Oil and Smoke...Go figure

[OTSWolf]

Hope you all had a great New year.

I thought my New Year was going to start off great with plenty of off-roading during my vacation time with new leather seats and carpeting to boot, but that didn't really happen, and I need some help from you all.

Some background. I transitioned to synthetic about 10,000 miles ago (Mobile 1). The LC currently has about 177,000 miles and runs great now that everything has been taken care of that I can think of (fresh fluids all around, new radiator and accompanying stuff, new alternator, new heater Ts, new front wheel bearings rotors and brakes, new rear brakes, new rack and ends, and new battery). Timing belt, water pump, and shocks were all replaced at about 130,00 before I bought it. Yes, it has had its quirks and issues, but it has been great.

Now comes the problem. I noticed that the valve covers were leaking and what I thought might be the rear main seal. Took it to my mechanic and they confirmed the valve cover and rear main seal. I told them to just take care of the valve covers and leave the rear main seal for the future. No dripping of oil after the valve cover change (it was really slight to begin with but I am a little picky). Drove it home, let it sit for a day, and when I went to turn it on, a good amount of smoke came out. A little whitish/greyish, so my fears of a head gasket being blown popped up so I quickly turned it off. Checked oil, all clean. Checked oil cap, all clean. Checked oil itself, all clean. So, I turned it back on and let it sit for a while and the smoke went away after a few minutes. Car ran strong, no oil pressure issues, no overheating, no smoke while driving, and no issues on a short drive.

Called the mechanic to ask if they noticed any smoke when they turned it on, they said no. So, I let it sit until the next morning. Checked the oil level, and it was high. Not a little high, but a lot high. Maybe about a quart over. So, I take it back to the shop. They let some of the oil out (yes, it was a little high but not by much), and because of that I also asked them to change the PCV valve as well thinking that maybe the PCV valve was not working properly and causing increased oil pressure or allowing oil to get into the intake manifold. Didn't smoke at the shop when I picked it up so I figured great.

Went home, let it sit until the next day. Turned it on the next morning and the smoke is back. Checked everything again, and everything seemed good. This time I smelled the smoke. It didn't smell like coolant, but more of a mixture of oil and gas, but it did smell. And the smoke didn't linger even though it was thick. So, I just said forget it and drove it on 200 mile round-trip, and then a few short trips just to see what would happen. If it sat for more than an hour, it smoked every time I turned it on, but the LC has been driving like a champ. Plus, it just passed smog after the smoke showed up, and I assume if it was running too rich or burning too much oil, I wouldn't pass. So, I don't know where to go from here, but I have some questions:

• If oil got into the combustion chamber, how long would it take to burn off? I assume rather quickly unless it is getting a regular supply from a leak.
• Could this be the valve seals leaking? I ask because I am wondering if the combination of synthetic and the increased pressure from non-leaky valve covers is causing oil to leak past the valve seals.
• Would a bad head gasket cause the smoke but not a decrease in performance or show any other evidence, such as overheating or oil and water mixing in the observable areas?
• Is it okay to drive it like this? My gut tells me yes, but I hate driving a vehicle not knowing the issues it may have.

Any thoughts would be much appreciated.
Thanks.

 

[2001LC]

Likely valve steam seals. As engine sets and cools oil makes it way passed the seals and settles in head intake port and cylinders. You get heavy smoke at cold start up.

Having rear mains seal and valves seals leak, indicates years of cheap oil with excessively long oil changes. This builds up gunk internal and on seals. The gunk damages the seals. Then synthetic oil works to clean out the gunk, including off the seals. They may then leak if dry and shrunken. I'd give AT-205 a try first. Second step would be new seals.

Another possibility is High Mileage oil (HM oil) was used at some point. It swells seals and damages them. They then need to be feed a diet of High Mileage oil. Again I give AT-205 a try first. If that does work, go back to using HM oil. Or replace seal.

 

[OTSWolf]

Likely valve steam seals. As engine sets and cools oil makes it way passed the seals and settles in head intake port and cylinders. You get heavy smoke at cold start up.

Having rear mains seal and valves seals leak, indicates years of cheap oil with excessively long oil changes. This builds up gunk internal and on seals. The gunk damages the seals. Then synthetic oil works to clean out the gunk, including off the seals. They may then leak if dry and shrunken. I'd give AT-205 a try first. Second step would be new seals.

Another possibility is High Mileage oil (HM oil) was used at some point. It swells seals and damages them. They then need to be feed a diet of High Mileage oil. Again I give AT-205 a try first. If that does work, go back to using HM oil. Or replace seal.

Ok. Since you are the one suggesting it, I feel a lot better and my thinking that it was the valve seals. Your explanation for why is better than mine. I saw your work on the cam pin in the other post. You are definitely awesome. I wish you were closer to me.

If the AT205 doesn't completely cure it, any real danger in driving it like this until I get around to taking care of the valve seals?

 

[2001LC]

Valve seals are only a possibility, but a likely one. The history of engine may shed more light on possible cause of smoke.

