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PT Cruiser Turbo Clogged

Our 2005 PT Cruiser has a 2.4 liter turbo. We had to replace the turbo at 78K miles due to “carbon buildup and clogged” so said the dealer. I can not get any local mechanic to tell me why this happened or if it is normal. My wife claims it is because I have been using the cheap, mid-grade gas. I tell her, no, it was because of the cheap oil I was using. I am now using synthetic oil. One mechanic said the turbo needs to be “blown out” occasionally, by either high speed driving or fast take offs. Bottom line: What would make the turbo carbon up so badly that it must be replaced? What can I do to have this not happen again around 156K? Must I always use premium gas?


I believe premium fuel is required in those.
Check your owners manual. Does it say recommended or required?
In my opinion I dont think the oil had anything to do with it.

Must I always use premium gas?

What does the owner’s manual say. Chose One:

  • Must use High Octane

  • Should use High Octane (you will a little more power if you use high octane when recommended.

*Should use regular.

Generally is to best to follow the recommendations found in the owner's manual.  

Note: High Octane does NOT have more power than regular. It may allow you to get a little more power with some engines or maybe not.

Again, different cars have different needs.  Check the owner's manual.  If you don't have or can't find an owner's manual for that make model year and engine, ask around for the correct information for your car.

Clean or replace the PCV valve ,

If it is a GT Turbo you need premium but with a Limited Turbo you can use regular.

Manual recommends 91 Octane. But would lower octane cause the turbo to carbon up? What else could cause it and is this typical?

The mechanic that advised you to drive at higher speeds might be on to something. I would forget “fast takeoffs” in a PT Cruiser. If you do a lot of in-town driving and short trips I think it has the possibility of creating carbon buildup because the turbo is driven by the exhaust. I don’t believe that oil will necessarily cause the buidup.

This is not an octane problem and the octane of the fuel has no effect on the turbo itself. “The Dealer Told You”…How many times have we heard that?? It is not correct… The person who told you that was a service writer who worked for the dealership. The OP said “replace the turbo”. To me, that means there was a inoperative turbo that the OP could inspect himself, his old turbo unit, and that examination would reveal what REALLY caused the turbo to fail…Most turbo failures involve the failure of the center support bearing caused by oil coking when the engine oil is low quality or is not changed often enough…78,000 miles is a reasonable life for a turbocharger that came as original equipment in an economy car…

By having an independent shop rebuild the turbocharger, (they disassemble the unit and replace the center bearing and clean out the oil feed and return passages) a considerable amount of money could be saved over having the dealership replace the unit with a new one…

Agreed with Caddyman.


if your on it b4 you shut her down make sure to lety it idle for a little bit so the turbo slows down and cools off . this way the oil dos’t get cooked . read the owners manuel about the turbo’s needs. a lot more newe cars our coming to market w/small engines w/turbos for more power when its needed and increased mpg when not pushing down on the go pedal. no reason why the replcement turbo won’t last longer if you tajke care of the little things promted oil changes with the correct oil and a quility filter use the octane fuel that the owners manuel says to use. todays turbos our more relible becouse the our waster cooled and few small changes in how you drive the turbo should hold up for a long time.

The important thing with turbo cars is simply changing the engine oil at short or severe intervals.

Turbo’s last a long time with proper oil changes. My mom’s Saab did 250k(sold) on original turbo and her likely dino oil changes every 3000 miles.

Our Subaru Legacy turbo (132k) is working perfectly fine with off brand oil(Amalie) from my mechanic every 3k-3.5k miles. Synthetic is better but I think early oil changes best. The engine also has seen SuperTech from Walmart when I did it.

Less than required octane will damage your motor not the turbo.

I agree entirely with Caddyman. I doubt you had “carbon buildup” on the turbo, and if you did it wasn’t caused by the gas. That said, there is almost never a reason to get midgrade gas. Either your car requires premium, or it doesn’t. If it does, midgrade is too low. If it doesn’t, midgrade is 10 cents/gallon extra for nothing.

