dropped half a quart of oil over night *PUDDLES*

[Krunk]

Okay, so been doing lots of repairs, getting the t4 looking and running good, now, all of a sudden I'm leaking oil....from the front of the motor?? the leak appears to be coming from above the harmonic balancer on the right side if your facing front of motor. There are what looks like two 12mm bolts just under the leek (I took upper dust cover off to see this) any ideas? I am charging camera battery right now, I will get a picture up in 5-10 minutes.

[Highlander]

Oil pressure sender, front main seal, or oil pump gasket (its driven off of the crankshaft).

[Krunk]

Just a couple observations, It has been running rough when you apply gas, i have at times had to give it alot of gas to get it to start off in first or it try's to stall, I replaced all vacuum lines a couple weeks ago, pretty sure I got them all right. I get tons of vacuum anyways and installed new pcv and gasket not long ago, valve cover gasket is new and no leaks, little leaky from around distro but nothing to bad.







This was the best picture I could get, if you look on the right side by the two 12mm bolts I think that is where the leak is, there is no oil on harmonic balancer at all even on the back which makes me think my seals are good.

[Krunk]

Also, it doesn't seem to be spraying out, just leaking, all the oil is bellow the leak no spray. I cleaned the front of the motor off, I think it is the main seal, the oil is coming out of the seal then draining back on the bottom of the cover then down and out onto the oil pan. Drips 1 drop a second while running.

[Highlander]

WOW! That's a lot of oil overnight!
The two bolts in your picture are some of the oil pump retaining bolts, and the main oil passage runs between them to the pressure sender and the filter. I'm not sure why they would start to leak suddenly.
Have you put a new oil filter on recently? If its faulty, then it could be keeping the oil from passing farther into the engine (or at least restricting the flow) creating backpressure which would make it leak from its weakest sealed point.
You said that you installed a new PCV valve recently, are you sure that you got in in correctly? it's a one way valve. if it were backwards, it could allow the crankcase to get pressurized which can push oil out of available orifices.
If you look at page LU-4 in the FSM, you'll see that the gasket behind those two bolts runs completely around the oil pump and is doweled. The oil pump cannot be removed (I believe) without dropping the pan (the only time I've done it is with the engine on a stand as part of a rebuild).
Just my thoughts, sorry I can't help more.

[Krunk]

I sprayed the area down with PB and then the high pressure water hose, then tightened all bolts slightly, all of them seemed to "break free" like they had not moved in awhile. The oil I used (pennsoil high mileage) said it removed engine sludge......maybe it removes old gaskets also? lol. I have no idea why it started leaking....I drove it about 300 miles this weekend, with no problems. It has not been driven regularly and has been sitting so I am thinking it sat to long, all the gaskets are swelling again or failing.

[Highlander]

That could be it, "back in the day" we used to make sure that if we ran non-detergent oil, that we NEVER ran detergent oil (especially in the British cars) because the buildups of 'sludge' as they call it today, helped keep the gaskets sealed, most gaskets in brit cars were paper or cork, and when they dried out, forget the sealing aspect. You had to drive it and keep adding oil until it resealed itself (gunked up the leak as it were).
Any engine knocking since the oil change?

[Petros]

If you have a lot of blow-by you will pressurize the crank case and oil will leak out in the strangest places. I have seen it blow out front and rear seals, and the cam shaft front seal. Check your front cam seal.

To check for crank case pressure build-up, pull the dip stick while running and see if you get a lot of exhaust pressure out of the dip stick tube when it is running. If that is the case you need new rings. Additives that clean and seal the rings might help in the short term, but it might be you need to rebuild the engine.

[keith]

Its really not uncommon for the front seal to suddenly "let go". It is also not hard to replace, as long as you DON'T follow the instructions in the FSM. You have to remove the timing belt and lower sprocket. Then just fish the old seal out with a dental tool or other tool with a hook in it. Slid a new seal on and put everything back together.

The first time I did this, I followed the FSM which involved dropping the oil pan and removing the oil pump. As I put it together, with the seal already mounted in the oil pump housing, it tore the new seal as I tried to gently slip the whole assembly back over the crankshaft. The second time, I just fished the seal out and slipped the new one in place. Waisted a whole day but learned something.

[Krunk]

Its really not uncommon for the front seal to suddenly "let go". It is also not hard to replace, as long as you DON'T follow the instructions in the FSM. You have to remove the timing belt and lower sprocket. Then just fish the old seal out with a dental tool or other tool with a hook in it. Slid a new seal on and put everything back together.

The first time I did this, I followed the FSM which involved dropping the oil pan and removing the oil pump. As I put it together, with the seal already mounted in the oil pump housing, it tore the new seal as I tried to gently slip the whole assembly back over the crankshaft. The second time, I just fished the seal out and slipped the new one in place. Waisted a whole day but learned something.

I was actually wondering if this was possible, thanks keith for the great info, this should help a bunch.

Now that I got it cleaned up for the most part, it does look like the front main seal.

I have heard no knocking, though I have noticed it doesn't like to rev past 5k rpms. So my power is all from 2500-4500 rpms, that's it.

I honestly think the vacuum hose I replaced was the same ID(inner diameter) as what I took off but thinker tubing for a bigger OD(outer Diameter). It all fix tight, and there are no vacuum leaks that I have found. They just don't make hose like they used to.

I will check my case pressure tomorrow as well as see if I can get a better look. thanks for all the info, hoping to get this fixed asap, I am not seeing alot of smoke which makes me think my rings are still good, and valve seals also. I have not yet reached 200k miles so i believe we got alot of life left in it.

[keith]

I don't think the front seal is subjected to crankcase pressure. This seal is actually part of the oil pump, but I don't think it has any pressure behind it. I could be wrong about the pressure part though, but usually a seal that is subjected to pressure has the retainer ring on the unpressurized side. I think this just seals from splash oil, but it can leak a lot of oil in a short time. When mine went, it would pump out a quart of oil in about ten minutes.

While you are doing this seal, you might as well do the cam seal as well. You will have done about 90% of the work to do the crank seal. A new timing belt might be in order too, depending on how old the current one is. Some will recommend a new tensioner, but I got over 300k out of the original tensioner in mine. It's a non-interference engine so a broken belt won't do any damage, unless you put a HP cam in it.

[Krunk]

My current cam seal is not leaking at all and looks good, the timing belt looks like it is just about ready for a change, little cracks but no heavy wear or strangeness. The oil pump and oil pan gaskets seem to be leaking, but I just changed the oil so going to wait about 2500 miles till next change to do oil pump and pan gasket. I picked up the main seal and timing belt the other day just waiting till I do not have to drive to change it. Figuring since I have to pull radiator and rent puller it will take me 2 days. Also there was no excessive pressure coming from oil dipstick. my pvc seems to be working fine, I am not seeming any oil in the air filter either.