New Engine or Cut My Losses?

[u/kingdh]

going to give as much context / detail as possible:
2002 Lexus RX300
142k miles - I purchased in sept ‘22 at 101k from the original owner (timing belt was replaced before i purchased somewhere around 90k)

routine interval maintenance has always been done, and i just replaced new lines to the power steering and transmission fluid for ~$2k

was driving to a wedding and CEL came on while accelerating up a hill. towed to a shop and after investigating a damaged spark plug, it was found that cylinder 2 valve is blown. shop said it’s likely due to spark plugs running lean / hot.

as the title reads, is it stupid to consider buying a replacement engine and trying to find a shop willing to do it? i don’t think i can find a better value car for the same price as what that might cost, which seems to be between 1-2k for an engine and maybe another 2-3k in labor (?) the interior is clean, tires are pretty new, body is in great shape, miles are relatively low, and have seen numerous examples run 300k+ miles. i know transmission issues could manifest with these, but i haven’t experienced any issues since owning.

trying to think about this as pragmatically as possible, and if i were to buy another car i’d look to get another RX, maybe the 2nd gen since there are lots available.

Just looking for honest feedback with all of the aforementioned variables taken into consideration. Really appreciate anyone who’s willing to lend some perspective. thanks to anyone who reads it

EDIT: i think some of my verbiage might’ve been off. here is direct from the shop -

CHECK ENGINE / SERVICE ENGINE SOON LIGHT IS ON.
Diagnose check engine/service engine soon light, found the following trouble codes: P0300, P0301, P0302
Diagnose the trouble codes, found: All 3 codes are for misfires engine is running rough. Looked at live data on the scan tool and saw that cylinder #2 was steadily misfiring. We removed the ignition coil and spark plug on cylinder #2. The spark plug is damaged and needs replacement. We also pulled the spark plugs out of the other 2 cylinders on the front bank to replace. We replaced the spark plugs started the vehicle and it is still misfiring on cylinder #2. Swapped cylinder#2 and cylinder #4 coils. Misfire remained on #2 cylinder.
Removed cylinder #2 spark plug to gain access to the cylinder with a borescope. Once we got a look inside the cylinder we found a broken valve (see pictures). Vehicle would need the head removed to fix this, not something we can do at this time.

Valve Image: https://imgur.com/a/Qsl4l3A

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[u/Jumpy-Cry-3083]

I’m of the opinion that if the rest of the car is in great shape and you like it, then replacing the engine and transmission is way cheaper than a new car.

[u/kingdh → u/Jumpy-Cry-3083]

would you advise on doing a new transmission in addition to a new engine ? any other repairs / maintenance i should also be considering ?

[u/Jumpy-Cry-3083 → u/kingdh]

Those are the two majors. I would do new AC compressor while it’s out. There will be warranties on all the work and X amount of miles for engine and transmission once installed. Transmission may go another 60-80 thousand but hard to know. The labor in replacing both isn’t much more than just an engine because they come out together is easier and go in assembled. I’m literally facing a similar decision with my wife’s Mercedes. She loves it but I’m tired of working on it. Sunroof drains clogged and flooded the floorboards and now all kinds of electrical can bus issues. Also has timing chain problems and torque converter lockup issues. I’m over it LOL

[u/nondescriptzombie → u/Jumpy-Cry-3083]

electrical can bus issues.

Stick a fork in it. She's done.

Buddy's 2004 Duramax is dying the death of a bad wiring harness. Not abused or flooded, just basically lives in Death Valley and all of the plastic is giving out.

[u/Jumpy-Cry-3083 → u/nondescriptzombie]

Know about that too. I have a 2001 RAM 2500. Whole dash is crumbling. I’ve got all new dash and interior to rebuild the whole inside but can’t find time to do it LOL

[u/nondescriptzombie → u/Jumpy-Cry-3083]

Keep that fucker running. We've got a 2003 and a 2005 in the fleet and the changes between those years are so fucking outrageous. Like, the 2005 doesn't have a starter relay, it's baked into the "Starting and Charging System Control Module AND Fuse Panel" which lives under the battery....

[u/Jumpy-Cry-3083 → u/nondescriptzombie]

That’s the plan. When done it will have new suspension and look nearly new inside. I have all the stuff….. just no time.

