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

Reply
 
LinkBack Thread Tools Display Modes
  #16  
Old 11-15-2008, 01:00 AM
Registered User
 
Join Date: Sep 2007
Posts: 52
I vote water pump impeller. Been there, done that.

Perplexed
'77 300D
Reply With Quote
  #17  
Old 11-15-2008, 01:43 AM
rrgrassi's Avatar
mmmmmm Diesel...
 
Join Date: Jun 2006
Location: Royse City Tx
Posts: 4,872
Stuck closed t-stat, or, er, um, heh, installed backwards...sheesh. I did not do that either...well, that's MY story...
__________________
RRGrassi


70's SPM #5608 Fairmont A-4 MOW car

06 VW Jetta TDI 210K miles

03 VW Golf TDI 5 speed 372K Miles

RIP--Lost in fire...82 300D 322K was My Daily Driver-On the search for a w126 now...

90 Dodge D250 5.9 Cummins/5 speed. 350K
Reply With Quote
  #18  
Old 11-15-2008, 08:03 PM
Unofficial wormcan opener
 
Join Date: Dec 2005
Location: Ashland, MA
Posts: 2,602
Quote:
Originally Posted by ik04 View Post
Howdy,

Now that there is funny ;>) No, I have not changed any engine parts lately.

Thanks to everyone for the responses! I will replace the tank, pull the thermostat and recheck the bottom hose. My hoses and radiator are only two years old, so that would be weird...

Does the area that cracks on the OM603 heads cause cooland to recirculate through the crack or is it a combustion chamber crack? My compression test shows normal pressures all around.

I've always heard about these heads cracking, and I have replaced two of them. Those cracks were in 20 and 22 heads and were in the combustion chamber.





This is the first time I have experienced cooling system/cracked head symptoms on my own car. I guess I'm due.

The coolant is not foamy or mixed with oil. It is clear and green, so I am leaning toward a thermostat issue. The engine ran cool until the day it suddenly overheated.

Please keep sending me ideas to check on. I'll have some time to work on the car next week and I'd like to get to the bottom of this starngeness...

Thanks again,

Kevin
Let me be the first to welcome you to the 603 cracked head club. It sure sounds like the same symptoms I had.

Can you please elaborate on the cracked 20 and 22 head that you replaced. Were they overheated? Where were the cracks?

Chris
__________________
1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss
Reply With Quote
  #19  
Old 11-16-2008, 01:11 AM
ik04's Avatar
Diesel-Doer
 
Join Date: Feb 2007
Location: Texas, where else?
Posts: 42
...Head cracks

Quote:
Originally Posted by Bio300TDTdriver View Post
Let me be the first to welcome you to the 603 cracked head club. It sure sounds like the same symptoms I had.

Can you please elaborate on the cracked 20 and 22 head that you replaced. Were they overheated? Where were the cracks?

Chris
That is a club I don't really want to join, thanks.

Thanks for asking about the cracked heads I have experienced...
They were both showing signs of compression loss and combustion pressure in the cooling system. The engine ran rough, blew steam out the exhaust pipe and nearly blew the top radiator hose off...

The heads were cracked in the combustion chamber between the exhaust valve seat and the prechamber bore. One was in cylinder 2, and the other in cylinder 5. I was able to find a guy in Tennessee who welded the number 2 cylinder crack, and that head went back on a 350SD engine and still runs fine (last I heard).

To tell you the truth, I don't remember the casting number on my head. l'll check next week and report back here. Fortunately, there is a good source for OM603 parts in my area- just in case the head IS bad :<(

...More to follow,

Kevin
__________________
Reply With Quote
  #20  
Old 11-26-2008, 04:14 PM
ik04's Avatar
Diesel-Doer
 
Join Date: Feb 2007
Location: Texas, where else?
Posts: 42
Thumbs down OK, now what???

I replaced the tank, pulled the thermostat and tested it in hot water.

