BMeek

Hi there,

My 1998 ES300 has ~307K miles but generally runs strong. I've been lazy about the more labor-intensive maintenance as the car has been running very well and reliably - until recently when a new issue has provided a forcing-function:

The car now sometimes fails to start, like it's flooded, when 'warm'. For example, if I drive the cold car a mile or two for a brief errand (maybe 5 mins in the store). When the problem occurs, the car cranks but doesn't fire right up like it always has (and still does when cold or fully warmed up). Sometimes, it threatens not to start with my foot off the gas pedal, with some gas pedal coaxing it'll stutter, start, rev, and then seem to run smoothly. If the 1st attempt doesn't start the car, subsequent attempts usually fail as well until the battery drains. If I then let it sit for an hour and come back with a fully-charged jumper battery, it fires up OK. Anyone guess what's causing this sluggish warm-start problem?

Side note: my idle has been too high (1200-1500 rpm) even prior to this sluggish start problem.

Anyway, I've resolved to do a bunch of things this coming week:

• Timing belt & Water pump change (ordered the Aisin Timing Belt, Water Pump & Component Kit from Rock Auto)
  QUESTION: Does the Water Pump in this kit include the coolant thermostat? I've noticed pretty big coolant temp fluctuations while driving via an OBDII app. When I read about replacing the thermostat, there's talk of pulling it from the water pump?
• Replace valve cover gasket and some adjacent stuff. Long ago I'd had a knock sensor code. Bought some parts including a (probably counterfit) Denso knock sensor that I never installed due to a successful 'bypass the knock sensor short hack'). Anyway, Valve cover's leaking quite a bit, so I'm diving in.
• Replace plugs - I'm currently running the Denso double-platinum (OE recommended) plugs, and I've ordered 6 NGK 3452 (dbl-platinum). Question here on plugs: when shopping for these NGKs I ran across the "E3 Spark Plugs E3.56 Performance Spark Plug" as compatible. They caught my eye as they look sorta like the double platinums I buy for OE compliance. E3's plugs actually have 3 electrodes, supposedly last 100K miles with their "DiamondFIRE" tech, and they're as pricey as the double-platinums! Anyone know about E3 Spark Plugs? I'm tempted.
• Replace Fuel filter, Air filter, Oil filter Replace fluids, etc. Happily running Castrol Edge High Mileage synthetic Oil.

Hopefully with the new plugs my "sluggish warm start" problem will be solved, but as I expect a fuel related cause on that problem, I'm also running some fuel additives to clean injectors, etc.

Arsenii

Hello,

Long time no see.

It would be a little difficult to come up with the solution with information provided, especially at such respected mileage, there isn't all that much to go from frankly. A video of the issue will be helpful. I would start with the parts you listed, as they all appear to be genuine from trusted sources, and see where it goes from there. I would swap out the Fuel Filter as well, the odds are it was never done before, mine was still original when I replaced it at about 210,000 miles.

Next step would be to get the scan tool and compare the parameters when the car starts fine, and when it stutters. Check that all the hoses are connected, you can try taking one of the Vacuum Lines off to see if that will help make the start easier, pay attention to the exhaust smell. I've had an issue with my ES stumbling a bit during cold start, it turned out that the MAF sensor became more of a random number generator, the values kept changing at every stop, even though the RPM and other parameters remained the same, the issue went away right after I replaced it.

Now about the questions you listed: No, the Thermostat doesn't come with the Timing Kit, as it is located on the opposite side of the engine, below is the video on it, I would always suggest replacing it if you are draining the coolant and know it was never replaced before, it's one of those parts that can fail at any point, and is not expensive enough to justify the hassle of accessing it later. A word of precaution is to Always use OEM Thermostat and the Seal (sold separately), while it may be a little more expensive, it is completely justified when you include the price of replacing it again.

My opinion about Knock Sensor Bypass hasn't changed, it is only good as an emergency patch for a week before parts arrive, it is not a solution, and it must be repaired properly at some point, Knock Sensors, and the harsh limits of their Fail-Safe mode are there for a good reason, in severe enough cases, knocking can literally wreck an engine within minutes.

I used Fel-Pro when doing my Valve Cover Gaskets the first time, mostly because they were cheaper than OEM, and were available in store at the time, with that, when I got in there for ... and unrelated reason (described here), it turned out that they started leaking after about 4 years of service, maybe even a little less. I went with Mahle gaskets that time, so far so good, dry as a bone, and I didn't have to RTV the entire gasket surface (khm), we'll have to see how they hold up later.

