Cleaning E39 Intake Deposits..

Hi All:
My '98 E39 (77k mi.) still runs well but have started feeling a degradation of power..looking at regular service records, a service tech at the dealership said likely intake needs to be cleaned. Can
anyone recommend an effective additive/product (available in the US) to clean the deposits? Thanks-
-Roger
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Sounds like BS to me, unless he's talking about the MAF
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"SunK" wrote

What's his definition of 'intake'? The additives you're talking about could be used to help clear up the fuel system (injectors, valves), but the stuff readily available at the stores such as Techron Concentrate or STP or BG44K will most likely not touch some of the more serious deposits. These additives, I feel, are more of a preventative measure than anything else.
FYI... clogged fuel injectors can sometimes manifest themselves as unstable idle speed.
And obviously, those fuel additives will do nothing for air intake. Here, as adder1969 suggested, you should look at replacing your MAF (cleaning an old one does not really work all that well), air filter, etc.
Pete
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What is the MAF..? I do not believe the differential fluid has been replaced - will that help? Thanks-
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"SunK" wrote

Mass Air Flow sensor. It measures the amount of incoming air that enters the combustion chamber. Based on this, the computer knows how much fuel to dispense in order to obtain a proper air-fuel mixture. As dirt accumulates on a MAF, its performance may degrade over time.

I don't think a fresh diff fluid will help with your "degradation of power" issues, but seeing as you're at 77k miles, it'd be a good idea to replace it anyway. It's not a lifetime fluid, unless you only expect a life of about 100k miles out of your car.
Pete
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dose of Techron. At 77k miles, you may consider trans and diff fluid changes. Contrary to the literature, they are NOT lifetime. Besides, Less than $100 for fluids beats $mucho for a new trans (plus labor, of course). BTW, I checked my intake valves (where they said deposits were) when I did my clutch at 170k miles. NOT A SINGLE DEPOSIT. Good gas and Techron every 4th tank. And the fuel tank was SPOTLESS and without water. So, the "deposits on your intake (valves)" is a lot of crap. It's just a tactic to get you separated from your money.
Bill in Omaha (mit SNOW) '86 535i
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Thank you all - had no idea about the LIMITED "lifetime" tranny and diff oils..idle speed seems steady..just the power seems to have diminished..will replace tranny and diff oils plus new sparks, oil & fuel filters..hopefully that should make a difference..thanks, guys!
-R
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Which engine is it?
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I believe it is M52 for the e39 chassis (1998/528i)..
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