Best Way To Desludge This New-To-Me Dodge Dakota w/4.7L V8?

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Hello all! New member here with my inaugural post. I've been an occasional lurker of these forums for some time, after having first stumbled across them some years ago while searching for the ideal oil to run in my vehicles when switching from conventional to synthetic. I come to you today with a specific oil-related scenario in which I could use the expertise of the collective hive mind.

About a month ago, I picked up a 2002 Dodge Dakota SLT Club Cab 4x4 with the 4.7L V8 SOHC engine and 104,000 miles on the clock. Since purchase, I've done a lot of reading online in the course of researching DIY repairs for some of the mechanical imperfections I inherited from the previous owner. In the course of so doing, I've stumbled across many threads related to the dreaded oil sludging problem in the Dodge 4.7L V8's, often attributed to the smaller-than-normal oil drain passages in the block. I don't have any maintenance records from the previous owner(s) of my truck, but judging from the way various things have been cobbled together under the hood, it hasn't been maintained by the book. That said, the previous owner (who owned it for only 8 months) did recently perform an oil change with Mobil-1 5W-30 synthetic and some Lucas Oil Treatment, which has only a few hundred miles on it at this point and is still fairly clean.

Partly because I'm a perfectionist and partly because I plan to use this truck somewhat heavily for business purposes, I wanted to find out what condition the engine internals were in and whether I have any sludge build-up or cause for concern regarding the oil pickup tube becoming clogged and starving the engine of oil, as has happened to many others. I read that one of the best and easiest ways to do this is to either remove the oil fill tube from the passenger side head or pull off a valve cover entirely. I therefore took a look down the oil fill tube the other day and could see a light, dried coating of sludge on its sides:

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After removing the oil fill tube from the passenger side cylinder head, I found quite a bit of soft goop at the entrance to the head and began to fear the worst:

[Linked Image]


However, upon pulling the passenger side valve cover things didn't look quite as bad as I had thought — the only true "goop" was located at the entrance to the head from the oil fill tube. The cam and rockers have a light coating of varnish with concentrations of light sludge in nooks and crannies, but there's not much that you could pick up with, say, a Stanley screwdriver. Below are some photos:

[Linked Image]


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While the exposed topside of my passenger side cylinder head looks far better than many of the sludged 4.7L V8 engine photos that I've seen online, it also looks quite a bit dirtier than some others I've seen which are more or less spotless. I'm thinking I more or less managed to catch this engine before it managed to accrue too much sludge to make it possible to clean it all out. I did run a borescope down each of the oil return passages in the head, and all of them are currently clear with no signs of restriction.

Sludge Removal Process
This brings me to the second part of my question — I'd like to clean out my engine of any and all existing sludge as best as I can now so I have peace of mind. I usually run Pennzoil Ultra Platinum 5W-30 Synthetic oil and Fram Xtra Guard synthetic filters in all of my vehicles, and strictly manage change intervals by vehicle duty cycle. I feel good about my ability to prevent new sludge from forming if I can just start with a clean slate.

I feel that now would be the perfect time to flush my engine, as the oil pan is rotting through and leaking anyway. I have plans to replace both it and the oil pump pickup tube, with the assumption that the screen on the oil pickup may be somewhat blocked. If my planned flushing were to disturb any hardened particles that would manage to stop up the oil pickup screen entirely, it shouldn't be a problem since I need to drop the pan anyway. If at all possible, I would like to clean out the engine as best I can before installing the new pickup tube and pan.

I've done quite a bit of reading on the topic of cleaning agents, and have found a host of different products / solvents recommended:

1) Automotive Transmission Fluid — I've read many recommendations to add a quart or so of ATF prior to an oil change, then let the vehicle idle for an hour or so prior to draining the oil. However, I've also read that ATF can soften rubber seals and cause leaks and that Marvel Mystery Oil will work just as effectively while serving as a better lubricant, making it a somewhat safer option. If I do go this route, what type of ATF is recommended?

2) Auto-RX — Read lots of glowing reviews on this product here on the forums, with many claiming its cleaning performance is second to none. However, I've also read posts claiming that Auto-Rx has employed paid forum posters to shill for their product, that they've changed the formulation and patent four times in twelve years, and that the owner of the company is a real piece of work. On top of that it appears to be a slow-cleaning formulation — the instructions state that it works slowly over several oil changes. This makes this a questionable fit for my application as I'd like to clean out my engine now, but the truck currently isn't road worthy.