About only concern I can think of which can get costly, is clogging or damaging the CATS.

 

[OTSWolf]

Valve seals are only a possibility, but a likely one. The history of engine may shed more light on possible cause of smoke.

About only concern I can think of which can get costly, is clogging or damaging the CATS.

Unfortunately, I only know what was used after I purchased it. I know that routine maintenance was done on the vehicle before I purchased it per the records I could find online and what the previous owner had, but I don't know the quality of the oil that was used. There was a lapse in records between the first owner and second owner. This is why I just decided to dump everything and start from scratch, including the brake and power steering fluids.

I will try the AT205 and see what happens. Thanks for the help!

 

[2001LC]

Two things you said made me think oil issue, caused valves seal to leak:

1) Rear main seal leak. Most often due to either build up of gunk on seals (improper PM, with cheap oil left in way to long) or the HM oil used multiple times. HM oil is like crack to a junky, according to makers of it like Mobil One Exxon tech support.. This can also damage valve stems seals.

2) It smokes on cold startup. Oil sit an seep down, into cylinder from along valve steam. That's part of what valve seals are meant to stop.

But if bad PM (extended oil change interval) or poor air filtration (air leak or bad filter). Valve guides and piston ring are in question also. But with rings smoking is more while engine running at temp, less so on start up. But when CATs at temp, we don't see minor oil ring passage.

Running engine at 2K RPM then very quickly pulling and inspect spark plug for oil, is one test of oil rings. Compression & leak down can give more clues.

Also looking under head covers. Engine heavily gunk, have build up there for sure. When head cover gasket was done, anything reported or observed.. Clues!

 

[OTSWolf]

Two things you said made me think oil issue, caused valves seal to leak:

1) Rear main seal leak. Most often due to either build up of gunk on seals (improper PM, with cheap oil left in way to long) or the HM oil used multiple times. HM oil is like crack to a junky, according to makers of it like Mobil One Exxon tech support.. This can also damage valve stems seals.

2) It smokes on cold startup. Oil sit an seep down, into cylinder from along valve steam. That's part of what valve seals are meant to stop.

But if bad PM (extended oil change interval) or poor air filtration (air leak or bad filter). Valve guides and piston ring are in question also. But with rings smoking is more while engine running at temp, less so on start up. But when CATs at temp, we don't see minor oil ring passage.

Running engine at 2K RPM then very quickly pulling and inspect spark plug for oil, is one test of oil rings. Compression & leak down can give more clues.

Also looking under head covers. Engine heavily gunk, have build up there for sure. When head cover gasket was done, anything reported or observed.. Clues!

I think you are right about the valve stems. They said the valve covers were gunky and needed to be cleaned. Other than that, not much, but I also didn't ask. I will check with the mechanic tomorrow and see. I have been diligent about the maintenance, but the previous owner was just ok and left things too long in my opinion.

I have only used synthetic oil and not high mileage, but again, not sure what the previous owner used just that the work was done.

Can the valve stems been done without removing the head?

 

[2001LC]

I've never done our valve steams seals. They should be doable without removing head. Good time to re gap the cam lobe to buckets (valve gap).

I'd run synthetic for a several oil changes, change at 2K, 3k & 5K. At this point gunk is being clean off the seal and internals of block and heads. This is when the leaks starts, as good oil removes the gunk plugging seals.

Now with most gunk out. Id use BG flush EPR for 20 minute run time hot & than add in MOA to the fresh new oil & filter.

By now the gunk should be off seals and leak & smoke on start up should be very bad. Add a measured amount of AT-205 to the oil one time, to soak in the now clean seals. Clean seal allows AT-205 to get to them.

This may stop your leaks and smoke. It may just help.

You should already have done a compression & leak down test. The above procedure may also improve those, as rings get cleaned out.

But understand, you likely have some loss of compression and oil pressure. I say this because you're signs are improper PM of oil and filter including air filter too most likely. So bearing & valve guilds are likely also loose. I'll bet throttle body and air pipe were dirty. Sure sign under maintained rig.

But these engine are beast. Just clean and tune best you can and drive. As long as you don't keep blowing oil on CATs and fuel mixture in limits, they should be fine

 

[txnight]

What weight oil did the shop put in it?

 

[nissanh]

177K miles is very low for a rear main seal on a toyota especially for a LC. My friend's Tacoma has been diagnosed by a lube tech as a bad rear seal and leaky valve covers. I said no way rear seal and just did the valve covers with OEM gaskets. No leaks so far and rear seal is good!

If the smoke you see is bluish, then it is motor oil else, it is something else. May be condensation.

 

[OTSWolf]

I've never done our valve steams seals. They should be doable without removing head. Good time to re gap the cam lobe to buckets (valve gap).

I'd run synthetic for a several oil changes, change at 2K, 3k & 5K. At this point gunk is being clean off the seal and internals of block and heads. This is when the leaks starts, as good oil removes the gunk plugging seals.

Now with most gunk out. Id use BG flush EPR for 20 minute run time hot & than add in MOA to the fresh new oil & filter.

