[unLIMITED]

Does anyone know for sure what the cooling system capacity is for a gen3 3.3/3.8 with the HD radiator and rear heat?

There seems to be several different numbers out there, most commonly 10.5, 13.23 and 16 quarts. I've also seen that rear heat adds 2.9 quarts, but it seems there should be at least 1 quart difference for HD/no HD since the longer lower hose and larger radiator would add at least a quart.

The last time I filled the radiator 2.5 years ago I used the 16 quart figure and added 9 quarts of coolant to aim for 55% concentration. Now I have lots of green glop (color and consistency of pea soup) in the expansion bottle. I bought a coolant tester and it shows a very rich mixture, around 70%.

I'm thinking now that the 13.23 quart number is with HD cooling and rear heat based on:

* 9/13.23 is 68%, which seems to be close to my current concentration.
* 13.23 is the only number given in my T&C Limited owner's manual and all Limiteds should have HD radiator and rear heat.
* 10.5 + 2.9 is about 13.23 so maybe the 16 quart number adds the rear heat twice.

 

[A.j. Schreiber]

Just recently upgraded my 2000 Dodge Grand Caravan with rear heat to the HD Radiator. Keep in mind those fluid capacities are when there is absolutely nothing in the system. With that said I put in a gallon of non-mixed coolant, a gallon of distiilled water, then topped it off with roughly a half gallon of premixed coolant. So all in all about 2 and a half gallons

 

[unLIMITED]

Just recently upgraded my 2000 Dodge Grand Caravan with rear heat to the HD Radiator. Keep in mind those fluid capacities are when there is absolutely nothing in the system. With that said I put in a gallon of non-mixed coolant, a gallon of distiilled water, then topped it off with roughly a half gallon of premixed coolant. So all in all about 2 and a half gallons

Thanks, A.J. I think that's consistent with 13.23 quart overall capacity since it doesn't sound like you drained the rear heater, so around 10 quarts for the engine and radiator. As I recall, I had a hard time getting all that 9 quarts of concentrate in! (I had flushed all the old coolant out with distilled water.)

 

[A.j. Schreiber]

if you want to get the coolant out of the block there are two 14mm bolts that drain the coolant out of each side of the block, one in front, one in back, the one in front is towards the driver's side (right of the oil filter if youre facing towards the rear of the van on your stomach) of the oil filter on the engine block, and the one in the back looks exactly the same and isnt hard to find. remove those and the bad fluid inside the block will drain out

 

[AllanC]

I'm thinking now that the 13.23 quart number is with HD cooling and rear heat based on:

* 9/13.23 is 68%, which seems to be close to my current concentration.
* 13.23 is the only number given in my T&C Limited owner's manual and all Limiteds should have HD radiator and rear heat.
* 10.5 + 2.9 is about 13.23 so maybe the 16 quart number adds the rear heat twice.

I reviewed the factory service manual for 2000 model minivans. Equipped with 3.3 / 3.8 L V6 engine and with either standard duty or heavy duty cooling, capacity is 12.23 quarts and if equipped with rear heater option, 16.13 quarts.

On or around page 244 of the owner's manual cooling system capacities are listed. 3.3 / 3.8 V6 engines show 13.23 quarts. Read below a few lines and there is a note to add 2.9 quarts for rear heater. Add the 2 capacities and you get 16.13 quarts.

 

[unLIMITED]

I've changed the coolant on my van now and am convinced that there is no way it holds 16 quarts of coolant. It is about 13 quarts, not including the overflow bottle.

First, I drained out all the old coolant that I could including the front and rear heaters and got 12 quarts. Then I thoroughly flushed out any remaining coolant with water, added exactly 6.5 quarts of antifreeze and filled with distilled water in the radiator as needed until all the air purged. Once the radiator was filled I used 50/50 mix to bring the overflow bottle up to the "add" line. Next I mixed a small amount of antifreeze with exactly the same amount of water to get a "known good" 50/50 mix. I used this to check the calibration on my coolant tester, and it showed -37C. After driving the van and letting it cool I tested the antifreeze in the radiator it also showed -37C.

Based on this I can say that with the rear heater and less the overflow bottle, the coolant capacity is very close to 13 quarts. The overly strong mix of coolant I used to have was probably the cause of the green goo that was in the overflow bottle. Also, even though the new Prestone is called "extended life", I would say that a 2 year change interval regardless of mileage is still a good idea for these vans.