Hi folks. My 1958 Fleetside with 235 engine is leaking coolant from the head gasket at the back of the motor.
I think it's a bit of a Frankenstein motor, not the original from 1958. Block casting:3837004 F56Y at distributor, with milk can solid lifters. Has extra oil line in lifter area to central head bolt, and external oil line from oil filter to central head bolt as well. Cylinder head: 3836848. Rebuilt with new valves, guides. Surface was cleaned up. Not sure how much was taken off by machine shop. Maybe .010" ?
Once the engine warms up and coolant is under pressure from rad cap, it starts a steady drip coming out rear passenger head gasket area.
In talking with an older neighbor who worked as a mechanic at the local Chevrolet dealership, he remembers a recall back in the 50's where some motors didn't have the head bolt holes drilled/tapped deep enough, especially the rear drivers side (he thinks).
When I put my rebuilt head back on, I did put a 1/2x13 tap down the bolt holes to clean them up, but with a regular tap, not a bottom tap.
Rather than take the head back off, I'm wondering if I could take out the bolts one at a time and re-torque them, and add a washer to the back 4 bolts or so to make sure that the head bolts are not bottoming out.
Any harm in this approach? Any hope that this might help? Don't want to crack the head. Or do I need to take the head off, and put in a new gasket. I have a spare Felpro fibre gasket, if I have to take it all apart.
John.
When God gives any man wealth and possessions, and enables him to enjoy them, to accept his lot and be happy in his work�this is a gift of God. He seldom reflects on the days of his life, because God keeps him occupied with gladness of heart. Ecclesiastes 5:19-20
Around 45~50 years ago I had one (think it was 1957 engine) that leaked just like that. Removed head, discovered the block surface should have been resurfaced but couldn't do that at the time. So I cleaned it up as best as I could and reassembled with new head gasket. Used a new (back then) spray-on gasket sealer which was supposed to be the best product for things like this. After that the leak was reduced greatly but you'd still see a bit at times. The good news is it never went into the cylinders nor the oil pan. I've never heard of the bolt hole problem, however maybe others have. If the bolts were bottoming out before they got tight enough, this sort of problem might happen, but you could check that pretty easily with a ruler, I'd think.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
I just measured a 1956 block. The bolt hole depth is 1.25" and the threads stop around 7/8" in into the hole. The head (with gasket) is right at 4 inches thick. As I recall, the head bolts are something like 4 17/32" long, so it is pretty unlikely in my mind that you could be hitting the bottom of anything...if this helps you feel better about that...
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
I'll pull the valve cover off and pull a bolt and check for depth of hole and bolt length.
Any risk of cracking a head if I retorque the bolts? With engine warm I presume.
If that doesn't work, then I guess I'll have to pull the head and check for flatness and try again.
John.
When God gives any man wealth and possessions, and enables him to enjoy them, to accept his lot and be happy in his work�this is a gift of God. He seldom reflects on the days of his life, because God keeps him occupied with gladness of heart. Ecclesiastes 5:19-20
Shouldn't be any concern on cracking the head. Usually I torque once cold, start the engine, warm it up and then torque a second time...torque in stages. 30#, 60#, 90#, something like that.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
So I've been working on a replacement engine for my Apache. I had it installed in the chassis, but then found that my original transmission leavers would bump into the bell housing on the driver side. So new engine has a different bell housing. So I took the bell housing off of my original motor, to get it ready to swap onto my replacement engine. In doing so, I finally found my coolant leak. Had nothing to do with the head gasket. There is a frost plug in the back of the block that was rotted out. It's covered by the bell housing so it's a slow leak.
When God gives any man wealth and possessions, and enables him to enjoy them, to accept his lot and be happy in his work�this is a gift of God. He seldom reflects on the days of his life, because God keeps him occupied with gladness of heart. Ecclesiastes 5:19-20
That's why I use brass freeze plugs whenever possible on an engine rebuild. They don't rust out nearly as quickly as steel ones. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Please, please, don't get it started again. The discussion of steel vs brass plugs is so old it has whiskers.
I bought an engine (1957) cheap because the PO said it had an overheat problem he couldn't fix. I found the same build up problem with hardened stuff I suspect was cast iron rust mixed with radiator stop leak. Someone on Stovebolt said the rust build-up only happens on 216 engines. Thanks to John, we now have pictures. Anyway, I removed the side plugs, drain petcock and water pump to get access to dig out the water jacket passages being careful not to poke a hole into the cylinders. Not an easy task with engine removed. Almost impossible with engine installed.
The large plug hole at the rear has a shoulder that can break if you try removing the plug like the others. GM coated the outside of the steel plug with a hard shellac-like substance.
When you dislodge this blockage in an engine block you definitely don't want it going into your radiator. Disconnect the radiator hoses. Flush the engine out the best you can.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
