np21

As a new owner of a 2005 LS430 with 140K miles, I've noticed some oil drops beneath the crankshaft casing, trickling down onto the oil pan. The previous owner had the timing belt and Front Crankshaft seal replaced at 107K miles, but I suspect they used an aftermarket seal. To investigate, I cleaned the area and added color dye to the oil.

I'm seeking advice from anyone who might have experienced a similar issue. Can anyone confirm if this is likely a crankshaft seal leak rather than an oil pump o-ring leak? Any guidance or insights on this matter would be greatly appreciated. Link to the video

Here a link to the Video of the leak

LeX2K

Looks suspiciously like a crank seal leak to me. There is no O-ring for the oil pump there is an oil pump seal aka crank seal.
https://www.japan-parts.eu/lexus/us/...ngine-oil-pump

np21

Thanks! That's what I wanted to hear. The local shop wants around $800 USD for the seal replacement. Is that fair?

LeX2K

Replacing the seal is the same as doing a timing belt job even if you don't replace any timing components so that's not out of bounds. Speaking of, if the timing belt needs replacement now would be the time.

BaconLS430

It could also be a cam seal leaking down the front of the engine. Definitely worthwhile to pull the cam gear covers and inspect behind them to verify.

pmesfun

Looks like the crank seal. Very unlikely it's cam seals since they are behind the upper timing cover plate.

np21

So I had the front cam seal replaced along with a new timing belt and water pump. The leak is back. The mechanic said the crank seals were not leaking. Any idea what else can be going on.

bradland

So a mechanic was paid to replace a crank seal because you thought it may be leaking.
He tore down the front of your engine to replace the seal and while doing so noticed it was not leaking.
He put everything back together, billed you, and sent you down the road without addressing the actual leak…?!? 🤷

np21

Yes that's pretty much it. He replaced the seal and confirmed that it was leaking. Hopefully he didn't botched the job.

thazadin

Just wanted to chime in, I recently bought an 06 with 108k and found oil leaking from the same area and when I got everything off turns out its the old oil pump RTV and needs to be resealed. All of it flowed down and made the crank seal look like the problem, I replaced it while I was there since its a 5$ seal but it is indeed still leaking and the upper and lower pan needs to come off to get to the pump. More involved than the crank seal alone sadly

np21

Yes that's what ended up happening to me. I had the oil pump leak as well rear seal too. Ended up costing an arm and a leg but it is all sorted out and drives like a dream.

thazadin

I just finished it this weekend myself, and all is well again! What mileage did you have when the rear main went? currently rear main and cam seals are dry on mine, hoping to let those go until next timing job at 200k

thazadin

Just want to mention there is indeed an o ring for the oil pump, attached a picture below. Very important to replace if the pump ever comes off, couldn't tell you if that was the cause of my leak personally or just 18 year old RTV in general

FloridaML

That is VERY interesting. Now I am wondering if the oil pump RTV could be the source of my leak as well.
Can you tell me where to look, or point me to a video that shows how to find this?

Here one of my posts about my leak issue:

https://www.clublexus.com/forums/ls-...eak-video.html

thazadin

I checked out your situation and sadly there is no way I can confirm for you whether its cam/crank seals or the oil pump. But I can assure you its one of the them, my first question would be are you doing the work yourself or paying to have it done? I can assist with how I would go about it in either instance but let me try to give you some insight on how my situation went.

I was not super transparent in that first post, I did do the crank seal first and found out if was not the issue before getting into the oil pump job. Not sure why I did that, I think I wanted to just get the message across to keep an eye out for the pump in general

And to add, I flew south for this car and the timing job was done 500 miles (10 days) prior to me picking it up. I did not hoist the car or even intend on looking at leaks/issues as I was comfortable at the price to fix whatever I found. A clean rust free chassis with good maintenance records was all I cared about. I noticed a burning oil smell on the last hour of the 19 hour drive home and found it at the same spot you're experiencing except mine had enough time on that drive to creep down the pans and fling onto the exhaust

For me I was able to pull the timing covers off by the valve covers and see the cam seals were dry, so I ordered up a crank seal and took it all apart to do it. When I got in there I noticed while the majority of oil was on the lowest part of the crank seal there was also oil higher up on the oil pump which made me think it either got flung up there or its coming from the pump. Wishful thinking it was just the crank seal so I installed it and sure enough within 50 miles of driving that aggressive leak was still there and I was sure the pump was coming off. (keep in mind, the crank seal can also be installed incorrectly and still leak, but it would likely change and be a bit better or a lot worse I would think and mine was the same)

I had enough shower thoughts to come up with a theory on why the pump was leaking in the first place, the upper/lower oil pan RTV was clearly OEM and dry. at 18 years old (06 here) it wouldn't bother or surprise me to see the RTV leaking but I was suspicious of how the pump sprung such a heavy leak and the pans were not even sweating.

I will attach a photo from the Toyota service manual of the oil pump for reference.

Letter B there is a long stud (12mm nut) that has thread locker from the factory and clearly states to not reuse. The rest of the hardware on the oil pump is regular bolts with 1 hex in there, My theory comes in at that letter B stud being the root cause of the problem and I'm 99% sure it happened during the timing belt job. When you are removing the alternator you will find a 10mm to remove and behind that is the 12mm on that stud to the oil pump. When I took my impact to take the 10 off from the alternator it also backed out that stud, I did not realize at the time it was mounting the oil pump and luckily that is why I was in there in the first place.

It would be incredibly easy to zip through everything with your impact taking all the pulleys, tensioner, alternator, a/c compressor, timing covers off to do a generic timing job. My theory is if you are unaware and that 10mm on that alternator is a tad seized on there, it will back that stud out with it and disrupt that old RTV and its a done deal and needs to be resealed. For anyone that is also unaware and is lucky enough to read this prior to doing the timing belt job themselves can prevent this by having a 12mm wrench on that stud preventing it from moving when getting the 10 off the alternator.

I also did reuse that stud and put a bit of blue thread locker on there but the big picture in my opinion is to just be aware of it whenever your alternator is coming off and it will never be an issue as long as that stud stays put and holds its torque.

I hope this was helpful, feel free to ask for clarity on any given part of that rant. I try to condense things to avoid writing novels