Please help me diagnose burning antifreeze


#1

Hey gang, I just picked up a 1998 Sebring convertible for a steel of a deal. It is however smokeing thick white smoke out the tail pipe. I belive it is a bad intake gasket, but how can I tell for sure??



I do NOT belive it is a bad head gasket as there is no water in the antifreeze, and no pressure in the coolent system with the motor running. The car also does not seem to over heat (I let it run for about 20 min and it never got over 1/2)… Any ideas??



Thanks as always.


#2

PS I almost forgot it does have 135K on a V6 motor… This is not a 4-cyl


#3

A compression test could rule out a head gasket problem. A vacuum gauge, one of my favorite tools, could possibly be used to differentiate.
Examining the spark plug tips could also help narrow it down as coolant will generally have a tendency to bleach the plug tips.

I’m not familiar with the design on this but if they use a throttle body with coolant passages it’s possible that a TB gasket could be leaking.
Fords used an EGR spacer plate with internal coolant passages and sometimes the gasket would rot out due to heat, both from the coolant and the EGR system. This allowed coolant to seep into the intake.
Just a possibility anyway.


#4

You should check out the tool from Autozone that checks for hydrocarbons in the coolant. It uses a blue liquid, which you will have to buy. You put the suction gizmo over the radiator filler and draw fumes through the blue liquid. If it turns yellow, IIRC, then you have a bad head gasket or a cracked head or block. I still think you probably have a bad head gasket.


#5

More Info: While looking in the basement for somthing for my wife, I found a chilton manual I forgot I had for this car. Anyway after looking thrugh this book, I do not think coolent runs thrugh the intake. So I guess I can rule this out. So what else can it be besides a bad head gasket/cracked head?? Where else can coolent get into the combustion chambers??


#6

bump


#7

I had a similar problem with my Toyota pick-up. I was sure it was a bad head gasket, but could not find a break or leak anywhere around the gasket. Since I had it all apart, I had the head tanked, and the valves re-seated. It was after I put it back together that I found the problem. The aluminum cylinder head was corroding from the inside out, and I had a pin-hole leak into the #4 exhaust port. When I probed the pin-hole, it broke open to a major hole.

After talking with some other wrench-turning friends, I wound up filling the hole with JB Weld. That fix is still holding up after 3 years.

P.S. I switched to a 60/40 mix of exclusively Prestone after that.