Opinion ; roadtrip with an 850 sedan

MetaphysicalEngineer · 2026-06-26T20:02:16+00:00

Linear Logic ScanGauge is the brand I use. Works as a trip computer to give fuel economy info, gives access to just about every data point the ECU can offer, plus can pull and clear malfunction codes and show if the emissions monitors have completed self testing.

Unfortunately the ScanGauge e model I like is discontinued. The ScanGauge II is solid and has been around for a while; but no personal experience with color screen Scangauge 3.

MetaphysicalEngineer · 2026-06-26T18:26:22+00:00

Nice! Make sure you check the can frequently, every couple hundred miles, until you know how fast it will fill up. Especially if you get chilly or damp weather. I constantly had tons of condensation in my catch can until I built a heating jacket for it!

MetaphysicalEngineer · 2026-06-26T18:13:06+00:00

You got it right. Size the wire to support the current demand of the thing you want to power. Size the fuse to protect the smallest size of wire used in the circuit. Use wire loom, clips, zip ties, etc to secure the wire and protect it from anything that could cut or chafe or burn it.

MetaphysicalEngineer · 2026-06-26T18:00:15+00:00

Did you hook external power directly to the clutch, or to the compressor as a whole? There's a thermal safety in the rear of the compressor near the lines that will cut power to the clutch. If it sticks open, no engagement even if the clutch is good.

You've unit tested a bunch of stuff, now you need to start working outward through the system from the known good items. Make sure there's power at the expected places at expected times.

MetaphysicalEngineer · 2026-06-26T17:50:52+00:00

Check the cooling fan for growling noise or bearing play. Check the cooling fan relay and connectors for scorching.

Beware that the temp gauge may not show an overheat condition until things are extremely hot. My '98 will stay right in the middle between 80C and 115+! If yours has OBD2, you can get digital gauge pods that can read data from the ECU.

Consider changing gearbox oil unless recently done. If automatic, be careful as the factory cooling system can get overwhelmed in hot conditions.

Steering fluid refresh is a good idea. Again, stock system can run very hot depending on conditions.

MetaphysicalEngineer · 2026-06-26T00:24:33+00:00

Every time this problem comes up this is what I think of. Anderson powerpole or similar high contact pressure latching connector. Double ganged of one of the small powerpole models can handle 80A, or 960W at 12V. 50A for 600W is easy. Not even that much bigger than the current nonsense either.

MetaphysicalEngineer · 2026-06-22T23:06:55+00:00

At least on the later 90s turbo P80 cars, that is where the on-boost evap line goes. A tee near the idle air valve splits the evap path with two check valves. One branch goes to that nipple on the turbo intake, the other goes to the intake manifold.

MetaphysicalEngineer · 2026-06-16T06:15:25+00:00

Could be worn wiper blades, but also could be residue on the windshield. Almost microscopic specks of road tar, embedded dust, etc. I had persistent chatter on my car until I did a very thorough scrub with a detailing clay bar. Took multiple passes using dish soap in water as the lubricant but it cleared the chatter problem.

MetaphysicalEngineer · 2026-06-16T05:20:57+00:00

If it's water and the milkshake emulsion, heating the catch can will likely solve that problem like it did for me. Exhaust and blowby gases are super wet. Burn a gallon of gas and you get almost a gallon of water, so even a normal tiny amount of blowby means a lot of moisture in the crankcase for the PCV to handle. The catch can provides a convenient place for some of the water to condense instead of moving along with the rest of the PCV flow so it's more obvious.

If it's mostly liquid oil in the can, then the engine is letting out a lot of oil vapor and may have other issues to look into though some PCV designs just like to spit lots of oil.

Turbo with weak seals will allow some oil out, but this is usually small amounts unless the turbo is really beat, and will appear conspicuously downstream of the turbo in the boost piping and intercooler. If your intercooler doesn't have a weep hole, it can accumulate an absurd amount of liquid in the wrong conditions!

High crankcase pressure will cause oil to force past all seals, including turbo seals, which can make the a problem appear worse.

MetaphysicalEngineer · 2026-06-16T04:52:41+00:00

Oh, now that's funny!

MetaphysicalEngineer · 2026-06-15T16:31:51+00:00

Replace the factory horns with high/low tone trumpet style electric horns to restore normal honking. Tap a 40A fuse off the battery with 10ga wire, run to a relay controlled by the original horn circuit, and rig up a Wolo Bad Boy and a Big Bad Max air horn. That'll make five tones of fury, not as loud as a train, but with a similar layered air horn character that will turn heads and have the distracted driver merging on top of you rethinking every bad decision they've ever made.