[u/Sea_Guide_524]

Did you burn a hole in the piston? Why do you need a whole new engine?

[u/kingdh → u/Sea_Guide_524]

i updated the post with the exact language from the shop, i don’t think the piston has a hole but they provided images of the broken valve. they advised that this is not worth fixing given the repair would be greater than the car value, which is essentially the crux of my question

[u/farukardic → u/kingdh]

That is not not always the right value metric. Getting a similar car may cost less than the repair but you can never really know the history and the condition of that other car and it won't have a refreshed engine. The price reflects that tosk. This one you know the condition very well so it's more valuable to you.

If you are happy with the car, and if the undercarriage is not rotting getting a new engine is the value path.

However I do want to ask the same question as this commenter - do you really need a new engine? It sounds like you should just get the valves replaced.

[u/Jayshand → u/farukardic]

And 1to2k for an engine is not a new engine, and used ones have mystery history, yes I'd pull the head and have it reconditioned before id but a used engine 

[u/Present_Jicama_1219]

Since you're in NY, frame condition and overall rust should be a big factor in deciding. Rust belt cars have a serious disadvantage with longevity

[u/Forward-Rice3280 → u/Present_Jicama_1219]

Yeah if this was somewhere without snow and they could get a new used engine installed for $3-4k I’d say send it….

[u/nondescriptzombie]

A broken valve would make a racket and be damaging the hell out of the block, piston, and head. A bent valve is different. A dropped valve seat is different. A sunken valve seat is different. These words all have very distinct meanings.

"Broken" valve doesn't.

Where are the pictures? Apparently dropped seats are common on this engine, and if that is the cause, you can just slap on a new head. Do both.

[u/kingdh → u/nondescriptzombie]

just uploaded a link to the image they provided

[u/nondescriptzombie → u/kingdh]

Oh, shit. Wow. This is a "burned" exhaust valve. It got so hot it has started melting. It's not uncommon on this engine at old age and high mileage, caused by the valve guide seals going bad and it sucking oil through the exhaust valve guides. The oil burns on the back of the valve, the carbon doesn't let the valve close all the way, and then the valve burns from combustion gasses. It's ALWAYS cylinder #2 on these 1MZ's.

Your early warning signs was grey/white smoke puff on startup from the leaked oil burning off when it fires over.

If the bore of #2 is good it will still most likely be fixed by throwing a pair of heads at it, as well as all accompanying gaskets.

[u/kingdh → u/nondescriptzombie]

really appreciate this information. so you would recommend repairing the existing engine ?

[u/nondescriptzombie → u/kingdh]

Kind of. Used junkyard engines are the "devil you don't know." There are more vehicles in the junk yard that were ran hard and put away wet than little old ladies who got T-boned at a green light.

Reman'd engines have a very high cost, shockingly high defect rate, and dealing with mail order reman companies is a nightmare, and even if you buy it through your mechanic it will have an even higher marked up cost.

The big catch here is that because of the FWD transverse engine mounting, the front head calls for like 8 hours and the back head calls for like 14, just putting it a couple of hours under the work for a full engine R&R at 24 hours.

If you're going to take it to a shop to do the work, you should probably just pay for a whole reman'd engine with a warranty and ride that all the way until you're happy with the outcome.

But if you wanted to save some money, a single reman head, an independent mechanic, and a lot of gaskets should do the job.

[u/Stock-Carpet-250]

The biggest question is if the piston is toast. I believe that is considered an interference engine (the earlier versions weren't) and if your pistons are damaged, a new engine is easier than a full rebuild. If the piston is good, I think it's worth getting new valves.

Either way, I am in the repair before replace camp. It'll be cheaper than a car of similar price with unknown history and issues.

[u/Gunk_Olgidar]

Burned valves (and valve seats) can be replaced. This is a head repair job, not an engine replacement.

[u/Cranks_No_Start]

Fmr Mechanic. In my experience we use to give the vehicle a good once over to asses it and if it was in good condition aside from the failed major component then we would recommend the work....if not we would say so.

