SomedayJ

Hi guys.
I'd like to replace the coolant in my 4R first gen. But I'm having problems with the coolant engine drain plug (stupid, I know). The 17mm hex-head bolt's stuck. I removed the driver's side wheel to have a better access and I put generously penetrating oil, I waited a couple of hours but the bolt doesn't move. I don't want to apply too much force, knowing my luck...

I know it's a stupid problem, so I'm going to place this --> here, you don't have to search in the smilies list for it when you answer in this thread, just copy and past.

Do you have any tip to remove a stuck coolant engine drain plug?
Thank you.

SomedayJ

Solved.
The PO used a thread sealeant for high temperature in the coolant engine drain plug, it requires heat for disassembly
I went for a 30 minutes ride and after that I could loose the bolt, the stubborn's not fixed anymore.
I'm letting the engine cool down to drain the old coolant, I'll tell if I find gunk in the engine drain hole.

SomedayJ

Hi guys,
Is it possible that the coolant engine drain plug doesn't fit all the way in the engine hole? It turns 4-5 times but after that it stops, almost half way. I noticed this in 2 4runners. Do you know why?

rustypigeon

I never measured the threads but I assume they are metric pipe threads. They sure feel like tapered threads when you insert the plug. Mine only go in about 4-5 turns as well.

gsp4life

Are you trying to remove just the brass drain plug or the larger steel fitting the plug threads into? (it has a small hole in the side)

The brass plug will stop after a set number of turns before it's fully threaded because the seal is made when the flat spot on the end of the plug contacts a shoulder inside the steel drain valve. It shouldn't need anything else, but if it's pitted or damaged a light coat of thread sealant can help. IIRC, the steel valve is tapered pipe thread.

SomedayJ

Hi guys.
I didn't know that detail, tapered threads, I thought the plug had some problem.
I'm posting this pic in case other member needs this info, you can see the number of turns this plug can do counting the black threads.
Thank you for your help!

briholt

I appreciate this post. My drain cock isn't a hex head bolt but an Allen set screw. Not looking forward to breaking it loose.

snippits

Get an impact Allen. Oil adapters on Jeep XJ were prone to leaks, and they had a big Allen bolt/screw. Impact took them right off. No way by hand.