I may sound like an old geezer with no imagination left in mind, but I am yet to come across something actually descent in terms of those "revolutionary" spark plug design. In fairness, I haven't tried any of their products, so I have no right to strongly suggest avoiding it, but I am not about to put my engine and amount of time it takes to replace the plugs on the line to experiment. OEM-spec plugs work quite well already, they are trusted, and could last upwards of 80,000 miles if you are careful, that is more than enough to deter me from delving into gracious world of potential alternatives.

Hope this helps and best of luck!

BMeek

Hey Arsenii! Thanks for the thoughful response... Yeah - I really like this forum, but my attention has definitely been elsewhere. Hard to believe our cup-holder hack discussion was 3.5 years ago! Good to be back for guidance :-).

OK, I believe my intermittent won't-fire-up-when-luke-warm challenge is due to 4-year-old plugs (currently running the Denso double platinums) and a sub-optimal fuel path from cheap gas & neglect, coupled with a broken cold-start mechaism (is there a cold start mechansim?). Anyway, I had ordered a fuel filter (Aisin) as I suspect it's the original in there now.

I've got the Aisin OE Temp thermostat and outlet seal in my Rock Auto shopping cart. You don't think I'll need either the left or rear housing gaskets? I don't see any video reference from you but I'll look for the Thermostat replacement how to.

Understood. I plan to see if the knock sensor wiring harness looks destroyed by heat and replace it with the OEM connector I bought 5 years ago :-). I won't put in the counterfit knock sensor I bought at the same time. I'll cross my fingers that the original sensors are still good, since new ones are ~$100ish, and undue the hack near the interior fuse box.
I'm sure glad you mentioned this - I thought I had bought a valve cover gasket long ago, but turns out I only have the . I expect I'll need this too... What else am I missing? I've now got the Mahle gasket set with the spark plug tube seals coming from Rock Auto.

Any other gaskets, o-rings or clips you suspect I'll need in this?

Also, is there any [access to stuff] benefit to doing the intake removal + valve cover gasket replacement operation at the same time as the timing belt & water pump? Does the former require a coolant drain for example? I work slowly and will be doing so on my only car at the moment :-)

I hear ya, and thank ya. E3 Spark Plugs' pitch is tempting and they've been at it for over 20 years, but I'll stick with the NGKs I just received.

Arsenii

I would say it has more to do with the mileage than with age, my plugs are not new either, but they don't have that many miles, so it will be a while until I replace them again. As for the fuel, not sure about your area, but around here the price difference between Standard and Premium gas is not that substantial, add that to the fact that you do get a better fuel economy, and help the engine perform better, and the price difference becomes marginal at best.

[EDIT]: Just realized you are from California .... emmm ... just ignore all the rambling about the fuel I guess..

Emmmm .. nooo, there isn't one in there, whatever that is...

Huh, I wasn't aware of Aisin making filters as well up to this point, do you have a link to the place you got it from..? I went with OEM there, yes it is a little pricier than I think it should be, but it's not like you need to replace it every year. If not that, Wix makes good options as well.

Never tried Aisin thermostats either, nor did I know they made them, not sure if I want to trust one frankly, considering that OEM is not that much more expensive and I do trust it, but it may just be that I forgot how to trust people at this point.

Wait did I forget to link it..? Welp, let's fix it here, better late than never I guess.. The process is a little tedious, but if you are taking the intake off completely, it will make your life a lot simpler.



Unfortunately, the wiring usually survives until you start trying to unplug it, it's like an old leaf that can sit for months on end, or until the moment you touch it. Considering the amount of work and time required to dismantle everything, let alone the cost of gaskets that should probably be replaced each time you take the manifold off, it may be beneficial to get the sensors replaced as well, though it all depends on how long do you plan to own the car. Here is a good place to get them.

The last time I dug in there, I looked through the catalogue and got just about every gasket I could find for the heads and coolant system, as I was taking everything apart, and they weren't too expensive. In your case, you will definitely need some Toyota FIPG (00295-00103), as it is the best gasket maker I could think of (even though the price reflects it quite well), here is a post about a plate that needs to be taken off and resealed, as it is a common cause for coolant leaks, and while at it, the rubber hose shown in the picture (P/N: 16261-20010) is also a common failure point, they used to be metal at some point until the cost cutter came around..

