Wednesday, December 17, 2014

PreviousOwner: Thermostat

Going to start a new type of section where I'll just show jobs done by previous owners (or their mechanics). Figure it'll be a convenient way to demonstrate what kind of shit people do to their cars to "fix it." 

So in today's installment of PreviousOwner, a thermostat / thermostat housing job on an OM603 in 93 300SD. 
So this PO seems to have been met with a thermostat issue at some point in his "caring" for the car. Might have gotten stuck, who knows. All I know is that the coolant on this beast wasn't replaced as often as it should have been in the 299k miles this thing was run. The rubber seal welded itself to the aluminum housing with some other build up. The PO just cut the bottom of the thermostat off to let coolant flow through. This was a HUGE problem with this car because it wouldn't get over 40*C in coolant temp. No good. Imagine the carbon build up from incompletely burnt fuel. 

You can see here the build up around the edge of the housing. Probably what gave the PO a hard time.

Here's the original O-ring and the cut thermostat. The bend in the brass piece is from me yanking on the damn thing to free it from the housing. Just completely gross. The seal was so fused to the housing that I actually yanked out some of the deposits with the remainder of the thermostat.

Overall, holy shit.

Took my drill with a wire brush on it and went to town to get what I could of the deposits on the housing. It's not totally perfect, so rather than installing dry like I usually do, I'll run a very small bead of RTV gasket maker along the housing to perfect the seal. It's not worth it to me to replace the housing on this, it's a one and done deal that doesn't need an absolutely flawless sealing surface. If the degradation of the housing continues it'll leak and that's when it'll warrant replacement.

The coolant passages, from what I'm able to see, are in good shape.

For now,



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