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DIY: IS350 Spark Plug Service
08-24-10, 10:27 PM
#47
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The FSM doesn't say 14 - 18, it says 25 N-m or 18 ft-lb. They're not offering a range of torque, they never do. They also don't say anything about oil, anti-seize, or any other kind of thread preparation. They expect the plugs to be installed dry.
If you change plugs frequently, anti-seize will help you keep the aluminum in the threads and not pull some out with every plug change. This was a very big deal when I worked on air-cooled motorcycles because plugs didn't last all that long in them. It's not such a big deal when the recommended service interval is 60k miles.
FYI - for all the junior tuners out there - you can't tell jack about what kind of service life is left in a plug by looking at it. A bad plug can look perfectly normal and be worthless in service. There are machines which are capable of testing a plug under service conditions by applying pressure to the area where the gap is and measuring the voltage required to strike an arc. If you don't have access to tooling like this, you'll need to decide when to change based on either the factory's recommendation (required to meet emissions standards) or by keeping track of your gas mileage sufficiently to know when your engine is running significantly worse (with seasonal adjustment).
I chose the factory interval only because it's easy and its guaranteed to work. Some people use this same approach to oil and filter changes, others don't. If I had the machine to test the plugs, I'd probably test them and find out if they still have some life left in them by comparing them to new. Since I don't and I really don't envision buying this machine to be cost effective even over the long haul, I'll stick with the factory interval.
If you change plugs frequently, anti-seize will help you keep the aluminum in the threads and not pull some out with every plug change. This was a very big deal when I worked on air-cooled motorcycles because plugs didn't last all that long in them. It's not such a big deal when the recommended service interval is 60k miles.
FYI - for all the junior tuners out there - you can't tell jack about what kind of service life is left in a plug by looking at it. A bad plug can look perfectly normal and be worthless in service. There are machines which are capable of testing a plug under service conditions by applying pressure to the area where the gap is and measuring the voltage required to strike an arc. If you don't have access to tooling like this, you'll need to decide when to change based on either the factory's recommendation (required to meet emissions standards) or by keeping track of your gas mileage sufficiently to know when your engine is running significantly worse (with seasonal adjustment).
I chose the factory interval only because it's easy and its guaranteed to work. Some people use this same approach to oil and filter changes, others don't. If I had the machine to test the plugs, I'd probably test them and find out if they still have some life left in them by comparing them to new. Since I don't and I really don't envision buying this machine to be cost effective even over the long haul, I'll stick with the factory interval.
08-25-10, 11:14 AM
#48
FYI - for all the junior tuners out there - you can't tell jack about what kind of service life is left in a plug by looking at it. A bad plug can look perfectly normal and be worthless in service. There are machines which are capable of testing a plug under service conditions by applying pressure to the area where the gap is and measuring the voltage required to strike an arc. If you don't have access to tooling like this, you'll need to decide when to change based on either the factory's recommendation (required to meet emissions standards) or by keeping track of your gas mileage sufficiently to know when your engine is running significantly worse (with seasonal adjustment).
BTW, no matter how well tune is your engine, they all misfire once in a while and it is how often they misfire that matters. Also depends on how you drive you car your plug can last more or less than the factory recommendation interval. Maybe Toyota tested with the worst case scenario (people driving like a maniac for 60k) and you don't drive like that, therefore making the plugs last longer than 60k.
I'm not saying that everyone should extend their plug life to 90k, but I'm saying that 60k seems VERY CONSERVATIVE and I probably will pull the plugs out to see if they are done for at that time. Pulling them out every 30-60k does reduce the chances of seized plugs and it's worth doing even if you are not replacing the plugs.
09-14-10, 02:31 PM
#52
Good advice Lobux...I have not experienced misfiring and such, but really would not know much to recognize it anyways. Sewell Lexus has the plugs online for sale and I just assume change them around 60K anyways and not worry for several more years. Not too expensive anyways and local mechanic will install them for $40. Peace of mind.
10-10-10, 08:33 PM
#53
Just did it this weekend. 5 of the 6 were super simple, did that in about 90 minutes and i was moving slow, wiping things down as I went along.
The screw on the drivers side, furthest from the firewall is a *****. This screw seemed tighter than all the rest and I ended up rounding the only 2 accessible sides (the screw is in a real crappy spot). So the only way I could get it out was to loosen up the manifold, rock it up a small amount and at that poin I could get my smallest socket in place. That part took me several hours and a few trips to the store to try to find a better tool.
My tip - take your time and make sure you have the wrench fully on the screw head. It doesn't take much to round it out. I'm generally pretty good with these things so I was surprised I had so much trouble.
The screw on the drivers side, furthest from the firewall is a *****. This screw seemed tighter than all the rest and I ended up rounding the only 2 accessible sides (the screw is in a real crappy spot). So the only way I could get it out was to loosen up the manifold, rock it up a small amount and at that poin I could get my smallest socket in place. That part took me several hours and a few trips to the store to try to find a better tool.
My tip - take your time and make sure you have the wrench fully on the screw head. It doesn't take much to round it out. I'm generally pretty good with these things so I was surprised I had so much trouble.
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Samu22 (08-03-19)
12-19-10, 04:18 PM
#54
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The last screw thrizzy is talking about can be taken out with time and care with a combination wrench. Loosen the wire harness nuts and bolts. Lift the wire harness out of the way as much as you can. Then use the combo wrench 1/8 of a turn at a time (thats about all you can do because of restrictions) to get it loose. Then use your fingers when it is loose enough. If you ever think you will change your spark plugs again put anti-seize on it!!!
12-26-10, 04:00 PM
#56
The screw on the drivers side, furthest from the firewall is a *****. This screw seemed tighter than all the rest and I ended up rounding the only 2 accessible sides (the screw is in a real crappy spot). So the only way I could get it out was to loosen up the manifold, rock it up a small amount and at that poin I could get my smallest socket in place. That part took me several hours and a few trips to the store to try to find a better tool.
My tip - take your time and make sure you have the wrench fully on the screw head. It doesn't take much to round it out. I'm generally pretty good with these things so I was surprised I had so much trouble.
My tip - take your time and make sure you have the wrench fully on the screw head. It doesn't take much to round it out. I'm generally pretty good with these things so I was surprised I had so much trouble.
Someone earlier mentioned that they were able to get a 3/8" socket on it, but no way that was going to happen on my engine. I'm going to have to make a trip to the store to find a small 10mm joint-type socket that will give me the angle i need.