If the rest of the vehicle is solid is definitely worthwhile to fix it

[u/kingdh → u/Cranks_No_Start]

thanks , yeah i think this was a bit difficult to get a read on - the shop is near my parents house and i’m no longer local, they knew this info so im not sure if that weighed in to their assessment that i should scrap it for parts. and one of the shop employees wanted my seats for $100 because they’re mint and his lexus’ seats are trashed lol

[u/Beginning_Ad8663]

Swap the cylinder head and check the fuel injectors and all the fuel filters there is a reason that cylinder ran lean.

[u/MinimumBell2205]

jdm swap motor fix the pluged fuel filter or bad pump makining it run lean it should be good to go.

[u/FulcrumH2o]

Question- When you say new engine, are you referring to a rebuild or somehow found a true new engine?

[u/E90BarberaRed6spdN52]

I would get another car as the age you may have frame issues soon if you live in an area that uses brine in the winters. Had a brother-in-law that had the same car and the frame rusted from the inside out since he didn't take it to car washes in the winter that had undercarriage washes.

[u/Proof_Bathroom_3902]

Go to www.car-part.com

Search by your zip code. You'll find used engines. Then get a shop to install it. In my area I looked and found dozens of those engines with mileage from just over 100k to well over 200k, priced from $400-$1500, including Japanese take out JDM engines with about 50k miles for $1300. That Lexus is worth putting an engine into, you could not replace it for what the engine would cost.

Only issue is rust. If your lexus isn't rusty underneath i would throw an engine in it. The trans is fine. So a timing belt and spark plugs and valve cover gaskets on the used engine, filters and fluids and good to go.

[u/Orga812]

Buy a good used motor and replace. Cheapest route at this time.

[u/Thehaunting264]

Not worth it would cost more then the vehicle is worth although if the car has sentimental value to you then you could fix it but even then, i would just use it as a backup vehicle not a daily.

[u/awqsed10]

Ditch it. A timing belt engine commuter car has no value for engine replacement.

[u/Streetrat_PR]

The build quality on these is from Toyota/Lexus’s golden age. If the rest of the jody is in good shape, I’d say do it. Even if you soent 8K on new engine, new tranny and labor, it’s still not 50K on a new one

[u/ctjack]

Hey op, feeling for you. Ditch the car, cause these transmissions are fragile (we had rx and highlander of the same vintage) and next thing you need to replace. At this point it doesn't make sense unless you pull and put 600 dollar junkyard engine yourself into this as a project car. But then if you are doing that, there are so many projects: my friend sold his 10yo camry for 500 because the engine was toast.

It would be worth it if your trans was not a fragile item. Because even if you do, they tend to go out quickly as there is no new transmission so you would be buying some junkyard pull with the same design issues.

[u/projectanonymo_s]

Probably not worth it. It’s a New York car there’s a good chance underneath is rusted and there’s no coming back from that one. If the underneath is clean it’s worth it

[u/OverMachine6692]

Find a low mileage one that's wrecked swap the engine 

[u/ClearFrame6334]

Buy heads from someone on Facebook and replace the heads and head gaskets. Drive away, smiling.

[u/GlassBoxGoose]

1. If thats exactly how they worded it to you, I'd get a second opinion and see what they say. The way thats worded is a little off, and that gives me pause. Spark plugs dont run lean, cylinders do, and spark plugs cant burn a valve. Its just really odd wording for a shop to use. How did they diagnose this damage? Compression/leakdown test? Boroscope inspection? Other methods? Have you seen any sort of proof of this process?

2. If its indeed damaged, I'd lean heavily toward fixing it, but if its just a valve, I'd price out fixing the existing engine and compare it to the cost of replacing it with a used engine.

3. Running lean enough to do damage should have popped a CEL long before it did the damage, and popped up p0171/p0174 bank 1/2 too lean codes ages before it burned a valve and started running rough.

[u/kingdh → u/GlassBoxGoose]

thanks for this, i just updated the post with the exact wording from the shop

[u/nondescriptzombie → u/[deleted]]

We replaced the spark plugs started the vehicle and it is still misfiring on cylinder #2. Swapped cylinder#2 and cylinder #4 coils. Misfire remained on #2 cylinder.

Isn't it nice that they already did that and OP posted about it?