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I used to post on here just a little bit many years ago under a different name. I'm quoting below an entire 2016 thread started by mdaz75 instead of replying to the thread as I wanted to add a more specific subject line.Sorry this post is long, trying to be thorough and pre-answer various questions. If you want to see the 2016 thread, it's here:
Like mdaz75 explained in 2016, I am also seeing oil in one spark plug tube (#3), and it also came back after I replaced the spark plug tube seals (later reinspected) and valve cover gasket and valve cover bolts, and the spark plugs. The oil was in the tube, not on the threads. I've never seen smoke out of the exhaust.
I'm the original owner of my 2004 MCS which has about 93,000 miles (150,000 km). It's running fine. I didn't drive it much for a few years because I lived way out in the country surrounded by nothing but gravel roads. When I rarely drove it I noticed that it was down on boost by a couple psi and decided I would have to deal with the problem later as my daily commute (in my big ol' truck) took a lot of time every day. Now that I'm closer to the city I'm spending a lot more time with my car.
I have recently fixed some vacuum leaks as in my search for the reason I am now missing about 4 psi of boost. I used to make 15 psi according to my mechanical boost gauge with my Alta 15% pulley, Alta CAI, Milltek exhaust, Detroit Tuned BPV (and fyi, VGS mod and Sprint Booster).
Recent 100k maintenance
In very recent preventative maintenance I serviced the supercharger (it still had lots of oil), replaced the water pump, thermostat, coolant reservoir, fuel injectors (380 cc), spark plugs (NGK 1-step colder), spark plug wires and boots, coil pack, PCV valve, supercharger air inlet tube and green gasket (I mastered it on the second, ok third-ish try), various "while you're in there" o-rings and gaskets, bled/replaced various fluids, and I replaced the belt tensioner, belt, idler pulley and replaced the crank pulley with the ATI Superdamper 2% (since re-torqued) and replaced the crank seal. The tensioner shows one hole. I also replaced my boost gauge for an identical one. Also replaced a leaking intercooler and got new silicone intercooler boots. I'm hoping to get a tune from adriancl but I'm held up by this problem.
I figure I should be getting somewhere around 16 psi of boost but the gauge always stops at 12 to 12.5 psi. The power feels "ok" but not as quick as it should be.
Smoke test
Yesterday I did a smoke test to figure out once and for all where the boost was leaking. I fed a regulated 15 psi through my crude smoke machine which was leaking air, so the pressure going in was probably 10 to 12 psi. I injected the smoke into the hole for the MAP sensor right by the thermostat. I removed the air intake box and filter and sealed off the silicone air intake so I could pressurize the whole system.
I was pleased to see no leaks from the dreaded green gasket or any other typical vacuum leak areas, but perplexed to see no leaks from boost-leaky areas. (Hint: use the genuine MINI green gasket; the design of the aftermaket one is not the same.)
However, I noticed smoke seeping very slowly out of spark plug hole #3. I pulled the boot out and watched the smoke come out of the hole.
It's the same spark plug tube that has accumulated oil a couple of times even after carefully replacing the seals and later re-inspecting them.
Hole/crack in spark plug tube
Looking into the tube with a bright head lamp on, I see that there is actually a tiny inward-dented hole or crack in the side wall of the tube. The hole is at the 8 o'clock position on the tube. The tubes all look clean and shiny but this one has this little zit in it. It looks like a little piece of dirt but I confirmed it is a hole or crack by gently touching it with a long screwdriver and I could feel it is a little dent or crack.
Looking under the valve cover
I definitely don't know much about cylinder heads but I will do my best to describe it using terminology from my Bentley manual. This morning I removed the valve cover and to my untrained eyes all looks normal. The intake rocker arm to the left of the #3 spark plug tube (that corresponds with the hole) looks normal. With this rocker arm and with the the one to the right of the #1 hole, there is a tiny bit of straight left-right play along the intake rocker arm. I do not see any contact with the tubes.
So it appears that oil (and air/smoke during a smoke test) are coming into the tube from within the valve cover. During the smoke test, the valve cover is pressurized with smoke through the breather hose that attaches to the silicone air intake tube. I believe I confirmed that it is not somehow coming from below, because when I detached and covered the PCV valve tube and the breather tube, there was no smoke from the spark plug hole.
At one point I detached only the breather tube and covered it with my thumb while still pressurizing. I did start to see smoke from under the intercooler (possibly where I have T'd into the the fuel pressure regulator vaccum line for vgs mod and boost gauge), but I wonder if I simply overdid the pressure - when I did the test with valve cover ventilation all attached normally, nothing leaked at all except for the small escape out of the spark plug hole.
