Isuzu SUV Forum banner

1998 Rodeo V6 Engine Noise

9K views 15 replies 12 participants last post by  mrjingstr71 
#1 ·
I have a 98 Rodeo 4WD with a 3.2 V6 w/120,000 miles that started making a noise about a year ago. I finally took it into to my local repair shop (a Chevy dealer whom I trust, but not an Isuzu dealer) back in May. They said the noise was coming from inside the engine, likely 'risk pins', and that it could go at anytime. They didn't open anything, just listened to it. They also indicated that a rebuilt long block would be cost prohibitive. I haven't driven it since. Like many Isuzus, this Rodeo consumes 1qt of oil every 1000 miles.

After reading these forums, I get the impression this noise could be one of any number of problems (e.g. dirty valves, the timing belt tensioner, etc.) My questions are: Is my mechanic likely right or could it be some other problem? What are "risk pins" (I have the Haynes repair manual and could find no mention of 'risk pins')? If not the risk pins, what should my first step be in diagnosing the problem? If the risk pins, is there any fix besides an entire rebuild?

Let me describe the noise: It is a tapping or perhaps even a rattle. It occurs when accelerating or going uphill or going over 70 mph when the engine is at about 2500 rpm. The noise is either there or isn't. In other words, it doesn't get softer or louder or change in tempo. If it has gotten worse over the past year that I have been driving it, I haven't really notice.

I'm not a mechanic. I have never worked on an engine or a transmission, but I have successfully repaired a Cavalier that I smashed into a deer at 70 mph including replacing the radiator, intake manifold, hood, fender and headlights. However, I do have a friend who is more knowledgeable about such things than I am. I guess what I'm looking for is if any of you have had this problem and could point me in the right direction for diagnosing or possible fixing the problem.
 
See less See more
#3 ·
Doesn't sound like lifter or tensioner ticks to me as those would also be present at idle. Sounds more like carbon knock which could be cured by some Techron.

As for "risk pins", maybe he said "wrist pins". Seems very unlikely this is your problem unless you have really abused the engine.
 
#4 ·
So on a 98 3.2l Rodeo, you'd have the "direct attack" valvetrain, and therefore if you have any ticking / tapping noises from valves, you'd need to adjust the valves using shims to correct. This type of out-of-adjustment valve condition is rare on the "direct attack" engines, and would likely also cause a poor idle condition. Isuzu recommends that valves only be adjusted if you are trying to cure either of the above conditions, but not at any specific mileage.

I would recommend that you search on this forum for "cylinder soak" using a product called "Seafoam", and also buy a bottle of Redline SI-1 Fuel System Cleaner and run a whole bottle with a tank full of gas and see if that helps your ticking/rattling noise.

"Wrist pins" are used to hold the pistons to the connecting rods. They're essentially a round metal dowel of sorts, but they need to be extremely strong as they transmit the full load of the combustion energy to the connecting rod, which in turn transmits to the connecting rod bearing, which in turn transmits to the crankshaft.
 
#5 ·
"MontanaRodeo": I have a 98 Rodeo 4WD with a 3.2 V6 w/120,000 miles that started making a noise about a year ago.....likely 'risk pins', and that it could go at anytime......

After reading these forums, I get the impression this noise could be one of any number of problems (e.g. dirty valves, the timing belt tensioner, etc.) .....

Is my mechanic likely right or could it be some other problem? What are "risk pins"

....If not the risk pins, what should my first step be in diagnosing the problem? ....

Let me describe the noise: It is a tapping or perhaps even a rattle. It occurs when accelerating or going uphill or going over 70 mph when the engine is at about 2500 rpm. The noise is either there or isn't. In other words, it doesn't get softer or louder or change in tempo. If it has gotten worse over the past year that I have been driving it, I haven't really notice.

I'm not a mechanic. .
well, it's a little hard to tell. what's missing from your description is how loud?

1.) a hard, loud rap rap rap that says (to even non-mechanics)
"oh-my-god-the-rods-are-going" is probably the timing belt tensioner you've been reading about. the solution is change the timing belt, the timing belt tensioner and the water pump while you're there.

2.) a little tap tap tap louder than you'd like and kind of like a diesel is probably the excessive valve tappets noise you've been reading about.

3.) a kind of rattle you describe above could be pinging which is associated often with octane issues and other factors, including lugging the engine, etc.

but i don't think a mechanic would confuse 2.) and 3.) above with serious rod noise, or with *wrist pins* (which attach the connecting rod to the piston).

he could, would make that leap if it were 1.) and he wasn't familiar with this common problem with isuzu's.

so, i, for one, am looking forward to more info on the volume and description of this problem.
 
#7 ·
If the noise only occurs under load, e.g. acceleration, uphill etc, then it could be pinging. Try higher octane gas for one fill up to see if anything changes. Generally, lifter noise is commonly heard more at idle.
 
#9 ·
Not to dispute the merits of Auto-RX (I actually like it), but it wouldn't really help resolve valvetrain noise in a 98+ Isuzu Rodeo V6 (or trooper) -- it's a "direct attack" system where the cams actuate the valves directly, rather than with a hydraulic lifter. Older Troopers and Rodeos do have hydraulic lifters, and they can get clogged so they don't retain proper pressure, and will "tap" or "tick".
 
#10 ·
hi.
i know this message was awhile back, but if you guys could help me, im having the same problem with the taping sound on the right side of the engine of my isuzu rodeo 98 6cyl 4wd whenever i reach around 70mph or going up hill or reving up to about 2700 rpms...even on neutral.

Its sort of a flapping..tapping...metal to metal type of sound. i heard this 2 weeks ago and brought it to a shop. they replaced my timing belt, tensioners, water pump, etc. ran okay after that.

a week after its back. ill drop by the shop later on to make sure they didnt mess up the timing belt, or if any misalignment has happened through out the week.

but my concern is if its not the timing belt then what can it be?
 
#12 ·
you know what i think i does also when idling.
first i dont hear it, then i rev it to past 2500 rpms then it starts tapping, then after i release the gas the tapping stays there until it goes away and it takes to about 5 minutes til it goes away (or the tapping sound weakens..)
what could be wrong with the valves?
 
#15 ·
on my way home the taping sound worsened. its like a metal to metal grinding sound that started from the right side of the engine and ran down to below the driver seat. then the cars acceleration weakened then the check engine light lit up.
i dont know if i should go to isuzu to have this fixed or could a shop find the problem. im leaning towards going to the shop instead. its an old f*ed up truck and i dont want to spend so much on it. i just want to get it to a decent running condition that will last 10k miles more.
if you have any ideas or have gone through the same problem before let me know. i just spent alot on timing belt replacements a weeks ago. i dont want to guess the problem again.
thank you for your help in advance.
 
#16 ·
I think I'm going through the same thing and trying to decide whether redo the waterpump, tmb, and tensioner which was done about 30K miles ago.

Mine sorta rattler when the i maintain rev and speed. Underload and when I let off and deccelerate you don't hear it. My truck's performance has not change a bit which I just drove ~500 miles from San Diego to the bayarea for the xmas weekend.

I'll try to video the sound today and post.

Gonna try to clean out the EGR and intake today (while the wife is out shopping :D ).
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top