Oil in spark plug wells

[2001LC]

Well bad news. Looks like oil "is" leaking in from bottom.

Using better light today. I pulled #2, 4, 6 coils. Found #2 SP tube dry, #4 w/0.25 oz oil, #6 w/1 oz. SP tube seals looked dry. Went back and looked closer at #5 & #7 head cover tube seal. Looks like #5 tube seal is dry. #7 tube seal oily, but may have just come off coil as I pulled it.

So I'm now thinking R&R spark plugs head cover seals, will be waste of time.

 

[Moby]

That sucks, I'm sorry

I was thinking about the comment about these not being as bulletproof as we like to think. But... compared to a F/2F/3FE there's a lot more going on. A lot more to get right and a lot more to fail. And we should remember that while some F series run a long time lots don't (3FE's for example like to crack the cast crank). And most all leak. My 3FE, rebuilt 3FE and 2FE leaked from the front cover, the side covers the oil pain gasket and the rear main seal (including buying a new pan to make sure the mating surfaces were straight and flat). I did all of these multiple times, as painstakingly precise as possible. It will fix it for a while, and then leak. And let's not forget the pressed in oil galley plug that likes to let go, dropping oil pressure so fast that you're likely to lose the engine before you even know it happened. The difference is that all of these are relatively cheap and easy... because the engines are dead simple. So there is a lot more to fail here AND it really expensive to have someone else fix them because the engine bays are so tight (I miss being able to almost stand on the frame rails in my FJ-62's engine bay).

So am I disappointed every time I hear of something like this? You bet. And then I remind myself that the best way to install an oil pan gasket on an F series is to swear at it. A lot. Makes it go much faster. Also you should kick the pan out from under the truck at least once after the gasket falls off again before you can get the first few bolts in. Makes it stick better after that. Just kidding the real secret is to tie the gasket to the pan with some fine string or thread through a couple of bolt holes (but I've done all of the previous just in case). After I remind myself of that joy I also make sure to think "good excuse to build a lower compression, built short block for the big Harrop blower".

 

[Taco2Cruiser]

@2001LC Sent you a PM

 

[2001LC]

Thanks @Taco2Cruiser!

I'm new to this issue. As some as some here in mud know, my specialty is the 100 series. So over last few days I'm trying to get a handle on this 5.7L.

I've heard Toyota press fitted these in earlier years, then went to thread spark plug tube to head fit.
Is this true?
If so what years?

 

[Taco2Cruiser]

Thanks @Taco2Cruiser!

I'm new to this issue. As some as some here in mud know, my specialty is the 100 series. So over last few days I'm trying to get a handle on this 5.7L.

I've heard Toyota press fitted these in earlier years, then went to thread spark plug tube to head fit.
Is this true?
If so what years?

I don’t believe that to be true. The FSM of a ‘19 still shows they are pressed in.

 

[2001LC]

By speaking with Toyota master tech (for over 20 yrs), Toyota parts guys, googling and talking with people from around the country. Trying to get handle on this bottom up oil seepage into spark plug tubes. Also speaking with a professor of "fluid" this morning. About heat transfer. He said; any fluid will certainly increase heat transfer rate, more than gasses. But doesn't know if would make coil hotter than normal.

I came away with:
Toyota:
Warranty will not cover.
States this is a non issue, with respect to the operation & performance of the vehicle.

I'm left with the questions:
Is the coils voltage/amps/spark effected when submerged in oil?
Are the coils or their boots, being damage soaked in oil?
Are these coils running hotter than normal?
Is this oil effecting coil or spark plug life or performance?
Is MPG being effected?

I've issue of low MPG of 11MPG HWY. In a low mile, very clean, seemingly well tuned 200 series I've in the shop now. Could 11 MPG, be issue with coils, due to soaking in oil. If so how can Toyota claim normal seepage, with no effect to operation of vehicle.

I've learned over the years. Just because a coil doesn't throw a code, doesn't means it's good. Some coils I can get to misfire, but can only be seen as it happens in tech stream. Some no codes (DCT) and can't see misfiring. But replacing coils, has eliminated hesitation during full acceleration on HWY and fuel excessive fuel smell and improved MPG.

I started a thread few years ago in the 100 tech section on when to replace coils. I learned there is testing equipment for them, which I could really use it today!

When to replace Ignition coils.

As our 100 series fleet ages we're seeing more ignition coil failures. Is there a certain mileage or age where our 100 series with the 2UZ-FE engine are seeing the need to replace one or more ignition coils? If you’ve replaced any coils please post any performance differences before & after...

forum.ih8mud.com

 

[PDoyle]

What about the PVC?

 

[2001LC]

Well, PCV seem okay first look. I will recheck. But if a PCV really stuck closed, so bad it blows out bottom of spark tubes. I'd think engine would leaking from many places. It doesn't.

 

[2001LC]

I just learned spark plug replace 3K miles before PCV valve less than 500 miles ago (before I saw vehicle). That valve did not clank when jiggled. Real test is seeing how air passes. But no clank is indication gummed up PCV valve. I'll see if that old PCV kept. If so, I'll get and test.

