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Engine/Transmission (1998.5 - 2002) Discoloration on used 1998 5.9 L Diesel? I'm new looking for help.

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Engine/Transmission (1994 - 1998) engine issue

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Sorry if this is in a thread already. I am brand new to here. If I should have posted somewhere else, please let me know and I will start getting the hang of it. I am looking at this 1998 Ram 2500 with a 5.9 L diesel. I thought I read somewhere to beware of orange-ish coloration on diesel parts. On this picture on the left of the engine, right of air filter, is that the turbocharger? Should it be colored orange like that? This has 120,000 miles on it. I appreciate whatever help you can provide. Thanks.
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Yes, that is the turbocharger. The orange colored part is the impeller or "cold" housing. Why is it orange? It looks like there may have been some sort of preservative oil or cosmoline on the entire turbocharger assembly that "burned" some when the impeller housing got hot. Even though that is the "cold" side of the turbocharger that housing will still get hot enough to do something like that. If that's what it is, its an indication the turbocharger has been replaced and the replacement turbo was covered in preservative oil or cosmoline.
 
Thanks CJMEYER1. No rush but if you don't mind, how long do turbochargers normally last before needing to be replaced? What happens to them so they eventually need replaced? Is buying a used truck with a replaced turbocharger good/bad/in between idea? I appreciate your insight. Shopping for first diesel, never had turbocharger either.
 
The more new parts the better, in my opinion. There's nothing wrong with a new turbo on a used engine or truck any more than there's anything wrong with new tires. If the old one is worn out or failed, you replace it. How long a turbo lasts depends on a lot of factors. The most important being how good of a part it is to start with. The good OEM turbos like Garrett, AirResearch, Holset etc will last pretty much forever if they're properly "used" and maintained. There are OTR trucks out there with over a million miles on the factory turbos. The most common "failure" of a high-hour turbo is wear in the bearings that allows the impeller or turbine to start wearing against the housing and/or excessive shaft endplay. Both of those "failures" are usually due to cold starts, hot shutdowns and poor overall engine maintenance and operation.

When I needed a cheap turbo in a hurry I bought a 450,000-mile stocker from a mid-90s Dodge on ebay for $200. I then proceeded to beat on it pretty hard for at least 40,000 miles running up to 40 psi of boost and at least 10 psi pretty much continually at highway speeds. It's still in one piece. The engine is still in one piece but it's got a knock in it now. It was always very slow to build oil pressure at startup as long as I've had it, and I think the slow oil pressure and continuous boost did damage the engine. But not the turbo - it would still smack the boost gauge needle to 40 psi even after the knock started. Good oil and a little common sense in letting a turbo warm up and cool down properly is all it really takes for good turbo reliability.

That said, I wouldn't go to the extreme of the 5-minute "cool-down" timer a lot of guys run on their trucks. If you just spent several minutes at or near full load and boost before shutdown, then yes, a 5-minute cool-down is a good idea. For day-to day-use where the engine probably never even gets to FULL operating temp to start with, having your engine idle for 5 minutes before it shuts off is a waste of fuel. 20 to 30 seconds is MORE than enough for those situations.
 
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Pull the intake tube off between the air filter and the turbo and run your clean finger around the inside of the intake tube. Is it oily? Dirty? It should be dry and clean.

Hard to tell but it looks like an oiled air filter element, if your finding even a small amount of grit in the intake tube I would avoid that truck all together.
Under normal circumstances a turbo charger should last hundreds of thousands of miles. I would ask the owner why it was replaced.

What happens is people install aftermarket air filter and don't know how to properly clean and oil the filter and it passes dirt, which in turn will destroy a turbo and dust an engine in short order, wiping out the piston rings and calling for an engine rebuild. This is worst case scenario but it has happened so frequently that Cummins does not recommend the use of oiled air filters at all.
 
The orange is burned clear coat. Cummins clear coated the engine after assembly. The charge air has been getting too hot, suggesting egt's have been too hot. The engine could have internal damage such as scuffed pistons and cracked valve seats. Also, the K&N filter indicates that the engine could have "dust out" meaning the dust that gets past such a filter will over many miles result in worn rings and cylinder walls, worn ring lands in the pistons. That translates to blow by and oil usage. I would definitely pass and look for another Ram.
 
Note the difference in the color of the exhaust manifold v/s mine. That one has been very hot. Mine is still grey at 232k miles with some mild power mods, 335hp/852tq. I don't baby it either.

Nick

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One of our May Madness guys had his clear coat burned like that but thought he was safe because he kept egt to 1200-1300 I forget which. He roasted #6 iirc, and had to rebuild the engine.
 
Oddly enough that engine that has supposedly been way too hot doesn't even have all the exhaust stud spacers rusted. It doesn't look like all the paint on the cylinder head is burned off adjacent to the exhaust ports.
 
Those are probably new spacers. The old ones probably were lost when the bolts fell out from heat cycles. There is a retainer that was made available to hold the bolts from moving - addressed in a TSB.
 
I wonder why my cousin's manifold bolts have never fallen out of his 24-valve after 300,000+ miles of hauling fence materials, firewood, skid-steers, tree shears, etc. Must not be enough heat cycles yet.
 
