Sorry I cant help you with the CD changer. 1994 UK market cars weren’t supplied with the w...
Sorry I cant help you with the CD changer. 1994 UK market cars weren’t supplied with the wiring already in place, though I am told US models were.
Coolant has an effective life of two years. After this time, the coolant breaks down and looses some of its cooling/anti freezing properties and thus should be replaced. If your coolant is less than two years old and there is no evidence of a leak/water loss then don’t bother replacing it.
In the UK its normal to use 50:50 mix year round. Our summers can be hot and our winters freezing. If you are not sure of your coolant's effectiveness, buy a test meter from an auto parts store and test the liquid by submersing one end into the expansion tank. These meters typically cost £15 ($20).
If you have decided that your 140 needs a coolant change then read on. The following applies to the W140 S280/S320 though I am quite sure that the S350, 420,500 & 600 aren’t too different.
(1) Remove the front lower engine tray. Undo the 8mm bolts on the underside. If the tray doesn’t come away easily then you have missed some out. Don’t tug at it if one end appears to be jamming, its likely that you've missed a bolt out.
(2) Undo the expansion tank reservoir cap, then locate the bleed screw on the underside of radiator. Undo the Screw and catch all the liquid. If you cant locate the bleed screw, then undo the lower hose on one side of the radiator (different locations depending on who manufactured the radiator but always at the bottom) Please don’t let this spill on your driveway, animals find the smell very attractive and drink it given the chance. It is poisonous. Dispose of the liquid in a sensible manor as per your local authority regulations. Don’t spill it down the drain.
(3) Re do the bleed screw or reattach the radiator hose.
(4) The coolant capacity for your engine type will be listed in the back of your owner’s handbook. The capacity is different depending on the model. Divide the total capacity by two (remembering you need a 50% mix) and pour this quantity of distilled water or tap water if you live in a soft water area (so to avoid lime scale) into a bucket. Fill the rest with quality coolant. The original Benz stuff is clear. Using a coloured coolant is perfectly acceptable. Most auto stores seem to stock blue coolant. This helps you locate leaks easily as you can distinguish the liquid quite quickly. Mixing the liquids is important. If you fill your car with water and then coolant the liquids will not bind imediately and the boiling point lowers, hence the mixing in a bucket.
(5) Refill the system with the coolant in the bucket. Remember that the liquid has to fill the engine as well as the pipes and radiator. Squeeze the pipes to ensure that air bubbles have dispersed.
(6) Turn your interior heaters on full with max fan speed and start your car with the expansion tank lid open let it reach operating temperature so that the water starts to boil, and the thermostat opens. This allows coolant into the engine and heater matrix. Kill ignition and top up as necessary.
(7) Based on the theory that air always rises to the top, restart the engine once its cooled off (allow 20 mins) and bring the water to the boil again. Lots of water will bubble up and start to spout up through the expansion tank in violent bursts. This is simply air heating sufficiently enough to come to the top and bursting through the water, flushing air locks. As soon as the water starts to overflow in a constant stream, i.e. no longer expelling in bursts, then the job is complete. Replace the cap and drive as normal. Check the coolant level daily, as this will need topping up as further air bubbles come to the top.
If you arent confident doing this job then get a shop to do it for you. You will get around charged 1.5hours labour or 18 Mercedes Benz WU (work units)
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Sorry I cant help you with the CD changer. 1994 UK market cars weren’t supplied with the wiring already in place, though I am told US models were.
Coolant has an effective life of two years. After this time, the coolant breaks down and looses some of its cooling/anti freezing properties and thus should be replaced. If your coolant is less than two years old and there is no evidence of a leak/water loss then don’t bother replacing it.
In the UK its normal to use 50:50 mix year round. Our summers can be hot and our winters freezing. If you are not sure of your coolant's effectiveness, buy a test meter from an auto parts store and test the liquid by submersing one end into the expansion tank. These meters typically cost £15 ($20).
If you have decided that your 140 needs a coolant change then read on. The following applies to the W140 S280/S320 though I am quite sure that the S350, 420,500 & 600 aren’t too different.
(1) Remove the front lower engine tray. Undo the 8mm bolts on the underside. If the tray doesn’t come away easily then you have missed some out. Don’t tug at it if one end appears to be jamming, its likely that you've missed a bolt out.
(2) Undo the expansion tank reservoir cap, then locate the bleed screw on the underside of radiator. Undo the Screw and catch all the liquid. If you cant locate the bleed screw, then undo the lower hose on one side of the radiator (different locations depending on who manufactured the radiator but always at the bottom) Please don’t let this spill on your driveway, animals find the smell very attractive and drink it given the chance. It is poisonous. Dispose of the liquid in a sensible manor as per your local authority regulations. Don’t spill it down the drain.
(3) Re do the bleed screw or reattach the radiator hose.
(4) The coolant capacity for your engine type will be listed in the back of your owner’s handbook. The capacity is different depending on the model. Divide the total capacity by two (remembering you need a 50% mix) and pour this quantity of distilled water or tap water if you live in a soft water area (so to avoid lime scale) into a bucket. Fill the rest with quality coolant. The original Benz stuff is clear. Using a coloured coolant is perfectly acceptable. Most auto stores seem to stock blue coolant. This helps you locate leaks easily as you can distinguish the liquid quite quickly. Mixing the liquids is important. If you fill your car with water and then coolant the liquids will not bind imediately and the boiling point lowers, hence the mixing in a bucket.
(5) Refill the system with the coolant in the bucket. Remember that the liquid has to fill the engine as well as the pipes and radiator. Squeeze the pipes to ensure that air bubbles have dispersed.
(6) Turn your interior heaters on full with max fan speed and start your car with the expansion tank lid open let it reach operating temperature so that the water starts to boil, and the thermostat opens. This allows coolant into the engine and heater matrix. Kill ignition and top up as necessary.
(7) Based on the theory that air always rises to the top, restart the engine once its cooled off (allow 20 mins) and bring the water to the boil again. Lots of water will bubble up and start to spout up through the expansion tank in violent bursts. This is simply air heating sufficiently enough to come to the top and bursting through the water, flushing air locks. As soon as the water starts to overflow in a constant stream, i.e. no longer expelling in bursts, then the job is complete. Replace the cap and drive as normal. Check the coolant level daily, as this will need topping up as further air bubbles come to the top.
If you arent confident doing this job then get a shop to do it for you. You will get around charged 1.5hours labour or 18 Mercedes Benz WU (work units)
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