Disappearing coolant

[malibujeff]

I have a 2000 Suburban with the 5.3L engine. It has 88k miles on it. Recently the coolant light came on. Looked at the tank and it was down about an inch. I filled it back up and a week later it was down again. The cycle continues...

There is no coolant on the ground and I cannot find a leak anywhere on the 5.3L engine. The engine still runs great.

Any ideas? suggestions? Is this problem the intake or the head gaskets? or something else?

Thanks,

Jeff

[adrenalinep]

My brother had the same problem, couldnt see the leak but could smell the coolant. We replaced the water pump gasket and it took care of the problem

[motoxlifer]

Could just be air pockets, but it could be more serious. Take the rad. cap off when it's cold & let it run until up to temp. then add coolant as needed, this should get rid of any air pockets. Check for excessive steam from the exhaust on a warm day and like adrenaline said you can smell it burning too. Smells like pancakes.

[docone882000]

My favorite is when you fire the vehicle up and it looks like a fog machine. It was a party favorite just glad it was not mine.

[Turborado]

In my experience dex-cool tends to evaporate or dry up from engine heat before hitting the ground with a slow leak. the best way to find it is with a pressure tester and let it sit for about an hour or until you can see it dripping. I have seen a slow leaking intake manifold cause this problem a lot, but more before the gen 3 motors. I doubt it is your heads. i would say intake gasket or possibly water pump. see if you can get under the vehicle and see dried up coolant on back of motor.

[RedHeartbeat]

<div class='quotetop'>QUOTE(Turborado &#064; Mar 9 2006, 02&#58;49 PM) [snapback]46544[/snapback]</div>

In my experience dex-cool tends to evaporate or dry up from engine heat before hitting the ground with a slow leak. the best way to find it is with a pressure tester and let it sit for about an hour or until you can see it dripping. I have seen a slow leaking intake manifold cause this problem a lot, but more before the gen 3 motors. I doubt it is your heads. i would say intake gasket or possibly water pump. see if you can get under the vehicle and see dried up coolant on back of motor.
[/b]

FWIW, there is no coolant passage in the intake manifold so count that one out. The only place there is coolant in the intake is in the throttle body if you haven&#39;t done the TB bypass yet.

[malibujeff]

I did the pressure test last night and could not find a leak anywhere. I think it is going into the oil. It is loosing coolant very slow. Over 7-10 days it will loose 1"-2" in the overflo tank.

Where can I get the oil checked to see if the coolant really is in the oil? Any other suggestions?

[motoxlifer]

If it&#39;s getting in the oil your oil will turn milky same with the transmission fluid. I would check the tranny fluid first because it could be getting into the transmission cooler from the rad. tank. The tranny in my truck had to be rebuilt for that same reason.