Last week on a long highway trip I noticed a knock in the engine under acceleration. Only 30k on this truck and I'm thinking it is a rod knock. I looked under the oil filler cap and see a milky film. Now I'm thinking a cracked head or blown head gasket. The next day I take it up to my brother in law who is a mechanic and I don't notice the noise and when he checks the filler cap, no milky film. I had filled the truck up on my trip with a brand of fuel I don't normally buy as my brand was not handy. Could what I was hearing have been the result of bad gas causing a spark knock?

Sign me perplexed and concerned.

 

rescueranger

I have a '94 Ranger with about 87,000 miles on it. I just purchased it about a month ago. I also have a knock or what sounds like a pre-ignition ping at highway speeds and under acceleration. I have done a complete tune-up and still have the ping. The motor is real strong, lots of pep. After doing some research I came across a Technical Bulletin Which address this issue. Apparently, 1990 to 2000 Rangers can develop what they refer to as a Carbon Knock On Acceleration with the 4.0L engines. I'm not sure if this might be what is starting to happen to your Ranger, considering only 30k on it. But I'm not sure at what milage such a problem might start to surface. They refer to it as a customer drive duty-cycle phenomenon that cannot be repaired with an engine exchange. They say this may be caused by carbon build-up within the combustion chamber. There are other issues that might cause similar symptoms, but this might be a poss. issue to address. They further state to NOT use a higher octane fuel to try and remedy this problem as this can increase the probability of carbon build-up. they do explain in the Bulletin how to diagnose this prob., how to de-carbon the combustion chamber to quiet the knock, as well as give tips on driving habits that might prevent and help keep the carbon from building up again. You might want to check out the technical service bulletin. There is a link on this site " Recalls/TSBs" that will likely direct you to such info. The Bulletin under Ford Truck Ranger V6-245 4.0L - Engine-Carbon Knock On Acceleration Article No. 01-19-7

I hope this helps and Good luck.

KF rescueranger

 

Hmm...not using higher octane gas is a new one to me. Actually though, Ford recommends the 87 or 89, whatever the lower one you normally see at gas stations is. Hehe, don't mind me, too early in the morning. As far as brand of fuel, make sure you're not using cheap stuff like some 7-11 brand or something. Too much water and crap in the gas. I know, probably stepping on toes with that but honestly now, isn't a $20,000 truck and engine worth the few extra cents to go to like Chevron or Texaco and get better quality gas? To me it is. I remember that one store, and to this day no one knows how the major screw up was made, but they were literally selling jet fuel as regular unleaded gas. Another 7-11 type store. Personally, I'd say every once in a while go ahead and run the higher octane fuel for a tank full. It cuts down on the pinging you hear and cuts back on pre-ignition.

Another thought with the pinging is to once in a while get yourself a bottle of some kind of fuel system cleaner additive and dump that in with the fuel. It might help get rid of the pinking by cleaning out the system. I know, 30,000 miles isn't a lot but the cleaner can keep everything the better off. But be careful on how much/how often you use the cleaners. Some have lead in them and will ruin the 02 sensor and on the newer vehicles, when the 02 sensor goes, gas milage goes down hill in a hurry too. Depending on how much you want to spend, could put in an ignition system (MSD, Jacobs, etc.) and from what I've read, that will cut down on the pinging too at all RPM levels.

As for the milky film under the oil filler cap, think I'd ask what kind of oil you're using. I've read and heard of some synthetic oils foaming or something to that effect and wasn't good for certain engines. So thats a thought. Hopefully this will help you and hopefully you wont have anymore problems once you figure out what route you choose to follow. Goodluck.

James

 

If you put high octane fuel in an engine that does not require it the gas will not burn clean and will cause a carbon build up.


>Hmm...not using higher octane gas is a new one to me.

>
>James

 

You might want to check out the post by NightRanger1999 Titled: "Cure for the dreaded Pinging, Knocking and tapping engine. It's just a few posts back. He had a similar issue with his truck. One thing you might want to think about is that you still have some miles left on your 36k Warrnty. His had just run out. You might want to take it to your local Ford Dealer and see if it is something that is covered? It ended up costing him around $600 + out of his own pocket. Warranties can be a beautiful thing, and when there gone, It's a whole nother world !!
Anyway you might want to take a look at it

Good luck,

Kelly
rescueranger