1 qt. in 300 miles this weekend, and that was with keeping the RPM's below 3K. If I get above about 4K I start getting smoke out the exhaust. Hit VTEC and it's really bad. I thought it might actually be a good feature to have when there's some dick following too close behind me. Downshift and punch it. Smokescreen the bastard like I'm James Bond or something. If it weren't for the terrible spark-knock I'm getting due to massive carbon buildup in Cylinder 5 might consider it. Oh, I've done an inspection of all cylinders using a boroscope and they're all immaculate except Cylinder 5 which has a ton of buildup on the cylinder head and exhaust valves. The valves on that cylinder are also making a lot of noise, presumably from carbon. Odd thing is, the compression test is still good. And there's no loss of power. So I'm assuming the compression ring is fine and it's the oil or scraper ring that is bad.
I have no interest in getting rid of the car. I've pampered it and everything else runs like a top. So I've contacted a couple of shops to get some quotes on engine replacement and rebuilds. I'm wondering, for those who have done major engine work, if you'd recommend just getting a low mileage engine replacement, or doing a rebuild instead. I'm not sure what the pricing differences are yet but they look to be somewhat similar. While the cost of the engine replacement includes purchasing an engine, the rebuild requires a lot more labor and a bunch of replacement parts. Also, the 3.5L is widely available, often for <$1000 even with mileage below 50K. And I'm pretty certain that this problem is isolated. I've never heard of this engine (or any J-series Honda engine) having a gross failure of a piston ring. Sure, any engines rings might deteriorate after a lot of mileage but it's typically across all cylinders, not a massive failure of one ring at 125K.
This may sound far fetched, my brother had a 3g tl with the 3.2 burning oil, I did a bottle of sea foam in the engine oil, and the sea foam upper engine/intake cleaner, sprayed the whole can in and let it sit for like a hour, It stopped burning oil! you leave the oil additive in and over time it helps to clean up the carbon in the engine and sludge, it may or may not fix it but worth a try, would cost you about $20 and a buddy + 10 mins.
I have nothing to lose so I'll give it a try. I did that about 20,000 miles ago and the oil turned pretty dark brown which I assume was from the seafoam cleaning out the crap. But I'll give it a go again. Thanks for the suggestion.
I have nothing to lose so I'll give it a try. I did that about 20,000 miles ago and the oil turned pretty dark brown which I assume was from the seafoam cleaning out the crap. But I'll give it a go again. Thanks for the suggestion.
Yeah that's probably the sea foam cleaning out the engine. Don't forget to try the upper engine cleaning spray. Hopefully it does something! I was sure surprised it did it's magic before, perhaps it was carbon that stuck a ring a bit.
That's what I'm hoping. I've kept it pretty clean though. I'm in the process of methodically trying different solutions based on some recommendations from the BITOG website (Bob is the Oil Guy).
After having three different shops evaluate the engine, all of them came to the same conclusion - oil ring. Compression ring appears to be fine but the oil ring is definitely letting oil through. I'm going to keep an eye on oil levels and compression to make sure things don't get worse. But I'm not having it fixed at this time. Price ranges for rebuilds and replacements ranged from $2800-$6500. But with the power, idle and mileage still good, I'm not going to spend that kind of money right now.
I did try one thing that cleaned up some of the carbon in the cylinder and reduced my knock - some water injection. It's a somewhat controversial subject but I have nothing to lose so I tried it. It worked quite well. It's done very similar to seafoam but you have to be careful to avoid hydrolock. It more or less "steam cleans" the combustion chamber which can free up some carbon deposits. The other danger is that hardened deposits may break lose, rather than the dissolving action that seafoam tends to do. But it's free, other than the cost of distilled water, and the chance of hydrolock is pretty low if you do it when the engine is hot since the water tends to turn to steam long before it enters the cylinder. I injected a full gallon of distilled water and got misfire codes on all 6 cylinders Had to reset the codes afterward. If you think seafoam stalls the engine, try water. It's much worse. However, it smoothed out the idle and visibly cleared up much of the carbon in cylinder 5 when I inspected it with a boroscope before and after. Personally, I can't think of other damage it might do to the engine. Rust really isn't an issue since water vapor is already a natural product of combustion and any residual water will nearly instantly be flushed out of the system via evaporation and steam. And I don't see how it would harm the cats. I may isolate this to cylinder 5 next time by blocking off the inlet ports in the intake manifold when injecting via the vacuum tube that feeds from the front valve cover (part of the PCV system). This can simply be done with duct tape or something like that. If you have a certain cylinder you want to isolate, that's a good method. Although in a healthy engine, I don't see why that would be necessary.
So I bit the bullet and had the rings replaced last week. Total cost = $1800. My next door neighbor has a friend that runs a small indy mechanic shop who was well versed in Honda engines. He did it on the side (not officially in the shop) which saved me a bundle. He honed out the cylinder, installed all new rings, replaced the oil pan gasket and rear main seal (and a few other seals I'm not familiar with). Used all OEM parts. Runs like a champ now. No more oil consumption. I watched him do some of it which was kind of cool. The ring had slipped out of place. It didn't break or crack. But either way, it was letting oil through. The good news is it didn't score the cylinder liner much at all so he was able to easily resurface it. I should have taken some pictures
At this point I'm considering purchasing an auto service warranty, just in case something happens again. Lyft offers a pretty good discount with some of them. We'll see.
I ended up purchasing a service plan yesterday through Lyft since it was a pretty good deal, about as much as I could make in a few hours driving on the weekends. I'm normally not a fan of aftermarket warranties but the price was right and I'm getting up there in miles. With winter coming up and driving in Park City, I think it will be well worth it. Hopefully I never have to use it but it will give me a bit of peace of mind on the engine and transmission which are items I don't have the time or talent to tear down and fix in the case of a failure. I also purchased a new set of Blizzak's (haven't put them on yet). Hopefully we have a good snow season like last year
08-14-2017, 08:48 AM
So much for the 3.5L not consuming oil.....
I pulled the plugs to see if any were fouled and sure enough, the plug on cylinder 5 was all fouled up. It also had oil on the interior threads and none in the spark plug well, so it's not the valve cover. I replaced the oil with 5w30 which vastly reduced the consumption but that's really just a band-aid. I know using thicker oil is sometimes the norm when engines get higher mileage but in this case, I knew that it was more than normal wear and tear. I figured (hoped....) it was the valve guide seals and not piston rings. Took it to my mechanic which has worked on a few of my cars in the past to confirm and sure enough, bad valve guide seal. I'm having him replace it since removal of springs and that type of stuff is beyond my pay grade. Maybe I'll fiddle around with it someday but not yet....
If it weren't for the terrible spark-knock I'm getting due to massive carbon buildup in Cylinder 5 might consider it. Oh, I've done an inspection of all cylinders using a boroscope and they're all immaculate except Cylinder 5 which has a ton of buildup on the cylinder head and exhaust valves. The valves on that cylinder are also making a lot of noise, presumably from carbon. Odd thing is, the compression test is still good. And there's no loss of power. So I'm assuming the compression ring is fine and it's the oil or scraper ring that is bad.
