Engine thermostat R&R

[msyoder]

I have an '87 300TD and was wondering how difficult the R&R on the engine thermostat would be. I've searched the archives and found several references that make it sound like I can do this without changing the antifreeze. Thanks in advance for any tips.

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-Mike
'87 300TD Turbo

[This message has been edited by msyoder (edited 11-25-2000).]

[mreid]

Might be a little messy if you don't drain the attifreeze down to the thermostat level.
If yours is like mine you can have it all done in less than an hour and thats with a beer brake too.

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Mark
82 300SD 100k
91 Caprice SS
92 Jetta TD

[msyoder]

I've got the parts and the need to do this job. I'm going to Vermont and it's been well below zero there at night. I don't think that the cardboard in front of the radiator is going to cut it for this trip.

Thought I would just test my proceedure out here before I do something foolish. I intend to drain just enough (how will I know?) antifreeze out at the radiator into a clean container to remove and replace the thermostat. Replace the antifreeze fluid. Test drive.

Assumptions: I don't have to drain the whole system. I don't have to drain the antifreeze from the block drain. The antifreeze is fresh from this summers 210kmi maintance.

Anything I've missed. I mean besides the beer break.

Sounds like all you've missed is the beer break.

Good luck,

[msyoder]

Great! Thanks, Larry. -Mike

[jcyuhn]

I just performed this job on my '87 300TDT last weekend.
Didn't complete the job in an hour, but I'm quite a slow
mechanic. I'd starve if that was how I made a living...

A few tips. Access around the thermostat housing is rather
tight. You can remove the two housing bolts, and even work
the thermostat out, but won't have enough room to install
the new part. I found it best to remove two parts to make
room to work. First the large rubber hose which feeds the
turbocharger from the air cleaner. A simple clamp on either
end can be loosened with a philips screwdriver. Second,
there is a temperature sensor threaded into the block
directly in front of the thermostat housing. Just unscrew
it - you're at risk of cracking the plastic parts when
attempting to work around it.

I changed the coolant, so I can't tell you how much to
drain - I don't like inhaling/showering/laying in
ethylene glycol, so I got it all out first.

- Jim

'87 300TDT
'98 E300TD

I recently did my '82 300CDT. There's not much room when it comes time to maneuver the bolts around but I didn't lose much antifreeze and the job took less than 15 min.

Mike,

There is a drain valve near the lower hose to the radiator. Put a clean pan under there and drain until nothing else comes out with the radiator cap off. Let it drain a little longer to let some more coolant work it's way out of the engine.

At that point, it should be low enough, that you at least won't make too much of a mess. When I reuse coolant that I have drained, I put a cloth in a funnel as I pur the coolant back in to strain out anything that might have fallen in the drain pan.

Good luck,

[msyoder]

Thanks everyone. I feel a lot more confidant have a few words of advice. This thread should work well for those searching for thermostat R&R.

[msyoder]

Hey, thanks for the good advice. Things went well and the engine is warming rapidly to +80deg C and then holding steady. It makes a big difference at the climate control.

I noted the failure mode of the thermostat was that the metal arch over the external part broke off. It definitely was not an OEM part. But now it is. I also replaced the expansion tank cap.

Larry, thanks for reminding me to strain the fluid while returning it to the system. It looked perfectly clean, but when I was done the the cloth was full of numerous chunks of crud.