Sheared Thermostatic housing bolt - (NOT the usual ones) - PeachParts Mercedes-Benz Forum

swheele2 · #1 07-24-2009, 08:54 PM

I managed to shear off one of the thermostat housing bolts on my 84 300D. No, not the bolts that everyone shears off (the ones holding the "front" part of the thermostat housing to the "back" part of the housing. I was careful with those.) I sheared off one of the long bolts holding the "back" of the housing to the cylinder head.

The bolt is fused with the thermostat housing. The bolt turns in the cylinder head (but of course I can't turn the whole thermostat housing because it is obstructed by the exhaust manifold, etc.)

When it first happened, I drilled a hole in what is left of the bolt and dropped a screw/bolt extractor in there. Then I broke off the bolt extractor! Now that the bolt extractor is stuck in there I can't do any more drilling. I have emptied a full can of PB blaster in there and have been tapping the housing with a rubber mallet to work the PB blaster in and hopefully break this thing loose. This has been going on for about the last 4 hours, with no real sign of progress.

Any other suggestions for getting this thing off? Is it worth a try to hit this thing with a blowtorch and tap it with a hammer while it's blazing hot?

Unfortunately, I am heading out of town for two weeks and my wife needs the car while I'm gone (this is her daily driver). The only other course of action I can see is to cut the housing off with a reciprocating saw (destroying the housing, obviously) and swapping on the equivalent part from a 79 300D.

So my first question is: are these two housing interchangeable? They look the same, but I don't want to cut this thing off and then find out the 79 housing won't quite fit. Also, on the 84 there are two temperature sending units on the housing (one has vacuum tubes coming in and then heading to the EGR, the other heads off somewhere else, presumably to the climate control system?) These are not present on the 79. Will it be a problem running the 84 for a while without these two temperature inputs?

Also, where can I get a new housing? I can't find them in any of the usual places online. I certainly don't want to destroy the housing only to find that getting a replacement will be a chore.

Thanks for any suggestions.

Steven

vlado · #2 07-24-2009, 10:34 PM

if it looks the same i would swap it.if your 79 doesnt have place for sensors drill and tap holes to fit your sensors.eather way you have to remove old housing off,it is just question wheather you will replace it with new or old used one.good luck

whunter · #3 07-25-2009, 12:30 AM

Quote:

Originally Posted by swheele2

I managed to shear off one of the thermostat housing bolts on my 84 300D. No, not the bolts that everyone shears off (the ones holding the "front" part of the thermostatic housing to the "back" part of the housing. I was careful with those.) I sheared off one of the long bolts holding the "back" of the housing to the cylinder head.

The bolt is fused with the thermostat housing. The bolt turns in the cylinder head (but of course I can't turn the whole thermostat housing because it is obstructed by the exhaust manifold, etc.)

When it first happened, I drilled a hole in what is left of the bolt and dropped a screw/bolt extractor in there. Then I broke off the bolt extractor! Now that the bolt extractor is stuck in there I can't do any more drilling. I have emptied a full can of PB blaster in there and have been tapping the housing with a rubber mallet to work the PB blaster in and hopefully break this thing loose. This has been going on for about the last 4 hours, with no real sign of progress.

Any other suggestions for getting this thing off? Is it worth a try to hit this thing with a blowtorch and tap it with a hammer while it's blazing hot?

Unfortunately, I am heading out of town for two weeks and my wife needs the car while I'm gone (this is her daily driver). The only other course of action I can see is to cut the housing off with a reciprocating saw (destroying the housing, obviously) and swapping on the equivalent part from a 79 300D.

So my first question is: are these two housing interchangeable? They look the same, but I don't want to cut this thing off and then find out the 79 housing won't quite fit. Also, on the 84 there are two temperature sending units on the housing (one has vacuum tubes coming in and then heading to the EGR, the other heads off somewhere else, presumably to the climate control system?) These are not present on the 79. Will it be a problem running the 84 for a while without these two temperature inputs?

Also, where can I get a new housing? I can't find them in any of the usual places online. I certainly don't want to destroy the housing only to find that getting a replacement will be a chore.

Thanks for any suggestions.

Steven

Warning:
Have a known good fire extinguisher within reach.

Separating the housing unit from the head:
* Thermal shock will generally do the job.
#1. Use a propane torch to thoroughly warm it (don't melt it).
#2. Aluminum cools quickly, so the next step you have roughly ninety seconds before it is too cool for best effect.
#3. Gently rock and twist (as possible) while tapping the housing with a LIGHT hammer to dislodge corrosion.
#4. Use SAE30 oil to cool/lube the housing/bolt, it does not FLASH fire easily, just smokes, and will wick up into the corrosion around the damaged bolt.
#5. Repeat the entire procedure as many times as needed.

Note: If it starts to move then suddenly gets tight, cool it and try PB blaster, wipe away the excess before heating again.

Have a great day.

swheele2 · #4 07-25-2009, 08:50 AM

Quote:

Originally Posted by whunter

Warning:
Have a known good fire extinguisher within reach.

Separating the housing unit from the head:
* Thermal shock will generally do the job.
#1. Use a propane torch to thoroughly warm it (don't melt it).
#2. Aluminum cools quickly, so the next step you have roughly ninety seconds before it is too cool for best effect.
#3. Gently rock and twist (as possible) while tapping the housing with a LIGHT hammer to dislodge corrosion.
#4. Use SAE30 oil to cool/lube the housing/bolt, it does not FLASH fire easily, just smokes, and will wick up into the corrosion around the damaged bolt.
#5. Repeat the entire procedure as many times as needed.

Note: If it starts to move then suddenly gets tight, cool it and try PB blaster, wipe away the excess before heating again.

Have a great day.

GOT IT! Thanks, you just saved my hide there. For about an hour nothing was budging but then suddenly the gap between the housing and the head starting looking just slightly wider. Now I can replace that bypass hose and get this thing back on the road.

Thanks again.

Steven