So oil I now see in tubes, may have come into tube after plugs R&R before PVC valve R&R. But this still indication tubes leaking bottom up. No other leak seen. So if PCV valve was stuck and now working. I'd think may have only slowed leaks. As either tube has good press fit or it does not. If good tight press fit, other seals would surely leak also, maybe even more under high crankcase pressure, wouldn't they?

Interest too, is forward tubes have less oil. Fact is #1 & #2 dry. That the further back, the more oil. Example #3 just a tad of oil in tube, may 1/4 oz. #5 about 1/2oz. Whereas back tubes like # 7 have the most over 1 oz. Same pattern both banks! Except #8 dry.

I'm "thinking" (sometimes not so clearly, with arm chair engineering) more oil gets into tube as engine sit cold. That engine as is running at op temp. Heat expansion would help expand metals tubes & heads, reduce oil seepage. That more oil in rear tubes, has to do with pocket in head holding oil near tubes. That as engine sit in bay front higher than rear. Oil runs to back of engine puddling more so than front, when cold engine off. Just a though subject to change, as see and learn more.

 

[2001LC]

Question for all:

Anyone have MPG date from 5.7L with oil in spark plug tube?????

If we find a correlation to low MPG. Well than ,

 

[TLC2013]

I am about to change my plugs in the coming weeks (2013 with 100k). Reading these types of threads leaves me scared to see what I find lol.

Ive seen as low as 11mpgs and as high as 17mpgs depending on the driving/throttle usage over a tank of gas. Average is 12-14 for city.

 

[BVE]

Question for all:

Anyone have MPG date from 5.7L with oil in spark plug tube?????

If we find a correlation to low MPG. Well than ,

That might be tough considering tire size, weight and height variants with each vehicle as well.

 

[2001LC]

Good point. So will driving style and altitude. So need to drill down into each case.

This 11LC 200 is getting 11MPG. Aftermarket steel front bumper and roof rack. I'll check with owner if he calculated for tire size.

But 200 series, does really handle weight well.
I was surprised at how well:
I towed a 100 series on a trailer (7K lb) behind my 11LC (oct 2011 build date) On HWY and rural roads for near 100 miles. This was in Denver area (mile high city). I saw 19MPG.
Going over & down mtn overpass in the Rockies. No extra weight. I saw 19 to 21MPG.

Note: We get better MPG at high altitude than sea-level. less O2 in atmosphere, so ECM trims back fuel. We also have less horse power.

 

[alta]

As far as our MPG Calcs, going from a stock 285/60r18 to a 305/65/18 (just shy of 34"), is only a 6.7% increase in circumference. This means when looking at the MPG Computer, we are only seeing a 1mpg delta at 15mpg in the computer's calc. 19mpg is about 1.2 off and 10mpg is only .67 MPG off. So, w my tires, if I am seeing 11MPG, I am only getting about 11.7 actual MPG. Before I calculated this, I was really hoping it was more like a 2 to 2.5 mpg difference in the computer's calcs vs actual.

But of course to BVE's point, the rotational force the drive train sees at the wheels is much greater w a thicker, taller, heaver wheel. And the point about adding air drag through bumper and racks, lift, etc will likely have a greater effect on MPG.

 

[bloc]

The quickest way to poor freeway mileage is to increase the horsepower demand of pushing it through the air. Higher speed? More horsepower.

Likewise, front bumpers uncovering so much of the front wheels and scooping air into the front wheel wells.. lots more aero drag. Roof rack, eliminating the smooth roof of the vehicle and replacing it with effectively corrugated metal.. more aero drag.

I think it is really tough to compare mileage on two vehicles that aren’t configured exactly the same. Stock would be easy. But finding the same combination of wheel/tire/lift/armor/rack/etc.. then add in altitude, ground speed..


But.. if oil in the tubes is negatively impacting mileage.. remove it. Clean that stuff out, and put a couple tanks of gas through it tracking mileage carefully. It’ll be a while before any appreciable amount of oil is back in there. If you want to take it a step further replace the coils that got significant oil on them, though I don’t think it is an issue, personally. Yes oil will increase heat conduction, but it is a static environment around the coil. It is going to end up at the temp of the head surrounding it for the majority of its life in the tube eventually.

 

[2001LC]

But.. if oil in the tubes is negatively impacting mileage.. remove it. Clean that stuff out, and put a couple tanks of gas through it tracking mileage carefully. It’ll be a while before any appreciable amount of oil is back in there. If you want to take it a step further replace the coils that got significant oil on them, though I don’t think it is an issue, personally. Yes oil will increase heat conduction, but it is a static environment around the coil. It is going to end up at the temp of the head surrounding it for the majority of its life in the tube eventually.

This is a good plan.

Inspecting the coil boots and seals. I see, the oil has swollen and soften them. I order 3 Denso boot kits last week. They're on back order so may take a few weeks.
I'll be suggesting we suck out the oil and replace the coil boots & seals. Then with MPG / GPS app, hit the HWY, take two back two back road trip of 300 miles or so. One through mtn over to western slop, the other on the plains of the eastern slop. Would get okay short term MPG data comparison. If I'm half right, of more oil seepage on cool down. Tube should stay relatively dry, if cool downs kept to minimum.


