2003 Lexus GS300

[Graham Piccinini]

I think it's fair to say that I found the source of low temps...

Put in a new thermostat in place of this thermostat frame. Refilled with water, and it got up to temps no problem. It's been running for the past hour at idle, temps never got above 185°F. Great success.

Replaced the air filter while I was at it.

Looks like something going on with the O2 sensors still. Full disclosure: I'm just a shadetree parts changer. NOT a mechanic. So I just pulled up everything that was related to oxygen sensors: long/short term trims, voltages, etc. Can't 100% interpret what all these stats are, but just looking for something to stand out. Looks like at least one is not behaving like the rest. (Any tips on correct interpretation of all this would be greatly appreciated.)

Another screenshot:

On the bright side: after over an hour of running at idle there are no CELs yet. I guess all of those CELs earlier were caused by absense of a thermostat? A few are likely to pop up though once I take it for a drive. Hoping for the best, but expecting the worst. For now I enjoy this no CEL screen

We'll see what the test drive brings. For now I have new oxygen sensors ready to go in, once the current ones give up and stop fighting me. Also new-to-me steering rack is ready to replace the current one, since the one in the GS is leaking badly and inner tie rod is nearly separated. Interesting how the inner tie rod that separated is on the driver's side, but it causes the passenger side wheel to have quite a bit of negative camber... Nothing else in suspension seems to be a suspect, but I can tell the steering rack has been replaced before. So likely improper installation by previous owner?

 

[michaelluscher]

Love the story

I'm here to see it through

 

[cptbarkey]

Holy heck, triple subscribed to this thread. Its a Lexus, tell yourself its worth it.

 

[Oro_O]

I’m not a pro with these, but it seems:

Since you cleared codes and memory, fuel trims look ok for sitting and idling. O2 Bank 2 downstream sensor is bad. I would replace just that one myself and then re-analyze, before doing more. B2S2 is the one behind the cat for cyl. 4-6.

Just a caution since you mention steering rack anomalies. I just recently had a baffler with this. Verify it is an OE rack and tied rods (measure and count threads if you have to). I had what I thought was just a bad tied rod on one side. I could not get an alignment or figure out what was going on. It turned out the rack had been replaced before and it was a compatible, but not identical model and shorter inner ties were used. Not that likely, but be aware to verify parts coming out are OE or OEM if you suspect prior work. ETA: oh never mind, I missed offhand that you were putting in a whole new rack.

I’m not at all surprised the codes were thermostat related. These come up to temp very quickly, so a t-stat failure shows itself. Must have been a very dis-interested prior owner!

 

[Oro_O]

Another thought(s):

1) That thermostat is too discolored for my taste. What color was the coolant? I’d be tempted to do a citric acid flush and then get a Red or AMAM through the system.

2) Which thermostat did you replace it with? The OEM thermostat on these is quite beefy, MUCH more so than the Stant or equivalent. For $10 more, I always go with that in this case (I am not an “OE parts or bust” type, but here it pays off).

 

[Graham Piccinini]

Another thought(s):

1) That thermostat is too discolored for my taste. What color was the coolant? I’d be tempted to do a citric acid flush and then get a Red or AMAM through the system.

2) Which thermostat did you replace it with? The OEM thermostat on these is quite beefy, MUCH more so than the Stant or equivalent. For $10 more, I always go with that in this case (I am not an “OE parts or bust” type, but here it pays off).

In the trunk I found a full water pump assembly (beefy full unit, not just pump alone). It seems that it started leaking, and someone replaced it with another used unit. Due to this the coolant was a fresh fill of universal green.
Thermostat housing itself was dirty, with some rust and pitting on the inside. Cleaned it best I could. New thermostat is AISIN (THT-011).
Current fill is temporary. Just wanna run it for a little bit, then will add a cleaner, and flush with distilled water a couple times. Then will go with Toyota Red coolant.

 

[Oro_O]

Solid plan. If you aren’t familiar with a citric acid flush, here’s a post. You can google others.

https://bobistheoilguy.com/forums/threads/performed-the-citric-acid-flush-with-great-results.272539/

I prefer it to any canned/store bought flush. Citric acid is cheap, too (for canning/food use).

I eventually lost cooling system components in two Lexus of that vintage because they came with green (heater valve in a GS and rad in an ES). Doing a real acid flush to get out contaminants and get back to red is your best bet for correcting and staying the damage. I would also try to get some red concentrate and go to a 60/40 mix. not so much the extra temp protection, but you are getting 20% more corrosion inhibitors and additives in the system vs. 50/50. Good insurance. The citric acid flush should take care of most corrosion, but you still might get a fair amount of additive depletion off the bat, thus 60/40. The look of that t-stat kind of dictates all that.

 

[Graham Piccinini]

New-to-me steering rack came out of a lower mileage GS300 with a blown head gasket. So hopefully it serves well for some time. Swapped out the outer tie rods on it. Here is my old rack, with the tie rod ends from the new-to-me rack.

This easy job took way longer than it should've... Initially neither of my 2 jacks could lift it high enough. Tried stacking bricks and wood to raise it in stages, but bricks started cracking, due to uneven driveway. Thankfully my parents swung by to see grandkids, and dad grabbed the big boy jack with him. That let me raise the Lexus high enough to stack its old wheels under it.

