ocean Posted November 11, 2009 Share Posted November 11, 2009 The options I get to choose from on the 89 commanche bolt size are 7/16 or 1/2"..... The half is too snug for the bolt and my 5/8 works perfect (WTF?).... It seems like I would order the 1/2 bolts and be ok right but how can I be sure on this one? I've checked it several times now and am more baffled than ever..... Opinions please? Thanks Link to comment Share on other sites More sharing options...
Eagle Posted November 11, 2009 Share Posted November 11, 2009 I don't understand your question. The ONLY bolt size you can use is the bolt size that screws into your block. And if the only two options are 7/16" and 1/2", and 1/2" is too big -- how did we get to 5/8" being "just right"? Link to comment Share on other sites More sharing options...
Oizarod115 Posted November 11, 2009 Share Posted November 11, 2009 what do you want bolts for? the exhaust manifold? the throttle body? the thermostat housing? i assume you're talkin about head bolts... in which case you should take the ones you have and match them up with the ones that you order and be sure theyre right. Link to comment Share on other sites More sharing options...
ocean Posted November 11, 2009 Author Share Posted November 11, 2009 I'm getting ready to replace the cylinder head and one of the questions that they (at O'reilly)ask is 7/16 or 1/2 bolt size when they are ordering the replacement cylinder head. Whats throwing me is that the 5/8 fits the bolts the head is mounted by. So I'm guessing that I have to have the 1/2 inch bolts right? I don't know why the 1/2 inch doesn't match the specs but maybe I have a sh*tty socket and wrech set. The other question I have is does a 89 renix jeep have a Coolant Temperature Sensor on block? Thanks for trying to help me out. Link to comment Share on other sites More sharing options...
ocean Posted November 11, 2009 Author Share Posted November 11, 2009 Sorry Eagle, Maybe my phrasing is off. The 1/2 inch socket and wrench will not go on the bolt head. The 7/16 obviously will not go on. The 5/8 fits perfect. When they are asking me what cylinder head I need the bolt size does not match based on the tool I am fitting to the bolt head. Maybe I'm just mildly retarded LOL :dunce: Ideas?+ Link to comment Share on other sites More sharing options...
Oizarod115 Posted November 11, 2009 Share Posted November 11, 2009 they are most likely asking you for the bolt thread size. the thread size is going to be different from the bolt head size. Link to comment Share on other sites More sharing options...
ocean Posted November 11, 2009 Author Share Posted November 11, 2009 ok that makes sense. Should I pull one of the bolts to determine that or do I need to do a different thing. I'm not driving it at the moment so I can pull a bolt without screwing the engine up, any more than it already is. Link to comment Share on other sites More sharing options...
jimoshel Posted November 12, 2009 Share Posted November 12, 2009 I thought all '89 MJ'S were metric. I strongly suggest you make sure what you got before you screw up your bolt holes' Link to comment Share on other sites More sharing options...
ocean Posted November 12, 2009 Author Share Posted November 12, 2009 I have never heard that before....anybody else. I'll check but I though it was not a metric measurment. I'll use the same bolts in the holes (the ones the jeep still has) but I still have to choose between 1/2 in and 7/16 measurments. Link to comment Share on other sites More sharing options...
Wildman Posted November 12, 2009 Share Posted November 12, 2009 They should be a 7/16" SAE bolts, with a 1/2" head hole (for alignment and clearance) I see where your getting the 5/8" from, Rule of thumb........the bolt head (or nut) is 3/16" larger that the bolt........IE: 7/16" + 3/16" = 5/8" Link to comment Share on other sites More sharing options...
Eagle Posted November 12, 2009 Share Posted November 12, 2009 Sorry Eagle, Maybe my phrasing is off. The 1/2 inch socket and wrench will not go on the bolt head. The 7/16 obviously will not go on. The 5/8 fits perfect. When they are asking me what cylinder head I need the bolt size does not match based on the tool I am fitting to the bolt head. Maybe I'm just mildly retarded LOL :dunce: Ideas?+ Back to ground zero, Grasshopper. The size hex wrench (or socket) that fits on the head of a bolt is NOT the size of the bolt. The bolt size is the diameter of the bolt shank ... the outside diameter of the threaded portion, or the diameter of the smooth portion if there is one (which there will be for a head bolt). Just take one of your old head bolts to the store and let them match it. Link to comment Share on other sites More sharing options...
ocean Posted November 12, 2009 Author Share Posted November 12, 2009 Thanks! :typing: lol Link to comment Share on other sites More sharing options...
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