Thermostat housing - water outlet question

[jharvat]

OK, I'm an idiot. I managed to shear off both bolts holding the water outlet to the thermostat housing on my '73 240. My question - are the holes in that top part threaded? I saw one on EBay and it appears they are not. If they are not threaded, should I be able to pop that top part off? If I am really that lucky, it should expose the remaining part of the bolts and I should be able to get a vice-grip on them.

Thanks for any info you can provide!

[Zedyone_kenobi]

Yes, they are through holes. But you probably have corrosion all around that bolt. It may prove a worthy adversary. I would try heating it a bit. You will no doubt ruin the gasket in there, but then again, you can always replace that.

[Walter Moore]

I ended up having to drill the sheared off bolts out of the housing. I do not recommend that since the bolts are steel and the housing is aluminum. Before it was all over I bought a new housing here:

http://www.thezstore.com/page/TZS/CTGY/SCC11

However I notice that you have a 73, and the site only lists 70-72 and 75-78. I don't know what 73-74 owners are supposed to do...

[jharvat]

I started picking at it last night and the water outlet isn't going to budge easily. Some prior owner put liberal amounts of adhesive on the gasket so it's stuck tight. I was thinking about trying to tap a thin, flat-head screwdriver into the gap between to see if I can pry them apart but I stopped, wondering if I'll damage the aluminum that way. I may try heating it first to soften up the adhesive. I then may try a putty knife rather than a screwdriver.

Walt - there seem to be a number of pieces of the 240z that are good for the 70-72 but not for the 73. I'm hoping I can preserve the bottom half of that housing. Worst case, the top half may be expendable.,

[siteunseen]

Use a sharp putty knife, not too sharp though. 1" would be good I guess.

Edited July 3, 2012 by siteunseen

[Zed Head]

You might be able to break the seal by knocking it on the side with dead blow or rubber mallet. It would help break up the rusted bolts also. Tapping back and forth would let any PB Blaster, etc. works its way in to the bolt holes. As Walter said, a drill will probably walk on off the bolt end and in to the aluminum housing. You might also put the thermostat cover back on the top and use it as a lever.

I've had one that I drilled and removed but ended up with the through hole enlarged, and another that I was able to knock loose and work back and forth to get free. The rust from the bolts fills up the through hole in the aluminum but will come out as powder if you can get it moving.

[Carl Beck]

However I notice that you have a 73, and the site only lists 70-72 and 75-78. I don't know what 73-74 owners are supposed to do...

I don't know about that site - but the Parts Catalog shows 11061-N3600 as superceding all previous numbers - and being for the L24/L26. At least in terms of form, fit and function - any L24 thermostate housing will work.

Courtesyparts.com lists the part at $31.69...

FWIW,

Carl B.

[jharvat]

Just an update to all who responded, a rubber mallet and a stiff 1-inch putty knife did the trick. I was able to remove the top part of the thermostat housing without damage and was then able to use a vice-grip pliers to remove the sheared bolts. Thanks to all who provided their insights!