88 XJ Engine Grinding Noise

hello :wave: **jeep wave**

my 88 cherokee (4.0L inline-6 automatic) did something not so good and i need some input so i can pinpoint the problem.

the past few weeks i've been noticing a whining/squealing noise from the engine during idle upon start-up. no problems actually starting it up, though. just the noise after.

everything with the jeep was going ok until yesterday. i drove 75 miles round trip and the jeep was having a lot of issues with shifting hesitation (refused to upshift into second gear when first driving onto the road) and slipping out of gear. it does that every once in a while when it's cold but it was a lot more frequent yesterday.

anyhow, on my way home it was dark and all of a sudden i hear this buzzing electrical noise coming from the instrument panel area and the instrument panel started to dim. this lasted about 3 seconds and then it was okay. it was scary, though, cos nothing like that ever happened before. then, when i put the heater on, the transmission started to hesitate until i turned the heater off. after driving about 10 more miles, i put the heater back on and it started to hesitate again, this time with the headlights starting to dim and the voltage meter reading was dropping. i quickly shut the heater off and once i got home, the jeep really started to act up. even though all accessories were off except for the headlights (on low beam), the voltage meter reading began to drop like the jeep was gonna stall. so, i got out with the vehicle running and heard this loud grinding noise coming from the engine. the engine was sounding like it was losing power, but i was able to park the jeep and haven't started it since yesterday.

also, the oil has this coffee creamer looking liquid mixed with the oil when i check the oil dipstick. the jeep has a persistent oil leak for years now that gets into the air filter, too. original engine and automatic tranny at almost 200,000 miles.

this is a really dependable jeep despite some of these ongoing problems and i'd like to get an idea of what could be causing this latest problem.

thanks so much,
elle

Wow....sounds like a couple of different things are up.

First, the grinding. Could be the alternator, which would contribute to the low voltage.

You could also have a bad battery (which will cause weird electrical stuff) or a corroded positive battery cable, which will do the same thing.

For these two issues, go to an Autozone or similar car parts store, they will usually check batteries and alternators for free.

The squealing is likely a worn serpentine belt which will likely need replacement. Check with the car parts store on this also.

The shifting issues could be the Crankshaft Position Sensor; problems here cause all sorts of funky things to happen. In my 2000 at 90k it wouldn't shift properly, cut off sometimes, and wouldn't go up a gear just like yours does. Also, check the fluid level in the transmission; these transmissions are sensitive to having a low fluid level.

Lastly, creamy oil. This often indicates water in your oil. It could be from a bad head gasket which is letting coolant down into the oil. Is your Jeep using coolant? I'd change the oil right away, then again in maybe 3000 miles, and send off a sample to an oil sampling company. The one I use is Blackstone Labs (www.blackstone-labs.com); (http://www.blackstone-labs.com%29;) they'll send you a free test kit with instructions, and can analyze your oil to tell you what's in it. The test is $30, but worth it.


Hopefully all this has been helpful; if this were my vehicle I'd check the transmission fluid level and change the oil. Next I'd be at the Autozone asap, have them check the battery, alternator, battery cables and serpentine belt. After that I'd drive awhile to see what improved.

Good luck, post back and let us know how it's going.

I started the Jeep today and here's what I noticed:

It took a second or two longer to turn over and the grinding noise was and still there and loud. The voltage meter guage was reading at the normal level. So, I turned on the radio, headlights, heater and it dropped to just before the red zone area and all of the lights (interior and exterior) began to flicker and dim. When I turned all of the accessories off, the voltage meter reading was back to normal, but the grinding noise was still there and the idle sounded rough.

The Auto Zone advice is great, but I don't think I trust to drive it that far right now - I'm afraid it won't make it. I've had the alternator go bad about 7 years ago and it never made any type of grinding noise. It just stopped on the road and I was able to drift off to the shoulder.

Anyhow, when I got down below the engine area and listened to try and pinpoint the grinding noise, it sounded a lot like metal knocking together coming from the middle/left of the engine area. It didn't sound like the belt was making the noise, but I'm open to exploring that option further.

I checked the battery terminals and they are perfectly clean and corrosion-free. I also have been noticed water dripping from the tailpipe, too. That goes hand in hand with the coffee-creamer goo in the oil on the dipstick. It happens in the cold weather.

For an oil change, should 30 or 40 weight be used?

I just don't want to jeopardize the Jeep by driving it or risk breaking down. Ugh.

Thanks fredjacksonsan for the input. It's much-much-muchly appreciated.

Elle

You're welcome. Hopefully we'll get a couple more guys along to put in their :2cents:

The 4.0 generally takes 10W30 oil; if the temperature is going to be below 60*F on a continuing basis, 5w30 is ok (based on Amsoil website info).

You said you got down under to listen to the engine; I'd think you could locate the source of the sound better with the hood open....but does the sound come from the bottom side of the engine?

