Do I have a bad head gasket?

[Jerryred94silvy]

My '94 4.3 has started blowing wispy white smoke from the tail pipe, it does have the "sweet" smell to it and it idles rough now. However, at one point it would lightly smoke and then go away and did this several times without any noticeable difference in engine performance, now it smokes significantly all the time. Before it started smoking it was losing coolant, but it wasn't leaking or smoking. I cannot see any coolant in the oil, or oil in the coolant. I thought at first it was just junk being burned out of the engine (the truck sat for quite some time before I owned it)
I just want to make sure it is a head gasket before I tear the top of the engine off.

 

[skylark]

Most likely but you can't rule out a cracked block or head without inspecting the head gaskets.

 

[PlayingWithTBI]

try a compression and leak down test before you tear it apart.

 

[RichLo]

X2 to both above, do some diagnostics first before tearing into it. Read the spark plugs as you pull them for the compression/leak down.

There is also a coolant pressure tester that is fairly inexpensive, its just a hand pump that you put onto the radiator cap opening and pump up to pressure with the engine off to see/hear where coolant is leaking from.

 

[PlayingWithTBI]

There is also a coolant pressure tester that is fairly inexpensive, its just a hand pump that you put onto the radiator cap opening and pump up to pressure with the engine off to see/hear where coolant is leaking from.

^^^ That too!

 

[JJDAG]

My '94 4.3 has started blowing wispy white smoke from the tail pipe, it does have the "sweet" smell to it and it idles rough now. However, at one point it would lightly smoke and then go away and did this several times without any noticeable difference in engine performance, now it smokes significantly all the time. Before it started smoking it was losing coolant, but it wasn't leaking or smoking. I cannot see any coolant in the oil, or oil in the coolant. I thought at first it was just junk being burned out of the engine (the truck sat for quite some time before I owned it)
I just want to make sure it is a head gasket before I tear the top of the engine off.

Also tge 4.3 are notorious for intake leaking internal. Make sure your oil isnt contaminated with coolant, coolant is corosive to engine bearings.

 

[xx94Z71xx]

do the compression and leakdown test. could also test the coolant for exhaust, if you have coolant leaking into a cylinder you should also have traces of exhaust in your coolant. i had a bad head gasket that was barely noticeable for months until it went completely. combustion was slowly eating its way through the gasket to a steam hole on the block. just some more advice

btw it passed multiple leakdown tests before it went. i was trying to diagnose small amounts of missing coolant and random air in a sealed cooling system.

 

[PlayingWithTBI]

Same with mine, the only difference was cylinders 5 & 6 were 5 psi less than the other 6 and that's where I found the leaks in the head gaskets.

 

[Jerryred94silvy]

Also tge 4.3 are notorious for intake leaking internal. Make sure your oil isnt contaminated with coolant, coolant is corosive to engine bearings.

If the oil having a greenish hue to it means that there is coolant in the oil, then yes I have coolant in my oil. And I noticed it takes a second after startup for the engine to start running rough and smoking, makes me think it's not burning coolant until it gets pumped through the radiator to the top of the engine or something. Is that indicative of a bad intake gasket? Also should I drain the oil ASAP? Or is a bit less bad if it's just sitting and not running?

 

[xx94Z71xx]

normally when i see coolant in the oil it looks like vanilla milkshake color after its been run for a few minutes. at this point you really need to do a leakdown test on your cooling system. it sounds to me like you have a blown intake or head gasket.