82 300D Trb. External Coolant Leak - PeachParts Mercedes-Benz Forum

will_sanderson · #1 04-02-2006, 08:02 PM

I recently purchased this 82 300 turbo and noticed on my way home that it overheated to just over 100 on a 3000' 7 mile climb. It has consistently run hot around 90 and sometimes 100 since. I replaced the thermostat and after some checking I found that the previous owner had had the radiator flushed...someone mentioned that this can plug up an old radiator with rust etc. from the engine. With this in mind I have ordered a new radiator.

I recently drove it into town and it overheated to 110. Now I have found a small, 1 drip per second leak (engine cool, no pressure). The leak is dribbling off the oil pan lip and therefore it would seem to originate from above, maybe behind the fan/flywheel.

There doesn't seem to be any oil in the coolant or vice versa and I assume either would be apparent. I haven't drained the oil to check but have only pulled the dip.

Any thoughts (praying this isn't a head gasket/cracked head)? I read in another post about a water pump gasket...

If it is the head gasket how much would an average labor price be to fix $?
I am fairly mechanically savy but haven't done the job myself, a valve adjustment is as far as I have gone...Is there a good guide out there? How much time am I looking at?

Thanks,
Will
82 300D Turbo ~240k

Strider · #2 04-03-2006, 12:52 AM

Check to make sure the water pump is working. A small coolant leak can occur out of the pump weap hole when the water pump is failing.

Also, check the condition of the coolant. It is MB coolant, not green stuff right?

will_sanderson · #3 04-05-2006, 02:18 PM

So I pulled off the old water pump as the leak seemed to come (when it was still connected) from right behind it. I have a new gasket and will install when I put in the new radiator.

The pump connects to a dough-nut shaped mount on the engine which has a small gasket also, should I replace this as well or is this much less likely to be the problem.

Also, is there a way to inspect the pump to check if it is working/failing? I cleaned it and it spins freely and well with no noise or vibration. I have one from another engine that I could use.

The coolant that I used was the green stuff, well diluted at that because of adding water to make it home. I didn't realize there was a MB coolant. Any opinions on it vs. Napa green?

Thanks,
Will
82 300d Turbo 140k
1 Tank VO

will_sanderson · #4 04-05-2006, 06:55 PM

Upon doing some research I found that when the water pump is failing it starts to leak- just kind of to let you know you should replace it. So I did and no more leak. Yahoo....

Also, I found out that MB coolant is in fact great and therefore better than Napa green for many reasons.

t walgamuth · #5 04-05-2006, 11:10 PM

you got the most satisfying answer to your question.

good work

tom w

will_sanderson · #6 04-08-2006, 12:38 AM

So...the water pump no longer leaks and is working just fine, however, the new (old) radiator I put in has a small leak on the top tank (black plastic part).

I bought two used radiators from a local shop for $50. Both are identical but for the fact that one is almost twice as thick. I used the thin one (with the hole) first because it was the same size as the one in the car.

My question: Can I use the thicker one? Keep in mind that all the holes are in the same place and it seems like it would fit right in!! Please let me know of what I don't know.

P.E.Haiges · #7 04-09-2006, 12:31 PM

Will,

I wouldn't consider 100*C on a 7000 foot climb overheating. Look at your temp gage and see where the red mark is. That's the point of overheating.

You may be fixing something that "ain't broken".

P E H