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420A Burning oil! 420a

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Jtdemler

Probationary Member
21
2
Dec 16, 2021
Niles, Michigan
Haven't found a thread specifically addressing my issue so if anyone could help me I would greatly appreciate it.

Ever since I got the car it's burned a slight bit of oil, big deal I thought with 160k miles, I figured it was fairly normal and always topped it off, was never an issue.

(Never burns while driving or at least isn't noticable or "smell able" and uses maybe a quart every 500-1k miles)

Doesn't seem like it's gotten any worse until earlier today when I was in a drive thru slightly tilted forward and it was just pouring smoke out of the exhaust like WAYY more than I've ever seen. Never done it before and the oil wasn't over full or anything. Keep in mind she's mint, has zero issues other than an oil leak on the rear of the engine. No check engine lights and it runs like an absolute champ other than the stated issues.

Replaced PCV few months back didn't change anything. Did the valve cover gasket and the top of the engine looked decent. Also no change.

So I'm completely stumped as to why it's doing this. Also I should note on a cold start there's a slight knock for maybe 30 seconds then it completely goes away. Always thought it was tolerance til it slightly warms and expands and then is fine.

Again if anyone can help me I'd appreciate it, maybe running thicker oil? Some additive? Or if she's just worn to shit and only has so long to live?

Or anything to get the most out of it while I save for another one, LOL couldn't imagine not having an eclipse I love them too much.

Thanks for any help in advance.


Added a pic of the top with the cover off, if it helps any.

I realize I've posted about this before but have a bit more info now since I know a little more.



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My 1999 Eclipse with a 420A was leaking oil from the head gasket with less than 97k miles on the odomoter. I'm not saying that's your problem, but this type of oil leak seems to be fairly notorious with the 420A. Do you think that's where your leak is coming from?

If it is the head gasket, brace yourself for an expensive repair, but if you pull the engine it's a good opportunity to replace the valve stem seals, the rear main seal, the timing belt, etc. etc since they could all be 23 years old by now.

As for that sound you hear on startup, it could be piston slap, or it could be something worse. I know my 420A slaps until it's warm.

If I were you, I'd get a qualified mechanic to take a look at it so you can see what you are up against. Then you can better understand what exactly is going on and what you want to do.
 
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Unless you want to dig into the engine, just put some 10w-40 in it and turn the radio up LOL

But if you'd like to take on a rebuild, this is the place to be. We'll help as best as we can.

Something I'll note. I've seen junkyard heads with less gunk buildup than yours. I wonder if the previous owner did oil changes on time, or at all. Or if the top end isn't properly lubricated for some reason.
 
Thanks for the reply.

I have no idea if it's the headgasket but I have also heard that was an issue on these cars so it's definitely a possibility.

I just remembered back when I changed the spark plugs the threads were oily on almost all cylinders but the plugs weren't fouled, ran good just wanted to upgrade to ngk plugs...if that narrows it down LOL

Sooner than later I plan on doing a compression test and a headgasket test along with pulling the intake manifold to see if it's getting oil in through there to try and find the issue and pray it isn't piston rings or something even more serious but I obviously know my plugs shouldn't be oily.

I'm not a big one on taking my car into the mechanic I literally do everything myself but this one.....yeah might have to get it checked out along with pinpointing the oil leak that somehow leaks but never drips on the ground.
 
Oil on your plugs (but not inside the combustion chamber) is a problem with the valve cover's plug ring seals. Very common.
Burning/using a quart of oil every 500-1K miles is quite a bit; means you're going through a full pan of oil in between oil changes.
With 160K on the engine and no obvious oil leaks I'd pull the plugs and check to see if you have any oil burn evidence. I'd also perform both a compression test and leakdown test. These should tell you if you have a head gasket issue, bad rings, bad valve seals/guides, etc.

Absent an obvious and large external leak, I smell a rebuild in your future.
 
Oil on your plugs (but not inside the combustion chamber) is a problem with the valve cover's plug ring seals. Very common.
Burning/using a quart of oil every 500-1K miles is quite a bit; means you're going through a full pan of oil in between oil changes.
With 160K on the engine and no obvious oil leaks I'd pull the plugs and check to see if you have any oil burn evidence. I'd also perform both a compression test and leakdown test. These should tell you if you have a head gasket issue, bad rings, bad valve seals/guides, etc.

