DIABL0

About every 500 miles I need to refill my coolant. Where is it going? They did a pressure check and it was fine. Wheat needs attention?

TinkersVet

water pump check the weep hole

Mr. Black

If it's leaking that much but it's not in the combustion chamber or oil you should be able to find it on the ground or smell it.

I agree with Tinkers by starting at the water pump. LS water pumps kinda suck.

A leak that bad should be leaving puddles on the floor or ground IMO.

DIABL0

Could it be head gasket?

lewislgZ06

Worst case scenario, Yes.

It has to be either leaking or ingesting it. How much coolant are you adding per 500 miles?

How does your oil look?

DIABL0

Oil is good. I’m adding about a jug

Mr. Black

If it's not on the ground then the cylinders are drinking it somewhere.

mstromquist

Wow, yeah! I would have to think that much missing is going to show up on the ground for sure if a component was leaking. Can you smell the antifreeze at all when you open the hood or whenever you walk around the car? I know you said the pressure check was good but these cars have an issue with the coolant tank getting rotten too. How old is your tank? You have any smoke coming out the tailpipes? You have an signs of anything on the rear-end cover? I know when my tank was leaking I'd get spots on my cover from the coolant. Took me a while to figure that one out.

Vetteman Jack

Moved to C5 Tech.

grinder11

How much is a "jug"???! I'll make this as short as possible (1st time for everything!!).......
I was losing an unknown amount of coolant each time I drove my car. Marked the reservoir with a pencil. Drove it 120 miles, checked the next day, and reservoir was down a good 2-3"!! I was getting ready to pull the heads and buy a couple head gaskets when I saw the problem. The original spring clamp on the upper radiator hose, where it clamped to the water pump, had a red drop under the hose on the clamp. Apparently, the tension was no longer good enough to seal coolant when fully hot. There was no coolant under the vehicle; it evaporated quickly driving down the road. A buck and half later, spent on a new, conventional hose clamp, and no more coolant loss. SO....It doesn't ALWAYS end up on the ground, or in the oil. Make sure ALL your clamps are still good-AND tight!!!! Hope this helps.....

DIABL0

I’m not getting any smells or smoke. I just looked on the ground and there is a massive puddle after a 15 min ride.

Mr. Black

Water pump is the usual suspect. They are a weak spot on LS engines.

feeder82

Coolant reservoirs leak along the seam also. check that over carefully

pjdbm

Also check the throttle body coolant hoses

DIABL0

When I take it to my mechanic what should I tell him to replace?

helga203

First of all don't take it to a mechanic yet. What side of the car is the puddle? Middle drivers or passenger side. Is it up front or under where the sits are . maybe we can boil it down so the mechanic doesn't see a sucker coming a mile away. Go in with some knowledge and they won't hit you as hard.

grinder11

I didn't, either. No puddle, either. It was evaporating before it could drip, and since it was a pressure leak from the pump, it didn't leak unless the engine was running at 2000+rpm.....

DIABL0

Seems to drip near the middle between the tires and puddle to the drivers side front tire

Napoleon_Tanerite

Check the small crossover tube that runs between the heads under the throttle body. A leak there will deposit it on the engine, and it will likely evaporate most of it before it reaches the ground, especially if you're out driving it.

helga203

to me that's seems like the water pump bit there are hoses u can check. Like the one right under the TB there's a 1/4 hose and the hoses from the radiator. Have you checked those. The pump will be a bit Harter to see because it's under the pump where the pulley is. I would jack the front t of the car up support with Jack stands and let it run for how long it takes tell u see it leaking. Then u can spot the leak. Is u have to get under the car if u feel comfortable doing.