Can someone please help me narrow down this problem. I picked up a 1999 Blazer with a 4.3 Vortec a few months ago and I have had to top off the coolant way too many times and it is not leaking externaly anywhere. I have googled this subject and cant find any straight forward answers. I suspect head or intake gaskets but the symptoms call for white and sweet smelling exaust/ coolant in the oil and overheating. Mine never overheats, there is no apparent coolant in the oil but there is signs under the oil fill cap, no white smoke but I do smell collant while its running at opperating temp.
I have heard that these engines are natorious for this and that there are updated gasket kits for these engines but I cant find them. I have to put nearly a gallon of coolant in it every couple of days so obviously it's going somewhere. Not on the ground and not all of it is going into the engine as Im pretty sure with that much loss the oil would be foaming. Must be burning it right? Wouldn't that be a blown head gasket?

 

Do you check your oil level?
Does your windshield fog up when you first turn on heater?
I suggest you drain a little of your oil first thing of the day and look for coolant in it.
Do the engine have a miss or run rough when you first start it in morning?

Not unheard of for it to go both into intake runner and cam valley.

Oh.. if you want to find an 'up to date' gasket set for any car, just search the engine and 'fel-pro'

 

Welcome to the Blazer Lower Intake Manifold Gasket Forum. A gallon every 2 days is quite a bit to be invisible but not out of the realm of possibilities. Since you haven't fried your engine the head gaskets are most likely OK but a compression test would confirm it. Since most of us here have changed the intake gasket at least once it's the most likely culprit. What can happen is you develop a small coolant leak into the valley of the engine that evaporates rather than dripping into the oil. Have no fear though as one of these days that little drip will turn into a gusher and there will be no doubt as to it's source. Numerous guides with pictures or video will guide you through the process...or you can shell out $600 to a garage.

 

Oil level goes down slowly but very slowly, I've only had to put a half quart in it in the last couple months, seems like it would go up/over fill if it were going into the oil. Could it be that the coolant is just not mixing with the oil and staying sepearte from the oil and thats why you cant see it on the dipstick? Yes it does idle rough (sometimes) at initial start-up. Windsheild does not fog up, not the heater core. I can not figure out for the life of me why there are no obvious signs as to where its going when it loosing as much as it is.

 

Thank you, I'm a wrencher through and through and a bit of a tight wad so I will be doing the work myself. Do you know of a gasket kit that is designed for this problem? I've heard that felpro has an updated gasket with a metal base for these engines and this problem.. True? Where do i find it?

 

Well.. maybe that's not fair, in context. You may not actually know there are two classifications of repair parts:
Service Grade
and Professional Grade

Service is what you buy and install when you just want to get the vehicle away from you.. or you think the owner might not mind paying for again a few months later.

Professional is what you buy when you dont want to do it again. Or have to warranty your work.

Now.. considering that the original cheap-*** gasket was installed with precision robotics to the tightest of specifications.. and the replacement will be installed by one guy in a driveway.. perhaps distracted by insects..
Then yeah.. you go in the parts store and ask for what you want.

It is NOT a specific problem fix, it's an engineered upgrade for a standard part.

 

When my LIM gaskets started to go on my '04 Blazer, the coolant went out the tailpipe. No visible leaks, but the coolant was getting away and leaving a nice spray of condensation-like liquid all over the passenger side rear brake caliper and inside of the rear wheel. Actually fooled me into thinking the brake caliper was leaking, but the brake fluid lever never dropped.

FelPro is the way to go. Best write-up I've seen on LIM gasket replacement is here:

How To Replace Intake Manifold Gaskets On A GMC Jimmy 4.3 Liter V6 To Fix A Coolant Leak - GM Truck Engine Repairs

 

Please make sure you are positive your overflow tank has no cracks and radiator cap is good before thawrasik surgery.

 

Oh I'm well aware of the differences in repair parts, as much as I like to wrench on things I will not be getting my replacements from AutoZone..lol
When I do things like this I always go the extra mile to make sure the chances of me having to do it again are slim.. I usally get parts from proformance and specialty sites found on the internet. Simple external parts I have from time to time been known to get parts from walk in parts stores.

 

Im actually going to drain the oil to see if there is any in there before I go any further and then replace the rad cap. I do believe ther is also a chemical test you can do on your fluids to see if they are contaminated.