Coil Pack replacement
09-19-16, 08:22 AM
#1
Coil Pack replacement
My son and I changed the coil pack for the Number 1 (back side of the engine on the passenger side) cylinder on my mom's 07 RX350, Saturday. I read a lot of the posts found on this forum to prepare, and they were great. Except the really thorough instructions were for an earlier RX 330, and there are a few minor differences (bold size and bracket location). Because the car only has 42000 miles, we decided to replace only the coil pack that was dying (and no spark plugs). We thought it was likely an anomaly that it was dying so early. Side note. The engine light was intermittent and there was no misfire, so we made sure the wiring at the connector was OK.
We removed the air box and throttle body so we could get a better view at what else had to come off. It turned out this was going to be required anyway, so you can wrap your arms around the engine to get to the backside bolts. In the end, it wasn't a difficult job, except for 2 bolts on the back side of the engine. There is a bracket that goes from the firewall to the intake manifold, right at the #1 cylinder. To make it even more challenging, they ran a wiring loom right over it. The bold (12MM) goes up into the manifold at about a 45 degree up angle. We (actually my son) tried a ratcheting box wrench, open end wrenches, and sockets with various extensions. I think the one that finally got it was the box wrench, but it was a royal pain. He spent the better part of 2 hours (off and on) on it from the front of the car with his arms wrapped all the way around the engine. As a quick aside, you MIGHT be able to get to the bolt from underneath with a long extension and a swivel, but it would still be hard to get around the wiring loom. We didn't have the extension, so we didn't try. Once the intake manifold was off, we moved the bracket by loosening the firewall end because the bracket was directly over the coil pack. Be careful if you do this, as it becomes problematic to re-align the bracket with the hole in the manifold when you're putting it back together. We ended up leaving the firewall side loose enough that we could move the bracket to get it aligned, then going back to tighten the firewall end. Ugh. There is a second bracket on the back side, closer to the #3 cylinder. You can get to this one on the top side pretty easily. In fact, you can see it. It took us 4 or 5 hours to do the entire job, with the VAST majority of the time taken with removing and replacing 1 bolt. Well, that and chasing the various wrenches we kept dropping onto the skid plates. We also took our time to make sure we didn't miss anything, and did a pretty close inspection of all the parts. It was remarkably clean. The throttle body looked brad new, which I think is a testament to quality gasoline. It would have been a LOT easier if we could have moved the wiring loom, but still not very easy.
We replaced the Intake manifold gaskets, but I'm not at all convinced we needed to. We didn't replace the throttle body gasket. We only made 1 trip to the parts store, and that was because we needed to find a socket driven #5 hex wrench so we could use an extension to get between the intake runners all the way down to the bolts (probably 5 or 6 inches). We also bought a set of stubby wrenches hoping it would help with the back side bolts. I think that's what he used to do the final tightening, but I'm not sure. All the bolts were either 10MM or 12MM, and the hex bolts were #5. All in all, it cost around $120 for parts (Denso coil pack, intake manifold gaskets, hex wrenches and stubby wrenches). Lexus wanted $705. I did find an independent that would have done the labor (no parts) for $300, so I feel pretty good about it.
We do have a weird issue. Her battery went dead on Sunday (we did disconnect it before we started working). I noticed that the auto headlights seemed to stay on a long time after we test started the car, and I wonder if the delay timer got hosed up when the battery was disconnected, leaving the lights on. I did actually do a very brief short to ground when I was putting the air box back in, when my ratchet clicked the positive post while on the bold (which was clearly grounded). I wonder if I screwed up something in the computer, but I have no way of knowing. I had previously (before we did the coil pack) noticed that the DRLs were very dim. I'm wondering if there is an electrical issue. Or maybe the battery is just too weak. It seems like it was replaced 2 or 3 years ago, though. We tested the voltage, and was charging, and the drain was at a normal rate when everything was off. Any ideas?
