Ok I have had a small coolant leak for about a week now. I took it to the dealer and they say everything tested fine and they didn't find any sign of a leak.It seems to leak after the car has sat out in the cold weather all night. But as soon as I warm it up and drive it the leak disappears.

 

Sorry to say this but that is the way water pump leaks usually show up, then get worse over time. There is an inexpensive way to temporarily fix it by using Barrs Stop Leak. Just Barrs not the auminum flakes stuff. The Barrs Stop Leak became pretty famous when the Navy started using it in Nuclear Submarines. It should definitely fix the problem till it gets warmer outside. In the mean time you can do some research on replacing the water pump yourself and save yourself some $$$. I used to use it when I was short on funds.

 

the water pump is inside the timing cover though...if it leaks it will go in the oil pan.....which is worse than on the ground. I can't say I've read of a faulty water pump in a maxima on here ever. I did buy one for when i did the timing chain replacement on my 95 so I have a new one on the shelf if you need one.

i would look for a loose hose clamp, or loose thermostat housing nut....perhaps even replace the thermostat and gasket.

how do you know its leaking..?..do you find puddles on the ground or do you just notice you have to add coolant every once in a while? if you have to add, but no evidence of puddles it could be a bad radiator cap.

I am not a big fan of the leak stop stuff...it gums up thermostats and generally decreases the effectiveness of your coolant system.

be glad your dealer didn't tell you it was a head gasket and drag you over the coals for nothing....

 

It leaks overnight. Once the car is started and warms up it stops. I haven't had to add any water. Doesn't seem to affect the level in the radiator. Where ever the leak is the coolant ends up dripping from the area between the oil pan and A/C compressor

 

If it makes you feel any better, my 95 is doing the exact same thing. I've beenwatching your posts to see if you figure out what it is. On mine, I just get a small puddle most mornings in my garage. Occasionally, I can smell a slight coolant odor when I pull into the garage after driving. I've been checking the coolant level weekly, and it's only leaking an ounce or so every 1-2 weeks, so it isn't that big of a deal yet. The coolant is coming from something between the A/C compressor and the front of the motor, or between the alternator and the motor. The drive belt also seems to be getting a little wet as well.

-Chris

 

It's something about the cold weather. I have searched all over and can't find where the leak is. I wanna go ahead and get the water pump replaced, but thats alot of dough if that isn't my problem

 

I'll give my theory as to why the cold weather nature of water pump leaks. When the seals are worn, the clearance between the seal and water pump shaft tends to increase. When It is cold my theory is that the steel water pump shaft contracts more than the seal thus increasing the clearance and allowing it to leak, Once you get everything hot again your engine retains enough heat so that it doesn't leak till everything really cools off overnight. That is why you when you took it to the shop they probably pressure tested it and found nothing wrong. The best way to test for leaks is to pressure test it after the car sat outside all night. I mean test it in the parking lot. Okay, I have on my asbbestos underwear, you can flame me now! Her its only a theory.

 

WOW, i just posted about this like a day ago. I guess nobody here reads or searchs before posting!!

Ant

 

So should I go ahead and get the pump changed to be safe. I live in Ga but the weather has been cold down here and thats wwwwwwwwwwwwhen the leak started whe it turned cold.

 

sounds to me like a thermostat housing leak...its right above where you are talking....if the water pump is leaking, you will find it in your oil...not on the ground.

waterpumps have a multitude of seals....some are face seals and others are o-rings on the shaft diameter. Silcone and nitrile (common seal materials) shrink very little...and besides, when designing a shaft-to-seal fit the seals inside diameter is smaller than the shaft...5% in rotating shaft situations. the amount of shrink the steel shaft will do (especially that small of a shaft) will be less than .001" from 90F to 30F.

"cold" and "georgia"...can you say those two words in the same sentence....it was -2F here this morning, the wind chill was 12 below....

 

sounds to me like a thermostat housing leak...its right above where you are talking....if the water pump is leaking, you will find it in your oil...not on the ground.

the thermostat housing is aluminum and held to the aluminum engine block with steel studs/nuts....aluminum expands/contracts more than steel for a given temperature differnce...so the force holding it to the block would decrease as it got colder....and its just a paper gasket under it....the thermostat is $15 at the dealer, and you can do it yourself with a screwdriver and a 10mm socket wrench.

waterpumps have a multitude of seals...most have three or four....some are face seals and others are o-rings on the shaft diameter. Silcone and nitrile (common seal materials) shrink very little...and besides, when designing a shaft-to-seal fit the seals inside diameter is smaller than the shaft...5% in rotating shaft situations. the amount of shrink the steel shaft will do (especially that small of a shaft) will be less than .001" from 90F to 30F.

"cold" and "georgia"...can you say those two words in the same sentence....it was -2F here this morning, the wind chill was 12 below.

 

As simple as it sounds, you might also want to tighten all your hose clamps (heater, rad etc etc.) Someone here also mentioned thermostat housing which is a good thing to check, too. I had this problem on a car years ago (not a Maxima, mind you) and it was simply a loose hose clamp. When the engine was cold it leaked very slightly around the connection. When it heated up, I guess the metal nipple thing the hose mounts on would expand, and the leak would stop.

 

I've look at the thermostat housing and the hose clamps. The only time I get a leak is after the car has sat in the cold all night. Once everything heats up it's fine.

 

BUMP



[QUOTE]Originally posted by blakkrob
[B]I've look at the thermostat housing and the hose clamps. The only time I get a leak is after the car has sat in the cold all night. Once everything heats up it's fine.

 

I had the exact problem with my 95. I had replaced all the hoses and the thermostat, and the leak continued. I finally took the A/C and altrenator off in an attempt to find the leak. It was coming from the back of the timing chain cover. I took it to a local radiator shop and had them replace the water pump and now it doesnt leak at all. In the end i was out $300. Change it now before you cant drvie it anymore.