M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: BlackBMWs on July 26, 2009, 11:34:49 PM

Title: Broken Thermostat bolt
Post by: BlackBMWs on July 26, 2009, 11:34:49 PM

Well, a small setback today, in that I broke the thermostat bolt at the 5 o'clock position on the thermostat housing.  The good news is that it snapped off just below the head of the bolt, so I perhaps can coax it out without drilling.  The bad news is that there is not enough wiggle room to get the thermostat housing off.  

(http://i402.photobucket.com/albums/pp105/BlackBMWs/318ic%20-%20DIY%20Thermostat%20and%20water%20pump%20replacement/DSC01699.jpg)

It's completly loose, but I suspect with all four bolts out, it prolly shifts up to lift off.  With the shaft of the bolt still in place, there isn't enough room to remove it.  

Anyway, I shifted to work on other items, but will have to come back to this next weekend.  Anyone have the same issue and a solution?  I did search with no like matches in the forum.  

Thanks for any insight...  :cool:

Title: Broken Thermostat bolt
Post by: KenC on July 26, 2009, 11:49:08 PM

Move the plastic wire holder...

Title: Broken Thermostat bolt
Post by: BlackBMWs on July 27, 2009, 12:16:56 AM

Quote from: KenCopperwheat;75906

Move the plastic wire holder...

Actually it is unbolted and moved in a later attempt after this photo, although I'll look again and confirm tomorrow.

Does the thermostat housing lift straight off?  I hope it's that simple...  

Thanks!   :cool:

Title: Broken Thermostat bolt
Post by: BlackBMWs on July 27, 2009, 08:21:12 AM

Update:  I was hoping it was that simple...  No, confirmed, it is not in the way.  Currently it's about 10mm off the housing and the housing only moves perhaps 1mm toward it.  :confused:

(http://i402.photobucket.com/albums/pp105/BlackBMWs/318ic%20-%20DIY%20Thermostat%20and%20water%20pump%20replacement/DSC01701.jpg)
(http://i402.photobucket.com/albums/pp105/BlackBMWs/318ic%20-%20DIY%20Thermostat%20and%20water%20pump%20replacement/DSC01702.jpg)
(http://i402.photobucket.com/albums/pp105/BlackBMWs/318ic%20-%20DIY%20Thermostat%20and%20water%20pump%20replacement/DSC01703.jpg)
(http://i402.photobucket.com/albums/pp105/BlackBMWs/318ic%20-%20DIY%20Thermostat%20and%20water%20pump%20replacement/DSC01704.jpg)

Here's two of the four retention bolts.  
(http://i402.photobucket.com/albums/pp105/BlackBMWs/318ic%20-%20DIY%20Thermostat%20and%20water%20pump%20replacement/DSC01705.jpg)

I wondered if they are just rusted or if the residue is Locktite red.  Replacing them all, plus the four for the waterpump.  

I was thinking about using a lever on the thermostat housing in case it just needs a little nudge, but I don't want to crack the timing case covers.  I'll think about what options exist.  

Also, any suggestions for extracting the remaining stud from the broken bolt would be appreciated.  It does look like red Locktite was used on the bolts.   Careful application of heat, PB blaster and a vice grip?

Thanks!

Title: Broken Thermostat bolt
Post by: 91_e30_m42 on July 27, 2009, 10:25:51 PM

wow i just replaced my thermostat and the bolts felt like they were barley tightened

Title: Broken Thermostat bolt
Post by: BlackBMWs on July 28, 2009, 09:23:09 AM

Quote from: 91_e30_m42;75948

wow i just replaced my thermostat and the bolts felt like they were barley tightened

These were in very tight and frozen, which is why I suspect red Loctite was used and over torqued.   Anyway, I'll try to pull the housing off later with a lever.  I'll have about 1/4" of the stud to work with to extract it.  I'll head over to Sears and see what they have to work with in that tight space.  

I'll tap the threads afterwards to clean them out.

The water pump bolts were in there vary tight too, but came out intact.  New replacement bolts all the way around.  :cool:

Title: Broken Thermostat bolt
Post by: KenC on July 28, 2009, 11:56:11 AM

It pulls straight off. I've done it probably a dozen times.

Title: Broken Thermostat bolt
Post by: BlackBMWs on July 28, 2009, 11:35:49 PM

Quote from: KenCopperwheat;75961

It pulls straight off. I've done it probably a dozen times.

Thanks, I believe you!  However, with a stud in the lower housing, I can move it around, but it dosen't lift off at this point.  I believe the gasket has detached.  Only lifting up about 1mm.  

I figure if the stud wasn't there it would lift right off.  Anyway, I'll try again this weekend ;)

Title: Re: Broken Thermostat bolt
Post by: MichaelP on August 21, 2015, 01:38:50 PM

In case anyone else comes searching (as I did) for a solution to this, I'll finish the story:

I broke the same bolt as the OP, in about the same place, and the housing was reluctant to budge. And yes, the housing comes straight off.

Stick the handle of a screwdriver in the left (driver's) port of the housing and give the part of the handle sticking out a good whack with a hammer. If you're lucky, like me, the housing will pop off and land in the tub of coolant that's been draining below.

In my case I was able to just twist out what remained of the bolt with vice grips. Bullet dodged.

Oh, and the replacement for the bolt? it's PN 07 11 9 906 123. And it's $6.00. Six dollars. For a bolt. Cheapest place I found it was at the dealer.