2000 2.7L 4x4 with engine code P0300

hey guys,
so i just bought this truck about 1 month ago. It seemed to be in perfect conditon and with a new motor that has about 52k on it. The frame has 157k. So it all started when i was driving home and it started to over heat. I called the owner and he said that it needed a new temp sensor and that it was in the glove box. So i checked and it was there, I drove home which was about 90 miles and the coolant temp needle was on red half the time. Me being a dummy thinking it was just the sensor, i drove home all the way with out checking the collant level.

So a few days later i bought an ultra guage and right when i conneted it, it gave me a engine code of P0300 which is a random/multi misfire. I could only tell the engine was misfireing at the beginning of a cold start, after that it seem to run fine. By the next day the CEL light popped up. I checked the coolant lever and there was nothing in there. I refilled and checked for leakes and found none. One week from then i changed the spark pulgs and checked the coolant again and it was about 2/3 empty. So the next day i checked my UG and it said i have P0300, P0301, which is a misfire in cylinder #1.

I am suspect that i have a head gasket leak into cylinder #1, that is why i am losing so much coolant, and when i pulled the old spark plug from cylinder #1 it looked as if the prong was corroded.

Any insight would be of much help. Thank you guys for your time.

 

Sounds like a gasket all right. The seller likely knew about it
and didn't tell you.

If you are lucky, though, it could be 2 different things.

The coolant loss could be from a leak high in the system,
causing steam, not water, to leak out. This would not be readily
visible like puddles under the truck.

The misfire could just be a bad injector, or ignition.

Not likely though, but I would rule that out first.

Pop the hood when motor is nice and hot, after running a while,
turn if off, and see if you can see any steam venting out anywhere.
This happened to me in a car I had. Took a week or so to lose half the coolant.

 

Mario, I am sorry that you have a problem. Let me ask you this, When the truck was over heating, did you smell any antifreeze smell from the motor ? When you opened the hood, which I hope you did when you got home, Did you feel a lot of heat come from the engine ? Why did the previous owner have that temp sensor and not install it ?
After you added water, and refilled the tank, did the gauge go back to normal or did it stay in the hot zone ? Did the engine ever cool better after you put in the new temperature gauge sensor ?
I know these are a lot of questions, but the answers you give will determine how much of rebuild you may need to the engine to get it back to normal. You will need to do a cylinder pressure check to see if the head gasket is gone. It sounds like it is, but some of answers related to how much heat got to the engine will determine if you only need a head gasket or a head redecked as it may have warped. I am sorry to tell you this, but continuing to drive after it showed hot on the gauge may have damaged the engine.

 

When i replaced the spark plugs, i also swaped #1 and #4 coil to rule it out. So spark is not the problem. Do you think if i did a compression test, it would confirm the problem. ?

 

When i got home i was not able to check the engine out but i was running late for work so i got into my gf car and left. I guess his mechanic bought the part for him but never installed it. He said it had a service prior to me buying the truck. I later added water and it returned to normal. I slso went to change the temp sensor and it did not fit, so i bought a new one and found out that the old one was fine, just the the radaitor needed fluid. My next step is to do a compression test to confirm.

 

Check your engine oil dipstick. See if the oil is a milky white color, and over full. The coolant has to be going somewhere. Either leaking into crankcase, boiling off through the radiator cap and overflow tank, or into the combustion chamber, and being blown out the exhaust.

check engine oil level
check oil filler cap for signs of "milk shake"
cylinder leakdown test (need a special tool for this)
combustion gas tester for radiator (again need a tool for this)

 

haveing the same problem
on a 2000 2.7 i just bought.
could it be thermostat?
mine never goes past halfway
on gauge,but is losing coolant
and hear it boiling in radiator.
any help would be great.
chays