I was wondering if anyone can fill me in on how to do a compression test on a 1984 mercedes benz 300 d turbo diesel and where can I find the necessary adapters for my engine. If anyone can give me some links on the correct procedures it would surely be appreciated.

Harbor Freight has a $25 diesel compression tester with the necessary adapters to go in through the glow plug holes. Need the 90 degree adapter on at least one. Pull a vacuum on the shut off valve while doing the test to stop fuel flow.

Warm engine. Pull all the glow plugs, pull the vacuum on the shut off, install tester in one hole, crank engine for a number of compression strokes. Read gauge. Move to the next.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I have seen this before but how do you get the engine warm ?
Run the engine, warm it up, then quickly pull the GP and do the compression test before it cools down ? or there is something I am missing ?

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2010 ML350 Bluetec
2012 Mustang Convertible

It's easier and quicker to run a compression test through the injector holes. The engine won't cool down as fast this way.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Why does it take any less time to pull an injector than it does to pull a glow plug?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

He would need to have new Injector Heat Shields when he puts the Injectors back in. That adds more than an extra $10 to the cost of doing the Compression Test.

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84 300D, 82 Volvo 244Gl Diesel

It is a more crampped area to work in and to work fast you need to completely remove the Hard Lines between the IP and the Injectors to make it easy to connect the Gauge.

One of the members also said the Glow Plug Adapter Connector on the Harbor Freight too can be delicate.

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84 300D, 82 Volvo 244Gl Diesel

Easier to break a wire, lose a washer or nut, hard to get at, not much fun on a hot engine. Haven't done a set of glo plugs with the resistors, but I imagine they would only add to the fun. I can have a set of hard lines off in about 10 minute, if that.

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CC: NSA

All things are burning, know this and be released.

82 Benz 240 D, Kuan Yin
12 Ford Escape 4wd

You're four times

It's hard to

more likely to

concentrate on

have an accident

two things

when you're on

at the same time.

a cell phone.

www.kiva.org It's not like there's anything wrong with feeling good, is there?

I believe the spec tells you a min temp of 70 degrees C. So if take the Engine for a 10-15 minute drive and when you come back the Engine temp is 80 something degrees C you have a little time to do the test before it drops to 70C.
It requires you to organize everthing before hand. Have all the tools ready.
You might even do a practice run on 1 or 2 of the hardest Cylinders to get at while the Engine is cold.
A 17mm Crows Foot on an Extension is handy for the Hard lines on the Injector and IP (or a 17mm Flare Nut Wrench). I do not have one but other Members like to use a 12mm Ratcheting Gear Wrencn on the Glow Plugs.

If you put the pointer over the Resourses button in the upper right hand corner and select and click on DIY Links you will find more detailed proceedures on the Compression Check.

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84 300D, 82 Volvo 244Gl Diesel

I can pull the injectors, return lines and hard lines way faster than I can pull the GP's. It's also easier to install the compression test adapter into the injector holes than into the GP holes.
Plus I'd rather not stick my hands in a hot cramped area unless I really need too.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Jeeez, all you big handed guys. I can change out all my plugs in 20 minutes without losing nuts and without removing any hard lines. I didn't have any problems with the Harbor Freight glow plug adapter.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I think the expression is ham handed.
Ideally if the GP's aren't all carbon cruded and the holes cleanly reamed to start they can be R&R'd in about that much time.
I can get the injectors and all their lines off in about 5 minutes.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

I moved a linkage and a hose without disturbing the fuel lines, but it took longer than 20 minutes.

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83 SD

84 CD

X2

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1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown

does the HF $29 compression test kit include an adapter to fil the injector hole??

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"