well it started yesterday when gf was driving home. the radiator was low and she put more in it to get home. when I checked it it was still full. I did a flush on it with the old thermostat popped open to ensure flow. I did think the water in the radiator was not moving very good considering that fact. I replaced the thermostat with a nissan brand one and then filled it back up with water. let it idle for a few minutes to check for leaks then drove it for a test drive. got just a few miles down the road and the temperature guage was climbing. will this happen just because it has straight water and no antifreeze? I wouldn't think so but not positive. the car is a 98 with 195k on it. how can I tell if the water pump is working properly?

ok so just checked the radiator and it was half empty. is there a certain way to fill the radiator up? went ahead and topped it off again and will see what happens.

 

Did you let the car run at idle for 20-30 minutes with the rad cap off after your refill to bleed the air out? If you did that, you should have seen that the coolant would need the be poured in more after the initial fill since the coolant gets cycled thru the engine...kind of like an oil change. You replace oil filter, fill oil, run car, turn off car, add more oil if necessary.

 

yeah in a rush I think I left that step out. topped it off after that then it was fine. drained it and put the antifreeze in and let it sit for a bit, added a lil more water and all is good so far. drove it around the block and never got over halfway. it's always ran just under halfway since I got it.

 

It sounds like there was air in the system. Water is actually better than antifreeze so that wasn't the issue.

Glad everything's fine now.

 

yeah I noticed when I put in the antifreeze I squeezed the hoses and got a big pocket of air to come out.

 

Chris, water is better than coolant? are you talking for diagnosis for getting air out? That doesn't seem right for normal operation.

 

Water is a much better heat sink then straight antifreeze. It's ability to absorb and dissapate heat is superior. However, you need the coolant/antifreeze to increase the boiling point and decrease the freeze temp of the water.

A cooling system with straight antifreeze/coolant will not be able to transfer the heat from the engine block to the radiator efficiently. Therefore, an engine could actually over heat running straight coolant.

 

There ya go

 

water + water wetter =

 

the 4th gen calls for 70-30 down to down to damn near northern canada weather. So unless you live far north. Go 70-30 for better cooling in the summer

 

Sounds like you have a leak somewhere. An air pocket is not going to be enough to cause the radiator to drop to half empty.

 

yeah the original leak was on the thermostat housing itself, found that out when i changed it. the nuts weren't much tighter than hand tight and I say that with the fact that it's a ***** to get you're hands in there. there was a big glob of silicone on the bottom side of the housing from previous owner. I remember a few times at start up the belts squeeling for a second or two. I have checked the coolant level the past couple days and it hasn't lost any so it should be good now. as far as the air pocket if the thermostat is closed when you fill the radiator up I do believe it is possible to get a pocket of air in that particular hose seeing how it goes from close to top of motor then down to the bottom of the radiator. and face it the radiator isn't very big.