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Need Help with Diagnosis, second/third opinions about p0300 code, head gasket, water pump, timing belt diagnosis from mechanic.


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Hello everyone,

 

I just got a call from my mechanic and he said my 2008 Rx 400h needs a new head gasket, water pump and timing belt. I haven't changed my timing belt so I probably should have done it sooner. But the head gasket as I was told by another mech was that is only needs to be replaced if it overheats. It's not part of maintenance like the aforementioned parts. He said he would like to take a look at it before I go through with the $3,500 repair.

 

What happened from the start:

I had 4 misfires on 4 cylinders and the p0300 which could be anything. I kept getting that code and my car shakes when I start it. 

They replaced all 6 coils and spark plugs and it still has that code.

Now, they took allot of parts to diagnosis my car (brought it to a shop) and they said it needs a new gasket, timing belt and water pump. Labor was expensive to diagnosis and take apart this car. But the cost to repair was $3500.

Should I get a second opinion or shell out the money? My dad said not do it and sell the car as is. Buy a used car. Is this a good idea if I need to do the repairs? I bought the car for $8000, 133k miles. I only drove it for 22k~ miles. Sad. I liked it.

The car has 155k miles and I think it's a nice looking car and drives like...well, luxury. Smooth. Considering it's an old car. 

Worth to keep or sell for 4000-5000 (mechanic special)? What other issues other than the hybrid battery and transmission should I be worried about?

 

Thoughts?

 

Thanks,

David

Edited by David_BayArea
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These are the classic possible causes of a p0300 code:

As you mentioned, it is a very vague code that should be followed by a very specific sequence of tests. What should never be done is replacing parts without knowing for certain that any have actually failed. Your timing belt and water pump should've been replaced at 90,000 miles and the spark plugs at 120,000 miles if the maintenance schedule is the same as the one for our RX400h.  Before you bought the vehicle, did you verify that the required maintenance was completed?  Ours has about 134,000 miles on it and the coils and injectors are doing fine.
But I think if the intake manifold gasket is leaking, that is the first thing that should've been replaced. A head gasket leak would typically result in white smoke coming out the exhaust or coolant in the oil.

 You may want to talk to the mechanic who diagnosed the vehicle. I would ask him:
1. What made you determine that the drivability issues were due to bad spark plugs and coils?
2. Did you know that there was a leaking head gasket at that time? What made you think the head gasket was leaking?
3. What exactly is needed to get the vehicle running right? If they replaced anything that did not cure the original driveability issue, then you should not have to pay for that, whether they are overdue to be replaced or not. The focus should've been on the problem at hand, not anything else unless those parts were near failure.

You may want to take your RX or have it towed to a Toyota dealership. The $180 diagnosis fee may be well worth it. Mechanics are famous for presenting a "laundry list" of things they would love to do to take in the big money, but you should always make it clear that you want to know which line items are needed to fix the issues at hand. Always know your maintenance schedule, beforehand.

In the meantime, find out how much your vehicle is worth if there is nothing wrong with it. Because you have a Lexus and used vehicles are selling for high prices, you may want to invest half of the value.

  

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Hi Rx,

I went to the shop in person and another shop nearby afterwards. They said it is the 

  • Leakage of the head gasket

So, the coolant must be leaking into the oil. 

 

1. What made you determine that the drivability issues were due to bad spark plugs and coils?"

I had 4 misfires, and the p0300. Once they replace the coils and sparkplugs, the 4 misfires codes went away. Not the p0300.


"2. Did you know that there was a leaking head gasket at that time? What made you think the head gasket was leaking?"

Me? Definitely not. I'm not a car guy/know much about cars unfortunately. Not me..but as mentioned, they examined the gasket and it is degrading or failing. Whichever way mechanics want to phrase it..
"3. What exactly is needed to get the vehicle running right? If they replaced anything that did not cure the original driveability issue, then you should not have to pay for that, whether they are overdue to be replaced or not. The focus should've been on the problem at hand, not anything else unless those parts were near failure."

They said this is unsafe to drive as is because of the gasket. They did replace something after the coils/spark plugs. I don't remember what it was but it was $500 and they said the p0300 is gone so safe to drive. When I started my car, the car shook and i ran the scanner, and it is the p0300 again.

