My truck is a 2003 Ram 1500 4x4 4.7 with 112,000 miles. I just bought it in January and have put 6K miles on it.

Check out these two pictures. One shows the driver side above cylinder #3 and the other is the passenger side above cylinder #6.


Here is the situation:

Last Saturday the radiator burst and the temperature got to just shy of the red before I shut it down. I replaced the radiator on Sunday and test drove around the neighborhood. All was fine.

Drove it to work on Monday and after about 10 miles it started running rough. I am a roof salesman so I was in the truck all day. It ran very rough at low RPM in overdrive. By turning off the overdrive it ran at higher RPM and ran ok.

Later during the day it started running rougher and rougher while losing power. By the time I got home it was very sluggish. It starts and idles fine with no noises. Revving the engine in neutral also produces zero abnormal sounds or vibration. I have codes: P0442, P0456, P0300, P0301, P0303.

So far I've checked the oil and antifreeze for contamination and both are fine. I know the 04 codes are emissions related (the hose to the EVAP canister is cracked...it blew off and spit oil all over the underside of truck. I have repaired this) and the 03 codes are misfiring cylinders.

What do you think is the cause of the burned spots on the valve cover and what would be your best guess for my power loss? Thanks in advance.

Jerry in Batavia.

 

Unfortunately if the 4.7 has an Achilles heel, it's the fact that it cannot withstand even a relatively mild over-heat. Aluminum heads just simply don't handle much heat without warping.

I'm guessing you've got a head gasket issue at best but probably some warping in the heads themselves...

 

Thanks for the reply. I'm going to pull the valve covers tomorrow.

This is my 2nd 4.7. My 1st is in my 99 Grand Cherokee. It has given me 202,000 trouble-free miles.

I'll post up what I find.

 

Good luck, I'm hoping it's not a head issue, but I'm afraid it sounds like it.

I've got the HO version in my '02 GC Overland. It's pretty stout just prone to oil sludging and overheats absolutely kill it. Keep it from doing either and it'll last a long time...

 

Have you ever seen burnt marks like those? That is new to me and I've been a hobby mechanic since the 80s.

 

I was going to say all of the same but Hammer beat me to it. The VC is interesting though. Cant wait for you to pull it so we can see the back side.

 

Yeah post more pics please

 

Nope, I've not seen burn marks like that, but I'm not a mechanic by trade, just an old, Georgia farm boy, shade tree mechanic. LOL...

 

I've got good news and bad news....

Good news is for me because the truck is running perfectly!

Bad news is for the suspense...we are going to have to wait to see what caused the burn marks.

Turns out that when the antifreeze blew out of the seam in the radiator it soaked the top of the engine on the driver side. I knew it had gotten wet but I didn't anticipate the problem it caused. Normally the o-rings around the coil packs keep water out of the sparkplug hole but this time cylinders 1, 3, and 7 all had a little antifreeze get passed. This caused the plugs to misfire.

The plugs were obviously original so I ran down to the parts store, purchased oil, filter and plugs and I'm back on the road none the worse for wear. I've driven it approximately 50 miles since the repair and so far so good.

I'll post up when I finally decide to pull the valve covers.

 

Was the coolant in the plug well only or past the threads where the plugs screw into the headas well?