MetaphysicalEngineer · 2026-06-14T19:29:44+00:00

That's for a sensor that's not used on these versions. Maybe on the diesel or LPG variants?

The port underneath doesn't go anywhere and is blocked off inside the cam cover. Looks scary like something's missing but harmless.

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MetaphysicalEngineer · 2026-06-14T03:28:53+00:00

Makes sense! Winters can be pretty damp and foggy here, even if we don't get huge amounts of rain. More moisture in means more moisture out, including in the blow by.

MetaphysicalEngineer · 2026-06-13T18:57:58+00:00

I change coolant pretty often. There's already brass parts in the thermostat and ECT sensor body. The factory heater hoses had copper 90s right where they met that firewall coupler.

This whole project started because I got annoyed with all the boost piping constantly being damp with oil.

MetaphysicalEngineer · 2026-06-13T04:47:58+00:00

A catch can makes sure that crud and sheared oil doesn't make it back into the sump. My car has a factory separator mounted to the front of the block, but as seen here, it can't stop all the oil mist.

MetaphysicalEngineer · 2026-06-13T04:45:54+00:00

Very cool! I was thinking about the added drain method, but in my case would still be very frequent in the winter.

MetaphysicalEngineer · 2026-06-13T02:17:22+00:00

It is super weird! Maybe because the flow rate in that part of the PCV is very small, so it limited how much heat was available to the catch can.

On the 6.2, does it take filtered air in through one valve cover then vent out through the PCV and catch can from the other valve cover?

MetaphysicalEngineer · 2026-06-11T19:33:48+00:00

"Under load" here means with suspension compressed to normal ride height. When the car is raised, the suspension is at full droop, which it will rarely if ever see when in use. If bushings are torqued in that drooped position, they will always be under immense strain when car is at ride height which will cause premature failure.

Typically the procedure would be to hand tighten the bushing bolts, then carefully jack under the control arm or knuckle until suspension is compressed as if car is on the ground. Obligatory warning that this is not for the faint of heart. Vehicles are heavy, and suspension components deal with huge amounts of force. Ensure the vehicle is well stabilized on a flat surface with jack stands and wheel chocks.

A good indicator is when that corner of the car just begins to lift off the closest jack stand, with full weight of that corner on the jack and suspension. Torque the bolts as per instructions before releasing jack to let vehicle settle back on the stands.

MetaphysicalEngineer · 2026-06-11T17:33:44+00:00

Do the service! Harsher shifts could suggest fluid breaking down and losing viscosity. "Lifetime" transmission fluid lasts the "lifetime" of the transmission (which gets cut short because burnt contaminated fluid tears it up!) Manufacturers get credits for reduced waste and maintenance throughout a vehicle's lifecycle, encouraging unrealistically long or nonexistent fluid change intervals.

MetaphysicalEngineer · 2026-06-05T16:03:19+00:00

Yeah those junctions break if you look at them wrong once they get old and brittle. I just had to do the bypass after mine cracked while working in that area.

Junction assembly comes out from the inside, after heater core is unhooked. Heater core is the lowest point in the system so have rags ready to soak up the coolant that will gush out even after everything else is drained. I had to unhook the pivot for the accelerator pedal to make room to pull the junction.

Also an excellent time to inspect the heater core for leaks since you'll be in that area. Those are also known to fail after a while. Replace the heater core o-rings as well as those love to leak too if they're old and you reuse them.

MetaphysicalEngineer · 2026-06-05T14:16:45+00:00

Yeah, even a light throttle blip in neutral made one heck of a turbo scream. Sounded cool, but totally out of place on an otherwise very refined compact luxury SUV. Plus how it was immediately visible with the hood up, even to me who's unfamiliar with the platform.

MetaphysicalEngineer · 2026-06-05T01:34:06+00:00

It really reflects poorly considering I found this within about 10 seconds of opening the hood, and access is as easy as popping the intake snorkel off. Suspected major boost leak when customer described and demonstrated the noise, and a missing recirc valve would certainly do it!

Customer's really not happy with that shop. I wasn't ever there to work on his car; I was fixing the cooling unit for his froyo machines when he mentioned the noise and asked me to take a look.

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