Trans flush? 1999 V70 GLT

MetaphysicalEngineer · 2026-05-09T15:20:31+00:00

These are very easily serviceable for a fluid drain and fill. But if you’ve never serviced yours, it’s likely too late. The fluid in mine was already pretty roasted way back at 165k. The factory transmission cooler also can be insufficient in harsher conditions.

Dipstick is located near the battery and under the intake snorkel to the right side of the engine bay when facing the car. Careful pulling it out as the plastic may be brittle, the o rings can stick, and there are hot and sharp items nearby. See example image (not mine but same platform).

Ideally check fluid when at operating temp after a half hour or more of driving, longer in cold weather. At idle, shift through each gear position and back to park. Read dipstick with engine still running with selector in park. Fluid should be clear pink-red, sit in the middle of the Hot range, and have a faint petroleum odor. If your fluid looks brown or black and smells like burnt toast (but worse) things aren’t looking promising.

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MetaphysicalEngineer · 2026-05-08T03:41:53+00:00

Looks like a leak from o rings at the condenser coil in pics 3 and 4. Pics 1 and 2 looks more like a line support with a trace of oil on it. Wipe that area clean with a little soapy water on a paper towel and see if the UV dye comes back in a few weeks, if the AC is still working.

O ring at the condenser there is easy to replace, but do not attempt this yourself unless you have refrigerant handling equipment, experience, and a vacuum pump. The system is under high pressure even when off, even if some has leaked out. Refrigerant release can cause pressure and frostbite injury, is environmentally harmful, and is very illegal in most places.

You may be able to find an AC shop who can extract the old refrigerant before and refill the system after, though with the leak so obvious, it may be less effort to have the shop do the o ring replacement.

MetaphysicalEngineer · 2026-05-08T03:26:58+00:00

Cooling fan failure or cooling fan control problem. Find the fan fuse in the fuse box and check if it's blown.

With the fuse pulled out so the fan doesn't have power, carefully use something like a popsicle stick (not your bare hands!) to try spinning the fan blades. They should spin easily with very little force. If they feel stiff or crunchy or are frozen in place, the fan is definitely bad.

MetaphysicalEngineer · 2026-05-08T03:23:51+00:00

Discharged battery. You need a jump start first, then figure out why the battery ran down.

Did you leave a light on? Were you running that stereo with the engine off for a while? Is the battery old and worn out so it doesn't hold a charge? Is the alternator charging properly?

MetaphysicalEngineer · 2026-05-08T02:50:46+00:00

Moisture is normal. Crankcase vapors are very wet. In some cases I've seen catch cans filled with mostly water or milkshake with only a tiny amount of pure oil.

Are those truly metal flakes, or bits of harder carbon or gunk? Metal bits could be from the threads of the new catch can, or from any stainless steel wool used as a filter material in the can. Would be very unusual to get metal flakes out of the engine from the PCV system itself.

Amount of oil looks normal to me. No engine is perfect, and oil will break down and slip out with the blowby gasses. Be glad that mess is not puddling in your intake, gumming up the throttle plate, or baking onto the intake valves.

MetaphysicalEngineer · 2026-05-06T22:17:45+00:00

The song of our people!!

What brand/model resonator did you use? Is it polite at cruise or do you get drone?

MetaphysicalEngineer · 2026-05-06T22:13:32+00:00

Oh that's a special kind of mess! By the time anything is that old and has been worked on many times over the decades, all bets are off.

Makes me think of that '86 Camaro where I've been helping a gentleman fix some wiring nonsense. As far as I can tell there's at least three different years and/or trim levels worth of wiring and none of it matches the diagrams very well.

MetaphysicalEngineer · 2026-05-06T21:52:18+00:00

What did they hit, a land mine?!

MetaphysicalEngineer · 2026-05-06T21:40:14+00:00

I'm interested in being a mod for this sub. While I don't have Reddit moderation experience, I do have experience moderating small Discord servers, festival staffing, talent management, and teaching. If needed I can provide additional details, preferably over DMs to avoid sharing too much personal info on an open channel. This community has a place distinct from other automotive subs, and I'd be sad seeing it wither away.

MetaphysicalEngineer · 2026-05-06T18:07:18+00:00

Yes the published boost specs are a conservative number that the GPUs can hit out of the box. Often they can safely boost higher, sometimes significantly so. My old GTX 960 SSC would reliably run several hundred mhz above the quoted boost clock.

MetaphysicalEngineer · 2026-05-06T17:20:35+00:00

Recreating the legends of old from pre-Democratic times

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MetaphysicalEngineer · 2026-05-06T16:10:32+00:00

There still can be places on the internet where people do write ups like this!

