Lexus IS Forum banner

1 - 7 of 7 Posts

Registered
Joined
1 Posts
Discussion Starter #1
*Short read in advance, Thank you for taking the time to read*
Hi Guys, I'm new on here! So I've had my is300 ge for alittle over a year now (163k miles, only the timing kit with select parts and belts were done at 150k, everything else is original. And it's time she has some tlc done. First, My valve cover gaskets need replaced, they're leaking on both sides and near the back. I am mechanically inclined but was wondering if there's a better brand or materialed gasket over others? Im not trying to order just ANY replacent that fits. Cheap is not what I want. Just the better suggested so it can be one and done for a few years with no leaks. (Hopefully馃槀馃
. Second, I have no codes for catalytic converter BUT I've been smelling fumes when coming to or leaving a stop with driver window down, or when backing up with window down. Cats seem to crackle pretty good after shutting her off after an easy 5-15 minute drive(Especially the one under the front seats). I know its not gas or burning oil, Definitely could be partial of an exhaust leak too. So im thinking about simply replacing the headers and y-pipe since its going to cost more to install new cats( if they are or close to shot) Any negative reviews on the GODSNOW header? I've read they were a step above obx a year or so ago, and have seen a few videos with Gte's having them installed and sounding nice. Quality is my concern if anyone has purchased or known someone who has/had one. I can get one that's longtube style for $125 used and in good shape with sensors along with a megan racing y-pipe with sensor aswell for $125 (already know they're pretty well known on the is300s). Seems like a great deal, especially only spending 1/5 of the price for shipping then getting them from a company. Some opinions or suggestions would be Well Appreciated!! Thanks
 

Registered
Joined
253 Posts
I recently replaced the cam cover gaskets on my car. I used the FelPro set. They are made of the nice blue rubber material that's been great on other applications.

My only complaint is the gaskets were a slightly loose fit in the groove of the covers. The gaskets really need to stay firmly in place while you're jockeying the covers back into place during reassembly. I solved this by "gluing" the gaskets in place putting 4 or 5 small dabs of RTV in the groove, putting the gasket into place, then setting the covers (gasket-side down) on a flat surface overnight.

Regarding catalysts: Your ecu has a strategy to diagnose the performance of your catalysts during operation. Essentially, the ecu purposely dithers the air/fuel mixture from slightly lean to slightly rich all the time. If you were to graph the signal coming from your upstream O2 sensors, their trace would appear as a sine wave. If the catalyst is working correctly, it will store extra oxygen during the lean swings, and use it to finish the combustion process of the exhaust gases during the rich swings - meaning the downstream O2 sensor's trace should be a flat line IF the catalysts are working correctly.

All this to say: If the ecu is not reporting a catalyst performance fault, I doubt your catalysts are working improperly.

Last, I've no opinion on what header to buy.
 

Mr. Roo
Joined
9,289 Posts
My valve cover gaskets need replaced, they're leaking on both sides and near the back. I am mechanically inclined but was wondering if there's a better brand or materialed gasket over others? Im not trying to order just ANY replacent that fits. Cheap is not what I want. Just the better suggested so it can be one and done for a few years with no leaks.
Definitely stick with OEM Lexus/Toyota parts. As the previous reply indicates, aftermarket replacements do not fit properly, and you'll be lucky if they work. I replaced mine with OEM, and they were super snug as a bug in a rug.


Second, I have no codes for catalytic converter BUT I've been smelling fumes when coming to or leaving a stop with driver window down, or when backing up with window down. Cats seem to crackle pretty good after shutting her off after an easy 5-15 minute drive(Especially the one under the front seats). I know its not gas or burning oil, Definitely could be partial of an exhaust leak too.
Replace the valve covers first. If you are leaking oil from there, it will burn and you will smell it coming in. My main crank seal is leaking, and I can smell that real good. Not pleasant. If that doesn't work, then worry about the exhaust, unless you know for a fact that you have a leak (you'd hear it).
 

Registered
Joined
242 Posts
I second OEM valve cover gaskets. I have nothing against Felpro and have used them countless times but for something that gets replaced once a decade if that I would spend the couple extra bucks for peace of mind.
I agree with that, beside the fact that I've used the Felpro kit because OEM was B/O at the time I was getting my parts. I didn't have fitment issues with it the gaskets were snug fit. Can't wait for spring to drive her again, she is currently stored :(
 

Registered
Joined
12 Posts
I have owned my is for almost 3 months now and am currently at 127k. I too replaced the original t belt/water pump/t stat/tensioner/pully/coolant right off the bat. I also did park plugs, trans fluid, oil change, resurfaced the front brake rotors, and cleaned the throttle body and maf. If you haven't done that stuff yet, I highly recommend it. Now I am getting ready to replace the front struts and front lower ball joints, followed by a front wheel alignment. I would highly recommend replacing the front lower ball joints too, based on how cheap thy can picked picked up for, as well as to avoid one of the many horror stories out there about them failing, leaving you wrecked on the side of the road.
 

Mr. Roo
Joined
9,289 Posts
Now I am getting ready to replace the front struts and front lower ball joints, followed by a front wheel alignment. I would highly recommend replacing the front lower ball joints too, based on how cheap thy can picked picked up for, as well as to avoid one of the many horror stories out there about them failing, leaving you wrecked on the side of the road.
Definitely go with OEM lower ball joints and drive with peace of mind :)
 
1 - 7 of 7 Posts
Top