The last time I changed my coolant, I used the drain and refill method. I did it about four times until the water was relatively clear drained out of the radiator.

I check my Haynes manual last night and was wondering about the mixture. They have a different way of doing the flush. Here's how they did it: drain radiator, disconnect top radiator hose, remove thermostat, reconnect thermostat attachment without the thermostat (so it's full open all the time), plug radiator drain, run water using hose to radiator. Susposedly water/coolant will come out of the top hose. You would watch the water coming out until it's clear (of couse have something to catch the coolant). Then you would connect everything back and fill with mixture of coolant and water.

What confused me was since all the old stuff is out and only water is in the block, wouldn't you just add pure coolant to the radiator? I did the same when I used the drain/fill flush method; add pure coolant to radiator. Am I doing this wrong?

 

i have a question about this also.. does lack of changing your coolant cause any performance degredation?

i mean does your car like lag or run slower when its warmed up?

 

Huh? The thermostat is connected to the bottom radiator hose on our car. So, the Haynes manual is somewhat suspect in its suggested method. Those manuals tend to generalize alot. Maybe they were referring to a 3rd gen Maxima.

DW

 

They did show pics for both 3rd and 4th gen thermostat location. I can see that it could be a hassle taking it out and putting it back again. I guess if you're changing your hoses and thermostat, Hayne's way is probably easier. With the drain/refill method you don't have to disconnect or remove anything.

For people who did their own flush, did you guys fill with coolant only into radiator or a mixture of it with water?

 

well the Haynes has both the 3rd and 4th Gens .. some times you have to watch what you are reading because the instructions are pages within each other..

 

Not changing your coolant will only cause corrosion to build up in the system and your water pump to fail earlier than it would otherwise. Eventually, your car will start to run warmer and warmer, and that will effect your performance. But, in the grands scheme of things, no, it really doesn't effect performance.

 

I used the drain and fill method. When I refilled it for the last time I used a 50/50 mix of distilled water and Zerex antifreeze, which I made before pouring in the radiator.

 

Since the block contained just water after the last radiator draining, I added the amount of pure antifreeze to make a 50/50 mix according to the FSM, then topped up with water so the final total mix was 50/50. I added a pre-mix of 50/50 to the overflow bottle though.

 

So basically at anytime you would only have 1/3 coolant in your system, correct?

 

Sprint, check this link out, especially the last paragraph.

http://www.bmcno.org/RadCap.htm

When I change the coolant, I open the bottom drain on the radiator and put a garden hose in the filler neck with enough flow to make up whats draining. I run the engine with the heater on high for 15-20 minutes to get all of the old coolant out of the block.

I don't think that you need to remove the thermostat, it will open when the coolant in the block gets hot. It will take longer to completely flush the system with my method, but with a lot less effort.

 

I have always done the open the drain plugs from the radiator, and the 2 engine block points. The front drain plug on the block is pretty easy to get to, but the rear one is kinda hidden. Of course I was fortunate that I had all the stuff under the car out, like Y pipe, splash gaurds and CV axles, but you can do it. Then, I take a garden hose and flush the coolant out completely. I just use Prestone green stuff diluted with distilled water. I hear some people here use Toyota red coolant in their nissan. Its really expensive but I guess it works. Fortunately for us, we have aluminum block and heads, so the rust isnt that much of an issue as an iron block would be.

 

Actually, this might take less time. So basically what's draining out is a combination of old coolant plus hose water. Once pure water is coming out the bottom, I assume you just pour pure coolant into the radiator after you put back the drain plug. Is my understanding correct?

 

I should have mentioned that also prior to the last fill, I opened the plugs on the block. They were a ***** to get to, but I wanted to make sure it was done right. There should be a true 50/50 mix in it now.

BTW, I've never heard of anyone actually removing the thermostat in a Maxima do flush the system. Way to labor intensive and messy.

 

Damn good point about the aluminum block and heads. Didn't think of that. But then, thinking a little further, rust may not be a problem, but corrosion may still be, maybe even more so than in a iron block engine.

And, you actually got to the engine block plugs Wow. I saw one of them and din't even bother. Waaaay too tight in there.

DW

 

Thats exactly what I do on all my cars. No need to jack up the car, just flush.

To fill I take the coolant capacity and add the Coolant first (50%). Then for the rest I use disstilled water (minus what is left in the block). Lastly I use a 50/50 mix for the resivior.