1994 Isuzu Trooper from North America - Comments

I recently bought a 1994 isuzu trooper with 190000. I love it. the previous owner didn't leave any service records in the vehicle, but I would like to keep a great maintenance schedule to make it last forever. I don't know where to begin. any clues? I started by having the tranny rebuilt.

I have a 1995 Trooper with 154000 miles, and had the same knocking noise from behind the timeing belt cover as Stephen related in his comments. Same fix, replaced tensioner, timing belt, waterpump, belts and gaskets and problem was corrected.

$735.00 with tax total repair cost.

Bill,

San Antonio, TX.

I am the proud owner of a 1995 Trooper with 175,000 miles. A light tapping lifters sound developed from about 25,000 miles. Took it back to the dealer and they thought I was crazy, "I don't hear anything, every thing sounds normal". Just recently, I was driving at 80mph and after getting off the freeway, my engine sounded like a machine gun going off, (sound coming from under the black right timing belt cover). Took it to the dealer and they replaced the Timing belt, Water pump, and Tensioner.

That solve the problem, but I also began to experience a loud noise from one lifter, (front right-first one). I was using 10W - 40W oil and I change to FULL synthetic and things appear to be back to normal.

Anthony,

Decatur, Georgia.

I am the owner of a 1995 Trooper with 190,000 miles. Had a similar, very loud knock. Was afraid I was about to blow the engine. Noise seems to be loudest on by the timing belt cover. Came to this site, and had a good sense it was the hydraulic tensioner. The noise almost disappeared about 2800 RMPs, similar to some other comments on this string.

Took it to a mechanic and assessment was right on. Cost: $380. When I picked it up, the service manager said it 'runs rough". Never had that issue other than old sparks. But it comments was an understatement. When I apply rapid acceleration, the motor chugs... like if you've ever had bad gas, but much worse. Never had the issue before the belt and tensioner were replaced. Wondering if mechanic accidently did something, or just unbelievable coincidental. Could a vaccuum hose of some sort be off? Bad fuel filter? Definitely seems gas, O2, or injector related. What happens if a timing belt is not put on properly, ie. out of timing? Looking for advice.

I, too, own a '95 Trooper SOHC. Mine started making lifter/rocker arm noise at about 100k. Since then I had a mechanic replace four exhaust rocker arms, which have a little hydraulic lash adjusters in each. Isuzu claims that the lash adjusters (some call these cam followers) become clogged over time. The TSB # SB00-01-S009 illustrates a procedure for cleaning the oil passages in said adjusters. My aforementioned exhaust rocker arms lasted about 25k until the sound returned. I believe the noise is from the opposite side (driver's) ; however, I'm not positive.

I opened up both heads without removing the cams (I draw the line here, as I'm an English teacher and not a mechanic.), followed the TSB advice and cleaned out all the noisy rocker arms and lash adjusters. Tedious, but free. My valves, cam, and rockers appeared pretty darn clean to begin with. No sediment or gunk. I've used Amsoil synthetic 5W30 since 60k. I have 145k presently.

I also replaced timing belt, tensioner puller, idler pulley.

Timing Belt --

To answer one of the above questions -- The timing belt is fairly specific and could be easily done incorrectly, even by a paid mechanic. I'd look there first for rough running. There are a series of marks, dots, slashes, and whatnot that must be lined up, rotated in correct sequence, et cetera... prior to startup. The Chilton manual has an okay description.

I found little difference in the rocker arm noise. I suspected this would be the case because when I put in the original "cleaned" rocker arms that were noisy, according to the TSB instructions, they were still a little loose when I jogged them up and down by hand. They should be tight.

My next step will be to replace the entire bank of six exhaust rocker arms and the shaft that supplies the oil to the rocker arms on the driver's side.

My questions are:

1) How long will these rocker arms stay tight?

2) What causes them to flatten out (loosen up and make noise) in the first place?

My oil has been changed and good filters used for the past 85k. Previous owner was a jet mechanic who traded the Trooper for a Jag.

Conventional thought seems to point to overly small oil passages, which seems the case, having looked at them myself. The suckers Are mostly as small or smaller than a paper clip.

I have also heard from an engineer in the Philippines that the cams may have been inferior.

Bottom line is that of all the "fixes" I have read about, none seem to be permanent and none seem to find the root cause. Perhaps a design engineer from Isuzu knows, but up until this point, Isuzu seems to politely pass responsibility on to the customer. Nearly every mid-nineties SOHC Trooper, Rodeo, Passport I have encountered knock.

Thanks and good luck.

Nigel of Bozeman, MT.

I also have a 94 Trooper SOHC that ticks. I wouldn't call it knocking, more like a tap tap tap. I think it started around 100k mark. What's worked best for me was switching to a 5-30w high detergent oil. I'm at 131K now and it runs strong, and only taps for around the first 30 seconds of running, and sometimes not at all. I live in a cold climate and the temperature plays big role in when it taps and when it doesn't.

Also note that it took a few oil changes to see the full benefits of the lighter weight oil. I would recommend doing a motor flush to get the gunk out, then do your oil change.

