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Chevy S10 - GMC S15 and Sonoma Engine and Underhood Problems



  • Have you gotten under the truck and looked or felt around for something loose?
  • I had somebody tell me it sounded like loose torque converter bolts, and that it was easy to tighten them. I crawled around under there looking for what he described, but no luck. There is some sort of brace, looks like it goes from the transmission housing to the bottom of the engine or suspension, that has the bolt missing on the transmission end, but the noise isn't coming from there. I have a Chilton's manual on the way, hopefully I'll figure it out. From what I've read here and elsewhere, could be lifter noise, but I'm wondering just how loud lifter noise is, cuz this is LOUD. If it is, I've read that it could be a bad oil pump.
  • The problem i see with loose bolts or lifters is that you said the noise didn't speed up with engine rpm. If it was either one of those the clanging would get faster or slower with engine rpm's. If it remains constant i would think it's something outside of the motor? Crawl underneath with the engine running and see if you can pinpoint the source of the noise. (Set the emergency brake, block the wheels, ....etc... to be safe)
  • eronieroni Posts: 9
    I would like to know, (from a kind person who has the service manual) the correct torque for the following bolts in a 2.2 liter VIN 4 GM engine of 1994, used in the GMC Sonoma (and other models):
    a) Flex plate (flywheel) to crank shaft bolts.
    b) Flex plate to torque converter bolts
    c) Push rods bearing bolts.
    d) Crank shaft bearing bolts.
    e) Drive shaft rear U joint bolts/nuts.
    f) Bell housing bolts.
    g) Oil pump bolts.
    h) Oil pan bolts.
    Thanks a lot, in advance, for the help.
  • s10fan_kys10fan_ky Posts: 1
    edited August 2010
    Does anyone have a vacuum diagram for a 2001 Chevy S-10 Crew Cab 4x4 4.3 V6 that they could send me? It is not in the manual that Autozone has, nor can I find it online. Any help would be greatly appreciated.
  • I have replaced batt,distrib,alt,plugs,wires heads gaskets cad convert and muffler and now have a problem that stumps everyone..on hot day with air on going uphill it loses power and rpms go up and down. Once over hill she runs ok and if I turn air off before hill it doesn't do it at all
  • My 2002 Sonoma has the same problem. Giakamo, did you get yours fixed? What was wrong? Anyone with any other ideas, please respond!!!
  • Did you find the answer to your problem mikeythekat? I have the same problem.
  • gmc4x4s15gmc4x4s15 Posts: 2
    edited November 2010
    okay just bought a 1987 s-15 with a 2.8 liter v6 when i try and start it after its been sitting and cooled down it takes forever to get it to fire and then when it does fire i have to keep pumping the gas for it to idle and even then it runs really rough and tends to die. after it warms up it runs good usually but sometimes will die on me.......replaced the gas tank, sending unit, all new fuel lines return and sending, new filter,new tps, new map sensor, and a new air filter. im pretty knowledgeable when it comes to motors but im stumped help is much needed
  • okay today was different. i read on a similar post to turn the key on and hold the gas petal to the floor. so i did this and it fired immediately still had to do it a couple times but it didn't take as long to get it running this time. any other ideas will help
  • hopkins7hopkins7 Posts: 9
    edited December 2010
    2000 S10, Extended Cab, 4.3 6 cy auto, 159k miles, well kept, serviced, and maintained for the past 10 years I've owned it. Recently began having roaring noise, seemingly from under the hood. Noise is most prominent, continuous and loudest at 68 mph, but is also noticable, and intermintent, at other speeds - 35, 50, 55+ mph. All wheel bearings, axle bearings, gear oil, and seals have been changed out. All tires checked and in excellent condition (it's not a tire/wheel noise). Noise is still there. My trusted auto shop for 25 years is stumped. Exhaust system/muffler checks out to be ok. Haven't been to dealer, yet. Any suggestions? Funeralman.
  • Sounds like your fan clutch has gone bad.
  • if the oil level gets higher on the dip stick the yes it could be coolant look in the radator to see if y have oil on top of coolant
  • your maf is located between yor air filter and tb if it is un plug see if truck runs better if it does try cleaning it with maf cleaner if does not help replace it
  • Thanks 2002sonoma, fan clutch is working fine, so that has been ruled out. It's a different sound.
  • I have run into this problem with several of my fleet trucks. The easiest way to find out what the problem is is to have a full diagnostic run on the vehicle, depending on the area you live in this may be available only from the dealership(the computer is very expensive and some shops just wont put out several thousand dollars for one). But I do have some advice on what the problems were with mine and I will offer a starting point. The crank position sensor was my most common, especially during wet weather, the cost is relatively low, about sixty dollars. the second problem I had was coil packs, I also had good fire, but it weakened when wet. The final problem I had was plugged catylic converters, this was rare though. I suggest starting with the crank positioning sensor, if it is not reading correctly you will get plenty of fire, just not at the correct time. Hope this helps.
  • Problem solved. Noise was unlike any I had experienced. The roaring noise was coming from my double cardan ujoints. Due to high cost of repairing the cardan ujoints, I had a new drive shaft with regular ujoints installed - expensive, but $200 cheaper.
  • We are considering buying a used 1989 gmc s15 which is 4 cylinder and 2.5 L and wondering how can we check vacuum ..I mean I want to 'tee' in vacuum gauge to intake manifold to check possible valve problems and more..but have not seen any s15 under the hood till if some one can show pictures or video that would be great...

    also I know how to check compression ....but don't know compression values in healthy engine so I don't know how to if some one can share ..what are those compression values in each of 4 cylinders?

    also this care does not have power steering or cruise control etc...its 2.5 L and 4 cylinder with TBI fuel how much its worth if everything is ok with compression and vacuum?
  • the radiator started to leak so I put in stop leak (followed directions) Tried to get home about 30 min later in the interstate the oil presure began to drop so We drifted in to a weigh station engine cut off comming in. The pressure droped to zero before cutting off temp was 240 did not red line.
    We let the engine cool down then put more collant in radiator heard a pop noise ( blue seam on radiator) Tried to restart engine turned over quickly but would not start.Had it towed repair shop said timing jumped or chain broke. Towed it home tore it down to timming chain not broke or jumped looks real good. Still wont start. Any Ideas?
  • gonogogonogo Posts: 871
    Remove valve cover and check for broken camshaft.
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