when i give my supra the gas i can hear water rushing in my motor. sounds like it is coming right from under my dashboard. its really strange.

is this normal? i read somewhere that this means i have a bhg. but the hg was jsut replaced before i bought the car. so im really hoping it isnt that.

its an 89 7mgte btw. thanks

Yes it's normal

Some of us refer to it as the waterfall.
Here's what you do to make it go away.

You elevate the nose of the car via ramps or an unused street incline.

You have air in the coolant system. Raising the nose and removing the cap helps the air to make it's way to the surface. So you park it like this and check on it every 15 minutes or so and keep topping it off with a 50/50 coolant mix.

It takes a long time to do this some guys have spent up 15 hours burping.

You can turn the engine over to circulate the air in your engine to help it rise.

If you do this enough the water fall will go away.

Personally, when my car is running I do this weekly because I don't have the patience
to remove it in 1 sitting.

Again, this will solve your problem.
As long as you're not overheating you should be able to drive the car just keep an eye on your coolant level daily and top it off.

Sorry for any typos.

thanks! very relieved...

No worries man.
Good Luck.