I left my car there and they found the timing belt, gasket and water pump problems. My timing belt was replaced at 90k miles by the previous owner. they said it needs to be replaced? it is only 155k miles.

I should ask for a refund for the $500 fix. I will look at the receipt to see what they replaced later. They said "it" was wearing out. 

 

I asked them if this car is worth the fix or sell it to someone as is. For 4000-5000. They said it is. but then again, you may be right..mechanics may be looking for some work.

My family has known them for years when we had BMWs and Mercedes. I don't know if I should it to the other shop and get a second opinion. Other shop quoted 500 less.

Isn't car dealer mechanics very expensive? I wouldn't mind going there knowing the mechanics there may not care about extra charges or unnecessary "fixes". Plus, it is the manufacturer who trains and employs these mechanics.

I really like this car and the look of it. 2008 400h, blue.

 

Thanks again.

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  • 2 weeks later...

Dealership mechanics, like mechanics at many independent shops, will often perform a "safety" inspection. Sometimes what they find as needing replacement can actually last months or years without needing to be replaced. Other times, a failed part or parts, like sparkplugs, coils, or injectors can cause other failures (catalytic converter, for example). 
Some dealerships will post a video or photos of the parts they inspected. If they don't, they expect you to trust their findings.  

 Frankly, I am baffled that your RX, which is newer than our RX, needs that many repairs. Is there someone you know who is a sort of shade-tree mechanic and who can go with you to discuss the issues? The timing belt should not need to be replaced. They should've taken a photo of the belt. Again, get them to reveal what is necessary to get the RX running well. 

Quote

They said this is unsafe to drive as is because of the gasket. They did replace something after the coils/spark plugs. I don't remember what it was but it was $500 and they said the p0300 is gone so safe to drive. When I started my car, the car shook and i ran the scanner, and it is the p0300 again.

This scenario should never happen. It tells me that they are not very competent. I'd be tempted to take it somewhere else, perhaps a Toyota dealership.

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42 minutes ago, RX400h said:

Dealership mechanics, like mechanics at many independent shops, will often perform a "safety" inspection. Sometimes what they find as needing replacement can actually last months or years without needing to be replaced. Other times, a failed part or parts, like sparkplugs, coils, or injectors can cause other failures (catalytic converter, for example). 
Some dealerships will post a video or photos of the parts they inspected. If they don't, they expect you to trust their findings.  

 Frankly, I am baffled that your RX, which is newer than our RX, needs that many repairs. Is there someone you know who is a sort of shade-tree mechanic and who can go with you to discuss the issues? The timing belt should not need to be replaced. They should've taken a photo of the belt. Again, get them to reveal what is necessary to get the RX running well. 

This scenario should never happen. It tells me that they are not very competent. I'd be tempted to take it somewhere else, perhaps a Toyota dealership.

That's what I've been telling my dad and sister. So many red flags for mechanics that's been doing this for decades.

I want a $500 refund. I kept asking them if it is safe to drive. They said to keep driving it until the other cylinders show up on the scanner. I could have damaged the engine. told me that I reset the system with my ODB2 scanner. SO i had to drive a week with this random misfire code until they know what cylinder is the cause of this.

 

They only replaced 3 out of 6 coils and sparkplugs. When I first took it there, I found 4 misfires, and the p0300. But they only replaced 3 out of 6. I thought replacing the other coils would work but it didn't. They replaced the other 3 and nothing was fixed. they replaced something for $500. Kept the car longer and found other issues.

After I paid for $500 repair...I looked at the dad and said to replace the other coils and spark plugs. Then left.

The 3 of us drive  or used to drive the Rx 350 and 400h. My dad says they're understaffed. Probably don't have time to do a thorough job? Have bigger jobs at hand? I hope they aren't looking at us (we own a small business that they know) as a quick way for some work. 

 

They said that my dad's 06' 400h transmission needed to be replaced. After that, he's been driving that 06 400h without issue. Maybe they saw it was wearing out and so they made that suggestion?

They said the failure rate of that head gasket happens to 200 out of 1000 cars like this.

I just want to make this drivable. I've been using an old Corolla for work.  I actually need a second opinion.

I don't know many mechanics. I didn't know mechanics at dealerships and independent parties take photos. That's good. When I do inspections, I take allot of photos so clients and realtors can look at it themselves. I want to be transparent. If I make a bad call, it's on me. 

