Pulling my horse trailer from Sacramento to above Placerville this weekend, basically a long hill
On the way DOWN, started to hear a high pitched whistle
At first I thought maybe it was a bearing, but it was highpitched, and it got louder as I applied the pedal
At a certain spot when I pressed on the pedal, it made a scary sound
A very loud hiss, like when you are letting air out of your tires, but LOUDER

I'm thinking I have an air leak in my ?
where do I start looking?
thanks

 

Do you have gauges?

 

i'd check the boots on the joints from turbo output around all the way to the intake mainfold. sounds like you got a leak on the pressure side.

 

Yes, I have gauges. My boost is usually running very low, around 0-3, hits 20 very briefly under load.

Driving without the trailer, on flat, I could only get the high pitched whistle, and that wasnt' very loud.

Thanks, I'll start at the intercooler boots and move on up. check my gauge tubing too, I guess
thanks, Jenni

 

The odd part is that the noise was happening on the downhill when you wouldn't have much (if any) boost. Would you get the same noises under load when boost was up?

 

how are egt's under load?

 

Those boost numbers look very low, a stock hx35 should be making more then 0 to 3 pounds at cruising speed. Maybe the turbo is just packing it in.

 

My bet is a leak in the boost gauge tubing at low pressure.
Probably at the connector at the gauge or manifold.
When the boost is up it expands and seals the leak.
Would also cause the boost to read low.

 

Maybe because I have a 5 speed, and I was traveling in 4th gear to slow down my load. When I was on flat ground, it took more pedal to get the sound.

I did check my intercooler boots, the one on the drivers side attached to the intercooler the clamp was loose- well, off, really. So I tightened all of 'em down even tighter--guess I was worried I'd cut the boots but guess I'll just have to keep an eye on them.

Haven't pulled under load yet, but I'll see if thats the complete fix soon as I can.
Thanks to all!
Jenni

 

My egts usually run about 900 at WOT, hit almost 10K max max. Runs about 300 cruising. It is cool how you can totally control the egts with the pedal,
but I haven't needed to worry about it at all.

After tightening up the intercooler boot, driving without a load,
my boost still runs very low,so per Infidel, I'm going to check the gauge connections on either end as well. I did a cheap trick trying to use silicone hose for the boost gauge, maybe its not working
Hope thats it and not my turbo!

 

That really sounds like the leak is on the exhaust side somewhere as opposed to boost. If you were going downhill in 4th, using the engine to slow the load, you wouldn't be making any boost, but you would have some pressure on the exhaust side. Plus, any exhaust leaks would contribute to lower than expected boost since you're loosing drive pressure that should be driving the turbo.

Glad you did find a loose boot. Better to find it now, then on the road somewhere when it goes completely.