coolant pipe drain plug thread size. (Page 3/3)
2.5 JUL 10, 05:01 PM

quote
Originally posted by FieroG97J:


I've taken a bunch of them out and never stripped one yet. Are you using a 5/16" hex key?



I've only done 2 cars but no prob. If they look bad I'd say soak with PB blaster 1st.
oneinch NOV 25, 12:51 PM
Fortunately, I was able to remove my plugs easily with a 3/16" hex key. I'll be replacing the plugs with something a little different. I'm nixing the internal hex plug altogether. I'll be using either an external hex head plug or an external square drive plug. Either way the plug will be 316 stainless steel. If you need fasteners (nuts and bolts, etc) you should give McMaster-Carr a looksee. Click here to see a selection of plugs. Maybe you're lucky enough to have a MC location near you. I do. If not, they ship promptly via UPS. I've replaced several other nuts and bolts on my car sourced from McMaster-Carr. One downside: sometimes you'll have to buy in a quantity more than you need.

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Stanton
'88 Formula, red on gray

[This message has been edited by oneinch (edited 11-25-2020).]

theogre NOV 25, 09:59 PM
Install w/ Non-Dry Teflon pipe dope not tape. This Dope will act as anti-seize later. Find it easy in Plumbing Section in many local stores.


quote
Originally posted by AL87:
Arent Fieros supposed to be GM metric vehicles?
I used a 5mm.

Not Everything is Metric in many old cars including Fiero.
Pipe drains, sender/sensor holes and some steering column parts are few that are SAE and/or NPT.

For Allen heads... Often Hex heads too...
Use the wrench that fits very tight regardless Metric or SAE. Rust in or on the heads/nuts can make odd size tool to fit better.

Hex bolts/nuts is best to use 6 point sockets not 12 points that most set have.

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fierosound NOV 26, 01:38 AM

quote
Originally posted by AL87:

I chased the threads with a tap and put in one of the plugs I pulled. and used thread sealant...



I replaced mine with brass NPT plugs with anti-seize. Will never have problems again.

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