w108 coolant hose replacement

[chazola]

hi, car is '67 250se with m129 engine. I need to replace the short rubber coolant hose that attaches at the bottom of the thermostat housing, but can't see how to go about replacing it easily- being short I'm guessing it won't be flexible enough to bend into place like you would a top radiator hose for example? Anyone done this job and can advise? cheers...

[daidnik]

I'm not sure about how your thermostat housing is on your car (W124?), but the bypass hose usually goes between the thremostat housing and the water pump housing (as on a W108 and many other early models).

Getting the hose is a bit of an artful wrestling match to get the ends over the upper & lower pipes without tearing or abusing the new hose.

If you have the thermostat housing loosened from the cyl head, you can slide it outwards on the studs to increase the distance between the upper & lower pipes a bit and this can help matters, but it also requires dealing with replacing the thermostat housing gasket, so this isn't usually done that way, so then you're back to wrestling and lube.

[Mark DiSilvestro]

Originally Posted by daidnik

I'm not sure about how your thermostat housing is on your car (W124?), but the bypass hose usually goes between the thremostat housing and the water pump housing (as on a W108 and many other early models).

Getting the hose is a bit of an artful wrestling match to get the ends over the upper & lower pipes without tearing or abusing the new hose.

If you have the thermostat housing loosened from the cyl head, you can slide it outwards on the studs to increase the distance between the upper & lower pipes a bit and this can help matters, but it also requires dealing with replacing the thermostat housing gasket, so this isn't usually done that way, so then you're back to wrestling and lube.

The original post is somewhat confusing because, while the photo is a W124 wagon, the text refers to a W108 '67 250SE, and the signature lists both cars.
As for that hose, the answer may be to move that thermostat housing.

Happy Motoring, Mark

[chazola]

Hi, thanks for the replies, it is indeed a 108, I own a 124 as well (hence the sig pic), here is a pic to prove it!

[JMela]

IIRC I removed the thermo housing, cleaned it up a bit, fitted the hose and reinstalled.

[chazola]

is it just the 2 studs that hold the housing on? 'cause i undid the nuts but couldn't get it to budge...

[JeffreyNMemphis]

Yes, it is two studs with two bolts holding the thermostat housing on.

Nice car! I love the euro lights, the mirrors and the sunroof. With right-hand-drive, you have a super rare Mercedes Benz.

[chazola]

thanks, the 250 is quite rare here in the UK, you see more 280s and 3.5s about.

I suspect the housing hasn't moved in a long time so I'll have to have another go at getting it loose...

[JeffreyNMemphis]

It may help if you loosen the upper and lower hose clamps. I just happened to be working on this exact same thing yesterday. I was taking off the water pump and the thermostat housing.

[chazola]

I did try that, but it still didn't want to budge... did you have to lever yours off or did it move fairly easily?

[bwostosh]

Welcome to the old motor blues.

I have used a thin blade gasket scraper between the housing and head and a hammer to release the thermo housing from the head due to the housing holes of the retaining studs being oxidized, filling the holes.
Just hammer it to release the binding.
Smear anti-seize on the studs for the next time.

Do a new thermostat while the housing is off

The screws holding the thermostat housing top will likely be corroded and break off.