For the past 3 weeks my car (94' stock rx7) has been acting up, when I get to a certain speed (usually 90-93 mph) it make this crazy noise that sounds like the releasing of air. So the first thing I could think of was, a boost leak to my second turbo? But then I thought "if the noise only starts at 90 mph, maybe it isn't boost related. But then if the noise INSTANTLY stops as I let off the gas (otherwise when the boost goes to vac), does that mean it could be a boost leak?
Please help me, everyone that I have asked, so far no one knows. Some say "boost leak" but most of them say "I don't know." Let me know what you think, because I live in South Carolina, and their aren't many rx7 experts, if you know what I mean!!!
Also, Oil in my coolant .... but no coolant in my oil could that still be a seal?

 

Hey could it be your turbo.

 

Yeah well, I thought about that! I not that dumb Sam!

 

Well sorry Lisa, you r turbo housing could be cracked.

 

You think it could be a boost leak?

 

Oh yeah, my name is not Lisa, you stupid dumb ***! If you want to know my name, quit being lazy and look at my profile!

 

Ohh ok sorry lisa, HT are bitches i was right!!! WEll have a good life i was only trying to help you!! "Sorry hi Boca Raton.

 

bump

 

Guys, I know this a pretty old post, but the problem that I stated above is still occuring, I need help!!!

Please if you can give me ANY advice, I'd really appreciate it!

 

Also, about 3 weeks ago, I had a new motor put in due to a blown rotor... point being, I was hoping that this problem would be motor related and it would be illuminated when the new motor was put in, but of course ... the problem continues!!

 

I'm guessing you don't have a boost gauge. That would really help to diagnose any sort of boost leak. Does the noise happen at the 90 mph regardless of whether you're in 4th or 5th? I'm just wondering if it could be speed related, and maybe something on the car is making noise at that airspeed. My old 85 used to suck the drivers window off the seal at 90 mph every time.

Good luck,

 

The best thing you can do is get a cheap auto parts store boost gauge. If indeed you are losing boost then you can try this remedy I copied from one of my old posts: I've found that the easiest way to find boost leaks is to take some soda cans or tennis ***** or anything of the like, and put them in the intake hoses(from the airbox to the turbos). Clamp the hoses tightly around the cans. Next, get a blower nozzle for an air compressor that can have a vacuum hose slip on. Put the vacuum hose on the blower nozzle at one end and an intake nipple at the other end. Tighten the vacuum hose down with hose clamps at both ends. Turn the car on(not the engine though). Now lightly blow air into the intake with the blower. The air will have no where to go except where the leak is.

 

P'cola FD, thanks for that!!

 

Well, had to edit this because I re-read your initiall post. Much more information is needed to get to the root cause. Haven't herd of a car that only dropps boost at 90MPH. That would actually take some doing to make that happen. So there are some other areas that you should check out that would give enough information that someone could determine what the problems actually is.

What RPM are you at when this happens?? You can get to 90 in more then one gear, what else is going on when you do this. Are you 1/4 mile racing when this happens??

How much oil are you seeing in your coolant. Yes it is unusual to see oil in the coolant but not unusual to only see oil in coolant but not in coolant in the oil.

Are there any mods at all, anything that isn't stock that might be effecting the opeation of the wastegate, tubos, boost contol, anything changed. Or how about I re-word this to have you removed or replaced anything on the car recently and what.

From that one can probably help to point you in the right direction but much more information is needed.

 

shred, this only occurs when I at 90 mph and higher and that happens no matter what gear! Also, that isn't when I am only racing, it will also occur even if I just cruise at 90 or higher! The weird thing is, it never occurs before 90 mph and it doesn't stop or getting louder if I go above 90 mp, it is just a constant sound. It has been like this since I bought the car, but it was to late to notify the seller by the time I felt comfortable enough to go at high speeds, so I couldn't tell right when I bought it!
About the oil and coolant problem, that has not occured since I got the new motor, so I am almost positive that the problem is fixed!
And like I said, about my mods, I doubt that would have anything to do with this because when I bought the car it was stock and even when it was stock, this problem still occured! I'm just scared that whatever it is, it could have added to blowing of that rotor and I really don't want to wait to late to find out if I will have to have ANOTHER new motor! If that made any sense.

Also, when the old motor was out and were checking out everything just to see what kind of damage had been done, I noticed that the turbo housing had 2 small cracks, but I think that was caused by me drving the car and not knowing that motor was blown because I didn't feel any effects other than I was running really rich and etc. POINT BEING... I am boosting but I think for some reason since the turbo housing is cracked, that could be the problem! And the reason why I didn't replace the turbo housing while the motor was out is because I am about to go single, so they wouldn't have made any sense!

Well, any help at all would be greatly appreciated!
Thanks, Nicole

 

Turbo exhaust housings always have cracks in them right around where the gasket goes in between the turbos and the exhaust manifold. Those cracks are nothing to worry about. A boost leak won't blow an engine, it could eventually wear out your turbos, but it won't blow a motor. This doesn't sound boost related, because it happens when you are cruising. I would think that either something is poking out somewhere and you're getting some road noise, or you have a problem in the drivetrain at constant velocity i.e. wheel bearing, differential, driveshaft u joints.

 

Gotta get a boost gauge, get like a autometer, the usually go for about 50-60 bucks and are very easy to install. That will give you the most information.
The second turbo kicks in based on boost not car speed so I doubt that this is the problem.
Do you have any mods to your car?