I noticed an oil leak around the fly wheel inspection plate. I had a mechanic at my work, I work for a Honda dealer, remove the inspection plate. I then poured some UV dye in the engine. I drove it for ~50 miles and then we checked it. It is still tough to tell but it appears to be leaking out of the main seal because the crank is wet.

Replacing the main seal is a big job. My dealership doesn't allow side work and this is not the type of job you want to be doing with jack stands in your driveway. Looks like I'll be paying a huge amount of money in labor to replace a very cheap part. It sucks but with close to 150,000 miles I guess it is what it is.

I haven't read many threads about the main seal leaking. Is this a fairly common issue with the RL? I know it isn't with most V6 Hondas.

 

Quite the contrary, it's VERY common in Honda V6s... Where did you hear otherwise..? Check the PCV valve, that usually helps alleviate it too

 

I have seen a few over the years leak in V6 Hondas but not many and I have worked for Honda for 22 years. Of course I am in sales not service so there are probably a lot more than I am aware of.

I changed my PCV valve approximately six months ago so I doubt that has failed already. I appreciate the idea though.

 

Have you been using synthetic oil? Some believe using synthetic oil on high mileage (100K+) Honda J series engines will cause the seals to leak.

 

I have been. I have used nothing but Mobil 1 in all of my engines for over 20 years. I bought this RL with ~106k miles on it. It has ~150k miles now. I have used Mobil 1 5w-20 every oil change since I've owned it.

 

I assume trying any "stop leak" oil additive is a bad idea. It may stop the leak but couldn't it cause other internal issues?

 

 

You mean don't use it, right? I wasn't planning on it but I wanted to be sure what you meant.

 

No don't use. Yes bad idea !

 

I thought so. Thanks.

Maybe I should try Mobil high mileage oil? It says it helps to seal leaks with high mileage engines. I doubt it will work but maybe it is worth a shot???

 

I've decided I am going to drain and fill the oil with Mobil 1 high mileage. I doubt it will stop the leak but it is worth the few bucks to try. I will post my results after a few weeks of driving but I'm sure we can all assume the results.

 

Premium grade detergent 5w20 it is.

 

I don't know if this is a sarcastic comment or what? Lol. I assume it is but I might be too naive to get it.

 

Beeker - PM me. I found and have been using a Honda mechanic in RI. He might be able to help you out or at least save you a few $$ if you move forward with the repair.

 

)))

I'm telling you what i learned from this thread: I'm putting that oil type mentioned in the user manual like a good puppy. "Premium grade detergent 5w20". (yes, they call it detergent in the manual, i dunno why)

No synthetic for me

 

Gotcha! Thanks.

I have used Mobil 1 full synthetic in all my engines for over 20 years. This is the first major oil leak I have had.

 

Oil is a major contributor to your
engine’s performance and longevity.
Always use a premium-grade 5W-20
detergent oil displaying the API
Certification Seal. This seal indicates
the oil is energy conserving, and that
it meets the American Petroleum
Institute’s latest requirements.

^From the manual

 

Hope it's nothing major. Fingers crossed.

If it is, maybe you're being drawn to one with a 6 speed tranny

 

I drained the regular Mobil 1 and filled it with 5w20 Mobil 1 High Mileage. I will check the results after 500 hundred miles or so. If it doesn't work, which I assume it will not, it only cost me $25.

 

When I first got my '07, I converted from regular dino oil to Mobil 1 full synthetic and within 500 miles the rear main seal blew. $600 worth of labor for an $12 seal. Went back to regular Valvoline 5W-20, no problems since. Just sayin'---

 

My brother bought a cheeseburger and onion rings, and a month later he dropped dead. I've eaten only tacos ever since, and my health is perfect. I think the conclusion is obvious.

 

I whore around a bit online and found this to be a balanced conclusion. https://www.yourmechanic.com/article...-in-older-cars

A good question to ask: does any car manufacturer recommend in their manual using a synthetic oil?


My choice to go with the premium regular oil is purely coz the manual said so. And, coz oil change intervals are the same 5-6 thousand KMs.

On my Audi, I always put in synthetic, and changed oil once every 12-15 thousand KMs.

 

IIRC, it is actually somewhat common for a car that has always run conventional oil to develop leaks after switching to synthetic.

When I decided on an oil for my Tundra which I bought used at 140k, I went high mileage Mobil 1 10w-40. The thinking was the high mileage and increased viscosity could help deter leaks.

