4.7 dodge sludge issues

-
1970 La

1970 La

Well-Known Member
Joined
Dec 25, 2010
Messages
633
Reaction score
30
Location
princeton mo
Anyone know of the cure for the sludge issues that are burning up these engines? I have the chance to buy a 2002 4 door Dakota with 120.000 miles on it but the motor is gone. 1000.00 seems like a fair price but would hate to put in another engine and have the same problems.
 
Yeah in fact, I do. The cause is the oil pump pickup is too small. I know about it because we just talked to a Jasper Engines rep about the 3.7 in a Jeep Liberty we have at the shop now with the same issues. They are the same engine except for the number of cylinders. Jasper actually puts a larger oil pump pickup in them. How or where they get them I don't know, but it's worth some research.
 
Hey thanks I'll keep looking. Sounds like this has made a lot of unhappy dodge owners to bad they didn't fix this I am sure they were aware of the problem.
 
I've never been impressed with either engine. The 3.7 is a turd that won't pull a greasy string outta a cat's *** and the 4.7 gets crappola for mileage. Not to mention the sludge issue. Worst thing they ever did was stop the 318 and 3.9. Dumbasses.
 
StrokerScamp said:
I've never been impressed with either engine. The 3.7 is a turd that won't pull a greasy string outta a cat's *** and the 4.7 gets crappola for mileage. Not to mention the sludge issue. Worst thing they ever did was stop the 318 and 3.9. Dumbasses.
Click to expand...

Bingo! Thank You!
 
How does the pick up tube being "too small" cause engine sludge?
How does anyone know if there is excessive sludge in an engine?

We have a 2000 Jeep GC with 4.7L V8. Has 130,000 miles on it, and aside from replacing a starter we haven't touched it. It's my wife's daily driver.
Oil gets changed every 6500 miles. We average 18MPG with my wife's heavy right foot.
 
The sludge issues come from a lack of oil changes i have seen several at work that have 150,000 + on them and no sludge issue at all but like stroker said it's not that great of an engine I get better fuel mileage with my hemi 1500 than the guys do with the 4.7L.
 
No this sludge problem comes from overheating the engine oil. It's something to do with there not being enough diameter for the oil to flow properly and it gets too hot in the pickup tube and that's where the sludge starts. We've talked to the local Chrysler dealer, Jasper and the local machine shop and they all concur. As does the factory Chrysler TSB.
 
How can the oil in the pickup tube get hot enough to sludge? The oil in the pan is probably the coolest oil in the engine. If anything, the oil gets cooked in the heads around the exhaust valve area which the hottest spot in the engine. It's also the area where the oil has to drain back down. The passages get blocked with coked oil and slow drainback, causing further oiling issues. I'd love to see the Chrysler TSB.

We have 3 4.7s in the family a Grand Cherokee with 85k and 2 Durangos with 130k and 160k. No problems. Just change the oil every 3k miles and they'll be fine. I know of at least 3 others with no issues, one of which has over 200k.
 
Look, I'm just the messenger boy. I don't give a flying fig if you believe it or not. I don't remember what all the guy said, but the way he explained it, it made perfect sense. Something about the oil supply is inadequate because of the small pickup and it causes the oil to overheat and sludge up. The 3.7 is much worse because it's an overworked turd to begin with. I'm tellin you, the guy knew what he was talkin about.
 
Mr.Ed said:
How can the oil in the pickup tube get hot enough to sludge? The oil in the pan is probably the coolest oil in the engine. If anything, the oil gets cooked in the heads around the exhaust valve area which the hottest spot in the engine. It's also the area where the oil has to drain back down. The passages get blocked with coked oil and slow drainback, causing further oiling issues. I'd love to see the Chrysler TSB.

We have 3 4.7s in the family a Grand Cherokee with 85k and 2 Durangos with 130k and 160k. No problems. Just change the oil every 3k miles and they'll be fine. I know of at least 3 others with no issues, one of which has over 200k.
Click to expand...

3K oil changes are a myth. There is no manufacturer that recommends it. Jiffy Lube started all that back in the 70s and the lie spread. Chrysler, recommends "no longer than 6K intervals" and Ford recommends 5K for "severe service" and 7500 for standard service. You're wastin your money. Waste away.
 
It's called friction.. you flow any substance though a passage of restricted diameter and the speed of the flow increases, the volume decreases and the temperature of the flowed substance increases. It's possible the oil exiting the tube into the pump is moving too fast for the pump to deal with which could lead to an oil supply problem, more friction, and the possibility the pump might be heating the oil up even more, if the rotors are being force-fed more oil than they can deal with..
Just a thought.
Maybe an engineer will chime in here eventually.

Alan
 
StrokerScamp said:
3K oil changes are a myth. There is no manufacturer that recommends it. Jiffy Lube started all that back in the 70s and the lie spread. Chrysler, recommends "no longer than 6K intervals" and Ford recommends 5K for "severe service" and 7500 for standard service. You're wastin your money. Waste away.
Click to expand...

Maybe, maybe not. I'd rather pay for a few more oil changes than a replacement engine. I'm aware that the manufacturers recommend 5k intervals. That's what I recommend to most of my customers, but on an engine that's prone to cooking the oil, I'll stick to my 3k oil changes. Still waiting for that TSB... :smile:.
 
Mr.Ed said:
Maybe, maybe not. I'd rather pay for a few more oil changes than a replacement engine. I'm aware that the manufacturers recommend 5k intervals. That's what I recommend to most of my customers, but on an engine that's prone to cooking the oil, I'll stick to my 3k oil changes. Still waiting for that TSB... :smile:.
Click to expand...

Look it up. I had to go to the dealer for it.
 
alan627b said:
It's called friction.. you flow any substance though a passage of restricted diameter and the speed of the flow increases, the volume decreases and the temperature of the flowed substance increases. It's possible the oil exiting the tube into the pump is moving too fast for the pump to deal with which could lead to an oil supply problem, more friction, and the possibility the pump might be heating the oil up even more, if the rotors are being force-fed more oil than they can deal with..
Just a thought.
Maybe an engineer will chime in here eventually.

Alan
Click to expand...

With all due respect, if that were the case then the oil should really heat up on the pressure side of the pump, not the suction side where the pickup tube is. You're assuming the pump can't accept the amount of oil coming from the tube when just the opposite is true. The reason for the larger pickup tube is more volume. That's why a lot of guys drill & tap the B/RB engines for the larger hemi pickup tube... more volume.
 
2005 Jeep GC 4.7 135000 plus oil changes every 5000 or so and this has been a great vehicle. It has nice power and we got 20 mpg+ with a cargo topper to Florida and back last Thanksgiving. I really like this vehicle and the only reason I might consider getting rid of it is our 9 month old 120+ pound St Bernard. She is getting a little big for the Jeep. Picture is when we returned home after a 2200 mile trip.
 

Attachments

  • WK home from Florida.jpg
    57.4 KB · Views: 467
You must log in or register to reply here.
-

Back
Top