2003 Dodge Ram PU 4.7 105,000 miles. My oil pressure dropped to zero. After shutting off the engine it was normal again. This happened one more time, then the pressure was irratic when accellerating. No overheating. Engine did not seize.Ive just learned this is a common problem due to sludge - though I've changed oil regularly. What to do now?.... Im going to have the oil pan and screen dropped and cleaned - and a new oil pump. Anything else? What about the top end? Ive had a faint rocker arm tick for awhile but never gave much thought to it. Help.Mike B
Hello and welcome to Just Answer!
The first thing you should do is get the oil pressure checked with a mechanical gauge!
We need to verify the pressure is actually dropping. This could be something as simple as a oil pressure sensor.
The only reason these engines sludge up is from the lack of maintenance(oil and filter changes). Anyone who changes oil and filter every 5,000 kilometers will not have a problem with sludge. The ones that go 10,000K and over will have problems.
Are you sure the tick is coming from a lifter and not an exhaust leak? A lifter will make a tapping noise and not a ticking noise.
Let me know! Thanks,
When I pulled over, I cut the engine and restarted it . I lifted the hood and noted the engine was running rough and "ticking/knocking" louder. This told me the engine was not getting oil on the top - and I shut it off again. I started it later since I was 5 miles from anywhere. The pressure then showed normal this time the engine sounded and ran normal.
I changed the oil 3 days ago and did see a piece of sludge drain into the pan. Other web sites have posts from other owners who have had problems when oil was changed per guidlines. Im concerned I have sludge blocking the intake/oil pump due to these indications. To be honest i probably went 4k-5k between changes but not ignored.
The only time we have seen an engine sludge up in our shop is when someone doesn't change oil at our recommended intervals which is every 5000 kilometers. The recommended mileage intervals in the owners manual in my opinion is way too high.
Short trips should have the oil changed even sooner.
You will find many cases on the internet about Chrysler engine sludge problems and the people that write these articles are the people that don't change there oil. We have never had an engine failure due to sludge on any of our customers that come back to us for their regular oil changes.
If you heard top end(lifter) noise when you started the engine and had no oil pressure showing on the gauge, then it is very likely the oil pressure did drop.
It sounds like the pressure relief valve in the oil pump stuck and that is likely why you had a pressure drop off.
It is very possible that the pickup tube could be restricted, but why the intermittent oil pressure drop. If the pick up tube was restricted, it should gradually lose oil pressure over time and then have low oil pressure. I have never seen a pickup tube plug that fast.
Have you owned the vehicle since new?
I have owned it since new.
Let me clarify my experience - after resuming my freeway driving the pressure stayed normal. Once on city streets the presssure would drop during excelleration so i would let off the pedal and the pressure would rebound to normal...kind of like something (sludge?) was being sucked into the pick up tube then released?
As I know there is some sludge there - since I've seen it ...I'll own my responsibility and be more diligent going forward.
Is there a risk letting someone run an oil pressure check with a mechanical gauge and seizing the engine? I've been reading too much online I guess.
You won't hurt anything when checking oil pressure as long as there is more than 5 psi reading on the gauge. If you don't have any oil pressure within 5 seconds, shut the engine off immediately. The minimum oil pressure at idle in gear is 4 psi. The oil pressure spec at 3000 rpm is 25 - 110 psi. If you have low oil pressure at idle don't check it at 3000. Typically I see 25-40 psi at idle and 50 - 80 psi at 3000 rpm on a good engine.
That is really strange that the oil pressure would decrease when you accelerate and increase when you decelerate!
I would suggest checking the oil pressure first. Then I would drain the oil and get someone with a borescope and insert through the drain plug hole to inspect the pickup screen and the bottom of the oil pan to see if there is sludge. I have a snap-on borescope and it works great for sticking through the oil plug hole. It gives a very clear picture and will tell if you do have sludge build up. This is way cheaper to do this than pulling the pan off.
If everything looks ok, I would change the filter add oil and run a Mopar engine flush through for 20 minutes and drain the oil again and see what comes out.
I hope this helps, let me know! Anymore questions feel free!
Assuming the worst - sludge is present in the pan.
So, I have the pump changed and clean the intake,screen, and pan...right?
Still do an engine flush?
What about the valve covers?
What is the long term prognosis? Am I spending money on a terminal engine, or is it reversable enough to keep the engine going?
If there is sludge present, I would install a new filter, 4L of oil and a can of engine flush and run the engine for 20-30 minutes on a fast idle while keeping an eye on the oil pressure with a mechanical gauge screwed into the sensor port. Then drain the oil and repeat again. After that I would inspect for sludge again and if it looks much better, I would install a new filter, oil and just keep an eye on the gauge for a while after. If it seems to be good, just use a can of engine flush before changing oil every time after. This will help keep the engine clean and reduce the sludge.
It is quite a bit of work to replace the pump and I would hate to replace the pump if we can get this cleaned up by a few simple engine flushes. I wouldn't remove the valve covers, just use the engine flush and see how that goes. The sludge that gets removed will stay in the filter and go no further.
Using a high quality diesel engine oil will also help keep the engine clean, it has better detergents in the oil to keep the engine cleaner. I would recommend something like a
0w-40 full synthetic diesel oil.
I don't think you will need any expensive engine work in the near future, if you try the things I have mentioned. I would recommend changing your oil sooner for the next few changes like every 2,000 miles and see how that works to clean up your engine.
I hope this helps, let me know how much sludge you find when you get it inspected.
OVER 22 YEARS EXPERIENCE AS A LEAD TECH/SHOP FOREMAN