1985-1998 [Subscribe to Daily Digest] |
 | [Main 9000 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: ari and others: headscratch for my saab indie... Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Tue, 29 Aug 2006 05:33:13
In Reply to: ari and others: headscratch for my saab indie..., rsfeller, Mon, 28 Aug 2006 21:12:52 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Let's see - 195K. I think it's safe to say that more than a few things are worn. My guess is that it is a combination of things.
There is a big difference in source fluid between blue smoke and white smoke (electing a Pope?) White is coolant, bluish is oil. So question one - how are your fluid levels? Dropping coolant level is usually the easiest to notice, because most of us don't change the coolant as often as the oil. If the coolant is dropping, I'd suspect head gasket. I'd also recommend re-torquing the head. It might be a hair loose when cold, but tighten back up when it warms up. A cheap possible solution.
If it's oil, there can be a lot of places. Valve seals do come to mind. As the engine sits, oil seeps through the valve seals and into the cylinder, and upon starting, the burning begins. There is an old test I know for checking this, useful on long drives, and may explain the intermittency. Get the car warmed up, and find yourself a nice long hill. Get up to speed, and drive DOWN the hill, foot off the gas. A decent steep hill on a highway is great for that. Watch out the back. At the bottom of the hill, get back on the gas normally, and note the exhaust results. If you see a great gout of bluish smoke, it's likely the valve seals.
As you go down the hill with your foot off the gas, the engine is seeing major vacuum. This tends to suck oil through the valve seals. Get back on the gas, adding air, and clouds result.
To check the valve rings, do a wet/dry compression test. If the wet number jumps up a lot (more than about 10 psi), the rings are worn.
OK, what about the turbo? At near 200K, it is likely worn. Don't confuse seals with bearings. You can have worn seals and the bearings are just fine. This could cause oil consumption.
The whine is the most interesting (and annoying). When you checked for play, did you check both radial (up/down/side-to-side) and axial (in-out)? You hear the noise warming up the engine. At idle, the turbo is spinning, but not very fast (in turbo terms). How does it sound as you drive off and get the revs up? For the turbo noise, three things come to mind - bearing, blade scrape, and acoustics.
When cold, the oil flow isn't great, and I wouldn't be surprised if your oil feed tube is a little narrowed after near 200K. The bearing may not be getting great lubrication when the oil is thick and cold. When spinning the turbo shaft, did it spin smooth? I assume so, or your mechanic would have replaced it. If it is the bearing, it won't make noise like that for a long time - it'll fail, then you'll know. How long has this been going on?
Blade scrape is just that - a mismatch between the turbine blades and housing. That is one place where bearing axial play could come in. Once the turbo warms up the clearances correct themselves. Frankly, other than annoying, probably not a big issue; you will lose some turbo efficiency, but the turbo has plenty of extra capacity. Acoustic is where there is an aero-acoustic effect from the blades spinning - just the right (or wrong) mismatch between the blades, housing, and hoses, causing a resonance. If it only occurs at engine idle, I could see this. If the noise keeps up after the engine is reved, probably not.
So what's the bottom line? This is a car on a long commute and driven by your significant other. Reliability is key. It's also got 200K and adding 20K a year, so it isn't a spring chicken.
If you're drinking coolant (or the engine is), that's a problem that can cause engine failure on the road. That is an unacceptable scenario for a good relationship. Get that head gasket checked out.
If you're burning oil, things are different, but in a good way. Ruining the environment for generations to come aside, feeding an oil burner is cheap compared to the repairs required. If the valve seals are weeping, that isn't a cheap fix, but even at today's prices, oil is cheap, and bad seals won't cause a panicked call from the side of the road without a lot more warning. The same with turbo seals. A blown seal may mean she'll make smoke like a destroyer outrunning a submarine, but she'll get home.
If the rings are worn, that will increase the crankcase pressure, and be more likely to blow oil into the intake (through the crank ventilation). Again, no big deal. It can wait for the engine rebuild you'll do when the car hits 250K, so it'll be ready to bring you to 500K. Yup.
The turbo noise is the trickiest. Since the sound is reproduceable, I'd make sure it was coming from the turbo. Get a cheap automotive stethescope and verify it is coming from the turbo. High pitched noises can travel. You can also make a hearing tube from a couple of feet of old garden hose. Hold one end to your ear, and move the other end (CAREFULLY) around the engine compartment to localize the noise. It may be a water pump bearing. If the sound is relatively new, I'd strongly suspect the main pulley (Harmonic balancer). When they start to fail, they squeal horribly when cold, then quiet down. The squeal gets worse with time, until finally every thing gets quiet. Oh, I forgot - squeal, loud boom, then quiet. There is a lot of info on the board about checking harmonic balancers. And if the pulleys (tensioner and idler) are more than 60K miles old, I'd suspect them.
A lot will depend on your plans for the car. Some things aren't worth fixing, and you can live with. But I'd make sure the noise is the turbo, and if you have a coolant issue, address that immediately. The others aren't going to shut the engine down. (As long as you keep the oil levels up)
posted by 192.249....
, Tue, 29 Aug 2006 05:33:13 <-- Viewing This Message
, Mon, 28 Aug 2006 21:31:53, Mon, 28 Aug 2006 21:56:02
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
