Coolant flush and Tstat replacement
 

The PO of my car said the Tstat was bad, and its never up to temp unless its really hot out, so m replacing it. I also want to do a coolant flush or change, i'm not sure of the life of my coolant so it should be replaced, how much do i need to buy? I'm going with Zerex G-05 not Benz i have been told its the same stuff. And i found that its half the price in my neck of the woods.

My questions are:

How much coolant should i have on hand when doing the flush? and should i follow the instructions on diesel giant and do a citrus flush with shout gel, etc?

BTW i have a 1987 300SDL

you should only need one gallon of coolant unless you mess up or you find sediment afterwards. But it certainly does not hurt to buy 2.

get 12 gallons of distilled water

the FSM says to remove the thermostat when flushing, but I've found you can't get up to full temp with it gone. Since you are replacing your t-stat, leave it in for flushing and swap when you drop your new coolant in.

how much coolant does the car hold?

what car do you have?


either 11 or 12 liters which is approx just under 3 gallons. If you wanted a 50/50 mix, you will need to buy 2 gallons. You can mix the coolant down to 30% at the minimum.

edit: I see the SDL. I do not have the info for your engine. This is for the turbo 617

10 quarts of antifreeze/distlled water mixture

for up to -30 use 4.5/5.5 ratio for antifreeze to distilled water
for up to -45 use 5.5/4.5 ratio for antifreeze to distilled water

I flushed my car with the T-stat out and the mono valve disconnected. This allowed me to flush the system without waiting for the engine to heat up. I also built a reverse flush kit with some 1/4 inch galvanized pipe and some garden hose. This way I could back flush the system.
When I filled the system with new coolant, I left the mono valve disconnected so that I could get coolant to the heater core easily.
Remember to have the car pointing uphill and rev it a few times to get the air out of the system...

I was under the impression that heat will act somewhat like a catalyst for the acid flush.

*patbob can back me up on this one*

its got the 603 motor in it... shes an 87 300SDL

i suggest picking up a w126 service disc if you intend to work on the car.