If air is escaping through the spark plug tube, this doesn't necessarily cause a loss of boost pressure...right? My understanding is that the valve cover would normally contain roughly zero or neutral pressure.
But I wonder if something is wrong with an intake valve to cause something to rub on the tube and if that problem coincidentally would cause a loss of boost pressure..?
Compression test
However, just 2 days ago I did a compression test and all seems "ok" and consistent across cylinders:
Dry/warm: 154 or 155 psi across all four
Wet: 175 to 181 across all 4
If the dry/wet differences are due to piston ring wear, it's consistent across the board so it does not seem to point to this particular issue right..?
In the thread below, ECS Tuning and Unbreakable Lump seemed pretty tuned in to the possibility of the spark plug tube being cracked or loose at the bottom where it is press-fitted into the head.
Questions
I guess my questions are - can I simply replace the damaged tube?
But what explains my low boost pressure?
Any other thoughts or suggestions? Questions?
Thank you very much for any help!
The 2016 thread is below the dotted line. I do not have the damage to the spark plug tube seals discovered by mdaz75, and they are installed correctly.
*******
Originally Posted by mdaz75
I have a 2002 R50. One morning last week the oil light came on, so I went poking around under the hood. I noticed oil on the valve cover all around wire #2. When I pulled the wire out there was, what I expected to see, oil in the spark plug well. A few days later I changed all 4 spark plug tube seals, started it up and...........the SAME problem(same cylinder)! What?! So, I thought maybe, just maybe I got a bad seal and I replaced it with another new one. STILL the SAME problem! Anyone have any ideas about what the hell is going on?
Originally Posted by David.R53
Look for cracks in the plastic cover.
Originally Posted by mdaz75
I did inspect it pretty thoroughly and I didn't see anything.
Originally Posted by David.R53
There are not many alternatives. The metal spark plug tubes are usually very tightly pressed into the head. Should be no wiggle.
Some cams can interfere a little bit with the tubes, so someone might have modified them. Just something to look for.
Originally Posted by mdaz75
I just replaced the head with a reman about 3000 miles ago and the cam looked fine as far as I could tell. I know that what you're telling me is right about a crack being a possible cause, but I just didn't see anything. Man, this is killing me.
Originally Posted by PelicanParts.com
Not that this is what your issue is, but found this info that may be useful (cannot link thread as it's blocked from NAM):
"Keep in mind the spark plug seals the tube at its base. It is possible the tube is at fault if there is a crack in the tubing wall seam; it is also possible the head is cracked, threads are missing, or the plug is cracked. Oil can be coming from the top (valve train area) or coming from the bottom (combustion chamber)."
Originally Posted by mdaz75
You just gave me a migraine, PelicanParts
Originally Posted by Eurothrasher
Is this happening with OEM MINI gaskets or aftermarket.
Originally Posted by mdaz75
Both OEM and aftermarket and just cylinder 2
Originally Posted by mdaz75
I don't know for sure if the spark plug tube is the problem, but if it is, is it as simple as pulling the old one off and sticking a new one in?
Originally Posted by David.R53
They are pressed in and should be hard to remove. If you can wiggle it or pull it out with your hands, you have your answer.
Originally Posted by elvis cole
Valve cover gasket?
Originally Posted by mdaz75
Well, I'm probably going to dig in this evening and get a closer look at the tube. As far as I can tell, at this point, the tube just pulls out and the new one can be reinserted and tapped in with a block of wood and hammer.
Originally Posted by AoxoMoxoA
Might not be a gasket/seal issue. It might be the plug itself.
Have you tried swapping the plugs to see if this condition follows the plug currently in cylinder #2?
Originally Posted by mdaz75
No, sir, I have not, but you can bet your butt I'm going to try that out in a couple hours! Thanks for the suggestion
Originally Posted by mdaz75
You see what's going on here, right? So, could this friggin insert be causing my problem?
Originally Posted by David.R53
Sure. If it's that loose that it comes off with the plug than it couldn't be well sealed.
Think you are on the right track.
Surprised that a rebuilt head had an insert. They usually will not accept them for rebuilding. An appropriate oil resistant thread sealant may be all you need. I have had great tech support when I have contacted loctite directly on a question like this.
Originally Posted by AoxoMoxoA
Bingo!
Yup... I'd be on the horn pretty quick with whomever supplied/installed the re-manufactured head to inquire about this...
