Volvo 740 Turbo with "shaved" housing with a hole in it ?

Can you get a picture? I can't think of any hole that should be in the turbo housing, where exactly is it?

As I said earlier, the guage is supposed to sit around 10 o'clock when the car is not running. Black is vacuum, yellow is boost, the place where they meet is atmospheric pressure, if the guage is not pointed there when the engine is off then it's broken.

Did something wear on it and make a hole? Or is it on the exhaust side? Perhaps the car ran lean and overheated the exhaust housing, melting a hole in it.

No, James. The ACTUAL TURBO CHARGER housing was shaved down (grind the metal down on one the left side) and a whole was created. I believe its a Garrett (it's got a metal little label that's all greasy)

So maybe that's why I've had the leak all this time? But the hose I replaced helped. I mean I accelerate and such.

Now by "exhaust side you mean after the intercooler and AMM, right? Because I mean the ACTUAL TURBOCHARGER housing, if that makes sense.

I took some pictures of it. All it looks like is picture the "donut housing" of the turbo charger and shaved down one side. It looks really weird. I can email you the pics.

I think you will find that James may be querying whether your car was fitted with EGR (the hole being on the manifold just above the turbo mount, should have a metal tube going to the EGR valve) that caused the PO a problem so he removed it.

All the best, Peter.

700/900/90 Register Keeper, Volvo Owners Club (UK).

Yikes, that's definitely a problem. By exhaust side, I mean the exhaust turbine housing, as opposed to the compressor housing. The former is cast iron and will be all rusty, the latter is aluminum and facing the front of the car.

Are your engine mounts completely shot? Only thing I can think of is maybe the turbo has been rubbing against something but I've never seen that happen.

You can see a good picture here of a T3

As well as another showing the inside, with the compressor and turbine blade assemblies joined to the shaft running through the center cartridge. The wastegate actuator is also visible.

I've never encountered a Volvo with EGR, I don't believe they used it in the US market. None of the manifolds I've ever seen have had any unused holes in them. The tube I'm referring to is a corrugated aluminum hose which connects a sheath over the exhaust manifold to the airbox, the purpose being to draw heated air into the intake when the engine is cold to accelerate warmup. There's a wax thermostat in the airbox which operates a flap valve to close off this tube, if it gets stuck open and hot air is drawn in once the engine has already warmed up then the air mass meter can be damaged.

Yeah, I've opened the airbox when I changed the air filter. I saw that flap that flaps open/closed. I accidentally "touched it" (because the car is so old and never maintained, touching can damage :P) and part of the flap crumbled. Where is the thermostat in there?

Looking at that pic---I don't know which side is which, hehe. But Okay, well, interested, here are the pics !

I see, well, the whole is on the compressor side, as you can see.

Crap! That's sure the first time I've ever seen THAT happen! That's a Mitsubishi turbo, same one I have in my '87. It's pretty clear that the aluminum hose has ground a hole in the compressor housing from years of rubbing, it's no wonder you're losing boost and getting funny sounds. Try patching it up with some JB Weld, just don't get chunks inside the turbo. A better solution, if you're able to do this, is to remove the housing and take it to a welding shop and have them TIG the hole closed but removing it with the turbo on the car is a real pain, there's not much wrench access.

James, I think it was intentional--there's no way that could have happened with rubbing.

I'm looking into it---FYI, the Volvo was a single owner--my uncle and it's been like that for years. And his son (who let's just say is had a somewhat drifty life) told him "Dad, I know a guy who fix turbo charger's for like $75."

It's steel, no way that could have happened, IMHO.

Would JB Weld hold up to the heat generated by a Turbo at full boil?

I think not.

The hole was hidden by that aluminium pre heat hose. Looking at the car --everything looks fine no obvious signs. I don't know, not to jump to conclusions, but it just looks devious.

Without pulling the turbo, what else would work? Muffler bandage maybe?

I replaced the pre heat house, as you can see in the pic, but the hole was blocked by the old house, that's why it makes me suspicous.

It's aluminum, and it's definitely a hole rubbed in it, look at how it lines up there, I'd bet money that's what happened. I have the exact same car with the exact same turbo, there's no hole there and absolutely no reason to have one. Aluminum is soft, my alternator has a gouge rubbed in it from the plastic cable sheath rubbing on it over the years, even steel will wear like that if a bit of oily road grit gets in there, it's the same way you can polish scratches out of metal or glass with a cotton cloth and some abrasive powder.

Not on the exhaust side certainly, but on the intake it might, it'd be iffy though. Best solution aside from replacing the housing would be to weld it.

I'm sorry, my bad. Yeah, aluminum. Well, it's on the intake side, so couldn't JB weld work?

I talked to my other uncle who says, well, it's not like it's on the exhaust side, so it might work.

I'd get it welded but--well, It's my daily driver and if it's from wear, it's been like that for years, so a month or two isn't going to make a difference I think.

FYI for clarification the turbo lacked power since about 2002. I thought I lost power, but I never really had it to begin with, hehe.

Well patch it with something, with a boost leak like that you're burning a lot of extra fuel since it's metering the air before the leak and fueling accordingly. You'll burn up your catalytic converter driving it like it is.

JB Weld is spec'd for up to 500F.

I doubt the compressor side gets much above 300F and the pressure is insignificant. The way I'd do it is to clean the surface with brake cleaner and JB Weld a piece of metal over it - I'm concerned the JB Weld might crack if you try to bridge the void with it. A coin that is slightly larger than the hole will conform to the curved surface reasonably well. JB Kwik or a small bead of the putty equivalent will hold the plug in place without the need to come up with a fancy clamp; you'll just need some patience to hold it until it sets - about five minutes. Then mix some JB Weld to apply around and over the plug. Epoxies harden best when hot, so the car should be drivable within an hour or so if you don't wind it up too much.

BTW, I would expect noticably better performance and fuel economy from repairing the hole. It is having the same effect that any other hole in the boosted side of the intake has: it draws more air through the AMM than the engine is really using, which convinces the ECU to inject fuel to match. I don't know how it got this way, but you'll be a lot happier when it is fixed.

Mike