"Yes oil will increase heat conduction, but it is a static environment around the coil. It is going to end up at the temp of the head surrounding it for the majority of its life in the tube eventually."

Sound right. But consider this also. Radiant heat transfer can be block with shinny surface. But behind shinny surface must be and air gap. Close the air gap and heat than transfers. Tube is a shinny surface and oil transfer heat. Basically I'm saying IDK!

Toyota states (from what I've read) It's a none event (oil in tube). Well is it? I can only say oil is damaging coil boots at this point.

I am about to change my plugs in the coming weeks (2013 with 100k). Reading these types of threads leaves me scared to see what I find lol.

Ive seen as low as 11mpgs and as high as 17mpgs depending on the driving/throttle usage over a tank of gas. Average is 12-14 for city.

Lets hope they're dry!

As far as our MPG Calcs, going from a stock 285/60r18 to a 305/65/18 (just shy of 34"), is only a 6.7% increase in circumference. This means when looking at the MPG Computer, we are only seeing a 1mpg delta at 15mpg in the computer's calc. 19mpg is about 1.2 off and 10mpg is only .67 MPG off. So, w my tires, if I am seeing 11MPG, I am only getting about 11.7 actual MPG. Before I calculated this, I was really hoping it was more like a 2 to 2.5 mpg difference in the computer's calcs vs actual.

But of course to BVE's point, the rotational force the drive train sees at the wheels is much greater w a thicker, taller, heaver wheel. And the point about adding air drag through bumper and racks, lift, etc will likely have a greater effect on MPG.

For sure many variables need to be considering. But already I'm see reported MPG lower from just the last few post, than I thought I'd see.

 

[2001LC]

Please give some feedback, anecdotal or thoughts you may have. I'm especially interested in those 5.7L engines that have had tube leak and than repaired!

Thinking about oil in tube and possible effects to normal running and health of coils. A few thoughts:
1) Heat transfer in liquid filled, vs air gap.

With air gap I think of things like thermos bottle, radiant shield, CAT heat shield, etc.. Take say a thermos bottle, it can shield from heat or cold loss/transfer all day long. Even sitting in the sun. Radiant shield or barriers block most heat transfer, They depend on air gap, don't they. Engine block relies on liquid to transfer heat, if we loss coolant heat does not transfer away from cylinders. radiator you liquid to transfer heat. So could it be we transfer more heat to coils in with liquid, than when normal air gap.Heat is the enemy of coils.

2) Do we loose and spark in tube by damage to boots and/or liquid on and around contact point (spark plug to coil spring).

I ran a logs on HWY yesterday at dusk w/OAT ~70F

I'm seeing BK 1 running w/ LTFT (long term fuel trims) staying above 5%. BK1 LTFT at ~9% -+ 2 % most all the time. ECT running 192-196F.
BK2 LTFT running ~4.7% -+ 2%.
Bank 1 head has 3 tubes with oil (#7 a lot), and more in 2 off the tubes, than any in BK 2.

I'm suggesting to run fuel system & CAT cleaners in gas tank, and keep logging before and after. Doing in similar condition on same HWY etc. Than try again with at least new boots on coils and tubes dried out (suck out oil.) Even better would be with new coils, which may be next.

If we find improved FT and/or MPG with this anecdotal evidence.
If we can also get others data, with 5.7L indicating same.
Well Toyota can't say non event.

 

[bloc]

The good thermos bottles don’t depend on air gap, they depend on a partial vacuum in that gap to stop convection. Even if we assumed there wasn’t much heat transfer through the air you have a hot spark plug and valve cover conducting heat directly at the top and bottom.

Personally I don’t believe there is any more heat in the coil over time with oil in the well vs air, but this is just my belief. I just can’t imagine the coil sitting there in that environment at 80F or whatever the ambient temp was while the engine has been at operating temp for 3hrs.

Edit: cat heat shields are primarily for blocking radiant heat, and depend on air flowing across the surface to cool them so they don’t just radiate themselves. Double layer waffle heat shields do similar, if they don’t have a layer of fiberglass sandwiched in the middle. This is different than our spark plug wells where the air sits there not moving, both radiating and convecting heat to the coil from the plug well.

 

[mark71]

I freaked out a bit when I first found the oil in mine. Now 50,000 miles and six years later, no change...still leaks, mileage still horrible and the power still makes me smile.

Oil versus air gap...I agree that the temps aren't likely to be any different since steady state for both will be the same temp.

Oil versus the boot itself...easy enough to watch for degradation, but no signs yet.

Oil versus coil...doesn't reach high enough to affect it.

 

[Hoosier Daddy]

I had oil in my plug wells when I purchased my 200 about 3 years ago. PCV was clogged, FWIW. I replaced the tube seals, which appeared visibly dried out as I recall.

I haven't re-checked since the repair, but if I get the time and the inclination this weekend I'll pull a plug or two and take a look.