98 k1500 smoke and hard starting help?

[jamesh23]

Hey everyone been lurkin around for awhile decided to register especially cuz my truck started acting up recently, let me give you a little info on my pickup, its a 98.5 OBS ECSB, rebuilt auto transmission,5.7 vortec, cold air intake, 6" BDS lift, on 35s, and not much else, its always ran fine, fired right up and ran with a lot of power, now lately it seems to be losing a little bit of power not a whole lot though just noticeable on the highway and sometimes it almost sounds as if its missing when it first starts at lower RPMS this clears up though, and its really hard to start (cycling the key doesn't seem to help) usually takes 3-5 times of crankin to start. and its started smoking some white smoke with a little blue in it and it smells really rich of fuel, im concerned about the smoke and hard starting and overheating Also the first time it overheated I checked the coolant immediately and it was 1.5 gallons low.. was full two weeks prior and I never noticed spots or smoking before. SO I topped it off and it continued to get hot, I then noticed that my overflow was filling up? so I replaced the radiator cap and it seemed to fix the problem, no more overflow full and no more overheating, then the other morning it overheated again and the coolant overflow was full again... thermostat opened and the overflow drained back to the radiator again, hasn't overheated since but the smoking seems to be getting worse, oil has no coolant in it, coolant has no oil in it, I can't see any obvious leaks. SO far I've replaced the radiator cap, fuel filter, plugs, wires, cap, and rotor just because it was due for a tune up. Trucks got 195,800 miles on it. Im weary of driving it anymore because I don't want to cause anymore damage. Im hoping I can avoid having to rebuild the engine but I'm not afraid to if I have too, just wondering ya'lls opinions?

 

[96Z71ECSB]

Opinion?
Head gaskets and/or intake gaskets.
Coolant is getting into the cylinders overnight and won't let the engine fire until most of it is pushed out.
Once fired, it burns whatever coolant is left in the cylinder (smoke).
Stop driving it and get her fixed

 

[great white]

Head gasket does sound like a likely culprit from you description. Put a pressure tester on the cooling system and see if it holds or leaks down.

A shop can check it if you don't want to buy a tester.

 

[96Z71ECSB]

Make sure the cooling system is full before testing. As it leaks down, you should see bubbles in the coolant overflow tank. That's a sign of a blown head gasket.
If coolant starts hitting the ground, then you've got an external leak somewhere.
A cylinder leak down test will also show if it's got a blown head gasket.
This procedure is usually left to professionals.

 

[great white]

Make sure the cooling system is full before testing. As it leaks down, you should see bubbles in the coolant overflow tank. That's a sign of a blown head gasket.
If coolant starts hitting the ground, then you've got an external leak somewhere.
A cylinder leak down test will also show if it's got a blown head gasket.
This procedure is usually left to professionals.

Small point: pressure testing the cooling system doesn't cause bubbles in the recovery/expansion tank from a popped head gasket, it just bleeds off.

Sometimes you will see bubbles in the recovery tank when it's running if the head gasket has failed.

You will likely see bubbles with a compression leak down test will because the cylinders are pressurized.

I used to take the spark plugs out when using a cooling system test to check for bad head gaskets. Sometimes you can hear the coolant being forced into the combustion chamber. At worst, I could bump the engine over and clear any fluid that had found it's way into the cylinders before putting it back together. You would be surprised how many people just elect to keep driving it after you tell them it needs a head gasket. Even after you explain to them what that means....

 

[96Z71ECSB]

Your right. I didn't write the paragraph correctly.
The "bubbles in the recovery tank" refer to a leak down test.
Good point with the "bubbles while engine is running".

I usually check for bubbles while running then do a leak down test to verify.

I wonder where my head was earlier?

 

[heavychevy98]

You can also start it cold and see how fast it builds pressure. No special tools required and your system shouldn't build pressure when cold.