contactmypics Posted September 17, 2015 Share Posted September 17, 2015 2007 RX350 70K miles I have a bad Ignition Coil #5 which unfortunately is in the back bank. Since these are tough to get at i am going to have my independent mechanic take care of this, and will replace the other two ignition coils at the same time. (as well as all 6 spark plugs: DENSO 3426 / FK20HR11 Iridium Long-Life (SIP)) I ordered: DENSO 6731309 Coil on Plug DENSO coil interchanges with OE Diamond coil; Diamond is the OE supplier for this vehicle As it appears that Denso is not the manufacturer of the stock ignition coils, are these an acceptable replacement? I know to stay away from cheap aftermarket products for something like an ignition coil, but will these be 'just as good' as Toyota/Lexus branded coils? Am i making a mistake not going with the Toyota/Lexus OE? The OE Lexus/Toyota part will cost $115/each... the Denso coils above about $60/each. Thanks for any input/comments. EDIT TO ADD: those spark plugs are the ones that should last 90K-120K?? Quote Link to comment Share on other sites More sharing options...
scottq60 Posted September 17, 2015 Share Posted September 17, 2015 Don't be led to believe that if it's not a genuine Lexus/Toyota replacement part that it's inferior in quality. That's the trap that dealerships/OEMs want you to fall into. Side note - I had to replace an air/fuel ratio sensor on my wife's '09 RX350 and ordered an OEM Denso sensor on Amazon for WAY less than even Advance Auto Parts could get it for ... ~$50 vs $185 at Advance. Amazon.com is definitely my "go to" source for just about everything..them and Rock Auto Quote Link to comment Share on other sites More sharing options...
contactmypics Posted September 17, 2015 Author Share Posted September 17, 2015 Thanks for the reply. While i agree that OE products are not needed in every instance, and there are some instances where a quality aftermarket may be better then the original equipment, an ignition coil is not something i would want to cheap-out on. Maybe in the front bank where it's an easy replacement (and if i kept a spare in the trunk), but with 3-4 hours worth of labor rates to access the back bank this isn't a part i would look to be penny-wise / dollar-foolish (which is why i'm trying to be pre-emptive and replace the other two coils, and the spark plugs, while they're easily accessible... although some may consider this to be the foolish part ;) ) I have read stories online of bad aftermarket coils (cheap ones) which is why i'm trying to confirm that Denso is considered to be an acceptable replacement and one of the better ignition coils (or if it's "just as good as" the OE). Thanks again. Quote Link to comment Share on other sites More sharing options...
scottq60 Posted September 17, 2015 Share Posted September 17, 2015 Are you doing the work yourself? You mention 3-4 hours worth of labor rates...this leads me to believe you're paying someone else to do it...is that correct? Is it an "indy" shop? So, if I understand correctly, you're having an indy shop do the work, but you're supplying the parts? Is that right? Denso is the OEM for the air/fuel ratio sensors...so if Lexus/Toyota allowed them to supply those parts, I'm guessing their coils would be acceptable as well....unless they just went with the "lowest bidder" as I'm sure many vehicle manufacturers do. Parts are always a crap-shoot - a bad one gets produced for every so many good ones. I'm getting ready to replace both front hubs/bearings on my wife's '09...the left one is noisy but I figured I'd be pre-emptive, as you said...that may change once I've done the left side, depending on busted knuckles/frustration/etc. :) I ordered (what I thought to be) complete assemblies from Rock Auto. The instructions in my downloaded "shop manual" suggest the bearings/races need to be pressed off and the new ones pressed on...but the new bearings are one-piece sealed units provided by "Dura International" and include a 1 year/12k mile warranty....so we'll see how that goes. Regards, Scott Quote Link to comment Share on other sites More sharing options...
contactmypics Posted September 17, 2015 Author Share Posted September 17, 2015 So, if I understand correctly, you're having an indy shop do the work, but you're supplying the parts? Correct... i'm supplying the parts but an indy shop is doing the work. The downside of using my own parts is that if a part is bad, i'm on the hook for the labor a 2nd time (vs. full 12 months warranty if going with mechanic's parts). I ordered: DENSO 6731309 Coil on Plug DENSO coil interchanges with OE Diamond coil; Diamond is the OE supplier for this vehicle The above (Rock Auto) indicates that Diamond is the OE. I've never seen/heard them mentioned on the forums, but generally have heard very good things about Denso (although not directly related to ignition coils). Quote Link to comment Share on other sites More sharing options...
