The diesel fuel thermostat on my 1991 350SD is leaking. On ShopForum there is mention of a rebuild kit.

Where can I get it?

What does it consist of?

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1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

I do not see a rebuild kit in EPC - what is the link to the reference you found?

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I don't see any rebuild kits either but when I search the ShopForum there are references to a rebuild kit.

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

The PO on my 91 300D said he just needed to replace the O ring that was in there. Worth a try?

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

What is the link to the reference you found?

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Yep, all you need is the new o ring. My 1992 300d was leaking there also and no leak now, I took the whole thing off the car so I could get to it.

Where is the best place to get an o-ring? viton for biodiesel!

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

OM601, 602. 603 Diesel fuel thermostat REBUILD parts list

I just replaced the o-ring in my fuel thermostat last week. Easy job. After you remove the old one clean around where the o-ring seats and use a little silicon grease. I picked mine up at the local MB dealership for $1.50. Mine was leaking fuel but no coolant.

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Western NC
1987 300SDL W126 Turbo Diesel 335,000 + miles
1976 300D W115 275,000 miles+

If you're talking about the fuel thermostat as opposed to the fuel preheater, there would only be fuel present. The fuel preheater is a coolant/fuel heat exchanger, which could have both present though! That is a darn good price for the fix nonetheless!

The "diesel fuel thermostat" (6010700126) is actually a pre-heater with a thermostat that is supposed to keep the fuel warm in cold weather. It has fuel in and out and engine coolant in and out.

It was leaking out of the fuel side. I haven't taken it apart, but there is apparently an o-ring inside.

I ran B100 for years and had few problems (another topic), but since I have not been able to find low-sulfur diesel, only ULSD, I have had some seals for the injector pump lines go out, and now the seal for the fuel thermostat.

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

Bob, we are talking about the same thing. You remove the fuel lines and 2 bolts that attach it to the bracket and then you can pull it up enough to work on it without removing the coolant lines if you desire. Remove the clip ring on the fuel inlet side and it pulls out with a spring and washer underneath. Pay attention to the direction of the inlet pipe.

My o-ring was quite flattened and loose fitting and leaked. I have used B-20 to B-99 fuel for 3 or more years now so I don't know how much effect that had on the o-ring. The car has over 300,000 miles on it now. I did have to replace my delivery valve seals twice though within about 80,000 miles.

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Western NC
1987 300SDL W126 Turbo Diesel 335,000 + miles
1976 300D W115 275,000 miles+

The fuel preheater system consists of two parts a thermostatic valve and a fuel preheater/exchanger. The valve has internal seals that fail and leak, the preheater/exchanger has no internal parts to replace.

The thermostatic valve is located just above the driver's side engine mount arm in fact attached to it, the preheater/exchanger is connected to the cylinder head at is far rear driver's side and in effect wraps around the oil filter housing, it is connected to the thermostatic valve with two hoses that from the factory also have a harder more durable protective sheath.

I've recently posted a couple of pictures of the fuel preheater itself and of it in the installed position in another thread.

Here is the fuel thermostat. The fuel leaking o-ring fits around "A" once you remove the clip ring and pull the fitting out.


http://www.peachparts.com/shopforum/attachments/diesel-discussion/53799d1207005905-92-300d-leaking-fuel-pre-heater-om60x-fuel-preheater-function.jpg

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Western NC
1987 300SDL W126 Turbo Diesel 335,000 + miles
1976 300D W115 275,000 miles+

I believe this unit is the same on all Mercedes diesels in 1991.

Attached Thumbnails

 

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside