1991 Chev K1500 coolant issue

[otis24]

I have a 1991 Chev K1500 with 4.3 V6 (86000 miles). I just purchased the vehicle a couple of weeks ago. It had a coolant leak. The radiator was wet, so I replaced the radiator and upper and lower radiator hoses, as well as replacing radiator cap. The coolant level continues to drop slightly (down a couple of inches inside the radiator). There are no visible signs of leakage under the vehicle, nor inside. There are no signs of coolant in the oil or vice versa.

After the vehicle has sat, there is a puff of white smoke upon startup. Guessing this is the valve stem seals leaking. The vehicle was owned by my current employer and saw short tripping in town, racking up only a 1000 to 1500 miles per year for the past 20 years. I do hear a lot of sloshing going on under the dash, but there are no leaks inside the cab. Could this just be an air bubble? If it were a head gasket issue, what would be the symptoms?

Thanks in advance!

 

[01rangerxl]

How thoroughly did you bleed it? I would expect an air pocket to have worked itself out after a couple of weeks, but if you haven't been driving it much, maybe not. How many times have you topped it off? Once or twice, or is this a daily thing?

The sloshing under the dash could indicate an air pocket in the heater core...try driving it around warmed up with the heat all the way up.

Any white stains around the water pump weep hole or gasket?

 

[Cardenio327]

White smoke combined with coolant loss sounds like a head gasket or intake manifold gasket to me.

Valve stem seals would produce blue smoke.

The head gasket might be making bubbles of combustion gases in your heater core, producing the sloshing sound. I had a VW Fox that did that.

 

[Clevy]

Puff of white smoke is coolant. Coolant intrusion will kill good bearings quickly.

 

[mehullica]

Pressure test the cooling system & watch for external leaks, or have a your coolant "sniffed" for HC's with a gas analyzer. Sounds like coolant is leaking into the combustion chambers.

 

[Warstud]

The 4.3 is known for bad intake manifold gaskets.
Solution: Fel-Pro Problem Solver Gasket.

 

[Nick1994]

Intake manifold gasket or head gasket

 

[otis24]

I would say that the smoke does have a bit of a bluish tint to it. Did not really bleed the system. The vehicle is driven in town, so it does not see a lot of miles. Perhaps 100 miles per week.

 

[otis24]

I last checked the coolant level about a week ago, it was full then.

 

[Nick1994]

Drain the oil in another week or so and see if it's discolored.

 

[mjoekingz28]

UOA time?

 

[otis24]

Everything seems to be working out. Topped off,melevated right side, and ran with the radiator cap off. Got a few bubbles out. Ive driven about 8 days now and the coolant level hasnt dropped.