I am catching a slight antifreeze smell whenever I exit my vehicle. It's a 94 4.3 Vortec. I can't find any wet spots anywhere on the engine or hoses, no steam is coming from the engine, and no spot of antifreeze is on my garage floor. I've been keeping an eye on the coolant level for a few weeks now, and it hasn't dropped. I must have a very small leak. About a year ago I completely flushed the entire coolant system and replaced the thermostat. Does anyone have any ideas as to where I might be leaking coolant? The truck is plagued by a slight rough idle. I don't know if a leaking head gasket may be the cause of the antifreeze smell and the rough idle or not. By the way, I just changed oil last weekend, and there is no coolant in the oil. Thanks for any help you can give me.

 

I have replaced my fair share of intake gaskets on these engines, in fact I just did another today. Usually they will leak at the corners. Korey

 

I too, have the same problem and symptoms as you, mine is the intake gasket, the leak just gets worse, there is some excellent links for repair on this site. the estimated time of repair on the links is 5-6 hours. so good luck. I am going through a gallon of mix every 4 days.

 

Wow, that is quite the leak guywm25! You are going to want to get that repaired ASAP!!

I have the leaky intake manifold as well, but mine is leaking out, not in and only enough so that I can smell it. It doesn't really even keep the leak area wet at all times either. I'll put a splash of coolant in every 3-4 weeks. Once it gets warmer out and I start driving my Bonneville again, I'll tear it apart and get it replaced. I already have all of the gaskets and everything necessary, just don't want to deal with it in the cold.

 

Chances are that it's intake manifold gasket if you smell it outside, or a small leak in the heater core if you smell it inside.

I posted a procedure for replacing the intake manifold gaskets in the DIY section. If the leak is emptying outside the motor, you can put off messing with it. If it leaks into the motor oil, then the oil will get grey and frothy and you must fix it or park the vehicle.

DO NOT believe 5-6 hours for intake manifold gasket replacement. The first one took me 20+ hours, and I've been working on cars for 30 years. Next time I can probably cut that to 10-15 hours.

 

The intake is so a 5-6 hour job for the do-it yourselfer. I just did one on a 92 with the cpi motor in about 2.5 hours. Brian this is the same one you have. What makes this intake nicer than the '96 and newer ones is that you don't need to pull the compressor and the bracket off the front of the engine. It is just removing the upper intake, the dist, and then the lower comes off. Of course this is the extremly condensed version. The parts I don't like about this job is fighting with the fuel lines, and the gaskets don't have locating pins and they like to slide around a bit. And then don't forget to set the timing. Korey.

 

Thanks for everyone's input. I'm going to see what I can come up with over the weekend. I will keep everyone posted. Thanks again.

 

This may sound goofy, but before you go through all the effort of the intake, have your battery checked. A battery going bad can smell like antifreeze. Don't know why but they can.

 

The battery is less than a year old, but I'll check that out.