So.....been outta the diesel world for awhile but jumped myself back into a 97 12 valve 5 spd 4x4 recently. Nice truck, 260k miles. Clutch feels good, put a new fuel plate in it #8 ( Previous owner removed ) and have a tick tick tick noise. Crack #6 and noise is gone. Replaced injectors with a set of 80 sticks from Industrial Injection. Same noise. Ton's of power, smokes a little excessive to me, whitish grey when cold and more brown/black when warmed up. May just need to adjust the afc some more....Temp gauge fluctuates a HOLE bunch . lol From cold to 195 or so, then gets less and less as it warms up. BUT......Quite a few Bubbles in the overflow and then the #6 noise lead me to think head gasket. Any thoughts or tips?

Updating sig shortly! LOL

 

Temp swing is normal, probably a cheap thermostat in it. Try a Cummins or premium NAPA Stant ( though my premium Stant still fluctuates some ) Check your valve lash on 6, or perhaps delivery valve is causing it somehow? I would say head gasket is OK unless you are loosing coolant or have a dead miss.

You are gonna LOVE the 97, best year IMHO, just MAKE SURE YOU TAB THAT KDP unless it has already been done, 97's like to bite you.

 

Forgot to add that. Valve lash was the first thing adjusted, and no change in noise. Coolant system was flushed and new NAPA thermostat was installed also. The bubbles scare me. Been driven plenty of miles and time for all the air to have been bled out.

 

Also....I've heard the fuel pumps are notorious for making noise, so the pump, filter and prefilter have all been replaced as well as the water pump and serpentine belt. I can also tell the fan clutch is relatively new as well.I'm guessing the previous owner was having similar issues. I had no history on the truck, so I just started doing anything that I could to get a fresh base line of maintenance items.

 

not sure if AFC controls idle smoke. Think thats more about the gov springs, DV's and injectors. AFC is pre-boost off idle fueling (?)
Noise can be lots of things. Maybe get an oil analysis done to rule out cam lobes, bearings, pushrods, etc.

 

On the thermostat, was it the premium one or did you just ask for a standard one? Napa has 2 levels of quality in their thermostats.

For grins, I would drill a 1/16" hole thru the blade and see if it helps, they are supposed to have a piddle valve to allow a bit of flow.

I still don't think you have anything to worry about unless you are losing coolant, oil, or seeing mixing.

With the compression these things have, one thing is for sure, if you are having combustion pressure escaping it will let you know very soon.

Just another thought, you say tick,tick,tick, could it be a small exhaust leak on #6? Get a mirror and look under it, see if there are any black streaks.......

 

It was the premium thermostat with the jiggler. I even made a point to put the jiggler to the top. I'll look at the exhaust. I never even thought of that. Thanks!

 

bad rad cap could be the bubble blower

 

Well......no leak at the exhaust manifold. Bummer.........seeing some white smoke at startup.......bigger bummer! LOL Can a headgasket leak like that cause that kind of noise? It goes away when I crack the injector line, so I still am thinking rod bearings are ok. I can make the sound change at low RPM's with the throttle. From a tick/knowck noise to a almost "hollow" sound the same pitch and frequency, just "hollow" for a lack of a better term. Any other thoughts before I rip the head off?

 

Not really, I would say I would test for combustion gasses in the coolant though before I ripped a head off......

http://www.tooltopia.com/uview-56000...ricegrabber_r1

One of many places to get a tester.....

 

X2 on the radiator cap, I thought I had a bad gasket for sure got half way into a 1000 mile trip towing and the little bit of coolant left in overflow tank was full of bubbles, turned out new radiator cap was the trick.

As for ticks cracking #6 and the noise going away definitely sounds like injectors but I had a little more smoke then I had hoped for and a slight tick from the lift pump a new OFV fixed it right up!

Good luck you'll love the 97 I am already on the look out for another hahaha

 

OFV was replaced also. Another thing I read about was a barrel/plunger in the pump causing noise. Might try swapping a couple cylinders and see if the noise moves?

 

Seems I have read its fairly common for the lift pumps to tick once they have some miles on them something to do with the pump rod wearing some. Easy trick with truck running depress the primer bulb and see if it goes away.

A tick that goes away when u crack lines would tell me its not related to anything other than fuel , my guess bad pressure, air in the system something like that.

Good luck

 

Noise still in #6 . Swapped delivery valves and holder assy from #1 to #6 .......noise still in 6. Bummed. Also......head gasket may be getting worse......found a little oil in the overflow bottle today. No coolant in oil so far. Bought a used engine to get rebuilt and throw in so I'm not without my truck for very long. Gonna drive it until then. Can't hurt much more than it already has......

 

Pat, just curious, what is the difference between '96 and '97 comparing 5spd 3500 DRW Club Cab Laramie trucks? My '96 has vacuum boost. Does all '97 have hydroboost? Is the '97 cloth interior better? Do some '97 have the 53 block? I have the 887 pump. Seems to run the same as the 913 I used to have in my last '96. Does the '97 have the revised shift tower?