Where's my Antifreeze going?

MyZ71 offroad · November 23, 2001

Guys, I've had my 93' Z71 5.7 w/121,800 miles on it for about 6 months now. I've had to put about a quart to quart and a half total of antifreeze in my truck, at different times.

I know that doesn't seem like alot, could this have something to do because the old owner just changed and flushed the antifreeze before I bought it? I just recentely noticed it when I started using my heater. I checked the floor in front of the passenger seat and it's dry. (heater core area) it's not dropping on my garage floor. Anyone have any ideas! The white smoke out my exhaust is only when the motor is cold, and it does go away when the truck is at temperature. Give me some ideas Chevy/GM guys & gals.

Thanks for the Help.

Brian

mikeb · November 23, 2001

Unfortunately it sounds like a blown head gasket, coolant leaking into the compustion chamber. You see the white smoke on start because the coolant leaked in when you shut it down. Hope you don't have a cracked head or block. Take the truck to a radiator shop and they remove the radiator cap and put a 'sniffer' into the coolant that detects any gases leaked back into the coolant from the combustion chamber. I hope I'm wrong though. A lot of times they'll do this test for free, or charge 5 or 10 bucks.

Also look in the performance forum, there are some posts concerning anitfreeze leaking from the heads, but you stated you didn't see any leaks, might want to check it out.

Mike

MyZ71 offroad · November 23, 2001

MikeB, It's not like white antifreeze smoke when starting it.

It's the water vapor that occurs when cold meets hot combustion chamber sorta thing. There's no antifreeze "sweet smell", and the plugs are dry and light brown as toast! I'm thinkin my water pump might be ready to take a trip south, and only occasionally weeps out the weep hole. Does this sound logical? I mean if it was a head gasket don't ya think it would smoke all the time, and you could smell it too? I had a head gasket go in a aluminum headed Pontiac....and when that one went there was enough white smoke to kill the mosiquto's in the neighborhood. And like my earlier post a quart, to quart 1/2 in 6 months. If it continues at that rate I'll just put a $1.50 in the darn thing every once in a while.

Brian

Shaners · November 24, 2001

Check all your fittings and hoses. It is possible there is a small leak that drips on something hot and evaporates (maybe around the thermostat housing?). With 120K + miles it is certainly posible your water pump is worn out... Also check for small puddles in brackets and framing. If you don't find anything it could be a head gasket or cracked head. Carefully monitor your oil to make sure it isn't a little milky or actually increasing in volume (ie. coolant in the crankcase...).

95 Silverado · November 24, 2001

I had to replace the intake manifold gasket and heater hoses on my '95 5.7. the intake leaked at the ends at the water crossover and the hoses were leaking at the quik-connect fittings, they didn't leak alot, you could just see the stains on the engine where it seeped out. If the back side of the intake gasket is leaking it would be difficult to see.

MyZ71 offroad · December 10, 2001

How much would a shop charge me to change the intake manifold gasket? How much did you all pay to have this done?

Thanks,

Brian ???

CapnDean · December 10, 2001

WHOA Nellie!

Remember...check the simple stuff first!

Check your overflow jug. Does it have a leak?

Full radiator, warm vehicle expansion blows coolant into the jug. Jug leaks down VIOLA. You lost coolant while you were away from your driveway. Come home...no leak in driveway....radiator has already achieved it's "hot level".

So you add some and lose it in the same way each time.

If your head gasket was leaking you'd know it. If your water pump is leaking you will see it at idle in driveway. (Wouldn't hurt to change water pump anyway at 120K miles assuming it's original.)

Least but not last. Check your oil. Is it foamy? Are you "making oil?"

Betcha you got a 'simple' problem rather than an expensive one!

[Least I am hoping that for you too]

bassdog · December 10, 2001

I have to agree with the Capn on this one. The owner before you flushed and refilled the system, more times than not, in my experience, you never get the whole system full in one shot after flushing. A quart isn't too much to be adding after a flush.

You'd notice if you had a leak in the manifold, white smoke all the time.(Blown two head gaskets and warped heads myself)

Fill up your overfill and keep an eye on it. Also keep an eye on your oil.

How long has it been since you added any antifreeze?

bassdog

MyZ71 offroad · December 13, 2001

It's been about a month now since I've added any antifreeze.

The coolant seems to be about where it was when I added it last month.

But the pulley around the waterpump where the serpentine belt goes around it has a little sheen to it like it might be letting some antifreeze past the shaft. Is this possible?

I'm thinking of replacing the waterpump with a new one because of the 122,000 miles. I'm sure it's done it's job and pumped over a million gallons LOL.

Thanks for the responses guys, I thought that if I had a intake manifold gasket problem I would be able to tell by the oil and the smoke.

The oil is fine, (getting a little dirty after 2,000miles) but seriously the orignal owner ordered this truck and it was his baby for 8 years! And I trusted him when I bought the truck that nothing was wrong with it. Heck the first thing he told me about the truck when I asked him if he had to replace anything he said "I screwed the tranny up around 50,000 miles pulling some snowmobiles withOUT being in OD." So I know the owner was trustworthy.

I'll let you all know how the waterpump job comes out.

Brian

kctrading · December 23, 2001

Easy way to know if you are throwing coolent out the exhaust! Start it up for 10 seconds and tasted the water coming out the exhaust...if it taste sweet like coolent you've got a problem...if it takes like nasty water you're ok.

You could also do a chem. block...also I've seen trucks that leak at the back heater hose connector but not enough to drip on the floor.

Also...I've used Aluminum Seal $2.00 (ground up aluminum) in the cooling system to get rid of little head gasket leaks and it works really good. Also did you know that the factory puts in sealer at the factory...true!

Ken

Ex GMC Master Tech