Originally Posted by mdaz75
About 60 seconds after understanding this situation, I called the shop where the head came from. However, because of a time difference, they're currently closed and I'm going to have to stew in my anger for another hour or two. Soooooooooooo, I'm going to give loctite a shot for now and see what happens.
Originally Posted by mdaz75
The shop told me that time-serts are commonly used when rebuilding heads. I, personally, have no idea if this is true or not. The shop manager said that they rebuild heads for high end cars on a regular basis and use time-certs, when necessary, in all of them. Anyway, he agreed to pay for the repairs at a garage of my choice.
Originally Posted by Unbreakable Lump
The spark plug tubes are pressed in with Loctite. If it is loose or wiggles with hand pressure, then there is no way it is sealing and will fill with oil from the bottom. Meaning oil will wick into the spark plug tube from the rocker area (where oil would normally flow to migrate to the drainback areas). The spark plug thread insert would have nothing to do with this except that the remanufacturer probably pulled out the tube to install the insert and pressed the tube back in without Loctite.
I should be able to get my hands on the original engine build book used by the Chrysler prototype build motor room that has the correct specifications for Loctite and tube installation procedure this Thursday. I can't remember right now if we used the green or red Loctite.
Originally Posted by mdaz75
Yea, I've been wondering how a loose insert would cause oil in the tube. I'm not a mechanic, but that doesn't make much sense to me.
Originally Posted by ECSTuning
Yea, they are in there pretty tight with loctite, should not move. Thanks for the additional info UL.
Believe it was red , you can see a little residue.
Originally Posted by David.R53
If you are going to do any of this yourself, call/email loctite or check out their newer "oil resistant" variants. They have updated many of the classic products with versions intended for extended contact with oil.
Originally Posted by mdaz75
I called loctite yesterday and they confirmed that the thread locker would provide a gasket type barrier against oil and chemicals. Can anyone confirm that the spark plug tubes can be pulled out and tapped back in?
Originally Posted by AoxoMoxoA
I'd wait 'til tomorrow on the "official" word from UL...
Originally Posted by mdaz75
Yea, that's what I decided
Originally Posted by Unbreakable Lump
I checked today with old Chrysler colleagues and due to the wisdom of "corporate document retention policy," the build book is no longer available. However, the repair procedure is identical to the SOHC 2.0l Neon engine. It uses the red loctite. My recollection is that the interference fit in the 1.6l engine is greater (and deeper) than the 2.0l due to this concern about leakage, (a known issue when we designed the 1.6) so might be harder to remove. This guy seems to have a good handle on it and references the Neon service manual in his video:
Yup, that's the video I watched a couple of days ago. I guess I'll yank that tube out of there, loctite/reloctite it, shove it back in and see if that fixes my problem. Is there a gasket down in the head that seals the tube?
Originally Posted by ECSTuning
New ones here, i would try to twist them out a hair, maybe with a pipe wrench and see it they budge. Just be careful when twisting and pulling.
Was the spark plug tube on your engine's #2 cylinder extended higher than the others as was the example in the video?
Originally Posted by PelicanParts.com
We have Loctite HERE if needed. Let us know if this fixes your issue, very curious!
Originally Posted by mdaz75
Nope, they're all the same hight and at that point I didn't really think to see if it was loose. I actually just found a little bit of oil in tube 1, also. That hadn't been there before today. I won't be able to pull the tubes until tomorrow or saturday, but I'll post an update when I have new information or lack of information. Thanks for all the help, it's greatly appreciated.
Originally Posted by mdaz75
Thanks, I've already been snooping around on your site.
Originally Posted by ECSTuning
Welcome,. we welcome the snoopers
Originally Posted by mdaz75
Ooooooookay. Now that I'm looking at this, here's a little more info. When I first got the low oil pressure light and oil in the #2 tube, I took off the valve cover and the gasket looked exactly like this. That gasket was only a month old, all new gaskets were installed when the new head was installed. So, I replaced it when it failed and that one failed two days later(but I never really inspected it when I took it out). So, now the one you're looking at is the third and it failed in a day. Could I be doing this myself while putting on the valve cover?
Originally Posted by David.R53
There shouldn't be any tears like that. How are you inserting the seals into the valve cover?
Putting the valve cover on the engine is simply placing it in position. Hard to imagine hurting seals. You shouldn't need to beat it into place.
Originally Posted by mdaz75
I just line up the holes and push it down into place. It's weird that this keeps happening to seal 2. I just don't know. New seals are on order.
