Parts Catalog Accessories Catalog Tech Info Tech Forums
  Search our site:    
 Cart  | Project List | Order Status | Help    

Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 04-10-2001, 09:55 AM
Registered User
Join Date: May 1999
Posts: 11
My mechanic checked the cylinder compression pressures in my '81 300D yesterday. The pressures were: #1=19, #2=23, #3=20, #4=20, #5=23. Pressures are in bars or kg/sq. cm. The pressure are reportedly supposed to be in the range of 24.4 to 30.6 bars. The mechanic said this will cause poor fuel efficiency and some oil burn. However, the car always gets 26-27 mpg, even with a lot of city driving. It does burn some oil but no more than the specs say it should burn normally. He says I need an overhaul ($4,000 so out of the question for me.) I haven't checked on rebuilt or salvage engines. Might do that or I might just continue as is. I haven't really had any problems accept smoke when I floor it and low acceleration which I thought was normal. It does seem to vibrate quite a bit which is what led us to the compression testing. The interior and body are in excellent condition. The odometer reads 93,000; I've had the car 3 years. Any thoughts or advice on what to do would be much appreciated.
Reply With Quote
Old 04-10-2001, 11:45 AM
goldenbear's Avatar
Registered User
Join Date: Mar 2001
Location: NorCal
Posts: 442
What were the symptoms that lead you to having the compression checked? The car has very low miles to require an overhaul, and the fact that you state that the car runs well and still maintains good mileage would support that theory. I have heard others speak of experiences of faulty compression checks, so you may be interested in taking the vehicle someplace else for a second opinion. Or, just drive it and be happy.

'04 ML500 - 53k, Inspiration Edition, Desert Silver
'11 Audi A4 Avant - Brilliant Black
'87 300SDL sold
'99 C280 Sport sold
'85 190E 2.3 sold
Reply With Quote
Old 04-10-2001, 01:07 PM
Registered User
Join Date: May 1999
Posts: 11
I like the "don't worry, be happy" route. I wondered about a faulty pressure check, too. Originally I asked the mechanic to check out a vibration I have in 3rd gear. He came back and said the engine was sounding bad and worse than it had on previous visits so he was afraid I was in serious trouble. Thus, the compression tests. The fuel economy rating is 19 - 26 mpg, so it couldn't do much better than the 26-27 I'm getting now. If anyone else has any thoughts please let me know. It's an old car but I hope to keep it going as long as possible.
Reply With Quote
Old 04-10-2001, 04:44 PM
Join Date: Aug 2000
Location: Holland, MI
Posts: 1,316
Check through previous threads. A common theme is that if a diesel has enough compression, it will start. If it doesn't it won't. Before considering a rebuild, or replacement, have the compression checked again AND be sure you can't live with the engine the way it runs now.

BCingU, Jim
Reply With Quote
Old 04-10-2001, 07:39 PM
engatwork's Avatar
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 11,232
du I would drive it and not

worry about a rebuild until about 400k miles (as long as you do what is right in regards to oil changes). I recently purchased a 1985 300D with 218k miles and it starts and runs great. I replaced the timing chain and the first thing I did after that was put it up to 95 on the interstate. The engine runs out great at around 4k rpm (I was scared to do this not knowing the history of the timing chain). Don't spend the $ on the rebuild and get another mechanic to give you a second opinion if you still have doubts. The key thing (I think) is to look at the differences between the cylinders) and not necessarily the numbers.
'85 300D
'95 E320
'97 CRV
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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
1985 300D - purging fuel injection line?? engatwork Diesel Discussion 11 08-08-2009 01:05 PM
low compression desert rat Tech Help 5 04-06-2002 12:17 PM
tire pressures AAL Wheels & Tires 2 02-17-2002 08:30 PM
Need A/C pressures High and low for a 91 300E 3.0 DIYBenzer Tech Help 0 01-30-2002 09:15 PM
AC low side pressures? petaling Tech Help 4 09-10-1999 05:28 PM

All times are GMT -4. The time now is 05:59 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page