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I recently did a bunch of work to my 79 635csi. I had the head off to replace a blown HG. I had the original rad recored. I finally started the car and after a bit of fiddling with the Distributor position it ran pretty good, although a little noisy. After a few minutes I noticed the temp needle climbing quickly. I stopped right away. The engine seemed really hot and rad was warm. I figured the t- stat was stuck. I thought I would temporarilly just remove the t- stat so I could enjoy driving the car a little more before throwing more much needed parts at it. Of course one the thermostat cover bolts just snapped off. The thermostat housing and cover are pretty corroded. I figured I will just replace everything. According to Realoem the housing no 11531710959 is for a bunch of M30 engines, its the same one thats in my 87 635.

This housing has a bunch of sensor holes my car doesn't have:


Realoem also lists some screw plugs I assume you use to fill the holes you don't use


Is this what everyone is doing? I thought I'd just be replacing the same housing.

Next issue, is the tstat cover. The correct part number is 11531714861
which is $80 at pelican. Or the part no. 11531268650 for my 87 which will fit the housing. It looks a bit different but is $38



Given the choice I think Id rather save $40 if that cover will work. Anyone come across this before?

Next question is about the upgrade from screw on water pump to spin on water pump. I read somewhere about a better WP with bigger vanes. Anyone know the brand? Also I do have a pulley from a b32 I think will work but is there a better one to use?

OK , lots of questions. Thx in advance for any help. Also thx to Mike W and anyone else who has helped me get this old engine running again. Still a long way to go but its running

Unfortunately you need to spend the money and buy the early therm cover. The later cover will angle the radiator hose to the wrong angle.
And yes the earlier water sensor housing with fewer ports is nla now. Just use plugs, the ones you pictured. The later fan is good and bad, The later clutch doesn't work as well as the earlier version, but the early ones are very expensive. But of course the later clutch is very easy to come by when it fails at half the price.

OK thx. I did actually consider the angle of the cover. I guess I'll bite the bullet on that one. I also would rather have the ease of easily unscrewing the fan clutch instead of the fight it is now to take off the fan. Thx for the reply.

Unfortunately it looks like one of the plugs is NLA This one 07119919225





10 Screw plug AM12X1,5 X 07119919225 $0.85
10 Screw plug AM14X1,5 X 07119919228 $0.85

This is a bit of a backyard hack, but in these scenarios I've taken parts to the hardware store, found a bolt that fits the thread, then trim to size with bolt cutters. They're just metric plugs with corrosion protection, so you could check in on it after 6 months. I will need to replace my housing soon too and will have the same issue.
But I do see that part on a few of my favorite online stores listed as an oil sump plug for $2

Right thats a good idea. I was thinking that could be an option. I did see it called an oil plug. The picture on pelican doesn't even look like a threaded plug.
Thx

No probs, try FCP Euro, they've always come through for me and had obscure parts available when the others haven't.

if you are looking for OEM bolts and oil plug check out belmetrics
www.belmetric.com
have the same hardness 8.8 bolts

I actually ordered the housing, cover, both sizes of plugs from my local dealer and they were cheaper than ordering from Pelican parts which is my goto parts supplier. Not sure why Pelican has the one plug listed as NLA. The cover needs to come from the Fatherland.

Joe Boston wrote:if you are looking for OEM bolts and oil plug check out belmetrics
www.belmetric.com
have the same hardness 8.8 bolts

Thx. It would be great if they had yellow zinc metric fasteners

Not sure what you are looking for but, all of the fasteners, nuts, bolts that i purchased were all yellow zinc and in metric size.

Thats great. I haven't really seen metric yellow zinc for sale before. Thx for the link