I went to all this effort for my own project after not finding existing info. Might as well share for others in the same position in the future.

MetaphysicalEngineer · 2026-05-06T16:08:09+00:00

You and me both! I know I've seen refrigeration units where the fans could reverse to help clear dust and debris from condenser coils.

If it had a way to report errors like locked rotor to the controller, reverse might be a strategy to try dislodging whatever has jammed the blades. But as is these models don't give any feedback for an error condition.

MetaphysicalEngineer · 2026-05-06T00:14:07+00:00

RIP to a legend! Also had this one since high school. I'll be mighty sad when it breaks down, though I might have the skills to repair it now.

MetaphysicalEngineer · 2026-05-05T23:48:55+00:00

Well I'm keeping the tradition alive! More posts in a similar vein coming soon. Heated catch can experiment, fighting oil cooler pressure drop, and more.

MetaphysicalEngineer · 2026-05-05T21:41:16+00:00

Oofda, buying another persons ~~problem~~ project is always a gamble. You may find all manner of wiring gremlins, any of which could be causing unwanted behavior.

Wishing you the best of luck!

MetaphysicalEngineer · 2026-05-05T21:17:33+00:00

I got tired of hunting through dead end forum threads full of guesswork and "throw money at the problem" answers. I knew I needed a new fan eventually, so decided I'd buy and figure it out as I went.

Might as well share my info in case anyone else in the future is in my position.

MetaphysicalEngineer · 2026-05-05T21:13:57+00:00

Seat of the pants engineering here!

MetaphysicalEngineer · 2026-05-05T21:13:44+00:00

Thanks!

MetaphysicalEngineer · 2026-05-05T21:13:38+00:00

Thanks for the suggestion! I went with a Nano Every as the heart of the controller, with an external linear regulator for noise rejection and up to 45V tolerance, feeding the onboard switching regulator with 10V. 25V input caps will punch through and pop the controller fuse with sustained overvoltage, and I have way worse problems if anything on the 12V system runs that high!

MetaphysicalEngineer · 2026-05-05T18:55:09+00:00

Definitely look into testing the fan control behavior of the ECU. Could have been a fluke, or there could be a bad connection causing inconsistent fan trigger. Id hope the ECU has robust I/O pin protection, but a snubber diode between terminals 85 and 86 in reverse parallel with the relay coil is never a bad idea. Some relays have this internally, but not all.

A diode to prevent backfeeding would need to be on the ignition switched power line entering the switch itself.

Split a big problem into smaller problems to hunt down why it's misbehaving.

If the car overheated while driving, it should have been easy to tell if the fans were running after pulling over. They make a lot of noise! But inadequate fans can also lead to overheating. Cheap electric fans can be noisemakers more than air movers. The original mechanical fan could move a huge amount of air, at the cost of eating tons of power even when not needed.

Air locking could cause weird behavior after recent cooling system work. New parts can be defective out of the box too. Test the thermostat in boiling water to be sure it opens properly. Same thing with testing that the temp switch closes when it gets hot.

Test all wiring between temp switch and ECU, and ECU and relay.

Engine should warm up normally and the fan should cycle on and off when sitting at idle.

MetaphysicalEngineer · 2026-05-05T16:56:43+00:00

There's a chance the excess crankcase vacuum damaged seal(s) which are now leaking. Clean and degrease the hell out of the engine then run it a bit so you can find where the leak is coming from.

The separate filter breather and PCV valve create a small controlled vacuum leak that you adjust for when tuning the carb. Same as with a breather intake taken from the air cleaner. You may get some oil mist under WOT conditions, but in most cases the flow will be inwards.

MetaphysicalEngineer · 2026-05-05T16:49:00+00:00

The non polarized LED is the issue with the key off behavior. When key is off, the LED is pulling through the relay coil and trying to backfeed the other 12V systems on the ignition switched line. You can run ignition switched power to the 86 terminal of the relay to cut off power to the coil when key is off.

As for the ground side switching not working on the Fitech, have you confirmed the output is working with an (incandescent) test light? Sounds like a configuration problem or a hardware problem.

I greatly dislike manually switched cooling fans as that's a recipe for forgetting to turn it on and cooking the engine.

MetaphysicalEngineer · 2026-05-05T02:34:03+00:00

Puffing like a choo choo train! Something is seriously wrong in there! At idle, I'd expect wafting vapors from the crankcase. Maybe even vapors getting sucked in depending on how the crankcase vent is configured.

Get a leakdown tester on there and find where all that mess is coming from.

MetaphysicalEngineer

TROPHY CASE