oil additives to condition seals, your opinion?

When I had my recently car in a local shop to have the right drive axle seal replaced, I talked to the mechanic about leaks. He carefully looked under the engine and said "You might have a main seal leaking." He handed me a 12 oz. can of a product called CPR Engine Stop Leak and he advised me to mix it with my engine oil when I change oil; this was understood to be a one-time procedure.

Since I intended to change oil soon, I proceeded to do so and I did add the additive. I wish I had waited for awhile to observe the affect of the new seal but I went ahead and added this additive. It was thinner than oil and, therefore, I imagine it causes a bit of dilution of the oil. Since I used the 5W-30 oil I already had, I am wondering whether I should be concerned about the thinness of the oil now.

And, I am aware of differing opinions about various oil additives. So, I'm interested in opinions on this matter.

Back in 2004 I started getting the puff of blue smoke on cold start, indicating my valve seals were going bad. Had some other issues with oil deposits in the valve cover that prompted me to run some Redline Group V ester based oil to try & clean it up.
Group V oil is known for superior cleaning and seal conditioning (also excellent lubricant), and is used in high mileage oils for this reason.
Long story short, now 10 years and about 33K miles later, I have not changed the valve seals yet, no blue smoke on start up ever since and my varnish deposits are all cleaned up as well.
I've been adding a quart of Redline to each oil change since, use synthetic only and since it sees so few miles, only change the oil every 2 years.

The only time I use additives is as a band-aid until I can replace whatever is leaking. I know opinions vary, but mine is that you shouldn't need them under normal circumstances, and they definitely should not be used as a permanent solution. A flush may be needed after using them, depending on what kind of additive.

Thanks for the replies.

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Originally Posted by g.frost

Back in 2004 I started getting the puff of blue smoke on cold start, indicating my valve seals were going bad. Had some other issues with oil deposits in the valve cover that prompted me to run some Redline Group V ester based oil to try & clean it up.
Group V oil is known for superior cleaning and seal conditioning (also excellent lubricant), and is used in high mileage oils for this reason.
Long story short, now 10 years and about 33K miles later, I have not changed the valve seals yet, no blue smoke on start up ever since and my varnish deposits are all cleaned up as well.
I've been adding a quart of Redline to each oil change since, use synthetic only and since it sees so few miles, only change the oil every 2 years.

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I did not know anything about Group V oil. I might do some more research on it. However, I am inclined to think special additives, i.e. additives separate from additives normally used in motor oils, are generally not needed. I have a '91 Accord with 305K miles on it and I've never used any special additives in it, and it consumes very little oil between oil changes.

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Originally Posted by niles

The only time I use additives is as a band-aid until I can replace whatever is leaking. I know opinions vary, but mine is that you shouldn't need them under normal circumstances, and they definitely should not be used as a permanent solution. A flush may be needed after using them, depending on what kind of additive.

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I agree all your points. However, if the main seal is leaking, I probably will not be replacing it. The labor cost in having a repair shop do it is very high and it's not a job I'd want to tackle myself. So, if leaving this additive in for awhile, perhaps for the duration of one normal oil change interval, will be the end of this experiment, I think. In other words, if this additive seems to make no difference after trying it this one time, I'll just live with the leak, even though I very much dislike the oil spots left on driveway and garage floor. Still, adding some oil between oil changes, to the extent that is necessitated by a leak, is a very minor cost compared to the cost of replacing a main seal.

I think it's worthwhile to note that there a couple common seals that leak on these cars, some of which could look like a rear main leak. For example, the distributor o-ring is a common leak that these cars develop, and it runs downward and looks like the rear main. (3/3 cars I've dealt with leaked here.) This is a 3 dollar part from Honda and it's really quite easy to change. Also, another leak that develops is the oil filter base gasket. This one is kind of away from the rear main but its worth checking if you have a mild oil leak.

It's really work...?
My car start is out some blue smoke at cold start...
Want to try if truly effective..

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Originally Posted by gyates93

I think it's worthwhile to note that there a couple common seals that leak on these cars, some of which could look like a rear main leak. For example, the distributor o-ring is a common leak that these cars develop, and it runs downward and looks like the rear main. (3/3 cars I've dealt with leaked here.) This is a 3 dollar part from Honda and it's really quite easy to change. Also, another leak that develops is the oil filter base gasket. This one is kind of away from the rear main but its worth checking if you have a mild oil leak.

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Thanks for the suggestions. I've looked below the distributor and see no leaking there. And, I replaced the oil filter stand gasket last winter. So, I suspect the main seal is leaking.

I've been lucky to not have to replace a main seal, so I'm not sure how involved it would be. Are you running 5w30 now? Have you tried maybe 10w30 to see if it slows the leak?

All well formulated motor oils will contain seal conditioners. Group V ester based synthetic oil just happens to be the best. This is not an 'additive', it is a high quality synthetic oil. No oil seals have ever been replaced in my 88 at 164K , except the valve cover seal when doing a valve adjust. No oil spots in the driveway, no leaks. There is some evidence of seep around the distributor seal though.

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Originally Posted by niles

I've been lucky to not have to replace a main seal, so I'm not sure how involved it would be. Are you running 5w30 now? Have you tried maybe 10w30 to see if it slows the leak?