After all the reading I've done on this, I think this is just a bad design on Isuzu's part, and doing more frequent oil changes with a light weight oil is the only reasonable way to keep the problem in check. But I'm not a mechanic, just letting you know what has worked for me. Good luck.

To: 4th Nov 2007, 10:21.

Over the years, when I ran across an acceleration problem after a visit to a mechanic, the culprit was... the dad-gum mechanic. In every case, the worker had knocked a vacuum hose loose, or split a hose so that the vacuum was lost. Many of the cars I have owned used a vacuum signal to adjust the fuel mixture, or advance the spark.

I am not sure if this is the source of your problem, but it seems like a good mechanic would have noticed this and fixed himself.

I wonder if he lost the mark on the timing belt while trying to replace the tensioner?

Hi- I have a 92 Trooper and have been the sole owner now for over 14 years. It had about 400 miles on it when I bought it new in Texas. At about 60,000 miles I started to hear a very slight tapping noise and knew from past experience it was a "lifter". I reported it to Isuzu dealer in MS and he said it was "nothing". Well, we changed to synthetic oil - Mobile 1 and used it for a few years. It became ever expensive and in the end the noise became louder and more prominent. Took it twice to two different shops for estimate of repair. It would cost me over $2800 to get all 24 "lifters" replaced and new cam. I said NO!

I have made the oil changes regularly and have changed back to 10W30. Still have the noise which now sounds like a loud sewing machine, but I have 192,000 + miles on it now. Now I am ready to start repairing the engine since everything on it - the body that is, is still so like new. The 4WD is excellent. Any suggestions on the repair of the lifters like does anyone know if enlarging the oil jets would be fisable?

I own a '92 Trooper, bought it with 130K and now has 190K. Everyone I've spoken to with a Trooper gets the lifter noise eventually, as mine did. I used a motor flush additive before changing the oil the first couple of times and am using Castrol 10-40 For High Mileage Engines. It definitely responds well to fresh oil, in fact I never keep a log of mileage for changing, I just change it when the ticking tells me to (which I think is around 3 to 4 thousand miles).

It is getting worse, though, more and more frequent and often when the car is already warmed up and going.

I also changed the timing belt with tensioner (it was the 2nd belt for it) at around 165K. It does sound like it's going to come apart at the seams when it starts to rattle, you'll know it without a doubt. Mine cost $1100 at a mechanic, but also included complete overhaul of the cooling system just for grins since everything was off anyway.

Otherwise, the Trooper lives up to it's name, a trooper. Very reliable, safe, can climb a tree in 4-Low, very roomy and comfortable. I love it.

I have a 94 Trooper S SOHC and have clocked 345K miles. Great car overall. My only problem over the years was that the engine got quite warm when travelling slowly off-road over rough terrain. I solved that by replacing the radiator with a larger 19 x 26 inch cross-flow unit. The only modification was the removal of a little bit of metal on the p/s hose bracket by the radiator's output. I also changed to a 0psi waterless coolant they use in racing engines. I haven't had a problem since.

Bruno N. Los Angeles

hypertex @ mac. com.

I bought a 1995 trooper 4x4 with 150k on the speedo, I heard a lifter noise in it almost immediately, but its more like a nice japanese lifter tick and I don't believe it hurts it one bit.

Changed the oil with 10w30 and added lucas oil additive... it seals the rings, coats the piston walls and adds compression... the lifter noise went almost totally away in minutes.

Listen this is a rock solid truck... its rides like a truck... acts like a truck... climbs hills like a goat... yeah all isuzu's have a lifter tick... big deal...turn up the radio and drive it 250k...thru snow, mud, sand...it's a beast... boxy and dependable as it could be... just like the name says...it's a trooper!!!

I purchased a 1994 Trooper S with 184,000 miles on it. I had to replace the shocks and do a tune up on it, but other than that, the only thing is the lifter tapping. I believe that part of the noise is the timing belt tensioner too. I will be replacing the timing belt, tensioner, and probably the valve pucks really soon. Maybe there is a better designed valve puck with better quality metal that is available. I am lucky that I can do all the work myself and it will save me a large amount of money. Other than that, it is in perfect condition.

Did my cam belt last year after water pump failed dramatically.

SOHC 155,000.

Sod to do and get right. Lining up the marks seems easy at the time but I've doubts now that one cam didn't get rotated round. Runs OK ish but falters a bit and does about 10 to the gallon. Otherwise a great solid car.

I have a 1996 Honda Passport, which is pretty much an Isuzu Rodeo. I have 240,000 miles on it. Bought it when it had 110,000 miles on it, and when I bought, it had a little lifter noise, but I took it to my mechanic and he said don't worry about it, it's not a problem, they all make that noise after awhile. I use 10w30 mobil1 full synthetic and it hardly ever makes that noise unless it is really cold outside, then it usually quits once it warms up. The engine has never been rebuilt. Everything on this vehicle works as it should, and the vehicle still looks almost brand new. I just ignore the noise; it's a small price to pay for such an excellent vehicle.