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 ShopForum > Technical Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 12-25-2009, 03:22 PM
Registered User
 
Join Date: Jul 2009
Location: Tampa, FL
Posts: 70
Mysterious Coolant leak...

I have an 84 300D which has mysteriously developed a coolant leak on the front of the engine at what SEEMS like to be the hole that the arrow is pointing at. This is on the front of the engine just under the water pump:


What do ya'll think this is?
So here is the story:
I had just four days prior done a system flush, drained out all the old green crap, and had degreased it, had run a jar of coolant flush (was waiting for the citric acid to arrive). I replaced the thermostat as well. All was well in the world. Then I drove the car out of town, and when I parked it, there was a nice leak coming from the front of the engine. I checked every hose, the thermostat area, etc, but it doesn't seem to be coming from any of those places. It seems to be (but it is so cramped I can't tell for sure) to be coming from that hole. What is that hole? It seems to stop leaking when the reservoir tank is only about a 1/3 full, and will leak if I add more to it. I drove it 30 miles like this, and it was fine (no overheating etc) I stopped to check on everything, and added some more water just to be sure, and added 1/3 a cup of citric acid, just because I could. Well within 400 feet my car went to 110 degrees, so I pulled over just to see that now the leak seemed worse, but not that much. I pulled the thermostat (which is brand new) and now it doesn't overheat, but it still leaks in that hole. I have since drained everything out, but the leak is still there. What gives?

I disconnected the top hose from the radiator with the engine running, and it sprayed water everywhere, so I'm assuming the water pump is still good.


I'm about to pull the fan off and try to plug up the hole with some high temp muffler putty, but I wanted some input first. Thanks!
Reply With Quote
  #2  
Old 12-25-2009, 03:43 PM
tbomachines's Avatar
ಠ_ಠ
 
Join Date: Mar 2009
Location: Philadelphia
Posts: 4,600
Are you absolutely positive it isn't coming from the bottom of the water pump housing?? IMHO it is nearly impossible to tell exactly where it is coming from since the bottom water pump housing bolts are behind the crank pulley, unless you have the engine out and you can move around it easily. Money is on water pump housing...
__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth
Reply With Quote
  #3  
Old 12-25-2009, 03:57 PM
Registered User
 
Join Date: Jul 2009
Location: Tampa, FL
Posts: 70
I am not positive. I'm going to see if I can find some playdoh or something and jam it in that hole to see if that stops it, if not, I'll look elsewhere. Any idea on why the leak would materialize now? An old timer that saw me on the side of the road recommended putting black pepper in there and letting that clog the leak, not my way of doing things, but it was funny/interesting.
Reply With Quote
  #4  
Old 12-25-2009, 04:29 PM
Registered User
 
Join Date: Jan 2002
Posts: 18,352
Leaks in that area almost always come from the water pump seals which could have failed as a result of the flush.
__________________
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
Reply With Quote
  #5  
Old 12-25-2009, 05:02 PM
Banned
 
Join Date: May 2002
Location: Blue Point, NY
Posts: 25,396
Quote:
Originally Posted by kerry View Post
Leaks in that area almost always come from the water pump seals which could have failed as a result of the flush.
Agreed.
Reply With Quote
  #6  
Old 12-26-2009, 03:27 PM
Registered User
 
Join Date: Jul 2009
Location: Tampa, FL
Posts: 70
Life is sad

So after spending a good two days trying to get the viscofan off, and finally succeeding, four wrenches later, I found that the leak is most definitely coming from the bottom weeping hole of the water pump. I'm in the process of getting a new one. Any objections to getting one from Autozone tomorrow as opposed to waiting a week (or more) for one from peachparts?
Reply With Quote
  #7  
Old 12-26-2009, 03:43 PM
Registered User
 
Join Date: Jan 2002
Posts: 18,352
Quote:
Originally Posted by mikethezipper View Post
So after spending a good two days trying to get the viscofan off, and finally succeeding, four wrenches later, I found that the leak is most definitely coming from the bottom weeping hole of the water pump. I'm in the process of getting a new one. Any objections to getting one from Autozone tomorrow as opposed to waiting a week (or more) for one from peachparts?
Fan removal usually requires a 10mm box wrench ground down around the outside thin enough to fit over the bolt head. Fastlane usually doesn't take a week for me but Autozone should be fine.
__________________
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
Reply With Quote
  #8  
Old 12-26-2009, 03:47 PM
Banned
 
Join Date: May 2002
Location: Blue Point, NY
Posts: 25,396
Quote:
Originally Posted by mikethezipper View Post
So after spending a good two days trying to get the viscofan off, and finally succeeding, four wrenches later,
Do yourself a favor and don't rush the job. Those four screws are now toast and you are well advised to get a new set from the dealer before putting the fan back in place.

As stated above, you need to take a 10mm box wrench and grind the nose down to almost nothing so that it fits over the screws.

That job is a real PITA. I just got done with it so that I could install some alternator belts on the SD. Getting the screws started into the holes is damn near impossible.
Reply With Quote
  #9  
Old 12-26-2009, 03:50 PM
Bryan Automotive
 
Join Date: Oct 2008
Location: Bryan/College Station, Texas
Posts: 44
Hello. when this car was serviced was a new radiator cap installed also? I own a shop in Bryan, Texas. One trick that less reputable shops use is to install a new radiator cap. It is technically a maintenance item to replace. A shop can show the customer that the radiator cap is not holding the correct pressure and thus needs to be replaced. Customer oks it. Problem with this is that on higher mileage engines and cooling system parts is that the higher internal cooling system pressure from the new cap will tend to put more stress on seals and gaskets.


