View Full Version : How to Remove Engine Block Drain?

10-21-2007, 08:16 AM
I could not get the petcock to drain on my 2000 Maristar (Indmar LT1). Knock sensor on left side of engine came out fine, and did drain. It appears that on the other side the wing nut thing is stripped, it just spins when I try to open. Can anyone tell me how to remove the entire drain valve? Should I replace?

10-21-2007, 07:34 PM
I've got a Indmar 5.7 GM, and I just remove the whole drain plug, petcock and all. I always hesitated to just drain throught the petcock, since the opening is smaller, and I get a small amount of crud coming out with the help of some pipe cleaner.
If you've got the same type drain as mine, it just wrenchs out.
And I would replace the whole drain plug for next year.

10-21-2007, 09:39 PM
Get rid of the petcock and replace it with a brass plug. You can get them in the plumbing aisle of any big box or hardware store and you don't want to use cast iron or steel- they will rust in place. Petcocks are OK if you use coolant in the motor because they inhibit corrosion but water doesn't do that.

east tx skier
10-21-2007, 09:42 PM
What Jim said. 1/4" NPT. Brass at Napa is about a $1 or 2 a pop.

11-18-2007, 07:01 PM
Found one at the hardware store, thanks for your help!