94 4.0 OHV Lifter / Rocker Tick or Oil Pump failing?

[hal_94]

First, the truck:

94 Limited, 4.0 OHV, Auto Trans, AC

147K miles, generally runs pretty good, until something breaks. I've got a small oil leak somewhere on the back of the block, but I've never been able to track it down exactly--I figure a quart every couple of months isnt too bad. I also just noticed a small pool of coolant under the ignition coil pack, but not sign of where its coming from.


I haven't been driving it much lately, since I don't have a parking space in the city, so I leave it at a friend's place and try to start it up once a week.

This last week, though, I did some highway driving and then at after about an hour on the road, was at a stop light and looked down and saw my idiot oil gauge flicker once or twice, and then it was fine again.


This caused panic, because I knew I was overdue for an oil change, and I figured I probably have got some gunk on the oil pressure gauge sender.

Changed the oil (yes, FRAM filter.. I know, but I had a new one in the back of my truck already), Castrol 10W-30, same as before. I'm not sure how long its been since the last change--the last time I have written down is Feb 05, at 142K, but I'm dead sure it's been much more recent than that.

After the oil change, started the engine up to make sure everything was nice and tight, and it made a lot more noise than I remember--ticking like crazy from the top end as it started. Then, as the the engine warmed,the noise got quieter, and by the time the RPMs dropped after start up, the ticking was essentially gone--sounding like it was a bit dry on top, and then once it got the oil up there, everything was happy.

I changed the spark plugs a day or two ago, and it sounded pretty good. Then yesterday, I replaced the tube from air cleaner to the throttle body with one from the junkyard (mine had a couple of holes in it!), I started it up, and again, the top end was very noisy, but as the engine warmed up some it got quieter, and by the time engine RPMs dropped down to idling speed, it was pretty good

---

I figure that my truck is suffering from either the infamous lifter/rocker noise, dirty valves, exhaust leak, or perhaps (I sure hope not) that the oil pump is starting to fail/clog.

1) If it's just the noise from worn rocker/lifters, will this cause damage to the engine? Or is it a matter of just wear which causes some noise, but can be ignored? I haven't been able to really tell either way from the posts I've been reading.

2) Do I want to try a different oil weight? As far as I can tell from what what I have read, heavier oil weights will increase oil pressure and help this--but at the same time, it seems like some people use thinner oil which is less viscous to get it up to the top end quicker... which is the right way of thinking?

3) I figure I ought to go ahead and run some sort of cleaner through the engine (not the crankcase, necessarily), though a couple people have recommended Rislone in the oil as well. Any thoughts?

4) I suppose that eliminating the oil pump as a culprit would best be done with a set of real oil gauges to check the pressure--do you know if I can get a set at Autozone, and do I just hook them to where the dummy gauge sender is? (I'm guessing this is a messy one).

5) What else can I eliminate as the cause?

Thank you! I'm hoping to keep this truck around for many more years, since it is in really good shape--and I love driving it. Let me know if there is anything else which would help!

-AJ

[91FiveSpdExpl]

Did you fill the oil filter with oil first or just screw it on there dry ? I've noticed and also heard about. if you don't fill the filter before installing it you will get a nice ticking noise coming from the lifters area.

[Maniak]

The oil light is for oil level (sender is on the side of the pan), not for pressure (unless there is another light I've never seen)

As far as I know, the only low oil pressure indicator is the oil pressure gauge. If you haven't modified it, it will real low/no oil pressure when you have less than 5psi of pressure.

There are many first gen explroeres that tick, especially when not warmed up.

Ours does at idle (comes/goes).. I've heard others that do all the time. Some people have put in a quart of ATF in before they did an oil change (and then idle the truck for a while before changing the oil). Others have used an engine flush.. Others have had to replace the push rods, lifters and rockers to get rid of it.

You can't tell what it is until you find out what your oil pressure is.

~Mark