I have a new-to-me 95 3.4L that really needs a coolant change. How much coolant amI not going to get out of the engine ifI don't pull the block drain plugs and knock-sensor? I just have this bad feeling thatthose plugs will leak when reinstalled, so I'd like to avoid it ifI can (lots of Ohio rust!)

With all my older cars, I used to just flush and re-fill the system with water a bunch until it flowed clear out of the radiator, letting it run to get hot so the heater core got rinsed too. A friend recently told me I'm not getting the block flushed well by using that method.

2002 V6 T-Top
1995 V6 Convertible
1994 V6 T-top

 

I would recommend taking the car to any local radiator shop and have them do it. Yeah it's going to cost a few bucks but there are three reasons for this. One: You make quite a mess by letting the water and old coolant run all over the place. Two: There are enviromantal lawsand if the po po find out what you"re doing then there could be a huge fine. Three: The radiator shop can clean and flush your radiator better than your best efforts can produce.Just my thoughts on the subject.

 

If you are able to change your oil and do other basic maintenance then you should be able to change your coolant yourself... you don't need to take it to a shop for that. When I changed my coolant the other week I got out about 2 gallons. After it was all drained I flushed it with water and ran it for a while with just water in there with the heater on. Granted I did it more than once so I could get out the 8 year old Dex-cool. I'm pretty satisfied with it and got out quite a bit of sludge that Dex-cool is famous for producing.

 

Thanks for the response, and I don't have a problem with confidence in doing this, but the question was about the drain plugs.