Coolant leak

[73pony]

Was losing coolant. Found it was leaking from one of the water pump bolts on the lower driver side. Thought maybe the thread sealant failed. Removed bolt to find a small portion of the threads still on the bolt. See pics below. What are my options.

 

[Don C]

That appears to me to be Heli-coil threads, so that bolt hole must have been stripped and repaired with Heli-coil at some time in the past. They should have use Loctite thread sealant/threadlocker on the Heli-coil to lock it in place and prevent leaks.

 

[Aus73Mach1]

Doesn't look like a Heli-coil as they tend to have a tapered edge on the outside like a thread. The hole could possibly be repaired with one though. Water pump would need to come off to do it. If not a blind hole, use a good vacuum cleaner while drilling the hole to suit the Heli-coil to stop drill shavings going into the engine.

 

[Don C]

Doesn't look like a Heli-coil as they tend to have a tapered edge on the outside like a thread. The hole could possibly be repaired with one though. Water pump would need to come off to do it. If not a blind hole, use a good vacuum cleaner while drilling the hole to suit the Heli-coil to stop drill shavings going into the engine.

You are correct, I should have zoomed in on it. I have seen threads pulled out like that, don't remember any in cast iron, though. Hard to imagine someone tightening water pump bolts to that point. Surprised the bolt didn't break first.

 

[Aus73Mach1]

Don, I agree, cast iron doesn't normally pull a full thread out. Looks like fairly new bolt. Maybe tightened and when started to strip it was left. Does that bolt also hold a belt adjustment arm, might explain the extra force to strip it.

 

[boilermaster]

73 pony how about a picture of the exact hole this bolt came from?.
If it came from on top of the lower hose it would thread into the engine block.
If it came from BELOW the hose it threads into the timing cover and NOT the engine block, two totally different jobs.
If it is the lower, I do NOT recommend trying to repair it, but to REPLACE it. the threads in the timing cover are of a stamped then threaded nature and in my opinion, are short and weak.
Hoping in your case that is the higher of the two bolts.
Boilermaster

 

[basstrix]

As Boilermaster said, the bolt may be from the front cover. The threaded holes are first punched, then threaded. The length of thread is fairly short.

You might get away with using a time-sert (solid body thread insert) but I don't recommend a heli-coil. If you go this route, keep in mind that the metal shavings are going inside the engine, if you try to do this without pulling the cover. You can run a shop vac while drilling and fill the flutes of your tap with wheel bearing grease to catch most of the shavings. If you decide to pull the cover, you can tack weld a nut to the back side, but make sure you don't end up with any interference with the nut and timing chain/sproket.

Another thing to keep in mind is that the timing cover has a lip that tucks under the front of the oil pan...it's not all that easy to get it installed correctly without dropping the oil pan.

My suggestion is: with the front cover in place, wire wheel the gasket surfaces and inspect for corrosion damage. If the condition is not good, just get a replacement, otherwise, consider the time sert without removing the cover. If you go the time sert route, use the red lock tite stud & bearing mount on the outer threads of the insert ONLY.

 

[73pony]

Thank you for all the suggestions. Here is what I ended up doing. My flowkooler pump will accept a 3/8 bolt in this position. Without drilling I threaded a 3/8 tap into the hole with bearing grease as suggested. Threads were cut nice. Pulled what I believed to be all shavings back. Still wanting to be cautious drained the oil. No shavings seen. Reinstalled magnetic plug and pulled distributor. Dumped one quart of oil down the hole. Poured another down the valve cover opening. Waited about 1 hour and drained the new oil through a paper cone. The plug was clean and no shavings in the cone. Changed filter and refilled with oil. The new 3/8 bolt threaded in perfect and I torqued to spec. Refilled the coolant. Fired it up. Brought up to temp. Shut it down. Let cool. Drained oil through paper cone again. No shavings. Pulled filter and cut open. No shavings. Installed new filter and filled it back up. Might be overkill but better safe than sorry. This is a new build completed about a year ago. All water pump bolts were torqued to spec in two steps by me. The treads that I pulled out are not aluminum by cast iron so I can only assume that when the machine shop chased the threads it was off just enough to cut them too thin causing them to weaken and pull out. Regardless it is fixed and I am back on the road. Just in time for a beautiful 77 degree sunny Sunday to go for some ice cream with my daughters. Thanks again for the help.

 

[basstrix]

@73pony Out of curiosity, was it one of the bolts that threads into the front cover, directly? I think there are 2 down low and one up top that you can actually see.. I have a spare cover that has one of the holes tapped to 3/8.

 

[73pony]

Since the section of threads was magnetic I assume it was the block.

 

[Cleveland Crush]

You did an excellent repair @73pony, it will be fine.

 

[Cleveland Crush]

As a side note to 73pony's thread situation: Don't use a cutting tap to clean threads as they will remove/shave good metal. Please use only cleaning taps (chasers) to prepare for reassembly.