HI! I have a 2003 Ram 1500SLT 5.7 Hemi with 231K miles. It has never let me down! But I came down very ill last summer and the truck had to sit for about 9 months. It was started and moved from drive to lawn and not much else once in a while. When I got better this May, I decided to start driving it again and this problem below developed.
It starts fine, and warms up with the oil press. around 50 psi, I take it out on the road, it runs fine at first, but then after about 25 - 35 minutes of driving, the oil pressure drops to 0 - 4 psi (the dash has a needle meter - but I put an aftermarket psi gauge on in conjunction with the dash meter to get an actual pressure when this trouble started). There is NO ticking from the lifters and no other abnormal sounds from the engine - it purrs like a kitten! Of course, once the pressure drops, I shut the engine down, but I can start it back up immediately and the pressure goes back up to a range of 28 - 45 psi. It did this sooner, but I flushed the engine with Amsoil Engine Flush, and then put a good synthetic blend oil in it along with a new oil pressure sending unit/switch/sensor. My local mechanic suggested I drop the oil pan as he thought that maybe some gunk was floating around in there and stopped up the intake. As I was readying to do this, I decided to run a stiff wire with a loop up in there - it came out clean as a whistle. I'm at wits end. Please help! Is the pump bad? Where is it located? Is it next to impossible to change out? Any advice will be more than appreciated!
There is a service bulletin on a low oil pressure problem but it says the problem could happen when the weather is cold. I know that your engine does this when it is warm but it could be a possibility and should be looked into.
The problem of low oil pressure could be caused by a sticking pressure relief valve and also replacing the oil pump pick up tube with part number 53021522AD according to the service bulletin 09-006-04.
The replacement of the oil pump labor could be about six hours and an engine support is required. It involves the removal of the front cover and oil pan.
If you need more information on this just ask and I will try to help you as much as I can.
So this does sound like an oil pump problem?
Front cover? You mean the front cover of the transmission (which overlaps the back of the oil pan)?
How entailed is fixing or cleaning the relief valve? My mechanic (he's been real helpful, but with my disability and me not able to work = me not able to pay him to fix it) said I should drop the pan and pull the pump being sure to clean it well and especially clean/check the relief valve. I assume the tube is brittle and maybe cracked or even broken since it is in the tech report? The truck did sit through the winter this year.
The last time I got involved in something this entailed was on an 82 - 360 CID, when the oil pump was below the distributor! I've been thinking about just replacing the pump, but if a good cleaning would suffice, I'd rather do that. I'm not afraid to pull this pump - I cut my eye teeth as a mechanic on a nuclear sub, and this job doesn't appear to involve bearing clearances or crank removal - yet!
I appreciate the response and the info, plus any more you might have!
CAUTION: Oil pump pressure relief valve and spring should not be removed from the oil pump. If these components are disassembled and or removed from the pump the entire oil pump assembly must be replaced. With the amount of miles on your truck motor you should get a new pump if any work is to be done.
NOTE: The 5.7 Oil pump is released as an assembly. There are no Daimler Chrysler part numbers for Sub-Assembly components. In the event the oil pump is not functioning or out of specification it must be replaced as an assembly.
The oil pan, oil screen and front cover must be removed to remove the oil pump. If the cover you are talking about on the transmission is obstructing the access to the oil pan bolts then just remove that pan cover and then remove the oil pan and screen. The oil pump bolts to the front cover and must be removed.
If you need more information get back to me and I will help you the best I can.
Appreciate the help!