Hi guys. I have a 1983 928S. What will happen if I top off my coolant that is not Dex-Cool. What will this do the the engine?

 

If you don't know what coolant you have, try one of the universally compatible coolants for topping off.

 

According to some of the people around here, you might tear a hole in the universe.

 

 

Since you said coolant and not antifreeze, if you're in an area where it doesn't freeze and it's not super low, then just top it off with distilled water. That'll keep the mix reasonably close to 50/50. Does it have DexCool in it right now? If it does and you're really low, then add Dexcool/ddH2O. you don't know what's in it, then you probably don't know how old the coolant is- If it's more than 2 years old and the car's driven regularly, flush it all out of there (plus the engine block drains) and replace with DexCool (or whatever makes you happy) and ddH2O. Good fresh coolant+ddH2O > old worn out DexCool any day......

 

If the coolant tank is green dont mix it with Dexcool, If your not sure just add water then get the coolant system flushed and refilled ASAP. To flush it make sure that you open both of the block drains they are under the 3rd exhaust port on each side of the engie or said another way under 3 and 7 exhaust ports. The block will hold close to a gallon of coolant. If byour going to do this I would also consider to replace the thermostate or atleast inspect it and also the figure on replacinbg the BIG Thermostate O ring,....... and if your car also has the rear sealing ring that taps into the back of the hole forThermostate replacing this seal as well.
And if your heater control valve is older than 5 years replacing this part as well as the short hose, that connects it to the rear of the cylinder head.. ( they should always be replaced together. The engine will take just about 4 gallons of coolant so buy 2 gallons of the coolant and then add water ( your choice on where you buy it, IE distilled or tap water,) To fill the system remove the coolant bottle cap, add the coolant about 1.75 gals then add the same amount of water, this will take a little while as the coolant will be purging the air out of the system.
When the level stabilises and you have added about 4 gallons of liquid start the car and turn on the heater to defrost, and let the engine run with the coolant bottle cap removed , this will purge the air out of the system monitor the temperature when the car is warmed up and the thermostate has opened, top up the bottle to just above the seam, put on the cap and drive the car for about 5 miles with the defroster on, Then park the car and let it cool off when its cool top up as necessary

 

I prefer the GO5 formula. Good enough for new Benz, and still phosphate and silicate free, with out the issues of the dex-cool.

I would suggest you drain, flush, and re-fill if you are unsure of the age, and type of antifreeze you have in your car.

 

Thanks for all the help. I am just gonna do flush and replace the thermostat. I just got the this car a couple of weeks ago and so far its been a blast.

 

If you just got the car, and you are hazy on some of the maint history, this is a perfect time to baseline all the service stuff, including the coolant and all the coolant hoses. I hate getting stranded by 'stupid stuff', and having old hoses fail easily meets that definition for me. Besides, you'll have the coolant drained when you do the TB/WP baseline service. Just a few more hoses to R&R, and you are there.

 

replace the heater control valve and the short hose

 

The one from engine to heater valve?

 

Yep. 928.574.567.02. Only $4-5

 

^^^^
I had that one blow out on me at a track event! I was just entering the front straight. I had just past pit in. There was a car I was keeping and eye on to give a point by to and as I got out on the front straight I checked six and he was WAY back flashing his lights. At that very moment I smelled the coolant burning off so I knew exactly what was going on.

I got to the end of the front straight and since no one was coming went backwards down pit road with my flashers going. Actually I think I crossed over to the other side of pit lane (like where the pit crew would be w/ all their gear) as there is an opening right near the end there.

I pulled in and probably 6-8 DE friends fell on the car. Took about 5 minutes to figure out what happened. Took me another 10 minutes to find someone with a hose the right size that I could cut to fit...then I had a student to take out on track. By the time I got back the car was nearly finished!

We topped up the coolant and I didn't even miss a minute of my next run session!

Sooo...REPLACE that little hose! Good luck and as noted by others, just do a full update of ALL fluids (including brake and trans!) and that way you will know what was done and when it was done!