3) Diesel — I've seen #2 diesel recommended plenty of times to be used as a one-quart oil substitute an hour or so before an oil change, much like ATF. Some claim that diesel is what most "engine flush" products are based on, anyway. The upside here is the low cost on a per-oz. basis compared to other products, but this seems like it would be one of the more aggressive solvents with low lubricity that could possibly do some damage if you weren't extremely careful.

4) Kerosene — This is probably the second-most recommended product I've seen for cleaning out severe sludge immediately, second only to ATF. That said, the pros and cons seem to very closely mirror those of diesel. Low relative cost and immediate results, but low lubricity and the very real potential for engine damage if not used judiciously.

5) Marvel Mystery Oil — One of the most popular "snake-oil" additives for all types of things, MMO doesn't get rave reviews when it comes to sludge removal as it is a very mild cleaner. I get the feeling that it's more on the "protective lubricant" end of the spectrum as opposed to a cleaning solvent. That said, it's cheap at $3.88/quart and is recommended as being less harsh than ATF / Diesel / Kerosene and therefore lower risk. Likely won't provide immediate results, but will work slowly over time.

6) Pennzoil Ultra Platinum 5W-30 Synthetic Motor Oil — Pennzoil's Ultra Platinum is one of the most highly regarded synthetics, even more so than Mobil-1. Some say that it is so high in detergents that it is basically equivalent to an engine flush. It has significantly more detergents in it — Boron, in particular — than does Pennzoil's Platinum-grade synthetic, making it better at combating deposits.

7) Sea Foam Motor Treatment — Sea Foam is one of the most popular cleaners, with many stating they've obtained good results. However, others state that it's so thin that the cleaning agents likely dissolve quickly with engine heat. Another con is that the instructions indicate that it should be run at least 100 miles prior to an oil change for most effective results. It doesn't sound as if it works as immediately as ATF / Diesel / Kerosene.

Final Thoughts
Based on the above photos, how severe is the current sludge condition of the crankcase and valve train, and what product and process would you recommend for removing it? I am planning on tackling a fuel system and throttle body / combustion chamber cleaning separately, so this question is primarily intended to focus on solely the crankcase and valve train.

Since I'm not positioned to actually drive my truck for hundreds / thousands of miles during the course of an engine cleaning, I'm leaning away from Auto-RX, Marvel Mystery Oil, and Sea Foam. The more immediate results of ATF / Diesel / Kerosene are more appealing, and since I can afford to stop the cleaning if need be to drop the pan and clean the pickup screen, that con of the more aggressive cleaners becomes less of an issue. I likely won't rely on Pennzoil Ultra Platinum alone for the initial cleaning, but will be running it as my motor oil of choice after the fact.

It's also worth mentioning that I am currently performing a piston soak with Marvel Mystery Oil in an effort to free up some piston rings which I believe may be slightly sticking in the ring lands based on the results of a recent compression test. Once the 32 oz. of MMO has finished draining down past the rings into the crankcase, I could run the engine for awhile in an effort to see if it will perform any significant cleaning before draining it out.

I would be very interested in hearing recommendations on not only which product you would use in my situation, but what ratio of cleaner-to-oil to use, how long to let the engine run during the cleaning, and at what intervals you would swap oil filters during the flush. Thanks in advance!
 
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Run a treatment like sea foam for 15 mins at idle before dumping it, and switch to basic high detergent conventional/syn blend like pennzoil yellow bottle and go 3k interval. Slow and sure.
 
ATF should NOT be to be used at all. Delete that immediately from your list.

MMO is essentially snake oil and will not clean your engine appreciably better than any name-brand oil.

Based on the pictures in the OP and the fact that you say the M1 w/ Lucas oil looks clean, I'd hold off on any harsher cleaning methods until you pull the pan and see how clean things look. The sludge you show in your pictures at the dipstick hole may just be an area where oil doesn't flow, combined with too long of an OCI. That doesn't immediately mean that I'd start a harsh cleaning, but would keep an eye out for signs of oil starvation, just in case.

I'd simply recommend that you maintain an appropriately shorter OCI and cut open the filter to see what's in there after a few thousand miles.