scottq60 Posted September 17, 2015 Share Posted September 17, 2015 is there a huge difference in price between the shop-supplied parts and those you supply? If not, I'd take that into consideration, as well as the 2nd charge of labor, if your parts turn out to be defective. Quote Link to comment Share on other sites More sharing options...
contactmypics Posted September 17, 2015 Author Share Posted September 17, 2015 is there a huge difference in price between the shop-supplied parts and those you supply?My Denso: $60/each x 3 pieces = $180 Mechanic OEM: $115/each x 3 pieces = $345 Difference: $165 Quote Link to comment Share on other sites More sharing options...
scottq60 Posted September 17, 2015 Share Posted September 17, 2015 just to give you an idea of what may go wrong...I recently bought a Pertronix Ignitor, from Summit Racing, to replace the points/condensor in my '63 Falcon Sprint - installed it correctly (I installed on in my wife's '68 Mustang coupe) - cranked and cranked...wouldn't start. I reinstalled the points/condensor and it fired up on the first key-turn instantly...which led me to believe the Ignitor was bad from the start. Pertronix Ignitor is a HIGHLY successful product...I just happened to get a bad one. It happens. Though, in your case, if it's bad from the start, it will be discovered right away, under that first labor expense...so you can just get another one, but if you're ordering it online, what's the ETA on a new part? Chances are, you'll be fine...I'm sure failures (hopefully) are the exception, not the rule. Not trying to make you doubt your decisions...just offering up my experiences. Off to go get a 12pt 30mm socket...my six point will not remove the axle nut...it's ALWAYS something! :) Quote Link to comment Share on other sites More sharing options...
contactmypics Posted September 17, 2015 Author Share Posted September 17, 2015 Good luck with your current project. I try my best to make calculated/informed decisions, and to pay almost half the labor cost ($165) upfront (in the form of additional cost for the parts) as a 12 month insurance policy on the labor didn't seem like a smart bet. I assume there is much less then a 50/50 failure rate, which would put me ahead of the game, but as my statitics profecssor used to say, "you're not doing hundreds of samples... in this one instance the result will either be '0' (failure) or '1' (no failure)". As i know a little, but am far from being a mechanic, i just wanted to confirm that i was making a smart decision and not trying to save money where i should be willing to spend a bit more. Quote Link to comment Share on other sites More sharing options...
scottq60 Posted September 17, 2015 Share Posted September 17, 2015 thanks! I think you've answered your own question - and I think you made the right choice. I'm far from a mechanic too...just try to do what I can (since I despise paying those labor rates) if there's the slightest confidence I can do it myself. The aforementioned '63 Falcon Sprint - blew a brake line a few weeks ago on the way home from our "cruise in" here in Somerset. I (at my wife's urging) sprang for all new stainless pre-bent lines...just finished installing them a few minutes ago...a bit challenging (routing and length-wise), but I got it done. Now to bleed them and should be good until something else breaks. (the norm with a 52 y/o car :D Quote Link to comment Share on other sites More sharing options...
Maysport Posted October 13, 2020 Share Posted October 13, 2020 Going through the same situation and questions. Diamond is listed as the OEM coil manufacturer, but I haven't heard of them and don't seem them for sale online. I called the Lexus dealer parts counter to ask the OEM manufacturer, and he initially said Denso makes all the ignition parts. After further talking, he looked up the part for a 2008 RX350 and pulled it to find it has Diamond stamped on it. He hadn't heard of it either. I can save $187 on 3 coils (if I just replace the back 3 - #1,3,5), but want some feedback that folks have had good success with the Denso replacements. Quote Link to comment Share on other sites More sharing options...
RX400h Posted October 14, 2020 Share Posted October 14, 2020 Rockauto.com lists the Denso coils as "DENSO coil interchanges with OE Diamond coil; OE Quality Replacement Part" ($53.79 each) https://www.rockauto.com/en/catalog/lexus,2008,rx350,3.5l+v6,1438207,ignition,ignition+coil,7060 I would certainly trust Denso. 1 Quote Link to comment Share on other sites More sharing options...
Maysport Posted October 14, 2020 Share Posted October 14, 2020 I wouldn't think Denso would be any inferior. It's showing a random misfire code, but also a problem with #3, so I've got the back 3 coils ordered from Rock Auto as Denso to get replaced this weekend. Thanks for the feedback! Quote Link to comment Share on other sites More sharing options...
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