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Replacing a rear main seal is quite involved. I understand it requires removing the transmission from the engine, and perhaps even dismounting the engine from the engine mounts, but I'm not sure about the latter. Even if the engine does not need any dismounting, removing the transmission from under the car without the benefit of a lift to raise the car up to allow standing under it is not going to be an easy task. I would have been more inclined to tackle this when I was younger but I've reached an age where laying on my back under a car and wrestling with a transmission is simply not something I want to do.

I do have 5W-30 oil in the car. I agree that 10W-30 might be slightly advantageous in warmer weather.

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Originally Posted by g.frost

All well formulated motor oils will contain seal conditioners.

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Then, I should not need any extra additives. I've been using one or more of the Valvoline non-synthetic oils for quite a long time. So, I wonder why the mechanic recommended using this additive.

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Originally Posted by g.frost

Group V ester based synthetic oil just happens to be the best. This is not an 'additive', it is a high quality synthetic oil. No oil seals have ever been replaced in my 88 at 164K , except the valve cover seal when doing a valve adjust. No oil spots in the driveway, no leaks.

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And, is the Group V ester based synthetic oil what you've been using for a long time?

I switched to synthetic oils in 2004 after noting varnish deposits under the valve cover. Since then, at least one in 4 quart fill has been Red Line 5w-30 oil. Mostly using Penzoil Platinum for the balance of synthetic oil. Group III and IV synthetics are not as good as Group V for seal conditioning. I was not expecting such a long term cure for valve seals leaking. At this point though I have no reason to change them; they are fine after switching oils.
Keep in mind too that when these cars were new, SF-SG grade oils were the standard. Today's oils are much better for deposit control.

I also have a 2005 Civic with 128K that has had nothing but synthetic since new, mostly Penzoil Platinum. Under the valve cover looks just as clean as new, not a trace of deposits. This in itself may be not be such a big issue, but is indication of what is not deposited on the ring pack or is (not) fed into the intake through the PCV, depositing on the valves and intake.

Rear main leaks are rare on these cars. It's most likely your distributor seal. If you have an oring kit in the garage, it probably has the right size oring to replace it. I've replaced two now in the ~7 years I've owned the car. My dealer no longer carries the OE seal, but is happy to sell me an oring from their Chinese-made kit in the back. For the same price, of course.

Quote:

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Originally Posted by g.frost

Back in 2004 I started getting the puff of blue smoke on cold start, indicating my valve seals were going bad. Had some other issues with oil deposits in the valve cover that prompted me to run some Redline Group V ester based oil to try & clean it up.
Group V oil is known for superior cleaning and seal conditioning (also excellent lubricant), and is used in high mileage oils for this reason.
Long story short, now 10 years and about 33K miles later, I have not changed the valve seals yet, no blue smoke on start up ever since and my varnish deposits are all cleaned up as well.
I've been adding a quart of Redline to each oil change since, use synthetic only and since it sees so few miles, only change the oil every 2 years.

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why not fix them? it's really not that hard, if the smoking went away I doubt it was the valve stem seals, you must have never seen a set of the exhaust ones after a lot of miles, there is basically nothing left of them, no goop in a can will fix that, google rope method for holding up the valve during replacement,even with an air compressor, it's so simple I would use this instead of compressed air

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Originally Posted by Dr_Snooz

Rear main leaks are rare on these cars. It's most likely your distributor seal. If you have an oring kit in the garage, it probably has the right size oring to replace it. I've replaced two now in the ~7 years I've owned the car. My dealer no longer carries the OE seal, but is happy to sell me an oring from their Chinese-made kit in the back. For the same price, of course.

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they are available all over ebay, I bought a couple not long ago, it was in the honda packaging

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Originally Posted by derolph

Replacing a rear main seal is quite involved. I understand it requires removing the transmission from the engine, and perhaps even dismounting the engine from the engine mounts, but I'm not sure about the latter. Even if the engine does not need any dismounting, removing the transmission from under the car without the benefit of a lift to raise the car up to allow standing under it is not going to be an easy task. I would have been more inclined to tackle this when I was younger but I've reached an age where laying on my back under a car and wrestling with a transmission is simply not something I want to do.

I do have 5W-30 oil in the car. I agree that 10W-30 might be slightly advantageous in warmer weather.

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it's not that bad, you pull the transmission, and take off the flywheel. why would you have to remove the engine?, I mean if you have a hoist and dont mind disconnecting the drive shafts etc, and pulling the engine, just take out everything at one time, separate the transmission on the floor, do your seal replacement and put everything back in as one piece, making a suggestion if you dont want to pull the transmission from underneath

Group V synthetic oil is not 'goop in a can'. 'Goop in a can' is all the crap SF-SG etc. oils that cause varnish deposits, clog ring packs causing excessive blowby & wear, clog the PCV with crud, ...and cause rubber seal hardening and failure.

At 26 years and 164K miles, I don't know if my car is the only 3G that has never had the valve seals replaced. I will wait to see if and when they actually fail before replacing them. A sure sign, puff of blue smoke on a cold start; valve seals are the most likely cause.