New here. Just got a 2001 986 S with 142 on the clock

[MPDano]

Originally Posted by Geof3

I'm a little confused by the pictures. When you opened the cap, did you then see all the gunk? It looks as though there is no coolant in the tank at all? Or, had it been drained? IF there is no coolant in the tank, or hasn't been, that seems very odd. Sometimes, a cap can get white/brownish gunk as you see from condensation. Notorious in my Jeep, totally harmless, just means I need to drive it harder. Not sure if the Boxster has this issue potentially or not. I agree with the rest, no matter what route you take, you need to flush the snot out of your coolant system, until the entire system runs completely clear, then test from there.

Yeah, pic was taken after the test drive and coolant leaked right out the overflow tube under the engine. I tried to post a video but for some reason it says it needs a moderator approval.

[MPDano]

Anyways, I'll just post text and not a video. I bought the Harbor Freight Cooling Pressure Tester and the black adapter fit perfect. Pressurized to 12 psi (same as stock overflow cap psi) and it held. The video I took of it holding 12 psi steady for a minute. I even took off the oil cap just to make sure I wasn't sealing it. Same same, no leaking and had it hold for 10 more minutes.

I am thinking the PO put oil in the overflow tank and at the same time the overflow cap is bad.

Your thoughts?

[Jamesp]

I'd go with the accidental contam theory, and perform the multi flush and distilled water test. It's the cheapest and easiest way to start, and you might resolve the problem for the cost of a few gallons of distilled water. Kroger sells it cheap.

[MPDano]

Originally Posted by Jamesp

I'd go with the accidental contam theory, and perform the multi flush and distilled water test. It's the cheapest and easiest way to start, and you might resolve the problem for the cost of a few gallons of distilled water. Kroger sells it cheap.

Exactly what I am thinking. But why use distilled for just flushing? When my Yukon got trans fluid contamination, the trans shop used simple green and water to flush out the system. I was thinking purple power as it's a great degreaser. Just run it thru with tap water with car running to warm it up, heater on of course to get the heater core. Maybe do this a few times and clean out the overflow too. After it's clean, then fill it up with the recommended coolant 50/50.

It's just the process I was thinking. Also, since this is the first mid engine I ever worked on, is there a bottom hose on the radiator? I am assuming in front of the car? Please disregard the noobness in my questions.

[MPDano]

Video of pressure testing.

https://youtu.be/5IYbhv-xGpw

[Jamesp]

There is a drain plug in the bottom. As i recall its an 8 or 10 mm allen screw. Looks like a little round metal button on the aluminum tube manifold under and in front of the engine. Using detergent will greatly increase the cleaning, but it can also foam. I'm not sure how that behaves in a water pump. You'll want to make sure there is no detergent left in the cooling system when you are done if you go that route. If you do use detergent please take photos and let us know how it goes.

[MPDano]

Originally Posted by Jamesp

There is a drain plug in the bottom. As i recall its an 8 or 10 mm allen screw. Looks like a little round metal button on the aluminum tube manifold under and in front of the engine. Using detergent will greatly increase the cleaning, but it can also foam. I'm not sure how that behaves in a water pump. You'll want to make sure there is no detergent left in the cooling system when you are done if you go that route. If you do use detergent please take photos and let us know how it goes.

It seems that the purple power versus simple green came up a lot in google. Consensus seems to go with Simple Green HD. If the pros at my trans shop uses it, it must be the way to go. Yes, I saw a video of where all the hose connectors and that drain plug near the thermostat in a video. Going to also change out the thermostat and housing as well. A lot easier to do while all the coolant is out. I'm going to remove the thermostat and then do the flush, this way nothing is blocking the flow while it warms up. Pics for sure will come.

[Geof3]

Pretty sure I've seen it mentioned here, to NOT use any detergents in the flush. (maybe search) There are tons of nooks and crannies in these systems, and seems the best advice is to use simple distilled water. Also, unless you vacuum fill the system, you need to know the bleeding/burping procedure to get all the air bubbles out of the system.

[Quadcammer]

Originally Posted by Geof3

I'm a little confused by the pictures. When you opened the cap, did you then see all the gunk? It looks as though there is no coolant in the tank at all? Or, had it been drained? IF there is no coolant in the tank, or hasn't been, that seems very odd. Sometimes, a cap can get white/brownish gunk as you see from condensation. Notorious in my Jeep, totally harmless, just means I need to drive it harder. Not sure if the Boxster has this issue potentially or not. I agree with the rest, no matter what route you take, you need to flush the snot out of your coolant system, until the entire system runs completely clear, then test from there.

That is applicable to the oil fill cap, not the coolant

[MPDano]

Just curious and still learning. Although I did the cooling system leak test, exactly what does it diagnose on our cars? I know the obvious like a leaking overflow tank, hoses, but what else does it diagnose?

[jdlmodelt]

I did that with mine shortly after purchasing. Your coolant cap isn't sealing properly and when the coolant gets hot it overflows and drains through that little hose to the ground.

Originally Posted by MPDano

Well, looks like I have other issues. Since I am waiting on parts I ordered from Pelican. I gave the old girl a detail. Looked in the coolant reservoir and saw milky stuff. Yup, oil in the coolant. I know this can be multiple things, but is there a known issue on these boxsters? Here are some pics of the brownish milky residue in my coolant cap and reservoir.

Also, what seems to be the reservoir overflow tube hanging under the right front part of the engine was leaking coolant everywhere after a test drive.

[MPDano]

Ok, did a single flush, put about a cup of simple green in the overflow, mostly to break down the oil in there. Also, did the oil change and filter/cover, thermostat/housing, cabin filter and new spark plugs. Still got some gunk in the coolant but I'll do another flush later.

You can see a lot of oil gunk pieces floating around when I drained it. You can see how bad the gunk was in the old thermostat. Also noticed no washing of any of the spark plugs, which is a good thing.

Spent about an hour zipping around my neighborhood and one the main roads I was able to punch it. Got up to 60 real fast, these little cars are peppy and the handling is pretty awesome. The night was about 65 degrees but the Boxster never got above 180 during the test run.

[dghii]

Keep flushing! Certainly worth a shot. Sure hope it works for you.

[MPDano]

Originally Posted by dghii

Keep flushing! Certainly worth a shot. Sure hope it works for you.

Yes, will do. The gunk is old oil as you can tell by the color.