Arrrg. Broken bolt in T-Stat Housing

[240Z-Fan]

Catching up on the Z-car to-do list I decided I better replace the 160 deg thermostat with the 180 I bought from Nissan.

The rear bolt for the water neck loosened up fine but the front one was tight. I carefully turned it hoping, wishing it was just a little bit corroded and that everything would be alright.

No. The bolt snapped off about 1.5 threads above the housing.

I was able to remove the housing from the head. Now I need to know if I should heat the housing with a torch and try to use an EZ out. Or should I just punt and drop it off at the machine shop.

What do the experts say?

Thanks guys,

Al

[Nissanman]

Please, use no heat, I don't think the housing will survive that:cry:

My guess is that drilling it out from the top side is what needs to be done.

I would grind the broken section off flush with the housing surface.

Then punch the stud dead centre and drill down with a pilot bit say 4mm, followed by a 7mm bit [8mm x 1.25 pitch bolt right?].

If the remains haven't broken loose by then, you can then re-tap the hole with an 8 x 1.25P tap.

Use plenty of WD-40/CRC 5-56 or whatever.

Once you get started the remnants of the stud should peel away fairly easily.

I would strongly recommend NOT to use an EASY-OUT:rolleyes:

Whoever named them that, had a twisted, perverse sense of humour:mad:

Make sure when you put it all back together that you use plenty of COPPER ANTI-SIEZE on all the bolt threads.

May look like rust but it should prevent the new bolt threads from galling in future

[240Z-Fan]

Please, use no heat, I don't think the housing will survive that:cry:

I was concerned the AL wouldn't like the heat... The idea was to heat the AL just enough to break the bonds, then back out the bolt with the EZ out.

I would strongly recommend NOT to use an EASY-OUT:rolleyes:

Whoever named them that, had a twisted, perverse sense of humour:mad:

Yes, I don't think I have ever removed a bolt succesfully with an EZ-out. They just tend to add to the challenge when they snap off in the bolt then can't be drilled out at all...hence the heat.

Okay. I'll try drilling it out:nervous:

Al

[Z train]

The aluminum can take the heat.Put it in a vise,soak it over night with Liquid Wrench or PB Blaster,cut a slot to fit a large screw driver.Then heat it up good.It SHOULD come out.If not,i would use reverse drill bits.

[Zs-ondabrain]

why do you guys have to make it so technical? nevermind, dumb question.

Did any one of you offer him a new/used housing? They aren't that damn rare. Hell, I think I have 2 or 3 of them in a box somewhere.

What year Z and take a picture of it. I'll sell you mine if it's the same one for $10.00

No rethreading, no machine shop, no more hastle.

Dave.

[Nissanman]

Fine.

[Zs-ondabrain]

fine? fine what? I'm easily confused at this time of the morning. (1:22AM)

Dave

[mlc240z]

PO had already drilled out a frozen bolt and rigged a larger bolt that looked hideous.

bought a whole new housing for around $30-35.

as long as you already have it off the block, it's the way to go.

cheap fix, sprayed with clearcoat to keep it pretty, and anti-seized the crap out of it so hopefully no problems in the future.

[V8-240Z]

I also thought that a replacement was the best option, but having first read this at 12:30 in the morning I figured that maybe it would look a little different when I was really awake later today. But I have to agree with Dave and taking him up on his offer is the best bang for the buck.

[Arne]

I agree with Dave. Depending on the year, you can get them brand new from Nissan for less than $30. Why mess with the easy-out thing?

While you're at it, get a new temp sender and lock nut as well. Chances are you won't be able to get the old one out of the housing. Shouldn't be more than $10-15 for tose.

Here's a link to an eBay auction to give you an idea. I think you can do better than this price from the dealer, though.

http://cgi.ebay.com/ebaymotors/Datsun-240z-Water-Thermostat-Housing-NOS_W0QQcmdZViewItemQQcategoryZ33692QQitemZ220097763049QQrdZ1QQsspagenameZWDVW

[240Z-Fan]

Dave (Zs-ondabrain),

MANY thanks for offering to send me one of your parts. That is greatly appreciated. This is what I ended up doing:

I decided to shave some time (and improve my odds of success) and dropped off the housing at the machine shop. I will pick it up tomorrow. $20 (I'll see how it turned out). This, along with a new gasket and bolt should allow me to get the car going soon.

As Arne suggested, I also called courtesy Nissan and placed an order for new parts: a new housing along with all new bolts, gasket, and temperature sending unit. That should give me a better result, provided that the parts are actually available.

Arne,

I couldn't figure out which lock nut you were referring to. If it is in the fiche (CD) I couldn’t see it. I hope I won't regret not having it. I don't have the housing with me for reference, is it on the sending unit?

Everyone,

Thanks for all the input. Yes, I could have tried to drill it and/or heat it. I just need to get this done quick!

Many thanks,

Al

[240Z-Fan]

The bad news:

Courtesy Nissan called to tell me the thermostat housing is NLA. Well, sort-of. I could get one from Japan if I was willing to pay $400+ cost plus markup, shipping etc. Ouch!

The good news:

I got my housing back from the machine shop; It looks ok. I'll clean it up and use it, barring any surprises.

For those of you that have spare engines: Hoard your parts if possible. I scrapped a rusted out car with the running L24 about 6 years ago because I had too much stuff. Sure wish I had the engine now as it also was a 73.

Al