Coolant leak??

[rndsommer]

Have an 01 5.3 Tahoe LS with 117k. Coolant light came on when I parked on an incline. I just figured it was the sensor as the passenger side was quite a bit lower than drivers side. Low coolant light went off when parked straight but it was a little below the fill line so I topped coolant tank off. Put about 600 miles on the truck and noticed coolant tank was low again but not low enough to bring warning light on. It took about a quart to bring it back up to fill line. Oil looks fine, oil cap looks clean, truck running well, not running hot or any strange smells or exhaust changes. Stamp under oil fill tube is 862. I know there was a problem with Castech heads cracking but correct me if I'm wrong the Castech heads always have the 706 stamp?? Im going to change the oil and keep exact measurement of any anti freeze I add. I'm hoping it was just some air in the radiator. Can anyone shed a little light on the topic. Thank you.

 

[Opalelement]

If I remember correctly Castechs can be 862s or 706s, but the 706s are the ones that crack. Or maybe I have that mixed up; 706s can be either Castech or another manufacturer, but only the Castechs crack. Either way it's less likely to be your issue, but it isn't too hard to check; about half an hour from start to finish for me to check both of my heads.

You might want to check your water pump; because of the arrangement of the fan shroud and the skid plate/splash guard I never saw a single drip on my driveway, but the water pump and its gaskets were both gone. The weep hole is underneath the pulley so the easiest way I found to check it was to shove a clean paper towel into the bottom part of the pulley after driving a bit to build pressure; about 10min later pull it out and see if it's dry.

 

[Maximus1]

I agree ^^ usually it's the pump. Easy fix even for a novice mechanic.

One other thing, if it has a rear A/C-heater is to check it as well. Open the rear hatch and check for coolant leak on the passenger side. Remove the side plastic cover and should see the whole unit. Then remove the plastic cover over the heater core. It should be the big cover closer to the front of the truck the other is the A/C. Take a look at both sides of the heater core and the lines connected to it.

 

[Maximus1]

The connections are outside underneath.

 

[rndsommer]

Coolant was down about a pint 2 days after last post...about 75 miles. The oil looks like it is getting a little creamy looking but I might just be a little paranoid. Only 2k on the oil but it looks a little thicker than usual. My mechanic gave it a once over and didn't see any visable leaks anywhere. He said he could do some dye test so that's the next step. Thanks for the info

 

[RED TAHOE LS]

Ralph, don't forget to check the radiator cap, often overlooked and can loose coolant while driving. Can't blame you for feeling paranoid, lets hope not. JMHO and good luck.
David g.

 

[rndsommer]

It was a great truck....moved on to a 2015 Silverado. Thanks for all the advice fellas.

 

[MrBalll]

It was a great truck....moved on to a 2015 Silverado. Thanks for all the advice fellas.

Well, went from 0 to 100 real quick. Congrats on the new truck.