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Recently, It got code P0299, under boost condition.
The car drives fine from cold start, but throttle starts to get weaker after 20-30 mins of driving.
Then, it will go under boost condition. Code P0299 with CEL light up.
If I go aggressive driving, it will go under boost faster.
I thought, there must be boost leak somewhere.
Dropped the car to the shop here for a check up.
The tech scanned the car, found bank 1 turbo (Passenger side) is having under boost issue.
He unplugged vacuum hose from wastegate actuator, and there is quite a bit oil dripped out from actuator and hose.
He traced back where the oil is coming from. He found my brake vacuum pump is leaking.
I am wondering, is this possible ? brake vacuum pump oil leak all the way into wastegate actuator ??
And is this the real cause of underboost code ??
Recently, It got code P0299, under boost condition.
The car drives fine from cold start, but throttle starts to get weaker after 20-30 mins of driving.
Then, it will go under boost condition. Code P0299 with CEL light up.
If I go aggressive driving, it will go under boost faster.
I thought, there must be boost leak somewhere.
Dropped the car to the shop here for a check up.
The tech scanned the car, found bank 1 turbo (Passenger side) is having under boost issue.
He unplugged vacuum hose from wastegate actuator, and there is quite a bit oil dripped out from actuator and hose.
He traced back where the oil is coming from. He found my brake vacuum pump is leaking.
I am wondering, is this possible ? brake vacuum pump oil leak all the way into wastegate actuator ??
And is this the real cause of underboost code ??
I have the same issue on a 2014 s550, CEL came on and noticed under the car was oil dripping…I’m hoping it’s not serious, I didn’t hear any weird noises, but does feel low in power, has only p0299 code says low power in turbo 1, Please if anyone knows I would appreciate it, don’t want to go to a shop and they just try making me pay for stuff that’s unnecessary.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Well, unless you are good working on your car, you probably will need to take it to a shop.
By default, the wastegate actuator is normally held closed by a spring. The boost pressure line opens the wastegate when there is excessive boost. However, if the actuator spring has weakened, the wastegate may open sooner, resulting in an underboost condition. If there is a tear in the actuator pressure hose (usually rubber) and not enough pressure acts on the actuator, you may have an overboost situation. This may put you in limp mode to protect the engine.
The whole oil leak thing is troubling. If the turbo is leaking oil, the bearings may be shot and oil is leaking past the turbine shaft. But again, I don't see how that turns into a visible leak under the car.
If the answers given by the OP don't help, you should get a capable professional to tell you what is going on. (By the way, if the brake vacuum pump was leaking oil, I don't see how this causes the underboost problem.)
Well, unless you are good working on your car, you probably will need to take it to a shop.
By default, the wastegate actuator is normally held closed by a spring. The boost pressure line opens the wastegate when there is excessive boost. However, if the actuator spring has weakened, the wastegate may open sooner, resulting in an underboost condition. If there is a tear in the actuator pressure hose (usually rubber) and not enough pressure acts on the actuator, you may have an overboost situation. This may put you in limp mode to protect the engine.
The whole oil leak thing is troubling. If the turbo is leaking oil, the bearings may be shot and oil is leaking past the turbine shaft. But again, I don't see how that turns into a visible leak under the car.
If the answers given by the OP don't help, you should get a capable professional to tell you what is going on. (By the way, if the brake vacuum pump was leaking oil, I don't see how this causes the underboost problem.)
I went and got it checked, I noticed it had a broken plastic connected to three hoses, I got the part number and turned out to be something Called “cooling water change over valve” was told this feeds coolant to both turbos, they told me ima have to change both turbos most likely, but said to relace that part first and hope the turbos are still ok, I replaced that part and filled the coolant tank on the center under the engine cover…reset the code and drove it and still came back, is there any way since it says passenger side turbo in the code that the drivers side turbo still is good? Was also told I had a small leak on the radiator and the oil leaks is possibly the oil pan and gasket that need to be replaced. Was quoted $7,000 usd and to me that crazy considering I can get a new engine close to that price.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
First, where did you have the car checked and how much did they charge you?
Did you find any coolant in the engine bay or smell it. Coolant has a very distinctive smell. You did not mention low coolant before.
Are you being told that your radiator leak is allowing oil and coolant to mix? Or are those separate conditions?
It's easy to check if the turbo(s) are shot. Remove the air inlet hose coming from the air filter to the turbo and spin the turbine (compressor wheel) by hand. If it turns smoothly and easily, and there is no play in the shaft, then there is nothing wrong with the turbo. Here's a couple of diagrams. On my engine, M276, the turbo housing and exhaust manifold are one piece. Not sure how they are on your engine, but you should be able to find a rebuilt turbo for far less than $7000. (By the way, if you can get a new M278 for $7000, please let everyone here know. Just be careful that you are buying a complete engine and not just a block and head. If that's the case, you won't get turbos with it.)
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Actually, it looks like the turbos are separate from the exhaust manifolds on your engine. That should make it easier to check and replace/repair, if necessary.
01-20-2018, 05:31 PM