We removed the air box and throttle body so we could get a better view at what else had to come off. It turned out this was going to be required anyway, so you can wrap your arms around the engine to get to the backside bolts. In the end, it wasn't a difficult job, except for 2 bolts on the back side of the engine. There is a bracket that goes from the firewall to the intake manifold, right at the #1 cylinder. To make it even more challenging, they ran a wiring loom right over it. The bold (12MM) goes up into the manifold at about a 45 degree up angle. We (actually my son) tried a ratcheting box wrench, open end wrenches, and sockets with various extensions. I think the one that finally got it was the box wrench, but it was a royal pain. He spent the better part of 2 hours (off and on) on it from the front of the car with his arms wrapped all the way around the engine. As a quick aside, you MIGHT be able to get to the bolt from underneath with a long extension and a swivel, but it would still be hard to get around the wiring loom. We didn't have the extension, so we didn't try. Once the intake manifold was off, we moved the bracket by loosening the firewall end because the bracket was directly over the coil pack. Be careful if you do this, as it becomes problematic to re-align the bracket with the hole in the manifold when you're putting it back together. We ended up leaving the firewall side loose enough that we could move the bracket to get it aligned, then going back to tighten the firewall end. Ugh. There is a second bracket on the back side, closer to the #3 cylinder. You can get to this one on the top side pretty easily. In fact, you can see it. It took us 4 or 5 hours to do the entire job, with the VAST majority of the time taken with removing and replacing 1 bolt. Well, that and chasing the various wrenches we kept dropping onto the skid plates. We also took our time to make sure we didn't miss anything, and did a pretty close inspection of all the parts. It was remarkably clean. The throttle body looked brad new, which I think is a testament to quality gasoline. It would have been a LOT easier if we could have moved the wiring loom, but still not very easy.
We replaced the Intake manifold gaskets, but I'm not at all convinced we needed to. We didn't replace the throttle body gasket. We only made 1 trip to the parts store, and that was because we needed to find a socket driven #5 hex wrench so we could use an extension to get between the intake runners all the way down to the bolts (probably 5 or 6 inches). We also bought a set of stubby wrenches hoping it would help with the back side bolts. I think that's what he used to do the final tightening, but I'm not sure. All the bolts were either 10MM or 12MM, and the hex bolts were #5. All in all, it cost around $120 for parts (Denso coil pack, intake manifold gaskets, hex wrenches and stubby wrenches). Lexus wanted $705. I did find an independent that would have done the labor (no parts) for $300, so I feel pretty good about it.
We do have a weird issue. Her battery went dead on Sunday (we did disconnect it before we started working). I noticed that the auto headlights seemed to stay on a long time after we test started the car, and I wonder if the delay timer got hosed up when the battery was disconnected, leaving the lights on. I did actually do a very brief short to ground when I was putting the air box back in, when my ratchet clicked the positive post while on the bold (which was clearly grounded). I wonder if I screwed up something in the computer, but I have no way of knowing. I had previously (before we did the coil pack) noticed that the DRLs were very dim. I'm wondering if there is an electrical issue. Or maybe the battery is just too weak. It seems like it was replaced 2 or 3 years ago, though. We tested the voltage, and was charging, and the drain was at a normal rate when everything was off. Any ideas?
Last edited by User 41924; 09-19-16 at 08:38 AM.
09-20-16, 07:15 PM
#2
My 2004 330 had a leak from the 4wd distribution box. From underneath, it looked easy enough but I don't have tools to pull out axles and re fit seals. Took it to Toyota. The seals cost about AUD 60 and the labour cost about AUD 1400.The one that designed Lexus seems to have thought it would be fun to let users remove the whole gearbox to access one bolt to take the distribution box off. And it seems the same train of thought prevailed when positioning the engine.
Try dropping a bolt that fits the stereo in to the abyss below. I removed all the plastics under the gear shift to reach rattling bolts but i could not even see where the bolt was. Still haunts me whenever i go over a pothole.
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