Bryan Automotive
www.bcsauto.com
Reply With Quote
  #10  
Old 12-26-2009, 04:19 PM
Registered User
 
Join Date: Jul 2009
Location: Tampa, FL
Posts: 70
A new cap was not installed. The current one seems to be just fine, the rubber is still nice and soft, and it seems to make a pretty good seal so I am leaving it as is.

Well, I would say that 2 days to remove 4 bolts doesn't count as "rushing" it. I got them off, and they are.... fine. I did not round the bolts, but I saw how they were begining to do so, and I will replace them, because having to deal with a rounded head would piss me off too much. I did the 10mm box head with the grind, and can add myself to the pool of people who claim there is NO other way of doing it without rounding those bolts.

Just wondering, it was a massive PITA to get the alternator loose enough to get the pulley off, do I have to tighten those bolts back to what they were when I am done (as in it took a 2' breaker bar and my big man arms to loosen them)? I don't have too much experience with cars, so what would the correct tension in the belts feel like?
Reply With Quote
  #11  
Old 12-26-2009, 08:21 PM
Banned
 
Join Date: May 2002
Location: Blue Point, NY
Posts: 25,396
Quote:
Originally Posted by mikethezipper View Post
Just wondering, it was a massive PITA to get the alternator loose enough to get the pulley off, do I have to tighten those bolts back to what they were when I am done (as in it took a 2' breaker bar and my big man arms to loosen them)? I don't have too much experience with cars, so what would the correct tension in the belts feel like?
Are you familiar with the belt tensioning system for the alternator? There is a tensioning adjustment screw right in front of the alternator that points laterally toward the right side of the vehicle.

Two bolts must be loosened............one that secures the tensioning bolt and one that allows the alternator to pivot (at the top of the alternator).

Once those bolts are loosened, the tensioner is tightened or released as necessary.

On the '84 with the 6" pulley and the 1000mm belts, the design doesn't allow installation and removal of the belts without removal of the pulley for the fan. It's a miserable design..........the alternator bracket hits the coolant tube.
Reply With Quote
  #12  
Old 12-27-2009, 01:17 AM
Registered User
 
Join Date: Jul 2009
Location: Tampa, FL
Posts: 70
I thought I did

Am I familiar with it? Well I wasn't, but now after fighting with it (and losing the first ten rounds) I am. I know how to adjust the tension, just have no clue now that I have taken the pulley off, and will be replacing the water pump, how to tell what is "enough" and what is too much tension when I reinstall everything.
Reply With Quote
  #13  
Old 12-27-2009, 02:01 AM
tbomachines's Avatar
ಠ_ಠ
 
Join Date: Mar 2009
Location: Philadelphia
Posts: 4,600
Also replace ALL the screws holding the water pump on with new ones of the same size/thread. After all of the heating and cooling the bolts can become very brittle. When I did my WP the first time (long story...) I ended up snapping off 3 of the bolts off in the old housing. Its a good thing I had a spare or else it would have been up to the screw extractor. The 10mm screws holding the fan on are definitely a PITA--a good soak in PB blaster and a good set of tight vice grips make them pretty easy though. Good luck, let us know how it goes. Be sure to order the gasket as well.

As far as the alternator bolts, I'd tighten them down pretty good so the entire load isn't resting on that little tensioner bolt. If that bends you'll have to order a new one since they are an atypical sort of thing. Tension the belts just as you would normally--enough not to slip.
__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth
Reply With Quote
  #14  
Old 12-27-2009, 09:58 AM
Banned
 
Join Date: May 2002
Location: Blue Point, NY
Posts: 25,396
Quote:
Originally Posted by mikethezipper View Post
Am I familiar with it? Well I wasn't, but now after fighting with it (and losing the first ten rounds) I am. I know how to adjust the tension, just have no clue now that I have taken the pulley off, and will be replacing the water pump, how to tell what is "enough" and what is too much tension when I reinstall everything.
I just did the belts on the SD. Surprisingly, with new belts, no slippage will occur even with 3/4" deflection at the center of the belts.

These two belts are very narrow and will easily stretch, so you don't want them too tight. My suggestion is to set them up so you've got about 1/2" of slack when you press in the center between the alternator and the water pump. If the belts are relatively new, they do not need a lot of tension. This will save both the belts and the water pump.

You'll know immediately if the tension is insufficient. With the headlights on, the belt will let out a squeal that can be heard down the street.
Reply With Quote
  #15  
Old 12-30-2009, 01:16 PM
Registered User
 
Join Date: Jul 2009
Location: Tampa, FL
Posts: 70
We have a go

OK, so I replaced the water pump, and now everything is good, except that it is running a little rougher. I push on the belts, and can get about 1/2" deflection, but I'm pushing with some force.

Anyways, now I'm wondering about the flush itself... I have done the citrus flush about FIVE times, and it is till coming out green.... Should I just continue doing the citrus flush until it is all clear, or just flush it with water enough times until it comes out clear? Note to all: If you need the citric acid, Ebay is your friend. I got 3 pounds for $7, including shipping. Much cheaper than from the dealer...
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 08:09 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, 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