My 98 12v is spewing coolant out of the overflow bottle. No oil in the coolant and no coolant in the oil.

Headgasket?

Oh what could it be????!!!!
Really do not want to have to do a hg this weekend....

MM

 

Sounds like a correct diagnosis to me.

A leak between the combustion chamber and a water jacket.

Start with a cool engine, top off the radiator, fire it up, let it run a minute or so, shut it off and pop the radiator cap.
If you have pressure.....you have a problem.
If not, it could be a small leak that shows itself after the engine is hot and everthing expands.....Either way, you have some work to do.

 

How long does it take to do it? Could it be as simple as a thermostat? Try the simple stuff first! You can also get a block test kit. Some parts stores will rent them. Make sure the coolant level is low and put it in the radiator neck. Then use the little bulb and pull some of the air thru the fluid and if it turns green.............your original diagnosis may be correct.

 

I would do as vzdude suggested and check the thermostat.

 

Also, if you overfill the overflow bottle there is no place for expansion when it the coolant gets hot and it will "spew"

 

Or the cap.

 

Ok, thanks guys. Good suggestions so far.

here is how it started.

Left the house this morning, air temps a bout 28*F forgot to plug in. Stumbled on start up and Idled rough for the first 2-3 mins. Waited a bout 10 mins till I took off. Didn't get boost over 10psi and I noticed a cloud behind me... not the wonderful Black soot kind but a white one. Stopped and popped the hood and had coolant flowing out of the bottle. Engine was not up to operating temp yet turned around and went home to park the truck. The temp gauge did not get to the 190* mark.

thanks agoin. am going to pick up a coolant system pressure tester tomorrow... May have to buy the sucker... no one seems to have one to rent here.

MM

 

Well, now that we get the Paul Harvey ( rest of the story! ) , given the cloud of smoke along with the other conditions, yes......I'd bet on a headgasket.

 

I'd also bet on the headgasket

 

I am an optimist. Noting that it was 28F outside, it could be as simple as a frozen coolant system. If the white smoke came out the tail pipe, head gasket. If it was just a big plume of steam that could be from the engine heating up with a huge restriction in the radiator (Ice). The pressure exceeded the volume constraints of the system (Radiator, expansion tank and block are all sized based on heat load of engine). Pressure goes up with no place to go, exceeds cap spring pressure and blows all your coolant out the overflow into the bottle.

I would also check the coolant for temperature capability (there is a coolant tester (five ***** in a mini turkey baster) that is avail at any auto parts store (Cheap) that will indicate based on antifreeze to H2O ratio how cold your coolant will go before freezing.

 

For the coolant to freeze with an overnight low of only 28F, it would have to be pure water. I would hope Moparmax would have mentioned it if he wasn't running antifreeze.

 

Nope no frozen coolant... I live in Alaska.... you never run just straight water or straight antifreeze. After -15* a few weeks ago it would have done it in then.

Thank you for you ideas and help gents.

MM