I have a 2000 3.0L VIN U with 248000 kms on her. It is acting like I have a head gasket issue however I talked to a mechanic buddy of mine and he suggested a bad fuel injector could be the issue. Has anyone heard of this before?

 

Symptoms would be helpful??

Head gasket issue or cracked head will first show up as extra pressure in the cooling system, which causes full over flow tank and slight over heating, or up and down movement of temp gauge.
Leaking cylinder might misfire on cold start and then start working again.
As it gets worse so will over heating.

To test for this remove rad cap on cold engine, make sure coolant is topped off.
Put rad cap back on
Squeeze upper rad hose, feel the pressure of it, or lack of pressure is what you should feel.
Start engine
Feel upper rad hose, it should feel exactly the same
Idle engine for a minute or two
Feel upper rad hose again, it should still feel soft, no internal pressure
If pressure is building you have a breach from cylinder to cooling system.

The reason a head leak goes to the cooling system is because each cylinder is literally surrounded by the cooling system, no where else for it to go.
The reason it causes over heating is because a cold cooling system has 0 pressure, and a cylinder has 160+ psi pressure cranking and 1,000+ psi when it fires, so some of that "air" is pushed into the cooling system thru the leak, this displaces the coolant in the head, when pressure in cooling system builds up to 14-16psi, rad cap pressure rating, that coolant is pushed into the overflow tank, of course with limited coolant engine starts to over heat, once thermostat opens some of that "air" can escape to radiator and it will stay at the top and it will be pushed out into the overflow tank, and the coolant in the rad will start to flow into the slightly above normal temp engine which will cool it back down, so temp needle goes down.

Exhaust can also show more white smoke than normal, and it will smell sweet, the smell of coolant burning.
If a cylinder leak gets bad enough it will spread to oil drain in head or valley or even an oil passage, and you will get coolant in the oil, the milkshake.

Not sure how a fuel injector could do that??

A coolant leak in the intake manifold could cause the white smoke and misfire on startup, also oil milk shake.
But you wouldn't get over heating until overflow tank ran dry

 

When I start her she idles rough and blows the white smoke, however after warming up the smoke dissipates and the engine runs smooth. There is no coolant in the oil. I changed the thermostat recently because it was floating, would go up to high, back to low and then level out. with the new thermostat temp stays at normal.

 

White smoke is usually a good indicator of coolant getting into a combustion chamber (cylinder). To prove (or disprove) this, let the truck cool, start it, let it smoke, then shut it off. Remove one spark plug at a time, and inspect. If one (or more) cylinders have a head gasket failure allowing coolant to enter the cylinder, the spark plug will be very clean, as the coolant will act like a steam cleaning for that cylinder.

 

I have a 1995 ford ranger 3.0 v6 with a five speed. I just bought is 4 days ago. It ran very well (considering ita age and mileage 160,000) but the second day driving it I heard a pop and the truck lost a lot of power and it started chugging and running very poorly. I read codes and there was a cylinder 5 misfire and a emissions purge valve. But the CEL was on before the motor started misfiring. So I changed plugs wires and the coil pack. Also noticed a brownish tint to the antifreeze. As if they're maybe a head gasket problem. There is still no change in the performance of the motor after new parts. Not that knowledgeable on cars so I need some help here.

 

Nice hijacking of someone elses post! ^^^^^

I'd start a new one of your own, as your question will only get buried in this post.

 

I already did. I didn't mean to post it here. I don't really know what I'm doing. Didn't mean to "hijack" anything