Removing Thermostat Housing Bolts Nightmare

[lexus082]

The car I am working on isn't a lexus, but I figured that this is a problem that happens sometimes and people might be able to benefit from other users input on how to approach something like this. Forgive me for it not being a Lexus. :) It my sister's car (95 mustang 3.8L V6. I was removing the thermostat housing by removing the two bolts that mount it to the cylinder head. The bolts were very tight even after several turns counter-clockwise to loosen they were extremely tight. I took a chance trying to further turn them to remove them completely and both of them ended up breaking off. So now there's two bolts without their heads stuck into the cylinder head. On of the bolts is pretty much flush with the cylinder head. The other is only sticking out at most 1/4 inch. They are 10mm bolts not sure how long in length. Does anyone know what to do or what to try to repair this. I bought a bolt/screw extractor drill bit at sears to try. But if anyone can help out with any suggestions that would be great. Also, I only was able to loosen only 3-4 turns before the bolt's head snapped off. They were so tight while loosening it was like I was tightening them. Any help would be appreciated, never had any fun working on that car.

[jzz30]

you have to try to drill it out or use your extractor. if the extractor can get it out then great! But if you have to drill it out, you may risk ruining the threads. so center punch the bolt, then drill with a small drill bit like a 5mm or sumthin and then use an 8mm or 5/16 and you should be able to get the rest out or it should jsut tear out by itself be sure to clean up the threads using a tap.

worse case scenario you need to use an insert thread, and that will get costly if its done right.

[lexus082]

Thanks a lot for the reply. Your response is very much appreciated! You've replied to many of my posts and are always a big help. So thanks again. Well see how it goes, I've never encountered this problem before so I'll be very pleased if it works on in my favor.

you have to try to drill it out or use your extractor. if the extractor can get it out then great! But if you have to drill it out, you may risk ruining the threads. so center punch the bolt, then drill with a small drill bit like a 5mm or sumthin and then use an 8mm or 5/16 and you should be able to get the rest out or it should jsut tear out by itself be sure to clean up the threads using a tap.

worse case scenario you need to use an insert thread, and that will get costly if its done right.

[Micah]

I replaced a thermostat on my ford conversion van. I wound up drilling out the bolts using cobalt drill bits (don't use the cheap ones, I learned that they dull very quickly even if they say they can drill metal). My dad had the bits and the taps. I started with a large drill that was the size of the housing to center the hole. I then switched to next to smallest bit and drilled a hole. I went to the next size and drilled all the way through as well. I just kept doing that until the hole was almost as large as the original bolt hole. GO SLOW AND DON'T PUSH HARD. If you break a bit off in the bolt you're finished, so be careful. The bits like to bind up, so I found that reving the drill all the way up and applying minimum pressure to the drill (pushing the drill into the hole) worked great and kept the bit from binding or breaking. LAST I finished it by retapping the hole. You will need to match the tap to the bolt you are replacing it with. (take it with you). Took me about 1.5 hrs to do 3 holes, but it worked great. I even accidentally drilled one too large, so I just tapped it with the next size bolt. Worked great for me, but its best if you know someone who has the correct tools. If not, you will do nothing but frustrate yourself and the tools are not really that cheap if they are quality tools. I tried the cheap ones from the auto parts store and the bolt extractor (i broke it off into the bolt. . .thankfully I was able to cut the end of the bolt off so I wouldn't have to drill through it). If it is in there so tight that the head broke, chances are that an extractor will not work unless you heat the head of the bolt until it is red hot then spray pb blaster onto the bolt. Not my preferred method as I thought it was easier (for me) to just drill them out. Hope this helps!

[jzz30]

im here to help!

[lexus082]

Yeah I found out the titanium drill bits get dull extremely quick I guess I will have to search for the cobalt drill bits. It worked for about the first 2mm into the bolt and then it was completely dull.

I replaced a thermostat on my ford conversion van. I wound up drilling out the bolts using cobalt drill bits (don't use the cheap ones, I learned that they dull very quickly even if they say they can drill metal). My dad had the bits and the taps. I started with a large drill that was the size of the housing to center the hole. I then switched to next to smallest bit and drilled a hole. I went to the next size and drilled all the way through as well. I just kept doing that until the hole was almost as large as the original bolt hole. GO SLOW AND DON'T PUSH HARD. If you break a bit off in the bolt you're finished, so be careful. The bits like to bind up, so I found that reving the drill all the way up and applying minimum pressure to the drill (pushing the drill into the hole) worked great and kept the bit from binding or breaking. LAST I finished it by retapping the hole. You will need to match the tap to the bolt you are replacing it with. (take it with you). Took me about 1.5 hrs to do 3 holes, but it worked great. I even accidentally drilled one too large, so I just tapped it with the next size bolt. Worked great for me, but its best if you know someone who has the correct tools. If not, you will do nothing but frustrate yourself and the tools are not really that cheap if they are quality tools. I tried the cheap ones from the auto parts store and the bolt extractor (i broke it off into the bolt. . .thankfully I was able to cut the end of the bolt off so I wouldn't have to drill through it). If it is in there so tight that the head broke, chances are that an extractor will not work unless you heat the head of the bolt until it is red hot then spray pb blaster onto the bolt. Not my preferred method as I thought it was easier (for me) to just drill them out. Hope this helps!

[Micah]

I had the same problem. The cobalt bits a very expensive, though. If you could get you some left handed bits (ones that drill in the opposite direction), the bolt might even back on out when you get it almost drilled completely. My uncle said his bits cost him 100 dollars (left handed mechanics bits). I don't know what my dad paid for his, but they worked GREAT!!! You might try sears, but be very very careful b/c if you break a cobalt bit into the engine you are done. You will have to most likely disassemble the upper manifold and have it machined out at a machine shop if you break the bit into it. Good luck, I have been in your shoes and don't envy them! Should be easy though with the cobalt bits.

[jzz30]

those Ti-N coated bits are rubbish! they work initially because the coating is hard but as soon as that wears away the drill blanks it selfs are soft and useless. probably only good for wood and plastics. and drilling bolts that have snapped are especially hard becasue the bolt has hardened from cold working. anyway its worth it to buy a decent set of bits costing 100-200 bucks for a 20-25 piece set. also using any kind of grease or wd-40 will help in drilling and keeping your bits sharp!

[lexus082]

I was very surprised it didn't take long for the coating to wear off. I picked up the cobalt drill bit I needed to do the job and it was only about $4. Doesn't sound the same as the expensive ones mentioned above. (Maybe b/c its a very small size bit? I will try tomorrow with the cobalt bit & grease.

[Micah]

Well, I had a whole set. One bit might not be that expensive (I didn't have to buy any or even shop for any) since my dad and uncle have loads of tools. The wd40 trick is a good Idea, I used liquid wrench as I believe it works the same. I have also heard pb blaster is the best to use, but I don't really know for sure as I've never used it. You will most likely need more than one bit to complete the job, though, and possible a thread tap. I used probably b/w 5 and 7 different size bits on each broken bolt (working my way up from small to large).

[Air Force Rascal]

The car I am working on isn't a lexus, but I figured that this is a problem that happens sometimes and people might be able to benefit from other users input on how to approach something like this. Forgive me for it not being a Lexus. :) It my sister's car (95 mustang 3.8L V6. I was removing the thermostat housing by removing the two bolts that mount it to the cylinder head. The bolts were very tight even after several turns counter-clockwise to loosen they were extremely tight. I took a chance trying to further turn them to remove them completely and both of them ended up breaking off. So now there's two bolts without their heads stuck into the cylinder head. On of the bolts is pretty much flush with the cylinder head. The other is only sticking out at most 1/4 inch. They are 10mm bolts not sure how long in length. Does anyone know what to do or what to try to repair this. I bought a bolt/screw extractor drill bit at sears to try. But if anyone can help out with any suggestions that would be great. Also, I only was able to loosen only 3-4 turns before the bolt's head snapped off. They were so tight while loosening it was like I was tightening them. Any help would be appreciated, never had any fun working on that car.

One thing you might do is call the Eastwood Company at 1-800-343-9353 or go to their website eastwoodco.com tell them about your problem..they may have a couple of tools that will help you out.

