Spark plug and coil failures

I have a 2008 5.7 Tundra with about 25,000 miles on it near Houston, Texas. I am retired and drive it sparingly. It has had about four coil and spark plug failures. I have replaced all of the coils and spark plugs once. Given the above, would you consider the life normal?

 

New member! Welcome from Houston as well! Thank you for your Service! Let's see your ride!

 

What about spark plugs wires??? Hopefully someone else will chime in to assist

 

Welcome from Ohio!

 

Welcome to the best forum

Wow, 10 year old truck with approximately 2,000 annual miles!!!!!

Colorado^^^^^^ made some great questions that you should consider- - send response

 

Welcome from CO. I have a 5.7L 2007 with 85K miles with absolutely zero issues yet with any of my spark plugs or coils. It is my daily driver. IMHO I don't particularly think the issues you have had with plugs and coils are normal. You do have low miles but it's also not driven much. These engines are built quite well. I can't see not using it much could cause 4 coil/plug failures but apparently it has somehow.

 

That does not sound normal to me at all. Our household has accumulated about 300,000 km on Toyotas with coil pack ignition, and I’ve yet to change one coil pack.

You’re not hosing down the engine with water on a regular basis are you?

Is it different cylinders when they fail, or repeats on the same cylinder?

No engine oil leaking into the spark plug tubes?

 

I know that when dealing with various types of coils at work, that sometimes a coil will fail with a sudden change in current and Inductance will build up beyond the coils' current rating and cause a visible spark across an exposed coil which is not a good thing. I'm thinking misfiring/fouled spark plugs are taking out his coils. Like you said, the coils are pretty reliable.

 

I wash the engine off when I wash the truck which is maybe once a year. This is not a serious wash...just some hosing off. I just had another spark plug fail this week, and the old one looks like new. See photo of old one. The first plug was replaced by the dealer in 2013 under an extended warranty the previous had. I have replaced all of the remaining coils and plugs myself. None of the plugs or coils I have put in have failed (yet). I do live near Houston where the humidity is high and I generally back the truck up daily to work in my garage and park it under with the hood shaded. No it hasn't been in a flood. The history is as follows... I don't see a pattern of a spark plug failure causing the coil to fail or visa versa. Not that it is of value, but the failures always happen at about 50 mpg after about fifteen minutes of driving. You would swear that a wheel is about to fall off until it settles out.

#2 plug in 2013 (failure by dealer)
#1 Coil in 2014 (failure)
#5 Coil and plug in 2015 (failure but not sure which went bad)
#7 Coil and plug replaced in 2015 as preventive maintenance.
#2 Coil in 2016 as preventive maintenance.
#6 Plug and coil in 2016 as preventive maintenance.
#8 Plug and coil in 2016 as preventive maintenance.
#4 plug in 2018 (failure)
#1 Spark plug not yet replaced. This is the only remaining factory spark plug or coil.

I don't know if I am getting oil to the plugs in the inside of the engine, but the engine doesn't leak oil at all.

https://tnstatic.net/data/xengallery/111/111381-63fa298219c73d139d66919f58be7b1e.jpg?1515938897

 

Those coils are fairly pricey right?

 

Check this article out. Also do another general google search for causes to spark plug failures....

http://www.underhoodservice.com/1-cause-spark-plug-failure/

 

Great link^^^^

 

The only somewhat related issue I had was a leaking valve cover gasket at 90k that caused oil to get on one of the plugs.

 

I quoted this article as:

When I replaced my plugs last year, even though I had the valve cover gasket leak, about 3 or 4?plugs seemed to have been hand tightened

I used no force whatsoever to unscrew them

Just a thought....

 

Hey guys, I"m a long time lurker here so I had to start posting somewhere. I bought a used 2014 1794 a couple of months ago and I'm really enjoying it so far. I was in a 2500 Ram for 13 years and am loving my Toy so far. It's made driving enjoyable again for me.

I've been fixing these things for years and it is a super common failure item on all different kinds of vehicles. It's a fairly simple job on the Tundra to change out the plugs and or coils. Prob 45 mins for all eight with hand tools.

I believe that the coil on plug ignition systems are susceptible to moisture build up in the spark plug tubes. When a warm engine cools off in humid weather it will condense water everywhere and it will build up in the tubes around the plugs and coil boots. As soon as the spark escapes the plug boot and finds an easier path to ground, other than through the spark plug, it will burn a carbon trail and that will be the new path to ground for that cylinder causing a misfire.

I always use a gob of Die-electric grease inside the coil boots to try to make it harder for the spark to find another path to ground.

It sounds like the lack of use would be a major contributing factor to the build up of moisture and then possible corrosion inside the spark plug tubes. You really need some long term heat build up to almost boil that excessive moisture off the engine.

It sounds to me like Flint needs a regimen of removing the coils on a regular basis (yearly) to dry out the spark plug tubes and apply Die-electric grease to the boots. Typically the coils don't fail but get burnt on the bottoms where the plug boots rest. I've literally fixed vehicles with just the grease application.

I hope this helps a little.

 

That^^^^^ Welcome from CO. Die-electric grease is relatively inexpensive and anti-seize when changing out.

 

Looks for a dielectric grease without fluorine, fluorine from what I think I recall seeing "wears" down the rubber on the ignition coil boot.

Sometimes the boot also loses its "tension" near the bottom where it rests with the hex of the plug. So sometime the coil itself is not bad, meaning the internal windings and such. Sometimes it could just be the boot ie pin size hole causing an issues.

 

Yeah, It doesn't take much. A tiny pin hole in a lineman's rubber glove can kill him.

 

Thanks for all of the advice. I plan to use the dielectric grease for the rubber part. I think the dealer charges about $75 or so for the part (not labor). Autozone has a range of $75 to $90. Amazon Prime has them for about $50 as I recall. Based on your comments, I suspect now that I am a victim of Tomball's (near Houston) humidity and lack of warm-up when I drive it out in the morning and back in the evening. Overnight, gaseous water condenses inside the coil and stays there. Most trucks have sufficient runtime to boil the water out before it stays long. Those who don't live in humid areas would be amazed at how tools in an unconditioned space rust. You may recall that the airbag issue with Tanaka was more severe in the South. I am guessing they have the same sort of issue. The coils are not hard to replace, but, for me, a mechanic's son, most jobs take at least an hour each because I do them all separately and never have the right tool. One thing I struggled with initially was getting the connector off of the coil. Is there any harm with putting dielectric grease in the electrical connector? Thanks for all of the kind advice. I have another mystery with the truck that I won't include in this thread. By the way, I use a OBDII reader and it is an absolute life-saver for this issue. It has directed me to the right plug/coil every time.

 

Most of the Tundras with AIP issues seem to be occurring in high humidity zones. Food for thought...