I'd also like to hear what you find when you replace the oil pan, as well as what your rate of oil consumption is.
 
Aren't 4.7's known for dropping valve seats? maybe I'm thinking of a different engine.

IMO I'd just leave alone. The top didn't look too bad, and the rest of the truck is an unknown. Some short OCI's and just drive it.
 
Unless you plan on tearing down the engine, I would do nothing and not use any chemical to attempt to clean the engine. It's possible to dislodge a lot of sludge, plugging an oil passage and ruining a bearing. Seen it happen several times. I would do several 2-3k oil changes and be done with it.
 
Rather than add something to thin the oil I would look for an ultra premium 0W20 with a good dose of Gp5 base. This should insure you get good flow to all parts and even semi restricted passages. The flow rate will increase but your oil pressure may decrease a bit. The gp5 should help dissolve varnish and maybe thin the sludge so you dont block anything. You will get more mechanical cleaning because of the increased flow.
 
the Best Cleaning will be done by motor oil in use. if it were me, I'd do a couple short oci's with a store Brand Synthetic(Meijer/Supertech/Orielly/etc), after which YOUR standard oil change sounds excellent.
keep on, keepin' on.

My Boss traded in a Jeep Commander with the 4.7 last year. it had close to 200K, that Car Replaced a Dak Similar to yours he bought back in his Army Days in upstate New York. it had Similar high Miles @ the end, but the "Tin Worm" had consumed Far too much of the body.... he always had both of 'em changed at the Valvoline IOC next to the store... probably maxlife and their jobber filters.

Don't over think it.

now on the other hand, My Brother has an 07, with the HO 4.7, with only 47k mi. It does a LOT of Sitting...anymore it gets driven once a week in Mowing Season towing his mower to the Lot he owns half an hour away... Maybe I should suggest/offer some syn to him...
 
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I'd say your plan of running PUP 5W-30 is a good one. Just run that oil at 5K intervals and you can cut the filters open and inspect them to monitor cleaning progress.

An engine flush, I feel like, is risky.
 
I read somewhere that SOME of the OLD FORMULAE of transmission fluids had the legendary cleaning power you're seeking but no longer.

At 104K I'd go with the "gentle cleaning" crowd. Do whatever you have to do given the Lucas product is already in there.

I'd just add Techron in the fuel and drive it normally.

I just remembered your rotting oil pan. How along is it? Maybe, before you replace it, remove the valve covers and have at cleaning.

Rinse the scuz down into the pan. Open the drain plug for an hour then begin the pan replacement.
 
1) No ATF.
2) From the pics I dont see sludge, more Varnish.
3) If you get it perfectly clean..its going to run basically the same.

If it were mine i would run Pennzoil Yellow Bottle and a basic Fram and cut open the filter at 2K just to see where you are on the cleaning.

Save the money and worries for other repairs on that 18 year old truck. Drive it.

Also focus on the PCV system and inspect all.. get those oil vapors out.
 
Not bad at all. No real sludge. I'd use mobil 1 high mileage as its claimed to be a cleaning oil. You could run a 10w 40 with kreen for an oci. But really there is not much there, compared to the late 70's 80's sludge.

Just good oil changed regularly will do a lot.

NO ATF.
 
Complete waste of time taking that engine apart IMO.

That oil fill tube is open to atmosphere, causing the "sludge" issues you found. This is why you'll see "sludge" on the oil cap sometimes. It's completely harmless, and Dodge had a TSB regarding the issue back in the day.

I'd focus more on cooling system maintenance than anything else with that motor. One slight overheat and they are done.
 
Run the 5W30 Pennzoil Ultra Pure Plus paired with your Fram Ultra for the great filtering. As mentioned earlier -- run some Techron Complete Fuel System Cleaner in the gas per bottles instructions and a new OEM PCV. Good luck and keep us posted!!!


Dale
 
Being a Mopar person I've always liked the old Dakota pickups but everyone I knew that had one got just terrible fuel mileage. I can put up with the 4-15 mpg in my 440 Fury bit not the 10-12 in a Dakota.
 
I'd change the oil, put it out on the highway for a good 30+ minutes and give it an italian tuneup, park it idling, put 1 qt diesel in, let it idle another 15 minutes, then drain HOT, giving it an hour to get every last drop out, then refill with your long term oil choice and then use a regular OCI.