Couldn't tell you on that one, but some did fall out. That's why there was a TSB to install retainers. A couple of mine loosened up once and I re-torqued the bolts and added the retainers. No problems since. I use it harder than some, easier than others. Since the spacers in the picture are not all the same color, might be that is what happened, but I guess it's hard for anyone to know for sure unless you were the previous owner.
 
It's hard telling with that one. Just looking at where someone put the pyro stinger you can tell a real "expert" has worked on it in the past.
 
It looks like a mixed bag of things going on there. The location of the pyro stinger makes me wonder more than anything else I see. I always get a kick out of how so many guys are obsessed with EGTs yet not obsessed with getting a true EGT reading.
 
Yeap, my 2001.5 came OEM with the retainers. Someone might think the Pyro probe was miss installed. However with the divider in the exhaust manifold one has the choice of installing it in the front runner or the rear runner. Given the the rear cylinders run hotter that location was the standard that many of us followed for years. Now maybe we are again learning that we did not know how to do yet another job on our trucks. How did we ever manage? Chris
 
Placement of the pyro probe has been a subject for discussion since before this forum was opened. The best numbers for health of the engine will be achieved pre-turbo. EGT's are generally within spec if the fueling is stock, even after 300,000 miles.
 
I'll stick with where the OEMs put their EGT sensors. I tend to think they know what they're doing. Can you provide EGT "specs"?
 
That is the problem with placement in the exhaust pipe--there are no real specs. Engine mfg. give a max egt coming out the exhaust ports. The turbo uses some of the heat, reducing the temp by the time it gets to the downpipe. A rule of thumb is 10 deg. per psi boost, but that only works within the maximum efficiency range of the turbo. For example, an HX35 at 35 psi won't give a temp difference of 350 deg, it could be 400-500 deg, meaning that you get a false sense of security when you see a resonable temp at the probe mounted in the pipe. This has all been discussed 10-15 years ago. Post turbo placement was supposedly to keep a broken off probe from killing a turbo. The only probe I killed was post turbo, from a broken off turbine wheel eating it. At the time I was struggling to find a turbo to keep egt's down, and put the probe in the pipe to get some sort of reading other than pegged. There is no reason to do this today with all the tubos available to us.
 
I've seen pictures of Cat 3406E engines running on the dyno with the entire manifold and turbo turbine housing glowing orange/yellow. What does that tell YOU about where to measure EGT? It tells me that measuring it in the manifold ahead of the turbo is pointless.

The fact that this was "discussed" 10-15 years ago means very little to me. The "science" on "global warming" is supposedly "settled" too. That EGT rule of thumb is so far off what's commonly seen it's completely useless. 900-1200 degrees F is commonly seen in OTR trucks under heavy load at rated speed. And that's a foot or more behind the turbo. Like I said, the turbo is an engine component and until the exhaust gas has passed through it, it's not actually "exhaust gas temp". Then there's the fact that a stinger mounted in a thick, cast-iron manifold upstream from the turbo is heavily insulated and is going to retain and read more heat than is present and is only subject to the airflow from PART of the engine. Which is going to cause it to read artificially high.

I'm also not sure how you have a "rule of thumb" relating boost to EGT. Boost pressure isn't a measurement of heat quantity of the intake air or even load in most automotive-type diesel engine applications. Without a steady load AND a steady boost pressure reading, you can't use boost to determine engine performance. And like usual, no one is addressing the fact that in an overfueling situation (if you're blowing black smoke the engine is being overfueled and more fuel is being injected than the engine can efficiently burn), any reading you get ANYWHERE is going to be made completely useless by the fact that there's actual COMBUSTION happening around the stinger itself.

I'm sorry, but I'm not the "conformist" type when it comes to subjects like this. Especially when someone wants to make vague and ambiguous references to past "discussions" as evidence that their opinion is correct. 50 years ago it WAS common to see pyro stingers UPSTREAM of the turbocharger. Especially when the engines were aftermarket turbocharged or factory turbocharged in an "add-on" fashion. In those engines, EGT was used to protect internal engine components from overheating because the cooling and lubrication systems were marginal for turbocharging. A lot of those engines didn't have piston cooling nozzles to direct engine oil onto the bottom of the piston crowns to cool them, they didn't use super-heavy-duty exhaust valves and seats and some had very little if any engine oil cooling capacity. The primitive fuel systems, some of which had no air-fuel ratio control, meant that it was relatively easy to melt down an engine.

The M&W add-on turbo kits for farm tractors back in the day come immediately to mind. You see pyro stingers in the manifold on those. If you wanted to go "whole hog" you could buy the big aluminum oil pan and new radiator fan and "do it right" and crank them up a little hotter than with just the turbo alone. Most guys just put the turbo on and used a pyro to keep things "safe".

Maybe we should just cut to the chase and the REAL reason so many guys put the pyro stinger in the manifold instead of the downpipe? It's a lot easier to drill and tap a hole in the manifold than it is to weld a bung into the downpipe.
 
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Does your medium-duty engine in your light-duty pickup get this hot? If not, you're overly obsessed with EGTs in the first place.

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