Missing coolant in coolant reservoir

[Kenji001]

I poured in coolant into my coolant reservoir yesterday. But after 30 min of driving, the coolant in the reservoir is all gone. The meter didn't show that my 1993 240SX is overheating.

Could the problem be that I didn't open air relief plug when I flush and refill the coolant? Or the water pump is leaking?

http://www.240sx.org/faq/articles/coolant.htm

Thanks!

[Okinawandrifter87]

Check your water pump. Its only like 34 bucks or something at autozone.

[s13speeddrft]

you need to be a little more specific on what you actually did. i.e. did you completely drain and refill the coolant. I gathered you did and didn't bleed it at all. So bleed the system completely and see how that goes. Another problem could just be that your coolant reservoir is cracked and leaking.

[Kenji001]

Two months ago, my friend and I completely drain the old coolant, and flushed the coolant system with home water hose. And then, we refilled the new coolant. However, when we flushed and refilled the coolant, we didn't open the air relief plug. So I didn't bleed my coolant system properly.

And then about one month ago, my car overheated in a very hot day. I checked the coolant reservoir. It was empty, so I filled in with drinking water. After that, my car has no overheating issue. However, whenever I refilled the coolant reservoir, the coolant in the coolant reservoir would be emptied after about 30min of driving.

The things that are strange are:

1) The meter shows no overheating. The needle stays in the the middle between "H" and "C".
2) There is no coolant can be found under my car.

My real question is: Where did the coolant go?

So this could be the following problems:

1) I didn't bleed the coolant system properly. Then, why no overheating but missing coolant in the coolant reservoir?
2) The coolant reservoir is cracked, so it's leaking slowly. Or some coolant hose is leaking slowly.
3) The coolant fan is leaking or not functioning properly?

Thanks!

[Okinawandrifter87]

Its your water pump bro. I just had the same prob on my s14 and replaced it and its fine. When I took off the old one i saw where it was leaking out of but couldnt really see too well from where when it was on.

[SilviaSR20DET]

i had the same problem in my s14, however, it was my radiator hoses that cracked and leaked coolant. So maybe check that while your at it as well?

[21Nemesis]

I'm actually having the opposite problem. All of the radiator fluid is being returned to the overflow tank. Plus, when I turn off the car after about 15 mins. + driving, it sounds like it's boiling/bubbling.

[Ninjabread]

^^ air in the system or blown hg .. its overheating

and to the original OP, my car does that sometimes when I have to bleed the coolant system. You don't always get all the air out, but when that pocket of air goes and lets all the water in, it will come out of the overflow.

My suggestion is fill it back up again and see if it goes down.

[S14DB]

You guys have your stock Rad caps? Swap out for a NEW 300zx cap.

[projectRDM]

You're not loosing fluid. The system was never full to begin with, IE it had an air pocket in it. Overheating caused the air to be forced out, displacing it with the water in the tank. Each time as air is purged, fluid is pulled in to replace it. Has nothing to do with a bad water pump or hose unless you're certain it is leaking.

Rebleed the system properly to spec, add the exact amount of coolant/water mix, and for the love of all holy do not use tap water. Your cooling system will be full of rust in no time.

Distilled water only.

[mifesto]

+1 on distilled water only!!!!!

i can understand using any clean water thats available on the side of a street in an emergency but at home, do it right.

[dino6192]

You're not loosing fluid. The system was never full to begin with, IE it had an air pocket in it. Overheating caused the air to be forced out, displacing it with the water in the tank. Each time as air is purged, fluid is pulled in to replace it. Has nothing to do with a bad water pump or hose unless you're certain it is leaking.

Rebleed the system properly to spec, add the exact amount of coolant/water mix, and for the love of all holy do not use tap water. Your cooling system will be full of rust in no time.

Distilled water only. damm you beat me to it all. he said it perfectly. I would say your coolant resivoir is just doing its job if your car is fine now. Keep it filled (WITH COOLANT OR DISTILLED WATER ONLY!) and check it often. +1 TO PROJECTRDM for beating me to it.

[anti-rice]

get a4aab so it will work

[Kenji001]

I found the coolant leak. I want to confirm that I need to replace the water pump. If yes, I will follow the guides.

http://forums.nicoclub.com/zerothread?id=220947
http://forums.nicoclub.com/zerothread/242595

http://www.youtube.com/watch?v=nDysgdtBzVA

http://img396.imageshack.us/img396/8913/cimg4659wk4.th.jpg (http://img396.imageshack.us/my.php?image=cimg4659wk4.jpg)
http://img176.imageshack.us/img176/6081/cimg4663rc5.th.jpg (http://img176.imageshack.us/my.php?image=cimg4663rc5.jpg)

And about the rattling noise, is that the infamous timing-chain-hitting-the-guide noise?

http://www.nicoclub.com/articles.php?id=105618

Thanks!

[Ninjabread]

That's what my water pump did when it went bad. Another way to confirm is by looking at the weep holes, you should see fluid coming out of them.

[Kenji001]

Where is the weep hole? Do you have pictures?

[S14DB]

Look on the side and bottom of the water pump housing. There will be a bb sized hole on the shaft section.

[Kenji001]

http://img370.imageshack.us/img370/650/cimg4689mg0.th.jpg (http://img370.imageshack.us/my.php?image=cimg4689mg0.jpg)

Sorry of the noob question, what are the two lower right pulleys for?

[S14DB]

Your AC? I can't see anything with your camera.

[reccakun08]

left- top: water pump bottom: crank
right- top p/s bottom: a/c

[Kenji001]

There are 6 pulleys.

Left: Alternator
Top center: Water pump
Bottom center: Main engine pulley
Top right: Power Steering

Bottom far right: ?
Bottom (between main engine pulley and far right pulley): ?

Which one is the AC compressor?

[S14DB]

Bottom far right: AC compressor
Bottom (between main engine pulley and far right pulley): Idler pulley. keeps tension on the belt.

[Z33dori]

glad this thread popped up... i'm having the same trouble since i did my head gasket swap....

i'll have to look into this next time i drive my car and check for leaks...

[Kenji001]

Thank you everyone.

I finished replacing the water pump yesterday. I didn't see any more leak, but I will check again tonight.

I still hear the rattling noise. I think it is the chaining guide.