96 Pickup startup rattling

slowr6 · Feb 5th, 2003, 05:01 PM

I have a 96 Pickup with the 2.4L, 5 speed tranny. I'm getting a short rattling noise when I start the truck that sounds like its coming from underneath the truck. I've been reading a lot about the infamous timing chain rattle and I'm curious if this was fixed by '96 or if this could be the problem. I can also hear the rattle slightly at around 3000 rpms, more often when I'm decelerating slowly. I thought it might be a heat shield but I'm not so sure, how can I check to be sure my timing chain isn't the problem?

Tolleyy · Feb 5th, 2003, 05:11 PM

It could be the nut on the exhaust hanger by the cat converter... happens to me all the time around 3000 rpm also. One of these day's I'll loctite the SOB. Check all those bolts and nuts on the exhaust hangers just to be sure before you go tearing into the motor. If it was the timing chain you could really hear the noise from the front of the motor where the chain is.

In 96 and 97 the chains seemed to be better, but the noises were still coming from the lifters and lower main bearings at startup. Nissan had a TSB in 97 and replaced the whole motor if it was noisy under warranty.

slowr6 · Feb 5th, 2003, 05:41 PM

I just went out and braved the cold for a little while and I found the exhaust isn't too pretty. A hanger was actually split, but I don't think that was making the noise I was hearing. I ripped off the almost rusted through heatshield that was covering the top of the exhaust, right underneath where the driver's feet would go. I'm hoping this is the problem but I won't be able to tell until at least tomorrow morning because for some reason the rattle only occurs when I start it cold.

BTW removing this heat shield shouldn't cause any problems correct?

Tolleyy · Feb 5th, 2003, 06:19 PM

Might make your feet a little warmer

Check and see if there is any computer boxes under you're drivers seat. That heat shield might be protecting those boxes. That Cat converter gets pretty hot!

Does the rattle come from the motor or under the truck?

slowr6 · Feb 5th, 2003, 07:17 PM

To me, it sounds like its coming from under the truck. But I'm not sure if it's echoing and throwing me off. It usually rattles right when I start the truck and lasts maybe 2 seconds so I can't really get out in front of it to hear what it sounds like from the engine compartment. I poked at the timing chain with a screwdriver through the oil cap and it seemed pretty tight from what I could see with just a flashlight. Now that I removed that shield we'll see if I still get the rattling tomorrow morning when I leave for work.

Dwntyme · Feb 5th, 2003, 07:21 PM

There is 2 reasons for the rattle. 1)The slackside timing chain quide maybe broken(mine was) this also happens when you let off the gas as well. the new one is all metal.
2) Use 5w-30 oil. for some reason on the HB trucks heavier oil is bad when cold.also try using a purONE filter, Frams drain back valve doesn't work right. Don't use Teflon PTFE additives (BAD) 20w 50 not good for cold starts
I've been building KA engines for awhile and everyone that I have taken apart have had the slack side guide broken...Hope this helps

himilefrontier · Feb 5th, 2003, 11:36 PM

Mine does this too,but goes away after it has run for a few seconds and the oil light goes off.I run 10w-40,and my truck(98 Frontier 5spd) has 190k on it.Is the guide problem just on the KA24E?or is it also on the KA24DE?I do run this truck pretty hard(I sometimes smack the fuel cutoff-ooops!)I always thought it was the lifters needed to pump up,since it does not do this if I start it warm.Anyway,I just thought I'd ask,and throw in my 2 cents.

slowr6 · Feb 6th, 2003, 06:44 AM

Well I didn't get the obnoxious startup rattle this morning, but I'm still getting a rattle here and there when I'm driving around, like I explained before. The only thing that bothers me about it is that I don't know what it is. I want to be sure that it either is or isn't my timing chain...

Dwntyme, if my chain guide is broken or worn would the chain have extra slack in it? I stuck a screwdriver through the valve cover and pushed against the chain as much as I could and it moved very little. Is there a better way I would be able to easily determine if that's the case or not?

Ichabod · Feb 6th, 2003, 07:59 AM

Could be your hydraulic lifters.

currykid3 · Feb 6th, 2003, 09:32 AM

If you let your truck idel for awhile does the sound come and go. I have a 96 that had the same problem, the same sound. It was the timing chain. It went at 60,000 miles. I wasnt to happy but it was a used vehicle and and who knows what the other person did to it. Had a 93 from new and sold it with 140k miles and never a problem. Get it checked out cause Ive seen the chain eat throught the housing if let go for a long time.

slowr6 · Feb 6th, 2003, 04:14 PM

I got the rattle again when I left work but after getting a look at my exhaust in the light I think that might be the problem. At least two of the hangers are busted.

But I'm paranoid and I'll be thinking about it until I find out for sure that its not my timing chain. Could somebody please explain how I can just check the chain or possibly the guides?

Tolleyy · Feb 6th, 2003, 04:34 PM

Never done it before, but I would think you would need to take off the front cover and see if anything is broke. Someone correct me if I'm wrong here

currykid3 · Feb 6th, 2003, 06:32 PM

Ok this is going to sound wack but you can insert your finger in to the oil fill hole and reach tward the front. You will be able to feel the chain on the top sprocket. If you can lift the chain with your finger its more than likely the guides/tensioner. It may lift a bit thats ok but if it moves alot I'd get it looked at by a shop or some one who can pull the covers off. Actually its not to hard to pull the covers. With them off you should be able to tell if the chain is loose. If you do pull them off put on a new gasket it may look ok but its better to replace. First get them hangers fixed, a swinging exhaust will bust the exhaust manifold quicker than snot on an ice cube. If you still have the noise or it starts happening more frequently or gets louder, get the chain ch checked.

http://www.nissanforums.com/showthre...threadid=14172

This is what can happen if the chain gets to crazy loose.

slowr6 · Feb 7th, 2003, 11:10 PM

I unbolted the cover and was able to lift it off 4 or 5 inches. The chain was pretty loose. I could swing it back and forth maybe 1/2 inch. The guides looked fine from what I could see but I don't really know what I'm doing. Where exactly would the chain be rubbing? Near the bottom gear or the top?

I guess it could be the guides or the chain tensioner or something. Anybody have a ball park idea on what this is going to cost to fix? Thanks again.

Dwntyme · Feb 8th, 2003, 12:45 AM

Quote:

Originally posted by currykid3
Ok this is going to sound wack but you can insert your finger in to the oil fill hole and reach tward the front. You will be able to feel the chain on the top sprocket. If you can lift the chain with your finger its more than likely the guides/tensioner. It may lift a bit thats ok but if it moves alot I'd get it looked at by a shop or some one who can pull the covers off. Actually its not to hard to pull the covers. With them off you should be able to tell if the chain is loose. If you do pull them off put on a new gasket it may look ok but its better to replace. First get them hangers fixed, a swinging exhaust will bust the exhaust manifold quicker than snot on an ice cube. If you still have the noise or it starts happening more frequently or gets louder, get the chain ch checked.

http://www.nissanforums.com/showthre...threadid=14172

This is what can happen if the chain gets to crazy loose.

Have your timing chain and guides replaced as I said your slackside tensioner is broken. If you'll look down(facing the front of the engine on the right) you'll be able too see that it's broken in half. also I stated that you should be using 5w 30 that is a must. also where the head meets the block is the only oil passage too the head and it's no bigger than the head of an ink pen, go back and look at my original post for the filter type and please don't use PTFE's in the KA24E the KA24DE corrected the trouble with oiling system and timing chain system...