Have a small anti freeze leak from the back of the head at fire wall . Just a hint of antifreeze sometimes any ideas? 1985 300 sd

Leave it alone.........keep an eye on it..........see how much coolant you lose over time.

Eventually, you'll need to address it............these things don't cure themselves.

What causes this to happen? The engine has 160,000 miles and I don't drive it hard.

How about adding some of that coolant sealer to the system?

The head gasket is over 20 years old. Failure at this point in time is usually typical.

Don't do it. It might stop the leak, but the stuff coats all the internal surfaces of the radiator and engine and the cooling performance will degrade because of the addition of the stop-leak.

If you get to the point where the leak is significant, you'll need to gather the resources and the knowledge to pull the head and change the head gasket.

It's not insurmountable.

I agree, leave it alone but monitor your coolant level as well as your oil, at least once a week, as long as there's no oil in coolant and engine oil doesn't turn milky white. Don't ever be tempted to use those stop a leak stuff. My 300D, a daily driver, has been doing it for at least more than 3 years now and I'm just adding approx less than 1/2 quart 50/50 anti-freeze every 2500 miles every oil change. It already has 340K miles on the clock and still counting and running strong, so I'm not worried, it's concerning but not alarming at this point.

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'85 300D Turbo - CA Version

First order of business, I'd check all the heater hoses down there behind the engine. When I had the head of mine, seemed like I had to r&r a bunch of hoses, clamps and a lot of other stuff. Could be as simple as a pinched hose or bad clamp. If the car runs well, no water in oil, no antifreeze out the tail pipe, then I'd look for the easy stuff first. Good luck!

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1998 E300D, 287k, barely broken in.

I second the above, as a good thing to check first. Have heard of that rear hose scaring more than one person......

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Are all the leaks that you guys are experiencing coming from the same spot as mine is at the back of the head right at the fire-wall

I would also take a mirror and light and try to determine the exact location of the leak. There might be a loose fitting or freeze plug back there causing it. While it might not be unexpected I would call it less than typical, in my experience.

The turbo motors seem to need head gaskets fairly routinely at between 250 and 300K. The movement between the head and block eventually wears enough that you lose seal.

The non turbo 616/617 motors never seem to need head gaskets unless run low on coolant.

Tom W

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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.

If you do try some leak stopping snake oil, use the alumi-seal. Its just powdered aluminum and it plugs the hole. It doesn't coat your cooling system like the others. Of course if the leak is big enough it won't plug it and actually makes the leak worse by scraping the sides of the hole as it gets pushed through.

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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

http://ecomodder.com/forum/fe-graphs/sig692a.png

Mine doesn't really leak but I should say "weeps" around # 5 cyl. at the bottom of the cyl. head/top of the block. There are times that I can even see it bubble and when I didn't drive the car for a day, traces of white dried G-05 trails down the block to the tranny bell housing.

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'85 300D Turbo - CA Version

Next time you do a valve adjustment...........give the head bolts a bit of a twist in that area.........maybe 45 degrees, maximum..........see if the problem is eliminated.

I think your chances of success are slim if it's been leaking awhile.......but.......you never know.

I was thinking about that but I don't have the star socket bit and even if I have, I'm scared that the leak will get worse or something not good might happen like, warp the head, strip the threads or break the bolt, but I might give it a try, maybe this fall when I do my annual valve adjustment in prep. for the winter. If I turn one bolt, do I have to turn the rest too? ....and quick question, can you confirm this?

Cylinder head bolts are not torqued and don't have a specific torque value? The bolts are just turn until snug , then tightened like 3, 6, 9 12... o' clock or like you suggested 45, 90, 180, 360.... deg. turns, evenly all across the head? ...and by the way, where can I get those socket bits for the star head bolts, and what is the technical name for it or MB part#?

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'85 300D Turbo - CA Version