How to confirm bad turbo?
 

I believe my car exhibits the symptoms of a bad turbo...in very cold weather, the turbo makes all kinds of noises. I think the turbo is performing, and I believe the boost is probably ok (engine not sluggish), but bearings are probably bad. When weather is very cold, bearings probably have more play (?), thus explaining more noises when cold. These symptoms dont appear in summer weather, so i'm not sure if I need to get a replacement cartridge for the turbo.

To verify bad turbo bearings, do I just take off the intake duct and feel for shaft play? (obviously when engine is cold and not running!!!!)

Thanks,

Mark

Re: How to confirm bad turbo?
 

Yes, just grab the shaft and try to move it in different directions. Be careful of the compressor blades, the edges are like razors. It should have VERY little or no movement. Keep in mind that even 1mm my not seem like much, but tell that to a turbo spinning at 100,000rpm+!

did one
 

If you are reasonably experienced DIY'er you don't need a cartridge just a rebuild kit. I got the kit from a local diesel shop much cheaper than online.

You won't know if you need a seal kit or a cartridge until you get it apart, alas.

Worst case is a turbo dumping oil out the exhaust -- surely needs a cartridge then.

Check for play (there will be a small amount, they run on floating bearings) and rotate the compressor wheel by hand. Any binding at all means the bearings are shot.

Screaming, growling, or slow onset of boost cold also usually mean bad bearings. Can also mean impeller or turbine damage. Such damage means a cartridge (bearing housing, shaft, bearings, seals, and wheels, you just bolt your end housings on).

Peter

Bad turbo
 

I knew a guy that thought his turbo was bad, paid about 600 for a rebuilt turbo, paid a mechanic 100 to put it in, and still had his noise. Turned out it was the heater blower.

Uh, that would be embarassing....

Usually turbo noise can be distinguished from other noises because it follows the throttle, but I suppse something in the blower could do the same. My old Aries used to get ash tree seeds in the blower (they dropped right through the screen) and they would fall into the squirel cage when I acclerated. Sometimes they ticked, sometimes they scraped, depending on exactly where they stuck, but frequency was always determined by fan speed.

Peter

I thought I had a bad blower motor in the Camry we used to own. It didn't seem to want to blow very much no matter how high I set it. I took it out of the blower housing and to my surprise I found a rat's nest in the cage!:eek:
I guess the rat had somehow found its way in there when I left the out side air lever in the open position.

thanks very much
 

Thanks for your responses. Peter (Psfred), your very helpful description...."growling, slow onset of boost when cold" ....was very helpful...seems to describe exactly what my turbo is doing. Now that the weather has warmed a bit up here in New England (in the balmy 20's) the noise is almost gone, but still detectable. When temps are in the zero vicinity, the turbo "complains" like crazy.

I was quoted a price of $200 for a cartridge....does that seem appropriate?

Finally, when I had the turbo out last year (when I had valve job done), I remember that removal of the turbo was fairly simple. Once I have the turbo out, is it simple to dissassemble and put in a new cartridge? Are there any other servicable parts (seals, "O" rings, and the like that I should have on hand before I do this.

Again, thanks very much

Mark

You will need new seals for the oil feed line and the oil return to the sump, and get a new o-ring for the return pipe, too.

The only problems I can thing of are getting the bolts out of the housings. Cartridge is the center portion, contains bearings, seals, shaft, and wheels. You only have to bolt the housings on. Should come with any housing to cartridge seals you need (I'm not sure there are any).

Good luck -- bet it will perform MUCH better after you get it replaced!

Peter

Install a boost gauge and go for a ride. Check to see at what RPM the boost comes on, check max boost under load, and see if the boost is sustained under load.

We replaced a bad turbo (leaky oil, waste gate toasted, impellar fins badly chewed) and all of the above readings went from wacky with the old turbo to solid repeatable boost readings. The two biggest improvements (along with performance) were how quickly the boost came on (2000 RPM) and that the boost was sustainable and predictable.

The boost gauge cost us 40 bucks and we lead the thin line to the glove box where the gauge can be easily read.

We have also noticed some different turbo sounds (a slightly louder growl) when it is colder out, but there are no differences in any of the boost readings or performance so I'm not sure I would base turbo problems on sound alone.

I will do that...
 

Good suggestions....given that the turbo growls only in cold weather (under 10 deg F), and boost seems delayed (on at 3,000 rpms)...the thing is probably on its way out. But, because most of the time the turbo is quiet and seems to perform well, it may be appropriate to just run it as is. I will check boost readings.

I do expect to have the car for several more years, and I think the turbo will get progressively worse. So I am inclined to put in a new cartridge in a few months when the weather gets nice (no garage).


For a temporary boost gauge, can't I just use a simple pressure guage with hard vacuum line tee'd off of the appropriate line??

Thanks,

Mark

Mark:

That's a very good description of a boost gauge! Must read air pressure from 0 to about 20 psi only, as you won't get more, and it's kinda nice to be able to see the difference between say 5 psi and 10...

Peter