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E250 Bluetec - coolant "tracking" from the thermostat housing?
I picked up this '15 E250 Bluetec with a bit of white coolant "tracking" on its t-stat housing.
Tried popping that plug out of the top of the t-stat housing, but it wouldn't really budge even with some prying.
But it also doesn't look like the coolant is actually oozing out of where the plug enters the t-stat housing. It looks like the white starts under that little flange. Pinhole in the t-stat housing possibly? Something else? Has anyone else experienced this?
In the pics, the top view is just to get your bearings. The side view pic really shows the white coolant tracking in all its glory.
Possibly a pinhole, yes - that would be my first thought, anyways. Clean it off and monitor closely.
I've been monitoring the coolant level and it hasn't budged in two weeks despite regular driving. It must be the tiniest of dribbles coming out of this area.
What's weird is I've never encountered (or heard of!) a pinhole in a nylon molded part like this, in all my time working on cars... is this something you've seen before?
I'd say it's unlikely there is a pin hole in the part. More likely there was a slight leak from the seal on that plug and it's now sealed by the deposits. As someone else stated, wipe the deposits off (put the clip back) and wait and see.
I'd say it's unlikely there is a pin hole in the part. More likely there was a slight leak from the seal on that plug and it's now sealed by the deposits. As someone else stated, wipe the deposits off (put the clip back) and wait and see.
Yep, did that. The white residue returned after the first drive afterwards. Still looks like it's coming from up under that little molded lip, and not from the plug.
I'm going to try applying some nylon structural adhesive first, just to seal it up while I wait for a new t-stat to arrive.
I've been monitoring the coolant level and it hasn't budged in two weeks despite regular driving. It must be the tiniest of dribbles coming out of this area.
What's weird is I've never encountered (or heard of!) a pinhole in a nylon molded part like this, in all my time working on cars... is this something you've seen before?
No, I've never seen that before, either. Definitley a weird one. But it sure does look heavier in the "pinhole" spot as if that's where it's coming out from.
I agree - that amount isn't going to show a drop in coolant level anytime soon.
I would still clean it and then monitor it very closely (much more often). Maybe just pressurizing the system with a pressure tester would be enough to see evidence.
The only other thing I can think of is spray from something forward and to the right of the splatter. But there's other things in the way that would likely be covered.
My first guess would be the oring in the cap is leaking, they dont last forever. Second guess is possibly like my 2014 ram diesel with twin radiators, the Y pipe is synthetic like that and it develops a crack eventually (known problem). You couldnt see or tell it was there unless the truck was at operating temp and even then was difficult to determine. Maybe previous owner tried removing the plug or just too many heat cycles on that plastic.
Like other leaks occasionally its hard to determine exactly where its originating from.
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