sung35

I recently replace my GS4 with TM sparkplug at 50K miles. I did it while the engine is still hot(safe to touch). It has been a week with about 500 miles on it. I took the sparkplugs out again yesterday to check its condition. To my surprise, there were some wet oil around the sparkplug thread and the sparkplug looked like it burned oil. All 8 of them have the same condition. I searched online and found that I should not work on the aluminum engine while it is still hot. Am I somewhat damage my engine header? I will try to take some pictures of the sparkplug this weekend. Meanwhile, if someone has this experience, please share. Anything I can do now to fix this? Thanks.

My car ran fine for now though. But I afraid that in the long run something will happen. So please help.

JellyBean

I seriously doubt that you damaged anything by changing the plugs with a warm engine. Lets see. The only ways for engine oil to get to the plugs would be through (a) worn valve guides, (b) warped head and leaky head gaskets, or (c) worn piston rings. Changing the plugs, even with a warm engine, wouldn't damage any of those areas.

So, the only thing that comes to mind that can suddenly affect all eight plugs at once would be a rich gas mixture right before you turned off the car and checked the plugs. Are you sure you aren't confusing the dark liquid traces of a rich mixture with engine oil? Do the plugs smell like gas or oil? Is/was blue smoke coming out of the exhaust? If you're burning oil in all eight plugs, you'll have blue smoke coming out of the exhaust. No if or buts about that.

Check again because I just don't see you ruining a single cylinder--let alone all eight--by doing what you did. The worst you could' ve done was to overtighten a plug and strip the threads. But that wouldn't cause the symptoms you mentioned. Good luck.

JB

sung35

JB,

I will check this evening after work for any blue smoke. I worried because the original sparkplugs all 8 I removed were in very good condition and no wet oil at all. I did not have a torque wrench so I only use my hand strenth to tighten the plug. Do you happen to know the torque spec for sparkplug on a GS4? I will take some picture this weekend and post here for you to inspect its condition.

PS. I noticed that the gas milage went down somewhat, from 21 mpg to about 19.5 mpg. The power band stayed the same.

JellyBean

I don't have the torque specs for the GS4, but I'm sure they're posted someplace in the forum. As for the gas mileage... If anything, you should be getting better mileage with new plugs, especially if the old ones were very bad. Are you sure that you installed the correct plugs for your application?

But lets not jump to any conclusions right now. Check for blue smoke, and if no blue smoke, double, triple, and quadruple check for correct plugs. Wrong plugs would cause incomplete combustion (and therefore wet oily deposits) AND decreased mileage.

JB

sung35

No blue smoke. That is a good sign. I will check with Steve Ganz at Carson Toyota for the plug info.

Thank you very much for your expertise JB. I will try to take one plug out of the engine tomorrow morning (if I can wake up early) and take few pics. I will try to smell the plug while it is out. I still has the old original plug and a new TM plug for comparation.

HarrierAWD

What are TM plugs? Aftermarket plugs tend to promise the world, but actually cause problems. I'd put the original plugs back.

A few things to check: Did you use tune-up grease when you installed the plugs? Did you use a torque wrench set to the spec? Did you use compressed air can to blow away the debris near plug holes before removing the plugs? If you answer no in any of the above, you may be in trouble.

Installing plugs on a warm engine is usually OK. Shops routinely do it in the same condition. If I were doing it myself, I'd do it in the morning when it's cold.

sung35

TM is Torque Master.

Here are the pictures I took this morning. "Old TM" refers to the TM plug I just remove from
the header this morning. "Old NGK Iridium" refers to the original plug that came with the car
that I replaced with TM plug last week. "New TM" refers to the unused TM plug (I have one extra
new TM plug). Notice the oil around the old TM plug's bottom thread and how clean the
old NGK iridium plug is (no, I did not clean it. It came as is when I removed it). That is my
concern. It looked much worst with more oil when I checked last weekend. So what you see
now is a one day 80 miles distance driving.

The old TM smelled like gas.

Maybe I am just worry too much on something very normal

left=new TM, middle=old TM, right=old NGK Iridium


Close up
left=new TM, middle=old TM, right=old NGK Iridium


When putting the old TM back, I noticed the washer was in the engine header sparkplug
slot, so I removed the washer from the slot, put it back into the old TM, and take another
picture shot.

sung35

No, I didn't do any of the above you mentioned . I had worked on few of my other cars and never had any problem. I am going to buy a torque wrench anyway to be sure next time. Thanks Harry.

JellyBean

The tip of the plug looks good, but there shouldn't be any combustion blow-by on the threads or gasket area. Again, assuming that those are the correct plugs for your car, it looks like the plugs were loose. But, all eight plugs???

This may be a very basic question, but allow me. Earlier you said that you hand torqued the plugs. Did you mean that you hand-tightened them (because you were afraid to strip the threads), or that you used a wrench--but not a torque wrench--to tighten them?

JB

sung35

The way that I alway used in tighten the spark plug is to hand turn the plug into the header slot, then use the wrench with little force until feeling the tightness, then give it about an eighth 1/8) to a quarter (1/4) turn. You can see from the picture that the washer on the TM plug did press compare to the new TM plug one.

I am going to get a torque wrench tonight and maybe tomorrow or maybe this weekend to re-torque them. It is a wait-and-see game. I will keep you post in about a week or two.

Thanks JB.

JellyBean

Sounds like you definitely knew what you were doing. I've also been guilty (foolish?) of skipping the torque wrench on aluminum heads on a couple of occassions. Being aftermarket plugs, I'll bet that they're a tad off tolerance and don't fit too well. (Had a similar quality control problem with my front Daizen sway bar.) Doesn't sound like anything serious though. That said, if you didn't notice any performace or mileage gains, you should consider going back to OEM plugs for peace of mind. Good luck.

JB

/Aerostar\

iTrader: (2)

Always use your torque wench on every bolt/nut you can