 

Do you think this rx 400h can go to 300+ miles? Should I sell it for 4000-6000 as is?

I paid 8000 when it had 133k miles. Got a mechanic to look at it prior purchase.

Thinking of a 2012 or newer Prius.

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At least one or two RX400h owners and members of this forum have over 250,000 miles on their vehicles, so yes, absolutely it is possible. Did you check autotrader, craigslist, and cars.com to see what your RX would be worth if it is running well? It it is worth $10,000 and you can have everything fixed for less than $5000, then it may be worth the expense but not as payment to those guys who don't seem to have a clue.

I suggest spending $180 or so for an inspection by a Toyota dealership. Check yelp.com to see what their ratings look like. If the issue is not related to the hybrid system, then an experienced independent shop's technician should be able to troubleshoot more effectively. If you ever watch Rain's garage or Car wizard on youtube, you'll see how troubleshooting should be done.

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21 minutes ago, RX400h said:

At least one or two RX400h owners and members of this forum have over 250,000 miles on their vehicles, so yes, absolutely it is possible. Did you check autotrader, craigslist, and cars.com to see what your RX would be worth if it is running well? It it is worth $10,000 and you can have everything fixed for less than $5000, then it may be worth the expense but not as payment to those guys who don't seem to have a clue.

I suggest spending $180 or so for an inspection by a Toyota dealership. Check yelp.com to see what their ratings look like. If the issue is not related to the hybrid system, then an experienced independent shop's technician should be able to troubleshoot more effectively. If you ever watch Rain's garage or Car wizard on youtube, you'll see how troubleshooting should be done.

This has been a headache. I don't even have the ability to tow the car from the shop to Toyota or another independent shop with AAA.

 

I've always thought these can go for 300k+ easy. Since it's a Lexus. How many miles is on yours?

I see a rx 400h, 153 k miles, gold for 8,800 on Facebook marketplace. And this model is the upgraded model with the DVD player. I got this Rx 400h for 8,000.

 

I just need another opinion before I sell this. 

Thanks,

David

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Ours has about 134,000 miles on it. The worry I'd have if I were you is whether you'd be able to sell it when it is not running well and if you are not perfectly sure what is causing the drivability issues.

Why don't you call a towing company to see what the cost would be to tow it to the closest Toyota or yelp-recommended independent shop?  

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3 hours ago, RX400h said:

Ours has about 134,000 miles on it. The worry I'd have if I were you is whether you'd be able to sell it when it is not running well and if you are not perfectly sure what is causing the drivability issues.

Why don't you call a towing company to see what the cost would be to tow it to the closest Toyota or yelp-recommended independent shop?  

Quote

 

I'm not worried about the $100 fee to tow it. I just don't know where and how much the dealership would charge for a simple to complex/serious repair. There's a dealership upcharge. I take it there to get a diagnosis and go elsewhere?

Official dealership mechanics seem to get the job done, are thorough and mechanics there appear to be impartial to customers and do their job regardless.

My cousin is a mechanic at a Toyota dealership.

I see a fair share of these rx400 or rx 350 around this mileage on FB marketplace. Or up to and around 200k miles. Decisions. I wouldn't mind selling it but you're right. People have to know what exactly is wrong with the car to not make it driveable. 

 

All those maintenance issues like timing belt and water pump are normal. I would be selling as is. People will know about the maintenance problems if they know much about cars. You're right. I need a diagnosis for the p0300 and fix whatever needs to be fixed. The mechanic appear to be certain it needs a head gasket replacement.

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I have a friend with a 1997 Toyota Avalon with V6 engine. It has 295,000 miles on it and has not yet required head gaskets. That's why I am a bit skeptical about that diagnosis. You may want to ask your cousin how many sub-200,000 mile Toyotas with V6 engines have had to have their head gaskets replaced.

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My goodness.  Haven't read all the back and forth, but 50 years plus of being a mechanic means you should RUN, or have it towed asap from the current shop.

Reasons:  No car in the history of the planet has 3 coils go bad all at once.  Not possible to diagnose injectors unless they are pulled and flow tested.  Head gasket problems are relatively easy to diagnose on the V6.  Since head gaskets don't blow simultaneously, unless you SERIOUSLY overheated the old girl, the sparkplugs on either bank will be utterly absolutely clean, cleaner than the other bank.  Really, the best way to QUICKLY check a bad head gasket is to smell the exhaust.  A sweet smell, obvious as hell.