The T-stat opened fully as the water neared boiling. The stat is marked 80 degrees, so that is right on the mark.

I put the whole thing back together and everything seemed to be working fine. The engine ran smooth and warmed up to about 82-84 degrees on the gage.

The heater was not making much heat because my little booster pump does not work. After about twenty minutes, the thermostat opened and I could feel heat in the heater hoses and the bottom radiator hose. The temp gage still showed steady at 82-84 degrees.

I was about to take the car out for a drive to see what would happen when...

Black engine oil spraying out of the top of the injector pump! In the ten seconds I was in the car checking the temp gage, I must have pumped half a quart of oil on my driveway...

OK, so now the overheating problem is on hold until I get the geiser fixed. Sheesh.

It looks like it might be leaking from the vacuum cutoff valve or the electrical connector thingy. Would a ruptured diaphragm cause oil to push past the valve housing. Since it is a b1Tc4 to get tool in there with the intake manifold in the way, I'll be fixing this some other day...

What next?

Kevin
__________________
Reply With Quote
  #21  
Old 11-28-2008, 08:44 PM
ik04's Avatar
Diesel-Doer
 
Join Date: Feb 2007
Location: Texas, where else?
Posts: 42
Unhappy ...Never mind, I'll just find a new head!

OK, I thought about why the little electrical connector would suddenly start spewing oil and figured out that the shop towel I gently placed in the PCV hole on the valve cover caused just enough back pressure to push oil out the (loose) electrical connector.

With the electrical connector tightened, the intake tube stuck back on the turbo (with PCV hose connected, duh), the oil shower went away.

I reconnected all the cooling/heating system parts and warmed up the engine. After 30 minutes of idling and occasional revs to 2500 rpm, the temp settled at the usual 82-84 degrees. The top and bottom hoses were warm and the heat worked. The engine ran smooth and I decided to drive it to see how long it would take to get hot.

The drive lasted much longer than before, perhaps 10 minutes of up- and down hill driving at half to full throttle. Even with almost straight water in the engine, it stayed cool.

Then, at the ten minute mark, it went straight to 120 degrees in less than 45 seconds!

I timed it so that I would be in the driveway shortly after the overheat. I immediately opened the hood and checked the engine. It did not seem very hot and there was no steaming from the cap and no visible bubbling or surging in the tank. I let it idle for a few seconds and it ran fine with the gage showing 120 degrees. I shut it off and wondered if the temp sensor was bad.

I watched the tank for a few minutes and noticed large changes in the water level.
[Don't try this at home, kids] I then loosened the cap, expecting an explosion of steam.
Yep, there was a lot of pressure and a whole bunch of water blew out everywhere.

I pretty much gave up at this point and put all the removed parts in the trunk and pushed the car behind my fence and closed the gate, RIP.

New thread: Anyone got a good rebuilt OM603 head?

Kevin
__________________
Reply With Quote
  #22  
Old 01-27-2009, 05:18 PM
Registered User
 
Join Date: Jan 2007
Location: North Carolina
Posts: 19
Why don't you take it to the guy in Tennessee to get it welded?
Reply With Quote
  #23  
Old 12-30-2009, 11:27 PM
ik04's Avatar
Diesel-Doer
 
Join Date: Feb 2007
Location: Texas, where else?
Posts: 42
Exclamation An update to my overheating... a year later!

Howdy all,

a couple of months ago I had the time to pull the head off my car.

I was really surprised by what I saw when the head came off. First of all, with 193,000 miles and never been apart, this engine was shockingly clean inside! I pulled the cam cover off and it looked like new engine in there!

The big surprise came when I looked at the area around the valves and precombustion chambers... NO CRACKS! The head looked clean and had very little carbon build up. The cause of the overheating looked obvious: a warped head allowed the head gasket to leak on cylinders 5 and 6.

