Stuck upper coolant drain valve

Post by **FireFox31** » 18 Sep 2021, 11:38

Hello, I'm doing a coolant flush on my 2000 V70 NA with 200k miles. I'm unable to loosen the upper coolant drain valve and looking for sage advice so I don't wreck it. The valve is up behind the exhaust manifold on the metal coolant line coming off the back of the coolant pump. Has anyone successfully loosened this drain and how did you do it?

I assume it's stuck due to the hot coolant it always circulates and its proximity to the hot exhaust manifold. I've already started spraying it with oil. I don't mind using a bolt extractor and replacing the valve, but after my caliper fitting thread surprise, I'm worried that the female threads are somehow wrecked.

I will try to order a new valve part 966723 (3531384). If the female threads are wrecked, I could replace its short coolant pipe part 9497011, but that will be a difficult job.

Post by **erikv11** » 18 Sep 2021, 12:10

Hopefully by "oil" you mean penetrating fluid. I'd use a 6 point deep socket and some PB Blaster or equivalent. Steady pressure alternate tightening and loosening direction, should be able to crack it loose.

Post by **scot850** » 18 Sep 2021, 12:45

+1 with Erik on this. Like he says, a good penetration oil (NOT WD40). Let is soak. Dissimilar metals is the usual issue so they 'bond' with heat and salt.

Tight space, but if you can get some heat on it that will help also to shock them free. Otherwise Eriks recommendation of 6 point socket and tighten/loosen is the only real option.

Good Luck!

Neil.

Post by **kallekula** » 18 Sep 2021, 12:50

I use Deep Creep by Seafoam. Best penetrating liquid IMHO.

Post by **erikv11** » 18 Sep 2021, 14:34

I've seen internet survey/experiments that rated Liquid Wrench as the best commercial one. I use AST Penetrant because my local machine shop recommended it. It works well https://www.antiseize.com/ast-penetrant-ii

Post by **scot850** » 18 Sep 2021, 17:24

I use Liquid Wrench, Deep Creep and PB Blaster. I have found they all work well. WD40 I use for cleaning.............!

Neil.

Post by **FireFox31** » 18 Sep 2021, 20:28

erikv11 wrote: ↑18 Sep 2021, 12:10 Steady pressure alternate tightening and loosening direction, should be able to crack it loose.

Thanks everyone. Aero Kroil is my lubricant of choice and I sprayed it with a second dose tonight. I always spray just enough lubricant so it doesn't drip off.

I must have loosened it a tiny bit on my first attempt because a little drop of coolant was hanging on the nozzle. I carefully tightened it and it moved slightly. Thus, erikv11's suggestion to alternate tightening and loosening seems like a great idea. Thanks.

I'm still going to buy a new valve if available. My 13mm flare nut wrench slipped while trying to loosen it, rounding it slightly.

Post by **erikv11** » 18 Sep 2021, 21:53

FireFox31 wrote: ↑18 Sep 2021, 20:28 ...I'm still going to buy a new valve if available. My 13mm flare nut wrench slipped while trying to loosen it, rounding it slightly.

Seems like a good move. Nice work.

Post by **abscate** » 19 Sep 2021, 04:33

A six point deep socket would better. I would give that three hot cool cycles with 20 seconds of propane torch to break that brass steel bond. If it’s moved a bit, let the penetrating oil work it’s magic

ATF and acetone 1:1 is the premier penetrating elixir.

Don’t forget to post the part number for that valve

Post by **ZionXIX** » 19 Sep 2021, 12:07

For future info I like this project farm video comparing several penetrating oils.