Timing problems, more than likely.  Car can easily be saved with a competent mechanic.  Don't be afraid to pull out of the shop -- money spent is money gone.  Which is why is use YELP, etc.  Good luck.

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On 8/3/2022 at 10:15 AM, RX400h said:

I have a friend with a 1997 Toyota Avalon with V6 engine. It has 295,000 miles on it and has not yet required head gaskets. That's why I am a bit skeptical about that diagnosis. You may want to ask your cousin how many sub-200,000 mile Toyotas with V6 engines have had to have their head gaskets replaced.

So are the other 2 mechanics I've spoke to....I talked to a third one while getting my Corolla's breaks replaced and he said that 4 cylinder typically have head gasket issues. Not 6 cylinder engines. So he found it odd himself.

He wanted to replace the engine w/ one with lower miles. Rather than change the belt, water pump and head gasket.

The more and more I read and talk to other mechanics, the more I have to tow it to another shop.

 

The mechanic also said that if it is a gasket replacement that I need..I may as well get a new engine (07 Highlander or Rx 400h) with lower miles.

We found a Highlander in Fresno with 68k miles for $1250 shipped. $2,000 is the labor that they charged. That solves the gasket, timing belt and water pump issues.
He said there is too much labor for replacing head gasket.

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On 8/5/2022 at 8:18 PM, 300EChuck said:

My goodness.  Haven't read all the back and forth, but 50 years plus of being a mechanic means you should RUN, or have it towed asap from the current shop.

Reasons:  No car in the history of the planet has 3 coils go bad all at once.  Not possible to diagnose injectors unless they are pulled and flow tested.  Head gasket problems are relatively easy to diagnose on the V6.  Since head gaskets don't blow simultaneously, unless you SERIOUSLY overheated the old girl, the sparkplugs on either bank will be utterly absolutely clean, cleaner than the other bank.  Really, the best way to QUICKLY check a bad head gasket is to smell the exhaust.  A sweet smell, obvious as hell.

Timing problems, more than likely.  Car can easily be saved with a competent mechanic.  Don't be afraid to pull out of the shop -- money spent is money gone.  Which is why is use YELP, etc.  Good luck.

I had 5 codes, p0300, p0301, p0305, p0302, p0303. We replaced the all 6 spark plugs and coils and everything but the p0300 went away.

So you think it's a timing belt issue? What problem do you think my lexus has? It shakes and has a p0300 code.

I want to leave. my dad OK'd the repairs. I 'm a bit iffy.

TIA

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3 hours ago, David_BayArea said:

So are the other 2 mechanics I've spoke to....I talked to a third one while getting my Corolla's breaks replaced and he said that 4 cylinder typically have head gasket issues. Not 6 cylinder engines. So he found it odd himself.

He wanted to replace the engine w/ one with lower miles. Rather than change the belt, water pump and head gasket.

The more and more I read and talk to other mechanics, the more I have to tow it to another shop.

 

The mechanic also said that if it is a gasket replacement that I need..I may as well get a new engine (07 Highlander or Rx 400h) with lower miles.

We found a Highlander in Fresno with 68k miles for $1250 shipped. $2,000 is the labor that they charged. That solves the gasket, timing belt and water pump issues.
He said there is too much labor for replacing head gasket.

Frankly, this is insane advice. Unless you already destroyed your engine by overheating it, swapping in a used engine is not only a potentially more expensive option, but is also very risky.

When I was 21, I had my 68 Cougar's engine swapped by one pulled from another 68 Cougar. The engine lasted about 1 year. 

Did you compare local shops on yelp.com? I would do the same for Toyota dealerships and their service departments. Conduct your due diligence and get back to us.

By the way, a Highlander with 68K miles for 1250 shipped is HIGHLY suspicious. 

 

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40 minutes ago, RX400h said:

Frankly, this is insane advice. Unless you already destroyed your engine by overheating it, swapping in a used engine is not only a potentially more expensive option, but is also very risky.

When I was 21, I had my 68 Cougar's engine swapped by one pulled from another 68 Cougar. The engine lasted about 1 year. 

Did you compare local shops on yelp.com? I would do the same for Toyota dealerships and their service departments. Conduct your due diligence and get back to us.