 

It is worth mentioning that the article you linked specifically defines "older car" as 1990 or earlier. The article explains that the engines in that era were built with looser tolerances.

I've been using synthetic (5w-20, then 0w-20) since taking ownership of my own RL with 35k on the clock. It's over 110k now, and it's never leaked a drop. But admittedly, that's a sample size of one (1) and falls far short of proving any general trend. I will freely admit that synthetic is arguably a waste of money in my RL, simply because I end up changing the oil far earlier than necessary just to stop staring at that damn yellow light on the dash.

Does any manufacturer recommend in its manual the use of synthetic oil? Yes, I believe VW does on some of its engines, especially the 4-cylinder turbos.

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That right there. I put in synthetic twice since i got in last Feb with 1000 km in between (clean up), then noticed oil life reach 15% around 6000 km. and the mechanic said to change oil every 5-6k km no matter regular or synthetic.

Unless synthetic is really doing my engine a favor, I too think premium will do just fine.

 

Valid point, 09.

One thing I do like about synth, though: In the hot and cold extremes of the Chicago climate where I live, it's reassuring to me to know my oil will flow freely right from the opening seconds, even in subzero temperatures (the moments that account for a very high percentage of engine wear), and avoid thermal breakdown in summer stop-and-go. As they say, it's hard to put a price on peace of mind.

Even so, I'll be the first to admit that with the continued improvement of dino oils, it's probably just me being anal. There's probably a much greater risk of fluid-related failure on our RLs from the automatic transmission than from the engine – which is why I also turn to the aftermarket for full synthetic ATF, as I've posted here in other threads.

 

No argument there.

Does the temp gauge in the morning on urs reach almost half way thru within 500-600 meters ? I found my car has no problems warming up within 2 mins of first thing driving.

I'm considering changing the thermostat next week along with the timing belt just to make sure its not something wrong.

 

You guise are silly. If you put synthetic in your engine, you don't change it at the predetermined factory interval. You keep track of your mileage and change it at 10-12K. Your can reset the light and odometer anytime you want.

 

It's nice tho to have ur 'ride' tell you her needs once in a while.

 

Let's see, the car had gone 74K miles using regular oil with no rear main seal leak whatsoever. I changed to full synthetic and the seal starts gushing like Niagara Falls. Change the seal, convert back to regular oil and 40K miles later, still no leaks. Maybe the rear main was ready to go at 74K but I doubt it, my experience being that rear mains last quite a bit longer than that. I can only make a diagnosis based on what changed or what was different so the conclusion was obvious to me.

Thanks for the obtuse comment though.

 

I don't question the correlation to the seal failure, but I'm willing to bet if you had put synthetic in with your new seal, you would be at the same result today.

 

Probably but I wasn't willing to spend another $600+ to find out. Only car I ever ran synthetic in was my NSX and only because it had used Mobil 1 from the beginning. I've always used Valvoline regular 5W-20 or 5W-30 in my other Acuras and changed every 5K.

 

Which will do just fine.

 

Update:

I now have over 157k miles on my car. I switched to Mobil 1 5w20 high mileage oil ~7k miles ago. The rear main seal is still leaking but it has reduced. At this point I would say it is seeping more than leaking. I checked the oil level before emptying and it was still up to the high mark on the dipstick. I also still don't have any oil in my driveway. At this point I am not going to replace the seal because it is so minor. Maybe at the next oil change it will be even better.

 

Update: I now have 179k miles on my RL. I switched from regular Mobil 1 5w20 to Mobil 1 High Mileage 5w20 about 20k miles ago. I changed my oil tonight and to my surprise the main seal leak is gone! It is completely dry underneath. I am shocked to say the least! Switching to the high mileage oil, which has additives to help seals, actually worked.

YMMV of course but switching to high mileage oil fixed my main seal leak .

 

thanks for the follow up! Very few ever update.

 

that's awesome! my dad's lexus rx330 rear main seal was leaking and like you i've replaced his synthetic blend oil to mobil 1 5w30 high mileage synthetic oil and the leak has subsided. Appreciate the update!

 

Also, you are using 5w20 high mileage synthetic oil right?

 

Correct.

 

I am now over 187k miles and the main seal is still dry as a bone! Again all I did was switch from regular Mobil 1 to Mobil 1 high mileage. Not only did it stop the leak it is still not leaking. I would have bet my life savings on the high mileage formula not helping at all. Luckily I didn't make that bet.

If you have a small oil leak try switching to Mobil 1 high mileage. Maybe it will work for you as well .