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1st Gen. Ram - All TopicsDiscussion for all Dodge Rams prior to 1994. This includes engine, drivetrain and non-drivetrain discussions. Anything prior to 1994 should go in here.
Hey Everyone. I'm new here. And new to having a diesel in my care. I have a boat ton of questions, but I really need help with something that just popped up this week. For starters, I have a '93 W250 intercooled CTD. I got her in April. I have no idea what her prior history is, but she had 153,xxx miles on her at purchase, and I've been driving the beans out of her since then and we're at 165,xxx miles now. She's had a couple of oil changes in that time as well as a fuel and air filter.
Now the fun stuff. Thursday morning, I noticed my oil pressure wasn't sitting at it's normal spot. It was still fluctuating depending on what we were doing as normal, just lower down on the gauge. She was running fine so I tried not to panic too hard. I did an "emergency" oil change that afternoon, just in case. (I was planning on doing one today anyway) Of course, it didn't change anything. I've noticed that as she warms up, the pressure drops though. At start up, it sits where it usually would, but goes down from there. That night when I got home, I also pulled the oil filler cap to see if she'd "tea kettle" it or would be puffing smoke at me. No tea kettling, and only the mildest of puffs that I had to stand in the right light to see. So the next day I bought a new oil pressure sending unit. I haven't installed it yet, but have at least been spraying the old one down with the ol' PB Blaster. I'm not sure the sending unit is the issue though... (I also have it on my to-do list to install a mechanical oil pressure gauge)
Yesterday she started having a... rougher? louder? idle when I'd come to a stop. After a couple of seconds, it would smooth out though. It doesn't feel like she's running a higher rpm, just more violent, maybe? When I got home last night, she was doing it again, so I popped the hood to see if my lack of knowledge would show me anything obvious. What I got out of it was what sounded like an industrial machinery type humming. I have no better way of describing it. It was quiet, but it was there. A slightly higher pitched smooth whining noise... I heard it from both passenger and driver side, not so much right up front. I tried to get the husband to come have a listen, but he wouldn't budge. By the time I gave up on him (less than a minute), it had stopped, and all I had was the normal Cummins clank-song. I don't know if anyone else would even pick up on the noise, but I've spent much time just listening to her (I am so head over heels in love with this truck!) and I know what is in her normal range of sounds.
So where do I start? Like I said, I'm new to diesels. Even with gasoline engines, I'm not that swift, though I sure do try. I haven't had to farm out any repairs yet, and I'd like to keep that track record going!
(Oh yes, I also collected a sample from my oil change to send off for testing, once the kit arrives.)
Well we don't see too many female 1st gen lover...Welcome to the board!
Congrats on your new truck, and glad you two are getting along well. As for your oil pressure...these factory gauges are notoriously unreliable. I have hooked up 3 different gauges to the same truck, in a matter of 5-10 min and they all ready different. Mechanical gauge is the only true way to know what is going on.
As for the humming...not sure. What transmission? If it does it again perhaps remove the front belt and start the truck back up. If it goes away you know it's one of the belt driven accessories, water pump, AC, alternator, fan hub, tensioner? If it's still there then you can always remove the vacuum/PS pump to eliminate that one as well.
Thanks for the reply and welcoming! I've been a life long fan of these trucks. I was brought home in a 70's model Dodge pickup, and I'll die in a '93 or older one as well. Or an old Daytona with a huge wing, but that's another fantasy...
As for her transmission, it's a 5 speed. Not exactly sure what model, but am assuming that it's a Getrag. I've poked around under her and couldn't find a tag or stamp or anything to tell me otherwise. For what it is worth, it's not consistent, but the hard idle seemed to back off once I let up on the brake peddle. (She also clunks when I'm shifting, unless I do it in "race mode." I don't like to do that to her all the time though. I'm trying to treat her well and not beat her up)
Where is this vacuum pump you speak of? Things aren't in the same locations on this engine as what I'm used to, and often enough look totally different. I'm really floundering with it!
The vacuum/PS pump is the unit right in front of the oil pressure sending unit. It attaches to the timing case from the back side by two 15mm or 16mm bolts? There is an oil feed line, PS lines, and some brackets that need to come off as well. Be careful removing it though, you can bust off that oil pressure unit if your not careful.
5spd...well it just keeps getting better. Unless it has had a conversion to a NV4500, then it would be a Getrag. Make sure you change the fluid with 5W30 synthetic...I believe that is the right stuff...and over fill an extra quart
Alright... I guess I'm going to start simple and pull the belt. I have dumb question though. Is the oil pump located in the same area as the vacuum/PS pump? My FSM isn't as good with the pictures as I need it to be, and dangit that Haynes doesn't have a Cummins book!
The oil pump is actually inside the front timing case...it is gear driven with all the other parts. For a port to plumb off for an oil gauge you can either T off the oil pressure sending unit port, or go off one of the ports on top of the oil filter housing.
Alright... I guess I'm going to start simple and pull the belt. I have dumb question though. Is the oil pump located in the same area as the vacuum/PS pump? My FSM isn't as good with the pictures as I need it to be, and dangit that Haynes doesn't have a Cummins book!
Genos garage sells the fsm for our trucks. Order it, as it be the best !$$ spent.
Take a walk around video of your truck, if you can replicate the issue. Put it on you tube with a link posted here. Also folks here would love to see the beast, how about pix of your ride..
