Hi, I have a 1984 300d turbodiesel with about 400,000 miles. The car has been sitting because of a overheating issue. It seems the car overheats as soon as I start to drive it it then dramatically increases to the white and stays there and then as soon as I shut the car off coolant comes out the bottom with lots of smoke. Im worried about seizing the engine and I would love to continue driving it. It just isn't the same driving my wifes car to work. The help would be appreciated. Just to let you know I have a fairly new radiator, coolant, thermostat hoses and such no more than 3 years of age.

Even if the thermostat is fairly new, pull it and test it to see if it opens.

While you have it off, replace the water pump especially if you don't know when it was done last. That's something that needs to be replaced probably ever 200,000 miles or so.

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1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

http://i.imgur.com/LslW733.jpg

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Do you know the root cause?? It is expensive, difficult to R&R and may not resolve it.

I suspect it the the head gasket. A few ways to check first.

1) Is the coolant system pressurized real quick after you start the engine?
2) when the engine is cold, remove the cap, top up coolant to marked line,start engine. Does the coolant rises almost immediately?
3) Losing coolant daily/weekly?

All these points to HG failure.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

it appears that the coolant only leaks out after driving and i have never had leaking issues with the coolant except in the last 3 or 4 months and it seems like it stays within normal levels, so i hope it isnt the head gasket. I do know that I do have quite a decent oil leak now that has increased since the overheating issue.

No. Neither do you, nor does he.

It's preventative maintenance.

If it hasn't been done in the life of the car to his knowledge, just do it, especially if you're going to even think along the lines of head gasket replacement. You'd want to replace it anyway. And it rules one more thing out.

A water pump is expensive and hard to replace? OK!

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1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

http://i.imgur.com/LslW733.jpg

The Baja Arizona Oil Burners Send a message if you'd like to join the fun
Left to Right - UberWasser, Iridium, Stuttgart-->Seattle,, mannys9130

Visit the W123 page on iFixit for over 70 helpful DIY guides!

True, I do not know either.

However, my check costs nothing. Changing the water pump costs something. I am not arguing with you on the merit of changing the WP or not. What I am saying is do NOT change anything until you have exhausted with the tests. That is what I normally do. Talking about PM, how about changing the radiator, WP, thermostat, hoses? Where does it end? I do not have a deep pocket like most members around here.

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

When the water pump on my car failed a couple of years ago, in addition to overheating, coolant was leaking from the water pump seal. It was pretty easy to see.

If it is the water pump, many, if not most of us here seem to think Laso, Graf or Genuine Mercedes are the brands to choose from. I used a Laso, and it's been fine so far.

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Marshall Welch
Seattle, WA
1982 300D-T

To be helpful you need to pinpoint where the coolant and oil are coming out.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.