# High mileage motor oil.



## veesix (Jul 18, 2004)

I have a 1988 V6 KingCab with 214,000 miles. Should I start to use a high mileage oil?

I understand that these oils have more seal swellers, but I don't know if that is the way to go with my engine.

veesix.


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## rogoman (Dec 16, 2004)

The high mileage oil costs more. High mileage oil is primarily to benefit seals. There is a slight cleaning, softening, swelling, and sealing benefit. If your engine is fairly tight, not leaking at the seals, then stay with the oil you've been using.


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## TheRepairMan (Jun 30, 2009)

This may not be typical, and I don't have an explanation for it, but I switched my 200,000 + mile Honda Civic to HM oil when it first came out, and it burned it off much faster than regular 10w30, or even full synthetics. 

I switched back to reg oil and all's well. Oh, it still uses some, but not like that! Just based on my experience I can't recommend it, but the engineers supposedly know better than I.
-R


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## veesix (Jul 18, 2004)

I do think that I have a very small leak at the rear crank. Maybe it is worth a try.


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## skramer360 (Aug 14, 2005)

'91 Honda Accord 297,000 miles, still use just the regular stuff. It uses/loses less than a quart in 3000 miles.


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## veesix (Jul 18, 2004)

But all the seals on the front of the engine are new, so I got that to consider. What I understand about HMO is that it will swell the seals and they will "wear in" that way. So, you are committed to the HMO forever. 

Who knows,,, I might pull the tranny off and put in a new seal.


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## smj999smj (Jan 1, 2006)

A lot of times on the VG's it's not necessarily the crank seal but the sealant on the crank seal holder or the rear lip seal of the oil pan. I usually install a new seal, reseal the holder, a smear some RTV along the outside of the rear pan end seal (clean any residual oil off first with brake cleaner).


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## TheRepairMan (Jun 30, 2009)

smj999smj said:


> A lot of times on the VG's it's not necessarily the crank seal but the sealant on the crank seal holder or the rear lip seal of the oil pan. I usually install a new seal, reseal the holder, a smear some RTV along the outside of the rear pan end seal (clean any residual oil off first with brake cleaner).


I've also found that as the seal material degrades it hardens and starts leaking between the outside surface of the seal and the seal mounting plate, or flange. I tried several things to help prevent this over a long run, and found that using Loctite thread locker on the outside of the seal has worked better than anything else. This may sound odd to you, but it works. Once it sets up, the seal isn't going anywhere, and they seem to stay sealed much longer than any other method I've tried. Silicon sealers applied directly on the mounting edge of the seal and mounting bore can let the seal push right back out of its mount. I've seen it happen several times. That won't happen if you do what smj suggested and just smear a coat on the outside edge of the seal where it mounts after it's installed, though.

I've personally had engines with seals I've installed go over 200K miles and still be dry. I also always put a good coat of grease on the sealing lip and around the tension spring. There are some graphite or moly impregnated seals out there in the aftermarket world that do not require applying oil or grease on the lip before installation, but I've never installed a seal dry.

-R


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