I too suspect your bearing failed, and I suspect it’s partially because of the “cheap oil,” and partially because you might not have been getting it changed often enough. Turbo cars require more care and feeding in the oil department than naturally aspirated ones do.

Start by thinking about where carbon comes from. It comes from hydrocarbons, either the gas or the oil.

It can come from the gas if the engine is operating too rich. If so, there isn’t enough oxygen in the mix to allow all the carbon in the gas to become carbon dioxide after the molecule splits. That could be due to a few causes, perhaps the most common being a bad oxygen sensor. It can also come from the gas if the maintenance has not been kapt up or if the injectors areen’t closing properly… Or if an engine is forced to run inefficiently because the owner is going for the “how long can I go without maintenance” award, that could easiy cause carbon buildup in the turbocharger.

It can also come from burning oil. How much oil are you using?

Oh, and if oil is getting past the seal in the turbocharger and getting injested, that counts as burning oil.

I believe this to be a case of an owner who tried to cheap out on the oil (and possibly also by extending the oil change intervals) in a vain attempt to save money.

Turbo-charged engines definitely need high-quality oil, and if I owned one, I would use only synthetic oil. Additionally, even with synthetic oil, I would make sure that the oil was changed every 4k-5k miles.
If the OP had done both of those things, it is very unlikely that he would have experienced a gunked-up turbo charger.

define cheap. Is it whatever was on sale or store brand synthetic oil or just regular oil?
Did you change the oil according to the owner’s manual? Did you go by miles or months? Even if you only put 3000 miles on your car a year, the oil still needs changed more than once a year. My car says to change it every 4 months or 5k miles; I have just under 7500 miles on it after 2 years of ownership and have changed the oil about 6 or 7 times already despite the low miles.

Do you let your engine idle after you’ve been out driving for awhile? If not, the oil may have been coked, and that’s never a good thing with a turbo charger.

Yup. That’s why I like turbo timers. Really, cars that come with turbos from the factory should come with timers from the factory too.

Idling (or turbo timers) are not needed unless motor is driven hard and then immediately shut off. Otherwise simply driving into your parking spot is “idle” down. Lastly many modern turbo’s use coolant flowing by convection once the motor is shutoff. So a turbo is cooled down in that manner.

However I know nothing of Chrysler and their implementation of this.

Since the advent of Chrysler’s TurboCharged 4 cylinder passenger vehicles in 1984 water-cooling has always been included. While it does aid in reducing the turbocharger’s operating temperatures bringing them closer to ambient it should never be relied upon to allow “Hot Shutdowns”. The engine should always be given enough time to cool down after spirited driving or when exiting the freeway. FULL Synthetic oil is a must for all turbocharged vehicles along with regular oil changes. We recommend Mobil 1 Full Synthetic oil because it’s the best we have found so far. It’s inexpensive when purchased at Walmart in the 5 quart containers (about $27.) DO NOT use Synthetic blends because they will not resist the heat exposure as Full Synthetic oil will.

As seen in the attached photographs coking can occur due to poor oil quality, extending oil changes and “Hot Shutdowns”. The needle sized bearing oil passageways can easily be blocked with the coking leading to imminent TurboCharger failure. FYI-Tried posting pics. Did not work.

When replacing the TurboCharger ALWAYS replace the oil feed line. Over time layers of burnt oil will accumulate on the inside walls of your feed line slowly restricting flow. Shards of the burnt oil can also break free and travel down towards the bearing passageways blocking the flow of oil to important areas of the turbo. Risking an expensive TurboCharger failure in exchange for a $40. savings of not having to buy the feed line is a gamble you will lose. And don’t even try to clean out the original line as you will only loosen the debris on the inside walls allowing it to break free sooner once back in operation

I hope this information proves to be helpful to all TurboCharger owners out there. If you need additional assistance don’t hesitate to contact us directly for New and Rebuilt TurboCharger sales and service.

Chris Wright

This is why I won’t buy a turbocharged car, I also believe they get misleading mpg numbers, the only time they get near their EPA ratings is when you drive them like you don’t have a turbo.