I'll be ready with my camera tomorrow, in case she does it again. That's a great idea! I'll see if I can get the in-cab hard idle and then an under hood of the whine. (It's quiet enough that I couldn't hear it until I popped the hood.)
The industrial sound might be a couple things, here are my ideas:
It is hot out, so you might be hearing your Cooling Fan Clutch locked up, making the fan spin at full speed/louder - and I found it quiet annoying when I got my first Cummins dodge, a 1989 D250.
The other thing is that for some reason, I'm not quiet sure, if you come to a stop braking hard, or point downhill, the RPM will seem to slightly go up, or be louder. Inversely, pointing uphill (and/or when hot) like stopping at the end of an offramp after a hot freeway towing run, it might seem to idle noticeably slower.
Just two quirks in my own experience with these beasts!
If you have a getrag, you can't miss the logo on them. It's embossed in the casting;
Very good transmission, just make sure it's filled all the way with oil. The best thing to do on these transmissions is drill a hole in the top hat for a filler. The vent will act as a blow out (somewhere for the oil to go). They due tend to leak from the back where the output is (like mine is now).
As for the noise, take a long screw driver or stethoscope and put it too your ear. I did this and found out the water pump on my truck went. I was lucky because it seized and took the belt with it. Some of them rattle out and chew the port pretty good.
Check the valve clearances as well, with that many miles they are more than likely out of spec. A diesel shop should be able to do this for less than $50. There really is nothing to it, pop the covers off and rotate the crank.
Also check the lift pump, the tabs sometimes break off and will cause that strange slapping against the lobe. Good luck and welcome!
I get a tank of not so good fuel from time to time that causes rough and slower idle.
it goes back to normal at the next fill up.
Also check the fuel filter for water.
Thanks for all the suggestions so far! I got some video of her and her noises today, but unfortunately it didn't show up in the audio. All that came through is the normal rattle. I did get my husband to hear it though. It was obvious even to him when I popped the hood. His gut reaction was that it sounded like I had an electric fan going (which I don't) so PapeCAT, you may be on to something with the fan clutch. I bought a stethoscope on the way home tonight, so when I hit some daylight again, I'll take a listen to what I can.
This morning on the way in to work, my oil pressure was actually reading in her normal range. All that had changed from the other day was I kept dousing the oil pressure sending unit with PB Blaster yesterday in preparation for when I do go to yank the thing out. So I'm thinking that maybe I just need to rebuild the sending unit connector, as described in one of the sticky topics.
This morning, I also saw her temp gauge fluctuating fairly quickly. We were at operating temps and had just pulled onto the four lane divided highway, running at about 65mph. After about three bounces (that I noticed) she quit doing it and stabilized. She did not do it again on the way home.
That's where we stand for now. Hopefully this just boils down to something fairly easy.
Thanks for all the suggestions so far! I got some video of her and her noises today, but unfortunately it didn't show up in the audio. All that came through is the normal rattle. I did get my husband to hear it though. It was obvious even to him when I popped the hood. His gut reaction was that it sounded like I had an electric fan going (which I don't) so PapeCAT, you may be on to something with the fan clutch. I bought a stethoscope on the way home tonight, so when I hit some daylight again, I'll take a listen to what I can.
This morning on the way in to work, my oil pressure was actually reading in her normal range. All that had changed from the other day was I kept dousing the oil pressure sending unit with PB Blaster yesterday in preparation for when I do go to yank the thing out. So I'm thinking that maybe I just need to rebuild the sending unit connector, as described in one of the sticky topics.
This morning, I also saw her temp gauge fluctuating fairly quickly. We were at operating temps and had just pulled onto the four lane divided highway, running at about 65mph. After about three bounces (that I noticed) she quit doing it and stabilized. She did not do it again on the way home.
That's where we stand for now. Hopefully this just boils down to something fairly easy.
Probably the main problem is poor instrument panel grounds. You'll soon learn that you have bought a million mile motor in a 150,000 mile chassis with a 30,000 mile electrical system. Nothing a few relays and fuses won't correct, though.
The fan clutch will engage and disengage like an electric fan starting and stopping. When it's disengaged, the fan free wheels, and when it engages, especially at speed, you can really hear the fan.
If you're hearing a bearing whine, it could be just about any of the bearings in the belt system. If it's bad enough to hear above the normal rattle, you can usually feel the bad bearing (with the belt off of course).
Many of us carry a short (non-AC) belt with us just in case the air conditioning decides to go south. It'll get you home in any case. Most of us have throwing on a serp belt down to about 5 minutes.
This morning on the way in to work, my oil pressure was actually reading in her normal range. All that had changed from the other day was I kept dousing the oil pressure sending unit with PB Blaster yesterday in preparation for when I do go to yank the thing out.
This morning, I also saw her temp gauge fluctuating fairly quickly. We were at operating temps and had just pulled onto the four lane divided highway, running at about 65mph. After about three bounces (that I noticed) she quit doing it and stabilized. She did not do it again on the way home.
That's where we stand for now. Hopefully this just boils down to something fairly easy.
Fix the ground and both problems will go away........... I never did have the patience to find and fix all the grounds on my Ramcharger, but the guy who bought it did, and those gauges went from reading all over the place to rock steady. I believe he ran an extra ground wire to the cluster as well.
08-30-2015, 06:06 PM
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