Yesterday we had snow accumulations of 6 inches and I was 4x4'in all day on the roads. Decided to change my PCV valve before going out to cruise. Been out for probably 3 hours with the truck and then I had decided to get on it down a really snowed in road that probably had about 8 inches of snow, then for about 2 miles I averaged 45-50mph down the road and never once touched 190 degrees (I have a 180 t-stat), The truck seemed to handle it all great, tons of power and fun times, anyway when I pulled out from the stop sign it felt very lagged trying to get going and the motor made a loud roar much like the old 80's 360s with a Thermoquad did when the 4bbl opened up, it wasn't anything like its ever sounded like.

I then made it back to town and put it in 2wd and everything seemed normal so I figured it was my transfer case binding or something to do with the 4x4 as a unit. Slowly but surely the truck felt more & more gutless until I decided to pull over and check it out. I popped the hood and the engine was dead quiet, but it was running, absolutely no sound coming out of the motor or tail pipe but it was idling rough at 300-400 rpm and it refused to rev over 1500rpm before cutting out. I pulled into a hotel to shut it off and inspect it for anything obvious for about 3-4 minutes, got back in and turned the key to find that it was pushing about 230 degrees on the temp gauge after not breaking 190 the whole night it was running. Because of the quietness of the engine I thought I had wiped some exhaust lobes off of my cam so I decided to pull the valve covers in the hotel parking lot and found that all the valves opened and shut normal and all the push rods were intact and not bent and no metal shavings on the dip stick.

So once I got the valve covers back on, my dad finally arrived to tow me and I started it and he said "damn it sounds normal, what did you say was wrong?". The engine idled great and normal and the sound returned to the exhaust pipe....WEIRD!. Then within a minute it was bogging again and becoming quiet.

I always figured that maybe I had the typical cracked head, because for the 2 years I've owned the truck I've added a quart of antifreeze every 3 months and no leaks anywhere to be found in the engine bay. Back in April of last year I noticed a kind of sweet smell out of the exhaust pipe along and intermittent white smoke that looked like condensation...(never really noticed it in summer). Lately the exhaust has smelled kinda weird but the engine ran like a top.

Today I disassembled most of the top end of the engine, found the oil to be slightly milky and tomorrow I plan to pull the heads and see what I find, if I see a blatant head gasket failure I'll feel so happy! because I'm trying to save up for a 2005 Hemi Rumble Bee Ram and I don't feel like buying new heads out of my saved funds.

I do have a video from the time the engine started making its abnormal roar, and I also have a video to show what the engine normally sounded like while getting on it. I will upload those to this thread in a few minutes.

Here's a Video of my motor what it sounded like running normal....


And here's what it sounded like at the exact time I noticed something was wrong and not normal about it.

 

Sounds like a failing cat to me.....

 

Done your plenum?

 

^ Says so in his signature!

 

Wow that's a left field kinda thought provoking assessment I'll have to check into. I was thinking I'd just cut it out of there anyway one of these days prior to this incident, but that does kinda make sense and I may be doing some exploratory surgery on the cat if the head gasket I'm putting on today doesn't do the trick. Seems like after the truck sits 10 minutes or so it runs & sounds normal...after it warms up a minute then its back to choking on its own rhythm.

I've got 20,000 miles on it since the plenum fix & tune up, I'll be redoing everything minus the short block when I'm taking the heads off. I almost even wanted to buy Roller Rockers for this build but I'll wait with those.

 

GAAAA!! Dangit..small print gets me every time....

 

My torch $hit the bed on me so I'll have to wait till I'm done with work on Sunday to chop my cat off the truck & check it out.

Whats the consensus everyone...do you think I have a clogged cat?

I tapped on it yesterday while trying to torch it off and it was rattling, so I think HeyYou is probably on the right track on thinking the cat may be to blame. Would make sense why it runs great for 20 seconds then won't rev over 1500rpm and becomes dead quiet.

Also the rear #7 & #8 plugs were wet & smelled of gas and the rest were dry. I guess that's better than smelling like anti freeze!. Other than that, the rest of the plugs had a nice tanish color to them, so I'm hoping to cut that cat off & find a clog.

 

Pull your front o2 and disconect it, then take it it for a drive and see how she feels before you go cutting the cat off. Sounds like a clogged cat to me but you say youve got milky oil?

 

Sounds like a good idea! I shall try that!.

As for the milky oil, I now think it was just condensation, because the milkyness was just on the bottom of the oil cap, I should have clarified that, I pulled the dipstick today and the oil looked normal and was not milky at all nor was the level any higher, its due for an oil change regardless but the oil looks like "normal" 4500 mile overdue oil, I shall also keep an eye when I drain the oil for any water deposits when I first uncork the drain plug. The coolant in the radiator looked vibrant green.

Was threw me that it might be a head gasket was the fact that after it had sat without running for 5 minutes the temp gauge showed it at or about 230 degrees with the engine off and just key on and I had never gone over 190 degrees the whole time I was driving it and actually running the engine. Also the last 5 minutes of driving it I didn't even crest 1500rpm or 20mph so it wasn't working very hard prior to this temp shift. The exhaust smelled a little off for the last few months but the engine ran great and the truck would run a good 8.5 to 9 second 0-60mph and never overheated or went past 200 degrees the whole time I've owned the truck.

 

Well, thats the thing...the engine block is actually hotter than the water so when you shut it off it stops flowing and it'll go up 20-30 degrees after a few minutes until another ten or fifteen minutes passes and it starts coming down. I concur on the cat, sounds just like it, the throttle plate is too far open, it's dumping fuel (your wet plugs) and the fact it idles way down after 20 seconds or so.

I probably wouldn't just "cut it off" replacements are about 200 bucks and can save you trouble with cops if they ever decide they'd like to write you tickets for the hell of it (yes it's an insta-fine, modifying/removing emissions equipment is a 50 state crime, they can even take your truck in some states)

Also, unless you plan to replace the pipe...don't torch it off, makes it brittle when you torch AND weld the same area on something that already gets hot and cold on a regular basis, makes for a cracked weld...Just nip it off with a sawzall and be done with it.