Absent an obvious and large external leak, I smell a rebuild in your future.
There is a leak on the rear of the engine (firewall side) that never drips on the ground but just stays slightly damp. Haven't pinpointed it tho.

Also, I did all those seals when I did the valve cover gasket and it never changed.
 
As the oil doesn't hit the ground, and presumably doesn't pool or run elsewhere, your oil loss issue is not due to this minor leak.

I would do a compression test and post the results. I'd also then do a leakdown test and let us know what you find.
 
As the oil doesn't hit the ground, and presumably doesn't pool or run elsewhere, your oil loss issue is not due to this minor leak.

I would do a compression test and post the results. I'd also then do a leakdown test and let us know what you find.
Will do, I'll post results when I get to testing the compression, most likely this weekend.
 
UPDATE:

Just scoped out the pistons and plug wells.

Let me know what you guys think.....

I numbered the pictures and got the best quality I could.

Also note that I can very easily see the top of the plug wells where the valve cover seats and it is bone dry it is 100% not the seals (which I just replaced about a month ago) only gets oily near the bottom of the wells.

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Agreed. Wells look like old plug seal leak and the oil burned/coked. Plugs and pistons look good - no evidence of regular burning oil like from a head gasket or valve guide/seal leak.

I'd do the compression and leakdown tests. Based on the crystalization on the sides of t
pistons 1 and 4 I'd guess your compression numbers will be down and a leakdown test will show air getting past the rings.

Compression numbers between 170 and 220 are ideal. If you get below about 140 you're running thin and are likely losing combustion gasses through the rings.

Interested to see what you find out.
 
Update #2

Just finished doing a number of things including a compression test and luqui moly engine cleaner prior to a full oil change. I bumped up my oil thickness from 5w30 blend to 10w40 conventional along with Lucas oil stabilizer.

Compression test went very well, cylinders 1-3 topped at 220psi and held at 200psi while cylinder 4 topped at 200psi and held at 180psi. I reran the test with some oil in #4 cylinder and it didn't change but maybe 3psi more holding pressure but still didn't go over 200psi while pumping up.

I did the compression test after doing the oil change and I'm still kicking myself for not doing the compression test before AND after doing so because I'm extremely curious to know if it upped compression because after sitting idle for 10+ minutes, multiple times, it burnt zero oil. Before, if I sat idle for more than 5 minutes it would start burning larger amounts of oil just noticable enough to see it and very obviously smell it.

Now, should I still do a leak down test or is the difference in compression and no apparent burning of oil (so far) small enough that there wouldn't be no reason to? Let me know what you guys think I should do next.
 
Because I don't like mysteries, I'd still do the leakdown test. Thicker oil to make up for increased clearances/gaps is a pretty good bandaid and will buy you time. But it doesn't resolve the problem of extra clearance and the resulting increased wear. Slow it, yes.

Anywho, I'd do the leakdown test with the engine having sat at least 12 hours not running. Give it time to get fully cold and the oil to completely drain into the pan. With your compression #s at 180-200 my suspicions move from rings to valve guides/seals. Head gasket is also a contender. Difference will be do you hear any hissing in the dipstick tube or in the valve cover. Might have to remove the vc to clearly id the valves. This is, of course, assuming you are losing air pressure during the test.

Out of curiosity, have you opened the throttle body and looked inside the intake to see if you have oil coming in through the pcv valve?
 
My current plan is to bandaid it long enough for me to get another vehicle and then I'm free to take on big repairs.

I'll still plan on doing the leakdown next weekend and look at the throttle body. I've never actually checked it but I did replace the pcv not even a month or two after I bought it and it changed nothing other than making an annoying rattle so I assumed it wasn't an issue.

Also interested to see if I still have that little tick sound when the engine is cold since it was still warm after the oil change.

Will update.
 
Sounds like a plan. Bandaid to the temp rescue! Agree that PCV probably isn't an issue.

Monitor your oil consumption and drive on. Good to know you seem to have some time to plan for major repairs.
 
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