By the way, a Highlander with 68K miles for 1250 shipped is HIGHLY suspicious. 

 

It's both equally expensive. 3250 for a new used engine. Versus 3400 for timing belt, water pump and head gasket.

 

I did check Yelp and Google. There isnt' a shortage of good mechanics here in the Bay Area.

 

Yes, it is suspicious now that you mentioned it. A 15 year old Highlander engine with 68 k miles. Some of the engines on Ebay have 15x miles.

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2 hours ago, RX400h said:

A new engine, installed for only $3250? That is a bit hard to believe. 😏

Everything is. Are you from t he Bay Area and know any good mechanics here?

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I'm way down in Southern California. Did you peruse the Yelp ratings of Toyota dealerships and independent shops?

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On 8/5/2022 at 8:18 PM, 300EChuck said:

My goodness.  Haven't read all the back and forth, but 50 years plus of being a mechanic means you should RUN, or have it towed asap from the current shop.

Reasons:  No car in the history of the planet has 3 coils go bad all at once.  Not possible to diagnose injectors unless they are pulled and flow tested.  Head gasket problems are relatively easy to diagnose on the V6.  Since head gaskets don't blow simultaneously, unless you SERIOUSLY overheated the old girl, the sparkplugs on either bank will be utterly absolutely clean, cleaner than the other bank.  Really, the best way to QUICKLY check a bad head gasket is to smell the exhaust.  A sweet smell, obvious as hell.

Timing problems, more than likely.  Car can easily be saved with a competent mechanic.  Don't be afraid to pull out of the shop -- money spent is money gone.  Which is why is use YELP, etc.  Good luck.

Check out this Toyota mechanic's Youtube channel on cars, car repairs.

Diagnosis on head gasket in Lexuses and Toyotas....

 

 

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That's a good one. I watch this channel every so often. The Sequoia in the video has 300,000 miles on it and it is only now having head gasket leakage.  The question is: Did the dealership do their due diligence?

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12 hours ago, RX400h said:

That's a good one. I watch this channel every so often. The Sequoia in the video has 300,000 miles on it and it is only now having head gasket leakage.  The question is: Did the dealership do their due diligence?

They weren't diligent the first or second time I left my car there. Maybe the third time when they pulled 'things' out to inspect. I don't know. I may be giving them too much credit.

that shop has 3 guys working there. I don't know if shops are normally that sized. One of them said they checked everything PRIOR to the head gasket diagnosis. He said that it takes a long time to make a diagnosis for the p0300 code. Looking at that Youtube video, it doesn't seem like it takes a long time to rule that head gasket issue out.

The third mechanic asked me if my car shakes when I brought up the head gasket replacement. So maybe the mechanic is right about the diagnosis. 

 

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Now you know what a good mechanic does to verify whether the head gasket is leaking. Knowing this information enables you to ascertain whether the mechanic verified the leakages without removing the head(s). If you do have your vehicle towed, make up a list of current symptoms, beforehand, but don't tell the new mechanic what the previous mechanics believe to be the culprit. Do give the new mechanic that list of current symptoms.

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3 hours ago, RX400h said:

Now you know what a good mechanic does to verify whether the head gasket is leaking. Knowing this information enables you to ascertain whether the mechanic verified the leakages without removing the head(s). If you do have your vehicle towed, make up a list of current symptoms, beforehand, but don't tell the new mechanic what the previous mechanics believe to be the culprit. Do give the new mechanic that list of current symptoms.

yeah...now I know a little about diagnosis..I mean, now I know I have to learn about cars in my spare time and get multiple opinions without telling each mechanic what so and so said. Now I know I have to google like no tomorrow and talk to people like you before signing off on a costly repair. 15xk miles, 2008 Lexus needing a head gasket. I mean, now that I talk to people, it is highly suspect.

We're in a recession. Wish mechanics took photos and videos of their findings just like I do when I inspect homes. Especially subarea photos. Some transparency and build trust. If I or they mess up, we mess up. Things are fixable.. Anyways, I just need this thing fixed. He offered to refund and take the part out for that $500 'repair'. 

 

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Good. I would take the $500 and have the car towed to a well-rated shop, especially one that has worked on your model, a non-hybrid version, or a different model but with the same engine. If they never have, consider a well-rated Toyota dealership.

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