Would've been a breeze with a lift. Eh...a man can dream. Until I achieve that dream, my reality is laying on my back on the driveway.

 

[Graham Piccinini]

Test drive went well. New thermostat fixed almost all the running issues. Fuel consumption is noticeably better: Almost 200 miles on half tank so far.
But it still feels like 3cyl are running properly, while other 3cyl are not at the top of their efficiency. Slightly sluggish compared to what my previously owned GS/IS vehicles felt like. That feeling is confirmed by a CEL for Bank 2 oxygen sensors.

Wheel alignment helped to improve the drivability, so now it's a proper daily driven vehicle. It did also reveal that both front lower control arms are due for replacement. Bushings are probably toast, as me and my alignment guy couldn't get it to spec no matter what we did. (It is a laser alignment rack.) Also looks like rear toe arms need replacement. Got it as close as we could to spec, but it was still slightly out on passenger side. Rear camber adjusted fine though.

Slowly, but surely I'll keep up with this road-storation. After driving it the whole day today I realized how much I missed this platform. Despite all of its current issues like many worn bushings, worn out shocks, oxygen sensors, dirty blend door servos (I'll clean them eventually... Tight squeeze for my sausage fingers in the dash...) Really digging this JZS160 platform. Hopefully after roadstoration is complete - I can move on to subtle alterations and improvements. No stance nation or any of that crap. Point is to improve the vehicle, not ruin it.

If I was one of those people that names their cars - I'd call this Lexus: "Kaizen". (IYKYK)

 

[Graham Piccinini]

Unfortunately the Jaguar wheels with spacers were just rubbing too much on full turns. So back they go on the Marketplace, while some 2000s Mustang wheels take their place. So far so good. Interesting how much more comfy the 16" are vs the 17", despite same 40PSI in the tires. I must be getting old with all this "comfy" talk... Eh, it is what it is...
Back end sits low since the full set of Jaguar wheels/tires are on the back row, and trunk has some tools and parts.

MPG stays around 19-21 average. Got some fresh SuperTech 15W-40 in the crankcase.

#noragrets as Scottie P. says.

 

[Graham Piccinini]

Life is full of miracles.

Back in 2015 I got in my 2001 Lexus IS300 after class in college, and the battery light turned on. I used to work at AutoZone at the time, so on whatever battery was left - I headed straight to my workplace. 5 miles, and IS300 died as I was pulling into the AutoZone parking lot. Being an employee at that location gave me access to all parts and tools, so I swapped out the alternator right there and then.

Fast forward to today. Now I have a 2003 Lexus GS300. I get in the car after work - and battery light is on. I turn off all unnecessary electronics and head home. Past experience tells me I got at least 5 miles worth of battery life. But somehow the Lexus kept on going for all of 23 miles, while slowly disconnecting one system after another. By the time I got home - all dashboard lights were lit. And the car died as soon as all 4 wheels touched my driveway.
Just crazy how that happened both times... So I made sure to send thanks to the Lord above for looking out for me again.

The swap itself is easy, 15-20 mins, 30 mins if you take a break halfway through. The driving to find one in stock took 1.5hrs. Let's see how long this Duralast alternator lasts...
There is significantly more space around the engine in the GS300 vs IS300. Same power train, but I always thought it's about the same space around the engine. I was wrong, waaay more space here. In the IS300 I had to drop the alternator through the bottom. While in the GS300 I took it out from the top with room to spare. Also on the other side of the block is an oil filter. On IS300 I gotta really maneuver it with precision to take it out through the top. While on the GS300 the top access is much easier and strut tower doesn't interfere at all.
Anyways, here is a new shiny alternator on an oily 2JZ block. I gotta swap out those notorious cam seals... And whatever other seals are leaking.

 

[Graham Piccinini]

Not many pics today, I'm too beat up to take any. Replaced a 5th alternator in my sister's 2009 Hyundai Genesis 4.6L V8, and then moved on to the GS.

Had a lot of intermittent issues with the Lexus, so today gave it the shotgun approach, and it worked.

First I attacked the knock sensor CEL. Easy fix, old one out and new one in. The connector is missing, so temporarily I just made it work until I can splice a new connector in there. The pin is there to attach to the knock sensor, it's just the whole plastic pin housing is completely gone. No more CEL about knock sensor.

Then I cleaned the MAF sensor again, just in case.

Then I moved on to the throttle body, since it has to be removed anyways to get to the spark plugs. Cleaned the throttle body, and while I was at it - decided to fix the common 2JZ issue. The APPS, or Accelerator Pedal Position Sensor. Here it is.

And here is the issue itself. The solder on these 4 pins cracks, and gas pedal stops reacting. This APPS sensor basically takes the cable movement input from the gas pedal and transforms it into a Drive-By-Wire signal, that controls the throttle butterfly movement.

My solder gun is on its last leg... Ugly, but it works. All other 2JZ cars I did this too are still running many years later, so hoping for this one to continue the trend.

