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Thermostat DIY - broken bolt

12K views 12 replies 7 participants last post by  Alexotronic 
#1 · (Edited)
Fellow fanatics

Never celebrate early. I was replacing belts, WP pulley, WP and thermostat. Completed belts, pulley and WP and when working on last piece - literally the last damn top bolt on thermostat housing , heard a click and bolt became loose. Checked socket and found broken bolt.

I removed the thermostat again to check if there is enough broken piece outside the engine housing and it's barely a thread to get any kind of grip on vice/pliers etc to pull it out.

Need help for options as i never worked with broken bolts or torch.

How much does a job like this cost as i'm worried about damaging threads in housing if i try something on my own to extract?

PS -- check out the last image. i see some impressions of partial threads. Can someone tell me what the heck that is in the thermostat block?
 

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#5 ·
You might actually need a 90 degree drill attachment in order to get it in there without pulling the front end of the car off...

I recently had to help a neighbor drill and easy out some bolts and it would have been impossible with my cheapo harbor freight drill adapter
It will fit in places that the full drill will not:



+1 on using a left handled drill bit. Often when you use the left handed bit the bit will catch and remove the bolt even before you have to use the easy outs.

-Rich
 
#11 ·
great piece of advice. I would guess that OP can get the bolt out with just a left handed bit once it catches.

and OP.. next time, do not torque down so hard. Those bolts need very light tightening.

oh, and please just buy the replacement bolt from the dealership. Possibly a few bucks at the most.
 
#6 · (Edited)
I'm a proponent of left handed drills, but you also need a reversible drill motor. Doesn't sound like the OP would have either.

If this was on my car. I wouldn't hesitate to try a sharp cold chisel around the outside. Just tapping lightly with the weight of a small hammer. Once the rust/oxidation is knocked loose, it might just twist on out under my thumb.

Then again, it could be rust welded in there and be a b*tch. :D
 
#7 ·
Do drill still come without being reversible? I think the only one I own that isn't reversible is an air drill.

Even the $18 harbor freight drill is reversible and would work for this. $20 for the 90 degree adapter, $20 for a drill, $10 for some cheap left handed bits, $10 for some screw extractors.

So that makes it $60 and some time even if you don't have any tools.

It isn't the most skilled thing int he world but you do have to make sure and keep the drill bit centered on the bolt so you don't drill into the block... Hopefully he can do that. :)

I might start with a nice quality drill bit and then switch to the cheapo lefty bit after I have a nice centered hole started.

-Rich
 
#9 ·
I have similar tool but there is not much clearance. i made a trip to big orange store and reversible drill bit/prick punch/ez out equivalent was about $20, i have reversible drill but need to buy 90 degree attachment. But i'm worried that all this work will require taking apart radiator to get some clearance as it's top bolt that is messed up. thinking of going to local garage which quoted about an hour of labor to remove [excludes thermostat].

I was wondering how much of overheating risk do i carry if i drive without the manual fan assembly as i don't want to pick it apart and reinstall it at the garage. Can i also run it on just distilled water instead of adding coolant as it will be drained when water pump is removed to take the bolt off at the garage.
 
#10 ·
If you don't get stuck in traffic, and it's less than 80°F out, you should be just without. Especially if you have an automatic car with the additional electric radiator.

Also, distilled water works just fine for short term. Long term you should have some coolant or corrosion inhibitor mixed in to prevent corrosion in the cooling system.
 
#12 ·
I ended up going to mechanic. An hour of labor and broken bolt was off. He also found another bolt that was on verge of failing - when i looked at it the bolt was slightly thin in top half.
 
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