Q: Hissing noise.

asked by on December 08, 2016

my car is a bmw 320i 1988 actually.. whenever i accelerate(at low speeds).. i hear a hissing noise...note it is the same hissing noise when starting my car in the morning..i think it is a belt issue..i checked the belts, pulleys and bearings...all are fine..so i searched a bit and found out that a center bearing in the car's driveshaft may cause some hissing noise..thanks for your help

My car has 152235 miles.
My car has an automatic transmission.

This may be a sign of a vacuum leak. High idle speed, stalling and hissing sounds are common signs of a vacuum leak. When a vacuum leak is present in an engine, this causes an excessive imbalance in the air/fuel ratio which creates a loss of power and causes the motor to run at a much higher RPM as a result of the increased oxygen present in the fuel charge being injected into the motor. I would recommend having an expert from YourMechanic come to your location to diagnose your vacuum leak as these can be very difficult and time consuming to trace.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

EML light on and caution light with arrow around came on the car, what should I do?

The warning lights mean that the vehicle's computer has detected a fault in the engine management system and/or engine controls which includes a lot of sensors and other devices. If the vehicle has not entered "limp mode" (reduced performance), is...

My truck is smoking, shaking and leaking some type of oil. What's wrong now?

Check the engine oil level. If there's a sizable oil leak and if the smoke is due to oil leaking onto the manifold, the oil level could be low. If the level is low and you suspect a leak, just...

Low RPMs

Hi there. This is a common problem for your vehicle. There are many different things that can be effecting your idle rpm. The Idle Air Control Valve for your Vanos needs attention. Vanos is the variable valve timing BMW incorporated...

Related articles

Top 10 Factors to Consider When Buying a Luxury Car
The The idea of owning a luxury car is appealing. The glossy paint, swoopy lines, and prestigious badges speak of the owner’s success in life, while the interior opulence offers scented leather surfaces, high-tech telematic devices, and all the creature-comfort...
How Long Does an Oil Cooler Adapter Gasket Last?
There There are a number of gaskets on an engine and each of them performs a specific purpose. For most car owners, their gaskets are not something that they think about until one of them begins to malfunction. Most of...
Is It Safe to Drive With a Diesel Leak?
While While diesel engines aren’t as popular in the US as they are in the UK and Europe, they do have their adherents, most notably in the heavy-duty truck sector. Diesel systems are very different from their gasoline counterparts, and...