8 replies to this topic

[BlackBrick]

1997 Volvo 850 turbo.

What I thought would be a little 30 minute job to replace a stuck-open thermostat has turned into a nightmare.

I got the front thermostat upper housing bolt out (barely), but the back one proved to be even tighter. I even used liquid wrench (or whatever it's called). Ended up stripping the bolt.

Upon trying to get the bolt out with larger torx bits and screwdriver and hammer, eventually the lower thermostat housing cracked off (I was not tapping 'too' hard, knowing I was up against aluminum). Inspecting it, I think the bolt was seized.

The top two bolts on the lower thermostat housing were a cinch, but that lower one...had to take out the power steering pump. Not a pain, but more work.

The access to that lower bolt is STILL tough. My torx bits are not that long, so the only tool I could get in there was my T-40 screwdriver. But I had to go in at a slight angle, as the alternator brace is in the way (And I didn't want to deal with taking that out too) I was very nervous that I'd strip this bolt, and be screwed. But LUCKILY I got it out.

Now I have to wait a couple days for the new part.

My question...what tool works best for removing this lower bolt? I want to make sure I get the bolt back in nice and tight. Can you buy 3" torx bits? None of my local tool stores carries such a thing.

How did any of you deal with the lower bolt?

Thanks!

[yangotang]

I bought one of these.

http://parts.digikey...40-6-77164.html

[BlackBrick]

yangotang, on 15 November 2009 - 07:36 PM, said:

I bought one of these.

http://parts.digikey...40-6-77164.html

Sweet! Didn't know this existed. I'll check Sears today if they have it. Otherwise I'll order it.

[heredity]

yangotang, on 15 November 2009 - 07:36 PM, said:

I bought one of these.

http://parts.digikey...40-6-77164.html

And try to get magnetic ones too, so your torx bit wont accidentally slip off. I didn't know some come magnetic, just lucked out with a cheap eBay purchase. I paired the long bit with a 1/2" drive ratchet. The screw was so tight that it felt like the ratchet was flexing. After I kept turning, it just came loose.

This was my setup to remove the bolt:

[BlackBrick]

heredity, on 16 November 2009 - 02:00 PM, said:

And try to get magnetic ones too, so your torx bit wont accidentally slip off. I didn't know some come magnetic, just lucked out with a cheap eBay purchase. I paired the long bit with a 1/2" drive ratchet. The screw was so tight that it felt like the ratchet was flexing. After I kept turning, it just came loose.

This was my setup to remove the bolt:

I've got a good magnetic cable for picking up everything I drop! ;-)

The three bolts holding on the lower thermostat housing were not too bad, I was able to get them off with my 1/4" drive torx plus screwdriver torx.

But the two on top of the upper thermostat housing, I could see needing a 1/2" drive. I will be putting anti-seize lube on the bolts when I put things back together. I wish the previous owner had done this!!!

[betterthingstodo]

Did you get new bolts to replace the existing thermostat bolts? Volvo has a replacement part made of harder material - part number 986228.

Some notes I made when I did my thermostat replacement: http://www.lakesided...lvo/Thermostat/

[Pauloil]

for reinstall get M7 fine 30mm(7mm-1.0X30) bolts
at Home Depot or a good hardware store
I think they have 12mm heads.

[BlackBrick]

I bought a new bolt from Volvo to replace the bad one, but the other 4 seem fine to me, so I'll re-use them.

[Aequitas_Veritas]

adam could probably help you. wait nevermind.