By now the gunk should be off seals and leak & smoke on start up should be very bad. Add a measured amount of AT-205 to the oil one time, to soak in the now clean seals. Clean seal allows AT-205 to get to them.

This may stop your leaks and smoke. It may just help.

You should already have done a compression & leak down test. The above procedure may also improve those, as rings get cleaned out.

But understand, you likely have some loss of compression and oil pressure. I say this because you're signs are improper PM of oil and filter including air filter too most likely. So bearing & valve guilds are likely also loose. I'll bet throttle body and air pipe were dirty. Sure sign under maintained rig.

But these engine are beast. Just clean and tune best you can and drive. As long as you don't keep blowing oil on CATs and fuel mixture in limits, they should be fine

A compression and leak down test was done when the engine was purchased and everything was good, but I couldn't give you the numbers off the top of my head. I will have to find the paperwork from the packed boxes from my move years ago (still unpacking after 2 years).

I will say that I did clean the intake manifold, replaced air filter, and cleaned the MAF last year.

I will have them do another compression and leak down test to see if things are still within range. I will then follow your procedure and see how things improve.

What weight oil did the shop put in it?

I always use 5w30 oil. Keep things the same.

177K miles is very low for a rear main seal on a toyota especially for a LC. My friend's Tacoma has been diagnosed by a lube tech as a bad rear seal and leaky valve covers. I said no way rear seal and just did the valve covers with OEM gaskets. No leaks so far and rear seal is good!

If the smoke you see is bluish, then it is motor oil else, it is something else. May be condensation.

I think you are right. They called valve cover and rear main seal, but after the valve cover change, I haven't seen the oil on the floor, but I haven't crawled underneath to see if things have changed in terms of dripping from the rear main seal. I took the approach of taking care of the least expensive issue first and go from there. Turns out I might have been right, but we will see.

 

[txnight]

Trust but verify on what oil they put in. Wouldnt be the first time a shop made an easy mistake.

 

[OTSWolf]

Trust but verify on what oil they put in. Wouldnt be the first time a shop made an easy mistake.

You know. I have not been able to do as much work as I want on my vehicles as I used. I have done timing belts, bearings and brakes, engine rebuilds with port and polished heads, to audio, simple upholstery, and even replaced a convertible top. I knew everything about my celica convertible and both the 5SFE motor and the 3SGTE I wanted to swap in there. I loved my Miata and enjoyed wrenching on it and taking it to the track. I remember on my first car, an 86 Mazda 626 from a junkyard. It didn't have A/C, but I found another 626 from a tow-yard that had it. I basically lined the two cars together, cracked open my crappy Haynes repair manual, and went to work on the transplant. It worked.

While I know a good amount about the LC and basic engine work, not enough as I would like. The only way to get that is to work on it and learn from doing, but with the wife, kids, and work, I don't have as much free time as I used to. Oddly enough my 3 year baby girl had enough patience to sit with me in the passenger seat of the LC and watch while I did the Nav Delete. Looking forward to getting her more interested in wrenching. In the meantime, got to learn to find a mechanic I can "trust" to do good work and not the dealer.

 

[2001LC]

I think the gunk reported in your head covers and rear main leak are the biggest clues. Flush with BG EPR than add AT-205 may buy you time. How much time who knows, only time will tell. But AT-205 should not do any harm, according manufactures ATP. It's replaces the plasticzer time and gunk leached out.

I only use when trying to stop a leak, not as a PM. I've not yet tried in and engine but know many do. I use very often in Power steering and differentials. It works if seal not shot, damaged or in wrong.

I'm even trying on and AHC.

The other test are just to help document and narrow down. But just with a rear main seal leak, I'd give AT-205 a shot.

 

[OTSWolf]

Likely valve steam seals. As engine sets and cools oil makes it way passed the seals and settles in head intake port and cylinders. You get heavy smoke at cold start up.

Having rear mains seal and valves seals leak, indicates years of cheap oil with excessively long oil changes. This builds up gunk internal and on seals. The gunk damages the seals. Then synthetic oil works to clean out the gunk, including off the seals. They may then leak if dry and shrunken. I'd give AT-205 a try first. Second step would be new seals.

Another possibility is High Mileage oil (HM oil) was used at some point. It swells seals and damages them. They then need to be feed a diet of High Mileage oil. Again I give AT-205 a try first. If that does work, go back to using HM oil. Or replace seal.

Alright. I wanted to give everyone a follow-up. As I kept driving the LC, less and less smoke was coming out at cold startup. Before doing the other things that were recommended, I decided to let it run and talk to the mechanic.

The mechanic mentioned that when they took the valve covers off, they were gunky as if there was a good amount of deposit buildup. That is why they choose to clean it. I assume the same was probably true for the rest of the engine, as was mentioned by @2001LC, due to lack of PM and cheap oil.

Everything seems good now. It has not smoked since last Wednesday after about 250 miles and maybe 10 cold startups.

I will be doing the procedure mentioned as soon as I get a chance, but gonna just drive it for now and watch it.

Thanks everyone.