Does anyone know the proper freeze plug size for a 1999 4.0? Its the plugs on the side of the block that I talking about. There are three per side. 6 total. Thanks.

I believe it is 1 1/2" diameter

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Thanks for the info. I pulled one and that is what I thought. But the 1 1/2" plugs i have I can't even get to start. I have a pretty straight shot at it but no go. I thought they may be a slightly smaller mm size and that is why i am having so much trouble. Afton.

If you got one out meassure it across side to side

I dont think they are metric sized

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Thats what i did. But to get it out I had to distort it a bit so thought I would double check. Its been a long time since i replace any of these while the engine was still in. Almost forgot how much fun it is.