For the oil side, VVT Solenoids tend to leak over time, Part Number for the gasket is 90099-14137, depending on how neglected the engine is, you should also take a look at the Strainers for the VVT systems, here you can find some pictures, Part Number for their gasket is 90430-16007. When taking the Valve Covers off, you should also re-seal the half-rounds on the side of the heads near the camshaft, here is a picture, as they sit on the gasket maker and tend to leak.

There is actually a good benefit in doing it all at the same time, as half of the engine will be apart, hence less stuff in the way. Draining the coolant helps as well, as you will be able to take the Radiator Hose off, getting better clearance for the Valve Cover, and you will also have a chance to take the radiator out completely to inspect it and clean out the fur coat that likely got stuck in there by now, and would prevent the efficient cooling.

Other than that, it's a lot easier to access the Thermostat when everything is apart, and it will allow you to access the plate between the heads mentioned above, as that's what the Thermostat is mounted to. While at it, the Radiator hose is sitting on the O-Ring as well (P/N: 96761-35031), while mine wasn't leaking, the area was quite dirty, and there was a lot of aluminum dust inside, so I cleaned it out and replaced the O-Ring while I was there.

That's about all I can think of, and maybe it is for the better, as the list is quite extensive already.. I would definitely reserve the weekends for a job like that, in my case, since I went there for completely separate reasons, it did take me about 2 days from 10 to 8 to finish it all, though I am sure it will not take as long for you, as I am hoping you will not be pulling the camshafts out to see if they work..

Hope this helps and best of luck!

BMeek

I've been feeling a bit guilty for ghosting this thread I had started, particularly after @Arsenii's thoughtful and extensive responses, so here's an update.

The urgency of my 'warm start' problem was temporarily mitigated with Sea Foam in the gas tank and a set of new plugs (installed in bank 1 with a nifty lengthy swivel sparkplug socket despite the in-place intake, etc). After ordering all the parts & supplies I thought I needed for the full maintenance project, the weather and my schedule just refused to cooperate for a big multi-day project in my unsecured carport.

Time passed and I began seeing CEL codes I thought might be pointing to a weak coil, as the 'warm start issue' threatened to recur (probably mitigated with a strong new battery that could overcome the engine's reluctance to get going).

I again began questioning my wisdom... putting all this money into a cosmetically-beat-up 1998 car with over 300K on it. I therefore chose to try a listed as the best sellers on Amazon that fit the old waste-spark 1MZ-FE in my car ($34 for the set of 3). They're working fine - noticeably better than the old original Aisin coils that had 300K+ miles on them. I've not had the 'warm start problem' since. Once again, I deferred 'the big maint project' that I had all the parts for.

Meanwhile, my CA DMV registration was paid but incomplete awaiting a SMOG test, and the readiness monitors refused to clear. I also began seeing P0125 and P1133/1135 fault codes, and I replaced the easy-access ECT sensor that had been intermittently reporting flakey low ECT values via OBDII for some time. The new ECT sensor eliminated the flakey ODBII temp readings, but the P0125 continued to appear occassionally along with the O2 sensor-related codes. I resolved to do the procrastinated maintenance and was ready to start, but while organizing all my parts & supplies I couldn't find the damn $25 tube of FIPG I had bought months earlier.

I thought: 'screw it! This is an omen!' and I chose to just focus on what would address the problems starting with replacing the stuck-open thermostat. With the new thermostat in place, my car quickly reached normal operating temp for the first time since driving over the Santa Cruz Mountains in slow traffic during last summer's heatwave. The previously-sluggish catalyst readiness monitor now began clearing quickly after clearing the P0125 and P1135 codes that, sadly, persisted.

I decided I did need a new A/F sensor, and since the correct OEM AF sensors for my CA car are about $150 each, I again tried the route. I bought two to replace both bank 1 and 0, and finally completed the bank 1 sensor 1 installation contortion exercise.

The car fired right up and after driving around for a few miles, all the SMOG readiness monitors including the O2-sensor-related ones had cleared (except the EVAP which I've never seen complete). CA allows one incomplete monitor, so I took it to get smogged immediately. It failed due to a high HC reading at idle. I was surprised, as I had passed smog with this car several times once the catalyst monitor finally cleared even though my idle has always been too high (~1100 RPM in Park or Neutral).