I sent the head to a machine shop and it was partially disassembled and pressure tested. Guess what? NO CRACKS again! The thing held pressure for more than four hours. The warpage is within repairable limits, so I am waiting to have the surface milled and the valves worked.

I'll fill you all in on how this adventure progresses.

Weird how a -14 head can warp and yet show no cracks at all...

Kevin
__________________
Reply With Quote
  #24  
Old 01-02-2010, 02:27 AM
sixto's Avatar
smoke gets in your eyes
 
Join Date: Jun 2000
Location: SF Bay Area
Posts: 20,757
Does pressure testing simulate operating temperature? What if the cracks appear only when the cylinder head is hot?

Sixto
87 300D
Reply With Quote
  #25  
Old 01-02-2010, 12:13 PM
Moderator
 
Join Date: Jul 2001
Location: Old Lyme, Connecticut
Posts: 3,596
The original problem you had, changing from "normal" temperatures to abnormal temperatures abruptly, remains unexplained. When did the "pinhole" develop?

As others have noted the pressure in the system at idle and with an indicated temperature at the sensor of 85C is not likely to generate gross pressure increases. There will be hot spots though where the local surface temperatures are quite a bit hotter, but the bulk water temperature is low enough and the flow rate is fast enough to prevent a significant steam bubble from forming. As you load the engine that is not going to be the case. These machines may be about 25% efficient under ideal conditions, and more like less than 20% under most conditions. So when you put more power to the wheels you are putting three to four times that into the cooling system.

A lack of pressurization for any reason (including your pinhole, or a leaking radiator cap, or hose) will cause local steam bubbles to form wherever the flow rate and local water temperatures cannot prevent the phase change to steam - remember the coolant system design depended on pressurization to prevent bubbles from forming, not on coolant flow rates to wash bubbles away when they formed. If the flow cannot wash the bubbles away (where they mix with the bulk, lower temperature flow and are condensed back into the bulk coolant) you will end up with a rapidly growing bubble, eventually evacuating the liquid coolant from the head high points. The steam does not absorb heat nearly as well as water. And it does not get dragged along by the flowing water well at all, leading to high temperatures in the pockets filled with steam. Which is not good. So don't drive around without the cap on the radiator and if you know of a pinhole, either seal it or replace the item with the pinhole.

Also, when refilling I always open the heater valves all the way (turn the interior heat on all the way) and drive the car either up a little hill or onto ramps to help the engine evacuate the air bubbles trapped in the various high points. On my older 240D's this was basically required or you would end up with swings in engine coolant temperatures and no amount of diddling with the hoses would fix the problem.

Jim

Hope this helps
__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)
Reply With Quote
  #26  
Old 01-02-2010, 12:20 PM
Moderator
 
Join Date: Jul 2001
Location: Old Lyme, Connecticut
Posts: 3,596
Quote:
Originally Posted by sixto View Post
Does pressure testing simulate operating temperature? What if the cracks appear only when the cylinder head is hot?

Sixto
87 300D
On old cast iron heads you could do a magnetic particle inspection. On these aluminum heads you have to liquid penetrant inspect them to really determine if there are any cracks. But, for the most part the pressure test is run at a pressure high enough that if you don't leak in a 4 hour period, the head is likely fine. Running pressure tests at operating temperature and operating pressure is probably dangerous - I never asked why but the shops I have used don't do it. And for aluminum heads I ask to have them Penetrant Inspected if I am looking for cracks.

Jim
__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)
Reply With Quote
  #27  
Old 01-03-2010, 12:46 AM
1984 300SD
 
Join Date: Feb 2007
Location: Vancouver BC
Posts: 588
There is a small tube that runs between the front of the head and the top of the water pump housing. I bled some air from the top banjo bolt and my erratic temperature fluctuations went away. This problem came up after a rad flush and new Antifreeze. Screw a ss screw and "O" ring into the tank for a quick fix.
__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom
Reply With Quote
Reply

Bookmarks

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 12:19 AM.


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