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

[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.

[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.