If you're ambitious enough to drop the oil pan and check the pickup filter and clean sludge out of the pan right after the diesel flush, that would be best.
 
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If this was mine, i would run any sn plus or diesel spec oil and call it a day.

i see no reason in those photos to pull anything apart in that motor to clean.
 
Originally Posted by sloinker
Being a Mopar person I've always liked the old Dakota pickups but everyone I knew that had one got just terrible fuel mileage. I can put up with the 4-15 mpg in my 440 Fury bit not the 10-12 in a Dakota.


Here's what mine gets. That includes towing as well.

4.7L/5-speed manual/4x4.

[Linked Image]
 
Thanks to each and every one of you for the input and advice, guys! I hold both this forum and its members in high regard, and you certainly didn't disappoint. Consensus appears to be that the sludge condition of my engine isn't all that bad in the grand scheme of things, with which I generally agree. For sake of reference, you can find some photos of a well-maintained valve train from the same engine with slightly more miles on it at this link.

The idea of attempting an engine flush was primarily driven by the fact that these engines are known to plug up easier than most, coupled with the fact that I need to replace my oil pan due to it being rusted through and leaking fairly severely — even after an attempted patch job. Since dropping the oil pan involves some combination of dropping / removing the front axle as well as the steering rack, it isn't a job I want to have to do again anytime soon. My thought process was that if I could flush the majority of that varnish / sludge down to the pan prior to going to all of the trouble of removing it, I would feel comfortable with my regimen of PUP oil and Fram XG filter changes to catch the remainder.

It sounds like most don't recommend the use of ATF, so I will likely scrub that from the list. Many also recommended using PUP and some frequent OCI's to clean out what varnish buildup I do have. Will the detergent package in PUP alone dissolve varnish? I figured it would help with sludge, but was unsure of its effectiveness on much else.

The "gentle clean" approach recommended by the majority is definitely more within my comfort zone than any form of engine flush. I guess I didn't realize just how much cleaning power today's synthetics actually have.

Originally Posted by supton
Aren't 4.7's known for dropping valve seats? maybe I'm thinking of a different engine.

You're on the money with this one. From what I've gathered, the 4.7L V8 SOHC is a great engine with two disclaimers — they require frequent synthetic motor oil and frequent OCI's to avoid sludge buildup resulting in a loss of oil pressure, and the heads are vulnerable to dropping valve seats if overheated.

Originally Posted by john_pifer
I'd say your plan of running PUP 5W-30 is a good one. Just run that oil at 5K intervals and you can cut the filters open and inspect them to monitor cleaning progress.

An engine flush, I feel like, is risky.

This sentiment more or less mirrors my own. I feel that an engine flush could be risky (I've never done one), and would definitely be more comfortable with the plan of action you are suggesting.

Originally Posted by oilpsi2high
Complete waste of time taking that engine apart IMO.

That oil fill tube is open to atmosphere, causing the "sludge" issues you found. This is why you'll see "sludge" on the oil cap sometimes. It's completely harmless, and Dodge had a TSB regarding the issue back in the day.

I'd focus more on cooling system maintenance than anything else with that motor. One slight overheat and they are done.

If my oil pan didn't already need to be replaced, I would more than likely not be considering any type of flush at all. But since I DO have to go to all the trouble of dropping it, I thought perhaps now would be the time to give the 'ole 4.7L a bath.

I've read a lot about the location of the PCV valve and oil fill tube resulting in the condensation and "sludge" build-up, along with the TSB you referenced. Makes sense.

Cooling system maintenance is definitely on the docket — new radiator, thermostat, hoses will be going in soon.

Originally Posted by gathermewool
I'd also like to hear what you find when you replace the oil pan, as well as what your rate of oil consumption is.

I will certainly update this thread with any steps I do take regarding an engine flush, as well as photos of what I find when I drop the oil pan and oil pickup tube / screen. Should be within the next few weeks.
 
Originally Posted by supton
Aren't 4.7's known for dropping valve seats? maybe I'm thinking of a different engine.

IMO I'd just leave alone. The top didn't look too bad, and the rest of the truck is an unknown. Some short OCI's and just drive it.


Get them even remotely hot....And they will drop a valve seat!
 
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