Is the water from your tailpipe just that, water, or does it have an odor of coolant? If it smells like coolant, I'd guess head gasket.

There's definitely some electrical issue that's causing things to dim. How old is your battery? You said the terminals are clean, but take a look at the positive cable, sometimes there is corrosion inside the plastic. You might want to try cutting a slit for about 1/2" so you can visualize it.

Since you have 3 seperate issues, here are 3 replies.

1. Engine

I have some bad news for you.
Like virtually all car and truck engines, your Jeep uses plain (journal) bearings on the crankshaft and camshaft. Here is Wikipedia's description of the principle:

Journal bearings

Pressure-oiled journal bearings appear to be plain bearings but are arguably fluid bearings. For example, journal bearings in gasoline (petrol) and diesel engines pump oil at low pressure in to a large-gap area of the bearing. As the bearing rotates, oil is carried in to the working part of the bearing, where it is compressed, with oil viscosity preventing the oil's escape. As a result, the bearing "hydroplanes" on a layer of oil, rather than on metal-on-metal contact as it may appear.

This is an example of a hydrodynamic bearing which does not use a secondary bearing for start/stop. In this application, a large part of the bearing wear occurs during startup and shutdown, though in engine use, substantial wear is also caused by hard combustion contaminants that bridge the oil film.

Contaminated oil is one of the main causes of plain bearing failure in cars. In this case, the oil has been contaminated by water, which dramatically reduces the lubrication effectiveness of the oil. When you drove the car, the oil likely failed to separate the moving parts, so the bearing surfaces touched each other, causing severe damage. This damage eventually manifests itself in bad knocking/grinding noises (usually coming from the crankshaft main or rod bearings), just as you are hearing now.

Generally, oil that is so contaminated it looks creamy like a chocolate milkshake will (with no doubt) ruin bearings if the engine is operated long enough. By the time the damaged parts start making noise, major repair is necessary. An oil change will not fix such a problem.

I suspect your engine will need a complete rebuild, especially since there may be other damaged parts inside the engine, like pistons, piston pins, rocker arms etc.
BTW a loss in power may indicate the crankshaft and/or pistons are starting to seize due to poor lubrication.

Since the Jeep is 20 years old, installing a decent used engine may be a more economical alternative.

2. Air filter oil leak

This is not actually an oil leak, but is caused due to a blockage in the crankcase ventilation system and is a common problem with 4 liter, 6 cylinder Cherokees.

As any engine operates, there is a fog of oil vapor and partially-burned hydrocarbons that build up inside the engine in the crankcase. Older, more worn engines produce more of this 'fog'.

Your Jeep has a tube that directs a limited flow of such 'fog' into the combustion chambers where it is burned, to reduce emissions. In your case, this tube is blocked, so all the oil 'fog' is directed through an overflow tube into the air cleaner. So what you see as a 'leak' is the condensed oil and hydrocarbons from this 'fog'.

If the ventilation tube was to be cleaned out, this problem would diminish or go away.

3. As for the electrical problem, I suspect the 'buzzing' may be coming from the headlight relay because there is a short in the headlight system.

Thanks for the further input, guys. Again, I appreciate this soooo much.

To answer some questions...

I had the hood open while listening for noise along with getting under the engine area and the noise came from the middle-left bottom side of the engine around the alternator area. It's more of a grinding noise than metallic like I mentioned in my previous post. Regardless, I can't stand to hear my Jeepy making that noise. It's awful.

As far as the tailpipe water drip, I haven't smelled any coolant just in walking distance, but I will actually take the time and smell it tomorrow (which will definately be a first 'cos I'm not a fumes kind of girl).

The battery was brand new in August 2006.

The creamy color on the oil dipstick wasn't present at all during the warmer summer months, it just shows up when the weather gets all cold and wintery. I really took into consideration what MagicRat said about the oil not being able to lubricate the bearings enough in the engine. That really opened my eyes to something that I never really thought about that much, but now I sure am. I thought it was a cold weather kind of thing and that since it went away during the warm weather that everything was okay. The last time that the oil was changed was in June 2008 and it hasn't been driven the 3,000 miles yet to change it again (rountine maintenance), but I'll definately get it changed soon here.

Do you guys think that the alternator could be the main cause of this?

Elle

Well, I would recommend removing the drive belt first, its a pain due to the fact that you have to loosen the pwr steering pump to remove it. With the belt off, start the engine, if the sound is gone, then good news, its not the engine , but rather an accessory drive item. Likely your alternator. With the belt removed, turn the alternator by hand, it should turn freely, if you feel any binding or scrubbing then you found your problem. Failed bearings in the alternator. I hope this is the issue. If not I have an 89 4.0 that I am currently running, plan on swapping it out due to a little piston slap in #1 cylinder. If interested EM me. Engine is strong, any time it rains, I have to engage the FULL time 4wd, to keep from spinning the tires (Wrangler RT/S).