Question about 2003 Yamaha YZ 450 F

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1999 yz400f leaking milky out of the hose that comes from valve cover what could ot be

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You may have a head gasket on the way out

Posted on May 08, 2010

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All engines have a breather to equalize pressure between the internal crankcase(moving parts, blow by, etc) and the outside air pressure. Heating and cooling of the motor can cause condensation (also stream crossings, rainstorms, mud puddles, etc.)in the motor which will show up in the pollution tube, bottom of the air cleaner, or breather tube as a creamy tan or gray milky liquid. It is normal and nothing to worry about unless you submerged the bike in a stream and filled the engine with water. In this case you need to change the oil immediately and get the moisture out so you don't rust up the motor.

Posted on May 06, 2010

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I just changed the thermostat on 3.4 L 1999 Pontiac Gr Am GT THINKING IT WOULD FIX THE OVER HEATING. But there is white steam coming out the exhaust! The oil is not milky so it's not a head gasket. There's...

Are you adding coolant?
Yes ......means it's going somewhere.
Fill the coolant tank to the top...right to the top....leave the cap off and run the engine.
If you see bubbles you need a head gasket.
The intake gasket is another source of coolant leaks and at this area the coolant can be sucked into the engine and produce a white smoke.
Does the car run rough at the first start in the morning....could be antifreeze burning off in the cylinder or area that was leaking overnight meaning cyl gasket or intake gasket.
Look at the rear head to block area below the exhaust manifold.
Is there any trace of coolant or stains of coolant......yes means head gasket time.
Pressurizing each cyl at a time with air with the valves closed in that cyl will quickly show the location of the bad head gasket with bubbles coming out of the fill tank on the bad cyl (s).
Head gasket leaks don't always mean milky oil.

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Vehicle is 1999 T/C Limited (3.8L, V6) Leaking in 2 places.

Hi Briseno,

Solenoid pack leaking,
Cooler Lines to Radiator leaking,
Timing cover leaking,
They suggest changing the water pump at the same time as the lower rad hose, timing chain, and valve cover gaskets. This is because it either looks like the water pump will die soon, preventative measures, or the shop is trying to rip you off for an hours labor.

Either way, I would suggest taking it to a mechanic, unless you're a bit of a handy man.

Hope I've helped, don't forget to rate.


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