Smoking Engine, ? Stuck Ring

[Guest seakongs]

Greetings to all! This is my first post, but I've followed this forum off and on for about 3 yrs. after getting my '90 TC 3l V6 and greatly appreciate the info provided. First a short history. Car had under 50k when I got it, but it had sat unused for a while. I had the oil changed, coolant flushed, as well as the transmission serviced and the only lingering issue has been cold crank smoking, which clears up after start. I attribute this to valve guide seal leakage, which seems to have reduced by switching to the high mileage oil blend (Maxlife). Recently, the smoking has changed to a constant discharge of smoke with light blue color. Smoke smells like petroleum/gas, not like coolant. I've never had to swing a wrench on this vehicle except alternator change and and rear brake line. This is the first time I've had this type of issue with any vehicle, so I've done some homework and concluded that I've probably got a piston ring stuck allowing oil to enter the combustion chamber. If that's the case and I can't free it, then a rebuild might be in the future. I've done some research on various methods people have had success freeing rings and it appears the BG products may be the best. There were others who have used Seafoam, Marvel Mystery Oil, etc. Yesterday I was able to find a can of the BG Quick Clean and MOA. I did a quick search of this forum and didn't find much on the issue (or maybe I didn't put in the right keywords). I'll probably start by checking plugs & compression. The front three plugs are very accessible, but the back three are hidden under the airbox, which looks like is held on with one bolt hidden under the coil. Any other tricks to accessing the back three? Anyway, this is a long paragraph, so I'll close now and welcome any suggestions/questions. Thanks for your input!

[Guest My TC Toy]

No doubt, you are correct about the valve seals, the 3L is , more or less, famous for it. I do question a stuck ring, I would lean more to a broken ring possibly seized during the lie up. I have not experienced stuck rings in todays cleaner engines using detergent oils. Years ago it was a serious problem. You can try a compression test but if it is a broken oil ring, the compression may be ok. The back three plugs are problematic, but not impossible to get to. Let us know if a cleaner helps the problem. Good luck!

[Guest StudeDude 01]

Good to hear from you. The start-up smoke is definitely valve seal related; the other smoke issue may be from dropped a valve guide(s), another early 3.0L engine issue, which usually don't show up until the car has run for about 10 minutes.

The airbox is held on by 2- 9/16 bolts on the top as well as the 2 hoses---be careful of the oil drain hose on the bottom. Once you remove the box, 2 of the 3 plugs are OK; the one nearest the alternator is the biggest problem. I believe I used a plug socket and a box end wrench on the hex end of the socket to break it loose----not the easiest but not the worse I've seen. Good luck.

[Guest seakongs]

Thanks for the responses and here's an update. Last night I pulled the front 3 plugs (2,4,6) and they were clean, then I decided that it really didn't matter at that point if I found a fouled wet plug or a cylinder with low compression. If I was going to treat the whole system with a mechanic in a can, it was either going to work or not. Much to my surprise, it seems to have worked. I went through the protocol and went for a long drive last night and it appears I'm smoke free. This morning I held my breath as I cranked her up. I got my usual cold crank puff, then about a minute later the light water vapor, then...nada, no large plumes of foul smelling smoke. I ran some errands, start and stop driving, and dreaded the stop signs or red lights, but that cloud of smoke never appeared. I think I dodged a bullet on this one. Maybe it was the cannolli, I placed as an offering to the guardians of the pentatrident. I'm still in a bit of disbelief that this remedy cost about $50 and not $4K, but until a few more days pass without any issues I'll still feel a bit guarded. After I pulled the 3 front plugs I replaced them with new ones, so I still want to address those three rear ones. If anything unusual happens, like the smoke returns or the engine seizes up, I'll update with a not so smiley imodicon. Thanks!

[Guest d_voitel]

Tim's correct about getting to the spark plugs in the back. I had a similar experience changing the plugs on the rear bank. After putting a blanket on the fender and wriggling about, all the plugs were changed and the car ran just fine. The back plugs are a bear though. Good Luck! Enjoy the TC.