I suspect that my rear main seal is leaking. I'm getting a slight drip between the oil pan and the transmission dust plate (what else can it be besides the RMS?). I've recently noticed this (it seems) after switching from 10w-40 to 10w-30 oil. So, does anyone have any advice on this type of job? How tough of a job is this on these type of vans, that is, if it is the rear main seal?

Of course, I could just leave it alone for now since the leak is very minor, but the problem will no doubt get worse soon enough. I do not want to mess with the stop leak crap, so I may just go back to a thicker oil and see what happens. After that, decide if I want to do this myself or let someone else do it.

Edit: I've noticed that the oil is still dripping, even after the truck hasn't been started in over a day. Does this make any sense? My thought is that if it was the RMS, oil wouldn't still be dripping if the engine hasn't been run for 24 hours.

 

Guess you can try some high mileage oil which has the seal swellers/ seal conditioners mixed in already.

I don't like mixing things into motor oil, but if the manufacturer does it then there is little concern of incompatibility, IMO.

You got to clean the whole area good. Dirty engines can seep oil higher up and it takes a while for the drips to congregate at the lowest spot in their travel

 

I have stopped a RMS seal leak with an additive on my 170,000 mile '97 Toyota successfully now for nearly 6 years. I purchased the vehicle used with 125,000 and the RMS had been leaking for some time before I got it as it was quite wet at the rear bottom of the engine. I got a $600 estimate to repair, but I thought that I would try the seal conditioner stuff. Every oil change I use 5W-30 synthetic and a bottle of conditioner. I forget the brand of conditioner without going to the garage and looking. It is not a perfect fix, but has cut down on the leak at least 95%, saving my driveway.


I believe in at least trying chemical additives for oil, and so far, I might have spent less then one tenth the money on replacement of the seal purchasing conditioner. It has worked well for me and I will continue to use it. Just my two cents worth...

 

Taking another look underneath, it doesn't look like the oil pan is going to be able to come out without removing or lowering the front suspension.

 

I believe you have to lift the engine 4" or better to remove the oil pan. Its not a lot of fun on this vehicle. Engine can only be lifted or removed from inside, you have to do it by removing the passenger seat and working through the passenger door opening.

 

I guess so. If the pan was easy to get off, I would have done the job over the weekend. Since I'm going to have to be lifting up engines, I'm not going to touch it. Oh well, I'll just leave it be for now.

 

Well, a little update: My guess now is that there is no rear main seal issue. On my last oil change, I seem to have overfilled the oil. I was starting to see oil running down the oil filter as well as in other places. So, I've dumped out some oil and have the level right where it needs to be now. Apart from feeling a bit silly, I'm glad that I found out what the issue was and that it wasn't anything major. Moral of the story: don't dump your 5.1 quart jug into your engine without checking the levels several times. That 5.1 quart jug ended up leaving the oil level about 1/4 inch over the fill line. Silly rabbit, don't overfill your engine oil.

Luckily, the van was only driven three times for a total of 10 miles during the week of the oil change. Hopefully I didn't cause any issues because of this.

 

If your van is using the Purolator L30001 (big long filter, hope that's the number) then the overfill would not happen since the 5.1 is about right to top it all off.

Did the check engine light come on "if" the oil pressure spiked for those 10 miles???

 

Depends on the engine. The 5.2 and 5.9 oil capacity is 5.0 quarts but the 3.9 V6 only holds 4 quarts. Using the oversized filter you could actually come up around a pint low adding 5 quarts.

I mention this only because I do use the oversize FL1A filter. I couldnt figure out why I was refilling with the same 5.1 container but always seem to be about a half quart low when I check. My engine does not seem to leak or burn oil (yet) and I can't see oil pooling in the intake manifold so I don't seem to have the infamous intake plenum leak (yet).

Factory service manual generally has all the answers. It is well worth picking up a set.

 

I used the Purolator Classic filter. L14670, I believe.

There was nothing noticeably wrong with the truck while it was being driven. The fact that the engine wasn't being driven very hard and that the trips were short in duration probably helped.