Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

LinkBack Thread Tools Display Modes
Old 09-22-2006, 11:45 PM
Jeremy5848's Avatar
Registered Biodiesel User
Join Date: Mar 2006
Location: Sonoma Wine Country
Posts: 8,394
Thread size question 1985 300DT manifold

When I started thinking about an EGT gauge for my 300D, I discovered that the exhaust manifold had a nice tapped hole at the rear, just before the trap cat. The hole (see the first picture) was 10x1 mm and had a short plug in it.

I bought a pyrometer and thermocouple and a brass adapter to convert the 10 mm tapped hole to 1/8 inch pipe threads for the thermocouple. When I tried to screw the adapter into the exhaust manifold, it wouldn't go in, even though both the plug and the adapter had the same diameter and thread size.

By coincidence, the intake manifold also has a 10x1 mm tapped hole (see second picture) with a plug. Well, the adapter wouldn't go into that hole either. When I lined up the two plugs and the adapter (see the third picture) and stared at them, I realized that the threads on the adapter were slanted more than those on the plugs. I've never before seen threads that were the same but wouldn't fit each others' holes.

What's going on here and how do I adapt the thermocouple? I really don't want to retap the hole in the exhaust manifold and risk sending chips of steel into the tubo. Someone here a while ago suggested packing the threads of the tap with grease to hold the chips but that makes me nervous. I don't want to pull the exhaust manifold either -- way too much work. How do I make the existing tapped hole work for me?

Attached Thumbnails
Thread size question 1985 300DT manifold-exhaust_1417.jpg   Thread size question 1985 300DT manifold-intake_1416.jpg   Thread size question 1985 300DT manifold-plugs_1414.jpg  

"Buster" in the '95

Our all-biodiesel family
1995 E300D (W124) . .239,000 miles My car
1996 E300D (W210) . .313,000 miles Wife's car
Santa Rosa population 170,685 (2012)
Total. . . . . . . . . . . . 722,685
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 11:14 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page