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Steel Thermostat bolt removal

5304 Views 17 Replies 8 Participants Last post by  nbrcrnchr
I just got a used thermostat housing for a 2.0 ltr fuel injection system from the UK.

While trying to remove the two bolts that hold the thermostat cover in place, they twisted off. Now, I'm not worried about extracting what's left of the bolts, but, what I am interested in is any good recommendations for techniques or products or penetrating oils to free steel bolts that have fused with aluminum.

Currently, I have the housing soaking in carburator cleaner before I go any further.

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Chris, I've used "Rust Eater" from Autozone with good results, others have recommended PB Blaster for similar use. One thing I would heartily recommend is getting some anti-sieze compound before you re-assemble the housing. If you can't get the bolts out with an easy out of vise-grips, try heating the housing around the bolt holes with a propane torch, the aluminum will expand more rapidly than the bolts and may loosen up in the holes. HTH.

Rusty Bolts

One of the most powerful rusty thread "unstickers" is good ole Coca Gola (TM)! It contains phosphoric acid which reduces (chemical term) the iron oxide.

Truely, I have soacked old, rusty cylinder bores in the stuff to free pistons and also exhaust manifolds to remove the studs.

I replace the thermostat housing bolts with stainless steel studs to make the next time thermostat change easier.

Don't leave stuff in it too long as metal dissapears - a penny will last about two years while slowly breaking up into little coppery bits.

Go figure what it does to your insides .............:eek:
Thanks GtJim,

I can let you know some of what it does to your insides. This was quite the eye opener.

My brother-in-law drinks diet cokes or diet Dr. Peppers instead of coffee and he never touches alcohol, of any kind. (to each his own!) Anyway, he went in for a physical because he wasn't felling well. The doctor thought he was an alcoholic because his liver was so messed up. Apparently, all the coke or cola drinks had the same affect on his liver that serious drinking over several years has.

So, now he is on water to help clean it up and heal it.

I also know that Colas are great for removing barnicals from Abalone shells. That only takes a day or two submersed in about a 2 ltr amount.
Thermostat Housing frozen Bolt

I'm trying to replace the thermostat and I've managed to break one bolt and the other does not seem to want to budge. I've been spraying with pb blaster and not tapping but not banging on it with a hammer for the last couple of days. I'm somewhat leary of putting too much pressure on it considering how easily the other one snapped. If I go to the next step of applying heat, how much, where and how long? Do I go for just the bolt or the surrounding area or both?

Thanks in advance
I ended up drilling the remains out and inserting a Heli-Coil to replace the threads.

The housing I have had been exposed to years of England salt air and even the aluminum had been eaten into.
nbrcrnchr said:
If I go to the next step of applying heat, how much, where and how long? Do I go for just the bolt or the surrounding area or both?

Thanks in advance
The idea is to warm the alloy casting so it expands away fromthe bolt. So direct the flame onto the casting around the bolt's thread. Alloy melts at a low temperature so don't go heating for more than 10 or 20 seconds or - "GLOOP!" the casting may melt. Spray CRC or any other penetrating oil on the thread of the bolt from time to time as the heat helps it penetrate.
Stuck bolt

I'll give it a try. I don't really want to have to drill both out. Didn't even know my own strength on the first one.

Thank goodness this car is not my primary, I was finally getting rid of the solex and was changing out all the hoses and decided to change out the thermostat at the same time since it has been running barely warm the last couple of times out.

Good news bad news. I got the thermostat out but left a headless bolt. I don't think I could have gotten the bolts out with the upper hose connection on. Those bolts are severely rusted. Now that I've gotten the thermostat out, maybe I'll have better luck twisting the bolts out with a little heat, PB blaster and a pair of Vice Grips.

when you warm up the bolt cool it quick with water and it will break the chemical bond caused by the steel in alloy and will help you get it out ,
i like to use a little ptfe tape on bolts that go into alloy to stop the electrolitic action bonding them together in the future
PTFE tape? Is that the Teflon tape that plumbers use to seal around pipe fixtures?
tephlon tape

If your going to use tephlon tape, be sure to wrap the tape on the bolt in the correct direction.Otherwise when you tighten the bolt,the tape will start to shred,and you probly wouldnt want foreign matter floating around in your system.(yes I'm a plumber)This stuff doesnt break down real easy and will plug small orifaces Also, this will sound very strange but if you have a VERY rusted part,OXCALIC ACID (normally called wood bleach in the hardware store)will completely clean rust off ANY part. I collect beer cans,(you all remember that fad from the 70's!)Well, I use it to clean rust off cans and it doesnt harm paint!(it really locks onto rust and attacks it only) Use it to clean down to bare metal with an old toothbrush, wash it off ,then protect it with some oil or prime and paint. I swear, it works better than anything you'll ever find. just remember, it is a weak acid and certain rubber,aluminum and other parts may not like it! If you'd like the formula let me know!!!
i used to clean my lotus engine that was in my gt(in the bath) with line cleaner used in bars to clean the beer lines ,worked a treat unless you left the bits in too long as it dissolved aluminium like there was no tomorrow :D

Locitie (TM) make a neat liquid/paste version of teflon called "PTFE Pipe Sealing Paste"
It is a thick, goopy white paste that is much easier to get on to threads then the tape but does the same job.
PTFE = Poly Tetra Fluro Ethane ... which is why they call it "Teflon" - simpler!
It was an idea I got from Jim that I liked. Use studs and nuts on that area. Then you don't have an issue after using a bit of antisieze.

Still got that baggie of stainless steel studs and nuts then, Dave!
I have gone one step further now - nice stainless 8mm acorn nuts on the studs.
Using them on the rocker cover too - 6mm ones with stainless grubscrews used as studs so they can be removed to get the cover off in a GT as it is a bit impossible to lift the alloy cover over any studs .......

Alright, one down and one to go. After a week of spraying with a combination of PB Blaster, Kano AeroKroil, heat and every now and then hitting with a hammer I've managed to get one out.

Sometimes it's the little things that can make you happy. :D :D

Oh and talking about little things that make you happy, OGTS has the rubber plug that goes around the early dip sticks.

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