Time to fix the high idle issue. In wondering about it in the past, I had priced a new IACV (~$140), and just deferred dealing with it. I then found @Hayk's pointer to this video on youtube about properly and easily cleaning an IACV: I cleaned mine according to its advice. I fired up the car and drove around, seeing the idle drop to ~900rpm for the first time, and figured it would surely pass smog but it failed again. The next day, without making any changes, I had a very slow rough idle on startup and the car nearly stalled when going into gear and trying to take off. I searched and found references to "fixing" a slow idle by fully resetting the ECU and then coaxing the ECU into relearning things as the engine warms up with a series of revs to ~2,500rpm and shifting into drive and reverse with the e-brake on and briefly/gently accelerating to let the ECU get a feel for things. I disconnected the negative battery terminal for a while and went through the process since I had thoughtlessly cleaned the IACV with the battery still connected.

Indeed, the car is now running better than it ever has for me! It's idling smoothly at around 700rpm. After a spirited 20 mile drive yesterday, all the monitors (except EVAP) have cleared, but I'm wondering if I should wait a bit longer to let the ECU continue making the best of the car's current condition before asking the guy to test it for a 3rd time. Any thoughts on this?

I had no idea that the mid-90's computer/ECU in these cars did so much to compensate for marginal issues I'd left unaddressed, and didn't realize the importance of making the ECU take a fresh look at things when ANY work is done to the car that involves ignition and air/fuel related functions.

Finally, throughout this process I'd been thinking it's time to retire this old 3ES, so I had setup a Craigslist search alert to watch for new listings around the bay area featuring "lexus es". Two days ago, I bought this:

My 'new' 2005 ES 330's best angle.


Engine view of my 2005 ES 330. 104K miles.

Now I just need to decide what to do with my well-running 1998 3ES. Based on it's 320K miles and dents, it's not worth as much as it's current performance and relatively new shocks, tires, brakes, etc would suggest.

Anyway, I'll be around here more often once again as I restore and maintain my 'new' 4ES. Looking forward to it :-).

Arsenii

Welcome back!

May sound a little rough, but I would like to be honest here. There is only so much that distinguishes a RAV4 from a Chery Tiggo T11, and every time you reach out for the "honestly-not-counterfeight-trust-me-bro" option, you keep narrowing that gap between them. Toyota must stay a Toyota if you are to keep the dependability they are so renowned for, I can just about guarantee that if you take all that literal waste out of that car and put proper OEM parts into it instead, you will solve just about all the issues you have remaining lest it turns into a pumpkin after midnight, as they are a mere cascade from a spiral into madness that was taken..

Not trying to offend anyone, just want to make myself very clear. Early in my time I did try to cheap out on the Crank Seals, thinking I can cheat the system by paying half the price, I didn't even manage to drive out of the garage before ending up with a flood of oil washing all over the place, half of the oil in the engine ended up on the floor, another half was trapped all over the engine bay. I ended up paying more than a regular price for those to get them immediately on top of a price for the junk gaskets, add to that the amount of work to replace them and the utter mess those left behind that had to be cleaned. I learned my lesson the hard way so you don't have to..

That's a big part of the resilience that those cars are so well known for, they can take a lot of beating before finally collapsing, unlike some German counterparts that will refuse to go anywhere with any sign of fault, the difference is that with German car, you either fix it or learn to walk, you have to maintain it, Toyota will keep fighting to the bitter end, and by the time the end comes, nothing in that car is left to be repaired, if it fails, it fails completely and definitively. The fact that people can be standing beside a car that has its wheels about to fall off and saying that I never need to fix anything because it's a Toyota genuinely buckles my mind, but that's beside the point.

Looks quite sharp, great price for a Post-Facelift model, especially by today's standards (khm..). Seems like it should be less of a chore to maintain, so long as you right now invest into everything it may need, new fluids, check tires, brakes, suspension, I do mean everything, as you will have to do it anyway, may as well do it all at once, it's usually cheaper and easier. 4th-gen is likely the finest ES out there, at least it has been for a very long time, not sure of the newest ones, and yours is in just about the highest trim, make sure to take care of it, and you won't need another car for a good long while.

I burned that bridge a while ago, when I ended up spending more on parts than the price of a whole car, not including the work, I would never get the full value out of it at this point, good thing is that I am not selling my ES..

Hope this helps and best of luck!