Adding Antifreeze???
 

What is the easyest way to add a gallon ($26.00 Gallon from MB dealer) to my radiator,
I want to add it to the radiator not just into the overfolw holding tank.
Starting to approach freezeing here in seattle in the mornings, wont be long till we get a good freeze.
Is one gallon enough for my 91' 300e 3.0L.
Thanks!!!

The reservoir in the engine bay is not an overflow tank. It is part of the pressurized system. If you notice, there is no cap on the radiator so there's no convenient way to fill the cooling system except through the reservoir.

If there is a hose from the reservoir that disappears into the fender then perhaps there's an overflow tank behind the inner and outer fenders.

Sixto
87 300SDL

You really should drain the system and refill with the proper concentration of antifreeze rather than fudge the existing concentration. You probably don't know what the existing concentration is so throwing in a gallon could result not enough or too much of an antifreeze concentration.

Sixto
87 300SDL

Yeah, follow the above advise. Just drain the whole thing and refill with a 50/50 concentration of antifreeze and water. There are two drain plugs, one on the bottom of the radiator and one on the engine block.

If you are trying to increase the concentrion of antifreeze, is it that the car only has water in it right now?

un-known mixture in radiator, just purchased last summer.
looks to be just watter.

You can get one of those little devices that measures the antifreeze concentration from an auto parts store for a few dollars. You don't want the mixture to be a lot more than 50% antifreeze because then its ability to aborb and transfer heat will be reduced. i.e. if the mixture was 100% antifreeze it would abosrb less heat from the head and not cool as much during its run in the radiator.

If you want to take a little time, your best bet would be to drain and refill the system or just test the mixture.

Cheers. -Ali

Will a prestone branded antifreeze "meter" work with the unique MB fluid???.
A have a common prestone tester.

Yes it will. It works properly with any glycol based fluid. The MB fluid may have have a slightly different formulation that some other fluids, but it is still glycol based and thus the prestone antifreeze tester will work correctly.

If you have one, use it and see what it says.

just water

I used to have an 89 W124 that would give this gurgling sound somewhere inside the dash area when the system is running. Apparently MB issued a kit that would fix this. On my 95 W124, this has not been a problem so maybe MB updated the design.

So back to older W124s, is it just drain & fill the coolant? Would there be any 'air pockets' that need to be purged, and how to do this?

For the M103, on the horizontal surface of the head near the #1 and #2 injectors there are a couple of 13mm bolt heads. Some cars have one bolt head and one sensor. Remove a bolt then pour coolant into the reservoir. Keep filling until coolant leaks out of the hole. Cap the hole, top off the reservoir and you should be good to go. Check the reservoir over the next few trips.

Sixto
87 300SDL

Ah, but how do you know if it's distilled water?

https://www.mbwholesaleparts.com/StarTuned/pdfs/AntiFreeDec04.pdf

Check conductivity?

Sixto
87 300SDL

If you're running only water at the moment, this is my suggestion:

1. First get the coolant capacity (qts) of your system.
2. Drain all the water you can using the radiator drain and engine block drain.
3. Close drains.
4. Add 50% of the capacity with antifreeze, the remaining charge with water.

This is just the bare minimum that should be done. There are many other steps that can be added to this procedure - some of them can get anal - but this should get you started.

Running only water is never appropriate for a cooling system for many reasons.

If you want to read more archived information on cooling system maintenence, search using keywords "demineralized", "distilled water", "coolant flush".

Can I replace the expansion plastic tank with a bigger one on my 300E86? What is compatible?

where is block drain?
 

where is the coolant drain for the block on the 117 engine?

IIRC one on each side just ahead of the mounts. One bolt that pulls straight down on each side.

Sixto
87 300SDL

As important as freeze protection is CORROSION INHIBITION provided by the corrosion inhibitor chemicals in antifreeze. A concentration between 50 and 70 percent antifreeze will provide both freeze protection and proper corrosion protection.

The capacity of M103 systems is about 10-11 quarts, so you should start with 1.5 gallons of antifreeze and top off with distilled water.

Draining is simple. Pop out the small panel on the RH side of the valence to access the radiator drain. It has a nipple for about a 3/8" hose, so you can drain into a container.

The block drain has a nipple for about a 1/2" hose, and you simply turn it CCW to open. It's under the rear exhaust manifold and you can access it with a crescent wrench, box, or socket. IIRC the hex is 17 mm.

I also siphon some water into the overflow tank and then siphon it out to flush the overflow tank.

Remove the engine undercover for best access.

Fill the system slowly with antifreeze first, then start the engine and let it run until the thermostat opens. Add distilled water as required. I've never had to open the bleed plugs. It's alway self bled with no problems. There is an arrow on the outside of the expansion tank. This is the "full cold" mark and is just above the seam. (See the owners manual.)

You can use Zerex G-05 - about ten bucks a gallon at McParts. It's identical to MB antifreeze and meets the MB spec. Read the label.

You should drain and refill with fresh G-05 every three years, regardless of mileage if you want your cooling system to last and not be eaten away by corrosion, which can result in some VERY EXPENSIVE repairs.

A larger expansion tank is not necessary.

If you need more info or details, try the search function.

Duke

This could work in a Diesel or 119 with the thermostat in the radiator return line. How will the 103 thermostat open if there isn't liquid at the level of the thermostat?

Sixto
87 300SDL

anti-freeze
 

Keep in mind that a water/anti-freeze mixture not only lower's the freezing point of the coolant, but also raises the boiling point. This is why all vehicles should run a 50/50 or thereabouts mix. Plus, anti-freeze has propertie's which reduce oxidative damage in the block/heads/radiator/heater core.

On the other hand antifreeze has less heat capacity than water. You need water in the mix to do the job of transferring heat from the block to the radiator.

Sixto
87 300SDL