Good Luck

[jzz30]

smaller bits are relatively cheap. about 4-10 bucks depending on size. anything above 10mm gets really expensive, like 20 bucks a pop and if you really get big bits like a 20mm or sumthing its like 100 bucks!!!

[lexus082]

Just got done trying to use the cobalt drill bit and it worked better than the titanium one I used before but it didn't take long for it to get completely dull. So went into the bolt another 2mm but it would not drill any further. The mechanic at UPS where I work wasn't sure how easy it would be to drill into the bolt since the bolts have been heated and cooled so many times. It seems that in order to drill the hole deep enough for the extractor I would probably have to buy several more drill bits of that size. They only hold up for about a minute and then they just get too dull. Then if the extractor doesn't do the trick once the hole is deep enough than I back to the drawing board. I couldn't imagine trying to drill out the bolt with several different drill bits I would have to buy like ten of each size since they get so dull so quick. Thanks for all your replies. I'm not sure what to do next. Maybe I'll get some JB Weld and try to put the thermostat housing back on with that, just kidding.

[Micah]

What size bit did you start with. I drilled into a ford econoline van bolt with 170000 miles and they drilled easy with the cobalt bits. I used a very small bit to start with, though. The smaller the bit, the easier it will be to drill (smaller area you are working on). One bit will not do the job (I tried that too) even with the cobalt bits. You use the large bit to center the hole (makes a dent in the middle) then start with the smallest bit you can find and work your way up each size (ex. start with 2mm bit then go to 4mm bit then to 6mm, etc). That way you are not working as hard. You will not have to replace the bits if you do it that way. The van I worked on had overheated and was very old (a 1990 model) so I don't believe that it would be too hard for a cobalt bit as my van had been heated and cooled many many times too. I don't know why your bit dulled so quickly other than maybe you used too large of a bit to start with. Hope all that helps!

I was to the jb weld point too, lol! It will all work out! Be careful with that extractor. It is very hard and if you break it off into bolt its back to the drawing board.

One more thing, make sure you are lubricating the hole as you are drilling with wd40 or liquid wrench. This cools the bit and I believe it helps keep it sharper (i believe it dulls faster when it gets hot).

[lexus082]

I starting with a punch and then used a very small drill bit. So small I was afraid it would snap in half. I really don't want to pull the heads and then let a machine shop takeover. My sister was planning on trading the car in and buying a new one (in the next week). Book time to replace the head gaskets ie remove heads is about 10 hrs. So after failed attempts with drilling I went to the JB Weld website and am seriously considering using that to reconnect the thermostat housing to the engine. Goes against what I would normally do, but since she is getting rid of the car to save money on endless repairs why waste more money trying to fix this problem the expensive and correct way. Does anyone think I actually would have a chance of making this work with the JB Weld. One type of JB Weld was good up to 300 degrees F and the other was good up to 500 degrees and there was a considerable difference in tensile strength. If I decide to use this should I be more concerned about the tensile strength or the ability to withstand the heat. Since both would play a factor. I just thought I would try putting that stuff where the gasket goes and then also along the outer edge of the thermostat housing where it butts up against the engine. Is this a possible temporary fix? So happy its not my car this time :) Otherwise this last resort would never be mentioned by me.

[Micah]

Why not leave the thermostat out since you will be jbwelding. If you leave it it I would think that it would put a lot of pressure on the thermostat housing when the thermostat is closed (the water pump never stops pumping). If the jb weld isn't strong enough it would probably give way. 300 degrees should be good enough since boiling point of antifreeze and water mixture is around 275 degrees. As long as the engine doesn't overheat it should be ok if the jbweld performs to specs. The engine I believe runs at about 195 degrees. Without the thermostat, it would probably run cooler than that (not really good for engine wear, but you are trading it in). You might leave a note somewhere consealed to the next to be owner about the problem. I would feel really bad knowing that someone else unknowingly got this car in this condition. If the extractors and the drilling didn't work, then this might be your only option, but I am far from an expert. I have also heard of people welding a nut to the end of the bolt and the heat from the welding actually broke the nut free. It might be one last resort, but you need a welder to use that approach. If no welder, I don't know. JB Weld would probably last long enough to trade it in (maybe). I don't really know. Sorry my methods didn't help you as much as they did me.