Originally Posted by AoxoMoxoA
When installing the spark plug tube seals, they should be pressed evenly into place from the underside of the valve cover, using even pressure from a large socket, not by pressing with a sharp object such as a screwdriver.
The valve cover should then easily slip over the tubes and down into position.
Are all the spark plug tubes even with one another when running a straight-edge across them? If so, I don't think the #2 tube is the issue.
Might want to just bring your car to a good mechanic and take the head rebuilding folks up on their offer, rather than throwing more parts at it... I still don't like how that timesert came out with the plug.
Originally Posted by mdaz75
Well, the "head" people are only agreeing to pay for the time-sert fix, at this point, which isn't the cause of my oil problem. I think, somehow I'M the cause of that and I just can't figure it out. I'd like to bring it to my mechanic, however, not only am I trying to learn more about working on my own vehicles, I've also spent about $2k on this thing in the last 4 months and it's getting to a fix it myself or junk it point.
Originally Posted by AoxoMoxoA
Not sure if you understood (apologies if you did), but David.R53 (quoted above) was asking exactly how you inserted the new spark plug seals into the valve cover, not how you're lowering the valve cover onto the spark plug tubes.
Those seals need to be seated properly in order to work. They are on the hard side, and can be difficult to seat. I found the best way is to warm them up a bit with a hair dryer to make them more pliable, then press them into place with a large socket on an extension, so they pop in evenly. Pushing them in with a screwdriver or punch can result in tears like the one you show.
Have you checked for "play" in the spark plug tube on cylinder #2 that would suggest that it has loosened? Maybe there's a crack in the tube that occurred when he time-sert was installed.
I think a focus on the #2 spark plug tube should be next on your list...
It is the cause, if they wrecked the spark plug tube when they did it...
Originally Posted by mdaz75
Actually, I didn't have to use anything but my thumb to press them in. They went in very snug, but pressing all around the out side of each one with my thumb was enough. I knew to be careful. The #2 tube isn't seated any higher than the rest and, like all the others, it has no wiggle whatsoever.
Originally Posted by cristo
There are BMW/MINI special tools for extracting and driving in the spark plug tools,
but they are hard to find and quite expensive, and although helpful, probably not essential.
Originally Posted by mdaz75
Problem solved! It turns out that a rocker arm was lifting slightly higher than the rest and was tapping a hole into the seal. Thank you for the help, everyone. I own a 2002 mini, so I'm sure I'll be needing your brains again soon.
Originally Posted by ECSTuning
Thanks for the update, we need pics .
Originally Posted by mdaz75
Originally Posted by ECSTuning
Looks good with the BRG and the green Forrest. Nice shot.
Here's a summary: 2004 R53, 93,000 miles, original owner. I found a crack or hole in the wall of #3 spark plug tube, about 2/3 of the way down the tube. It is at the 8 o'clock position in the tube. This seems to explain oil getting into the tube and smoke coming out of it during a smoke test.
With the valve cover removed, the hole can't be seen as it seems to be hidden behind the intake valve spring.
I've never had smoke from my exhaust and my compression numbers are ok and consistent.
I do have a loss of about 4 psi of boost pressure compared to what I should have with my mods. Otherwise the car is running great. I've recently cured some vacuum leaks.
Should I just replace the spark plug tube and then keep an eye on it, or should I assume that some kind of valve movement caused the hole in the tube and take my cylinder head apart and replace parts? Anything else to consider?
Update: on closer inspection, the intake valve spring next to spark plug tube #3 is broken and seems to have worn a little hole in the spark plug tube. I am surprised the car has not shown worse symptoms.
I will have to replace the spark plug tube without the BMW special tools referred to in the Bentley service manual. Also the valve spring of course.
I may have gotten lucky in that I have been doing a refresh of many engine parts and as a result was able to narrow the performance issue down to this, before major symptoms occurred. I don't think i can see the break in the valve spring but I can see that it is out of position at the bottom and has definitely contacted the spark plug tube.
I am considering not only replacing the spring and tube but also rebuilding the head by taking it apart and having the head inspected, lapped etc by a specialist, then doing the re-assembly and re-installation myself. I do not have the experience to know whether this is the obvious course of action in this case, or whether it is going too far. Any thoughts anyone?
If I go the rebuilding route I will be researching all parts and tools I will need.
And if anyone has any ideas about how to yank out and replace the press-fitted spark plug tube without special tools, I would appreciate that!
