Loosing antifreeze

[dan34yo]

I have 2000 S10 pickup and im loosing a gallon of antifreeze about every 3 weeks or so. I do not see any on my driveway or any while im driving. None in the oil when i changed it so shouldnt be head gasket. Heater core not leaking either. I will get no heat when i know im low.There is a sweet smell coming from the back of the motor. Where is this antifreeze going?

[mike1224]

do you smell it while outside of the truck or inside? is the carpet wet? thats all i got right now.

[dan34yo]

Very little smell. Smell is coming from the back of engine more. Carpet is not wet.

[pipelinerr]

Originally Posted by dan34yo

Very little smell. Smell is coming from the back of engine more. Carpet is not wet.

could be at intake and dripping down onto exhaust have system pressure tested

[Cam1959]

Originally Posted by pipelinerr

could be at intake and dripping down onto exhaust have system pressure tested

my 1983 s10 2.8v6 started leaking coolant here and there until i stopped following coolant recovery instructiuons to keep rad full . leaving rad coolant level few inches below filler neck with stop leak in there stopped all minor leaks yrs ago. engine temp never goes above 110f. still puts out enough inside winter heat. leaving room for coolant warm up expansion with air space in there stops it forcing coolant out minor gasket or crack leaks.

[tom3]

Just about guarantee it's the lower intake gasket leaking. Real trouble with this is that it might also be leaking inside the engine. GM has a real problem with these engines with the intake manifold bolts that go straight down into the heads, hard to get a good seal on those gaskets. One of the most common failures of all the later V6 engines. See a post on the Blazer forum for full details of a fix for this.

[dmbrisket 51]

tom is partally correct, the lower intake gaskets are horrable on all new gm vehicals, not to do with bolt config. but beceause the sob for an engeneer made the gasket out of plastic and rubber, the split and the rubber blows out and you have antifreeze leaking inside the moter, sooner or later it will mix with oil or hydro lock the moter up, your looken around 650 or so for the job to be done, and its something that is needed or the truck goes buh bya, the good news is the plastic part of the gasket has been replaced with aluminum, so the new job should seal much better, and dont bitch about your blazer, the 3800 that gm uses in lots of cars are reccomended to be changed every 60k b4 the aluminum came out, dont know what/if there is a reccomendation for it with aluminum gaskets

[dan34yo]

Thanks for the replys. Wouldnt i see coolant in my oil if it was the gasket? Now my engine light is on and my truck isnt shifting right. Thanks Dan

[tom3]

When our Blazer started leaking, I checked the oil constantly, no sign of coolant. Only thing I could figure is that the high running temp, strong PCV system, and the Dexcool coolant gets evaporated or something. When I changed the oil it was sure a mess though. I did notice moisture on the under side of the oil fill cap. Now that it's fixed the cap is dry, even with short trip driving.

[dmbrisket 51]

the antifreeze doesnt leak into the oil, it goes into the intake manifold, it can go in the oil, it can leak outside, it can leak into the earl, it can do one, a combination or all of the above, but just because it does one doesnt mean it does the other two, if you do the work yourselfe and understand how the moter, cooling system, and oil systems work, it will make sence when you look at it

[brad66]

I think your best place to look is at the back of the engine at the intake gasket, just like a lot of others have said. it took me a while to find my leak and it was a tired gasket and intake bolots that had slowly backed off. i could smell it but couldn't see it, and then one day i spotted a small amount by the distributor. make sure you use thread sealant on the long bolts that penetrate the block and tourque them in the correct sequence.

[brad66]

I think your best place to look is at the back of the engine at the intake gasket, just like a lot of others have said. it took me a while to find my leak and it was a tired gasket and intake bolots that had slowly backed off. i could smell it but couldn't see it, and then one day i spotted a small amount by the distributor. make sure you use thread sealant on the long bolts that penetrate the block and tourque them in the correct sequence.

[Ventura77]

I just wrote about this on another forum. Do you have the 2.2L? If so, they are known to have head gasket problems. I have a 95 myself and have had the head gasket go out. What happened on mine was that there was a small crack in the gasket between the cylinder and water jacket, and then also between the water jacket and the outside of the motor. Very little actually leaked out the back side of the motor though but you could always see a little trickle way in the back almost right below where the heater hoses go into the heater core. Where the main loss was occuring was right from the overflow bucket. What was happening was that because of where the crack was as combustion was taking place in the cylinder some of the pressure was being released from the cylinder into the water jacket through the crack in the head gasket. It was then pressurizing the cooling system to the point where it would actually push the anitfreeze back out into the overflow bucket. Once the motor got warmed up really well it would push enough back into the overflow that it would actually leak out the hose that goes down to the ground from the overflow bucket. There are two small hoses on the overflow bucket, one carries the fluid to and from the radiator, while the other is just for overflow if the bucket gets too full. When the vehicle starts cooling back down it will draw a good portion of the antifreeze back into the radiator, and you'd really never know that is where it is going. Take a look at the hose that goes down off of the overflow bucket and see if it looks wet at all on the inside, I believe that it comes out near the "A" arm on the passenger side, at least that is the way it is on the '95. Otherwise, try and warm it up good and pop the hood when it is still warm and see how full the overflow is. When mine went it was not leaking any antifreeze into the motor at all which was fortunate, you may have the same situation.