[lenore]

Most drill bits sold to the public are not the optimum angle drill bits for drilling into steel. Machinist bits are cut at a different angle and with proper cutting oil will outperform most bits on the market. I wish I could remember the angles, but I know one of them is 117 degrees, but not sure if that is the machinist or common bit. Ford seems to always have bolts breaking in their blocks, been there and done that. Good luck.

[lexus082]

Well hopefully they won't try to resell the car to someone. The transmissions already starting to go in it. It just needs to run. My sister called a local "junk yard" that also sells used cars and she asked how much they would pay for it and they said they would give her $50 for it. When she offered it to another dealer they said they would take it as a trade in for $1500. I guess I will try the JB Weld w/o the thermostat. Although its against my morals :) Thanks for your suggestion about the thermostat.

Most drill bits sold to the public are not the optimum angle drill bits for drilling into steel. Machinist bits are cut at a different angle and with proper cutting oil will outperform most bits on the market. I wish I could remember the angles, but I know one of them is 117 degrees, but not sure if that is the machinist or common bit. Ford seems to always have bolts breaking in their blocks, been there and done that. Good luck.

Glad to hear it was another Ford and not a Lexus. Ford :chairshot:

[Micah]

That sounds like the best thing to do to me. The dealer will most likely auction it off and one of those smaller lots will probably get it.

[lexus082]

Well I gave up on the JB Weld and without even trying it I decided that it would probably not hold up with the vibration, heat, and so forth. And if the JB weld did break off while driving there would be a big coolant leak. Plus the fact if it did fail and then it would have to be repaired the correct way it would be very hard to clean the area where the JB Weld was applied since that stuff gets very hard. So I decided to have it fixed correctly. There's a guy that actually is equipped to come in his work truck to repair these sort of things. It was luck just to locate him. I knew those bolts were in there very tight and it wouldn't be a piece of cake trying to remove them. I tried to drill them out and this guy welded the studs to make them longer and then welded a nut on the end of them in order to loosen them. Did a very good job. Only con was the $85 service call + 2 1/2 hrs labor = $280 to remove two broken bolts. Seems like a lot to me, but then again I guess when your in a jam thats when you've no choice (which they know and are able to charge that much). I'm just glad I could save some money buy removing the PS Pump, Alternator, bracket myself since it was in the way of one of the broken bolts. Otherwise that would have been another $200 after correcting the original problem of it overheating. Which I am not sure yet as to why it is overheating. I know the coolant is in pretty bad condition but I'm not sure of the main source for it overheating. So I am going to replacet the thermostat, flush the cooling system, maybe replace the radiator cap and then I guess I will find out if any of that worked to prevent it from overheating.

[Micah]

sounds like you have it under control now. Overheating could be several things. . .the radiator (that was the culprit in my ford econoline), the radiator cap (that was a good idea to replace it), the thermostat, the water pump, or a blown head gasket. You would most likely see bubbles in the radiator if the head gasket were the case (or so I've been told). Best of luck!

[lexus082]

sounds like you have it under control now. Overheating could be several things. . .the radiator (that was the culprit in my ford econoline), the radiator cap (that was a good idea to replace it), the thermostat, the water pump, or a blown head gasket. You would most likely see bubbles in the radiator if the head gasket were the case (or so I've been told). Best of luck!

I believe I have finally fixed it. I replaced the water pump that was leaking and the thermostat of course and it seems to be alright. Could a radiator cap (alone) be the culprit of a cooling system overheating. Just curious.

[lenore]

Yes, The system usually is under pressure to help reduce the boiling point.

[lexus082]

Thanks for all the great responses. Now as for my car... I'm not sure why this is, but.... the temp. needle is usually at the same position all the time, but when it is very hot outside the temp needle actually goes down a little. I would think that on the hottest days the temp needle if it moved at all would raise slightly higher. Its doesn't make any sense to me. I'm kinda shocked when the temp needle is lower on the hottest days of the summer.