At that point I found that 3 out of 3 ignition coils are missing the bolts to keep them in place... That explains the intermittent misfires... Each ignition coil gives spark to two cylinders at once. So I removed spark plugs and filled the cylinders with some Berryman B12. Here is how it squirted all over me after the piston soak.

I had paper towels over the cylinders and random tools to keep paper towels in place. That didn't work as well as I hoped .

Replaced spark plugs, removed like-new Chinese ignition coils, and reinstalled old 20 year old original ones that I found in the trunk. Also found lots of questionable wiring, so I'm on the lookout for the whole wiring loom now. Someone seriously butchered up the spark plug wires in the past...

Finally this car drives like it should. Today, for the first time in 2500 miles of ownership, I was able to drive for 1.5hrs without a single misfire. And car finally feels as well as my other GS/IS vehicles did in healthy state. Which is 210hp at the crank, and about 160 of them making it to the rear wheels. So now my focus can finally go into suspension, safety, and aesthetics.

 

[Graham Piccinini]

Finally restored the headlights.
1500 grit sandpaper by hand, followed by Meguair's Heavy Cut compound, topped with couple layers of NuFinish.

 

[meep]

Friggen beautiful work. As seen here on bitog, when the nufinish wears off, clean them again and then paint them with Nu-pol clear gloss. It’s not cheap, probably close to $30 a can, but it dries super tough and blocks UV. I have done … many this way.

practice on another surface first to get the feel. It’s thin and heavy. One medium coat, 2 minutes, and one light coat. It clears and smooths as it settles and you need to watch it first so you don’t panic and keep recoating.

if I hadn’t said it yet, I loved my GS. So many great things about this car!

 

[Graham Piccinini]

Friggen beautiful work. As seen here on bitog, when the nufinish wears off, clean them again and then paint them with Nu-pol clear gloss. It’s not cheap, probably close to $30 a can, but it dries super tough and blocks UV. I have done … many this way.

practice on another surface first to get the feel. It’s thin and heavy. One medium coat, 2 minutes, and one light coat. It clears and smooths as it settles and you need to watch it first so you don’t panic and keep recoating.

if I hadn’t said it yet, I loved my GS. So many great things about this car!

Thanks. In the past I had really great results with "Wipe New" Rustoleum product. It was extremely easy to apply (compared to sanding) and after 2 years still looked as good as the day I applied it. Unfortunately wasn't able to find it anywhere locally, so went old school with sand/buff/polish. Once NuFinish is gone - I may try that clear gloss...

I'm definitely just as happy with a GS as you were with yours. Mine needs suspension work, but even as is - it's now truly a fun daily.

 

[ProbeGT]

Enjoyed reading about your adventure. Looks like you're making good progress with the mechanical issues. How's the condition of the interior (seats, headliner, etc)?

I've done several headlight restorations over the years. I found that UV protection is key for longevity. A few days ago I was refinishing my alloy wheels and had a little SprayMax 2K clearcoat left over, I figured I'd restore the headlights (again) on my '04 Vibe GT. We'll see if the 2K clear lasts longer than the singe stage clear I had used previously. That started to peel after 3 years in the hot Texas sun.

 

[Graham Piccinini]

Enjoyed reading about your adventure. Looks like you're making good progress with the mechanical issues. How's the condition of the interior (seats, headliner, etc)?

I've done several headlight restorations over the years. I found that UV protection is key for longevity. A few days ago I was refinishing my alloy wheels and had a little SprayMax 2K clearcoat left over, I figured I'd restore the headlights (again) on my '04 Vibe GT. We'll see if the 2K clear lasts longer than the singe stage clear I had used previously. That started to peel after 3 years in the hot Texas sun.View attachment 197424

I'd say 3 years is pretty good, all things considered.
The rear seats are great, and fronts have the typical cracked/ripped bottom. So eventually I'll either find better used seats, or recover the bottoms.

 

[Graham Piccinini]

Still doing great, still no misfires, MPG is as expected.
Still many things on the to-do list though. One of those things being a suspension refresh.
Tried looking into OEM, but at 21 years old not many parts are available in OEM flavor.
Looked at most aftermarket options. OE-style replacements look right, but reports show a hit-or-miss level of performance. That's brands like Monroe, Moog, Detroit Axle, etc... Then I remembered about TruHart.
Well...somehow this price tag is only slightly higher than some "Made in China" parts, and still a lot cheaper than OEM stuff, assuming that OEM stuff was actually available, which a lot of it is not. Tough pill to swallow here... The whole car and all parts, repairs, and alterations cost me less than that so far. But TruHart (at least in the Honda world) carries a reputation for being a reliable and long lasting budget option. Plus they have a 2 year warranty. So there is a maybe...eventually.

NOTE: The goal is factory height, or 1"-1.5" drop max. I hate all the slammed and stanced out "VIP" GS300/400/430...

 

[meep]

Love this thread. Keep it up

 

[Graham Piccinini]

can u get a reliable used car for under $3k anymore?

If your planning to buy southern definitely have a local check it out first - because I would say half of the used cars here originate up North, because used cars in general cost more here, and Southern cars are Shipped North and sold as Rust free southern cars. Might be different out West -...

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