Hi. I have a query regarding my 1984 300CD (130,000miles) I have noticed over the last couple of days my coolant level has dropped considerably. I'm assuming internally as there is no obvious leak on the ground.

I checked the oil no sign of coolant/oil mix on the dipstick. The car has never overheated in the 2 years I have owned it. No sweet smell of coolant from the exhaust.

I guess I should just monitor the situation over the next few weeks.

Although is it possible to have head gasket problems with this car at 130,000miles?

I'm in the middle of changing the head gasket on my wife's 1990 BMW 325i (95,000miles)at the moment, however, they have a very weak cooling system and I'm told it's normal to have head gasket problems even at low mileage.

I searched the forums for head gasket problems on W123 diesels and couldn't find many posts on the subject.

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1984 300CD 155k miles
1983 300TD 199k miles
2005 Legacy GT Wagon

Get hold of a cooling system pressurizing device and check carefully. Especially the weep hole on the water pump.

Its possible that there will be no drips on the ground. The leak is often small enough that the water boils/evaporates out of the leaked coolant and only a green/white/yellow crust is left behind.

I think mine does this too! It is very slow. No water in the oil or anything. No leaks on the ground

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1981 300SD 512k OM603

There does seem to be some yellow crust around the water pump and the valve cover??(is this possible?).

I'll pressure test the cooling system and take it from there.

Thanks

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1984 300CD 155k miles
1983 300TD 199k miles
2005 Legacy GT Wagon

Yes it is possible. The T-stat is near the valve cover, and since the water pump weep hole likes to drip, the wind in the engine compartment can make the liberated coolant land on different areas, making a failing water pump one of the last suspects. When the engine is cold, feel for some coolant under the water pump.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

Subtle coolant leaks usually only show up when the engine is hot and the coolant is pressurized, so you won't see drips on the ground. If you have signs of buildup on any of the coolant related parts you probably have a small leak. I would pressurize the system and with the engine off look very closely for leaks. They can be sneaky. There are a lot of tight places where these engines like to leak coolant. Check the water pump, the t-stat housing, and all the hoses. You may get lucky and just need to tighten a hose clamp.

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