Hello,
I recently(3 days ago), had the thermostat go bad on my 2002 Ram. I was in town when the temp would spike then drop as the thermostat was malfunctioning, so I stopped and bought a new thermostat and antifreeze. By coincidence, I was about to change the oil, so I replaced the thermostat/antifreeze then changed the oil. The radiator never did boiled over. When changing the oil, it did not appear to have any sign of water being in it, but when I took the oil fill cap off, there was milky cream inside the oil fill spout and on the bottom of the cap. I cleaned all the mess out of the filler spout and finished the oil change. I have been checking my oil level for any increase in volume and antifreeze for signs of oil and the engine temp has been completely normal since replacing the thermostat. Just as I thought I was in the clear, my "Amber Check Engine" light has come on and will not go away. All of the fluid levels are good, all the creamy mess in the filler cap has evaporated, and the engine appears to be running fine. I have filled it with gasoline since, to add another possibility to the mix.

Here are my questions, what should I be looking for now, and can the engine running hot cause water to get into the oil without there being a permanent compromise in a gasket or seal?

Thanks in advance for any advise.
John

 

Sounds like you took care of the overheating problem with the thermostat. Did it actually overheat, or did it get on the warm side and then cool down to normal? Also, I'd recommend replacing the radiator cap.

As far as the milky stuff on the filler cap.....rest easy my friend, as it seems that what you have encountered is simple condensation. If you do a search, you'll find others with this problem. Mostly people in cooler parts of the country and doing mostly short trips, say under 20 minutes. It seems to have been more common on the 4.7L, as far as reports go on the board. There is also a baffle on the 4.7L that can be pulled up and out which can be cleaned too. As long as the dipstick isn't showing milky oil, you're golden. To answer your question, a gasket must fail for water to get in with the oil, well, unless you suck up water through the intake, but that would hydrolock the motor.

Now you mention the gas cap. Damn that evil gas cap. If it wasn't tightened down all the way, do so now and see if the light goes away. You can also do the code retrieval procedure with the key and let us know what the trouble code is. I'll have to do a search to find how to do it, as I forget right now.

Found it Here

 

The engine never did boil over, the temp would spike then drop to normal. I used the ignition key to get a code. I cycled the key on/off 3 times quickly and got P0302 for a trouble code. The engine has started to run rough at start-up, but smoothes out when warm. All the fluid levels are stable and show no sign of contamination. What does the P0302 code mean and could that cause the engine to run rough when cold?

 

P0302 is 2nd cylinder misfire detected. When was the last time you changed the plugs and what mileage are you at now? What maintenance have you performed recently? What motor do you have?

 

It's a 4.7L with 75K miles, I have changed the oil and oil filter regularly, air filter too. The owner manual says the plugs are good for 100K, but the next thing I was going to try would be plugs and plug wires.

 

Are there any particular brand of plugs that work better with the 4.7L?

 

honestly just dont use the cheapo ones that came in the truck they are crappy, a great brand is NGK they have a bunch of levels but i have iridums in my 4.7 and i swear it runs smoother and idles better but only down side is that the plugs are like 7 dollars each.

 

I like NGK as well. I've used thier plugs in just about everything I own.....lawnmowers, boats, atvs, jetskis, etc. They work great and I've never had a problem with them. Never tried the iridiums, but I know thier regular resistor plugs work.

 

I didn't realize the 4.7L didn't have plug wires. It was been such a hassle free ride, I have'nt had to poke around under the hood much and was oblivious.
You recommended replacing the radiator cap. I had already replaced the antifreeze and thermostat before you gave me that advice and haven't replaced it yet. The irritating truth be known, on the way to work this AM, my temperature gage told me I was about to overheat again. The odd thing is that the Amber Check Engine Light has gone away, even though I haven't installed the new plugs yet. I will replace the radiator cap today, I would also like to know what the OHM reading should be on the temperature sending unit? I am suspicious of this because of the speed at which the gage was fluctuating.

Thanks Again,
John

 

I have had the Bosch platinum +4 plugs for 25000 and notice a quicker response off the pedal - I got 1-2 miles per gallon better gas mileage after putting them on as well.