Chevy Blazer Oil Pressure problem

familysize75familysize75 Member Posts: 1
edited August 2014 in Chevrolet
Ok I had to change the oil filter on my 02 Chevy Extreme Blazer 4.3L V6, because It was shooting out oil around the seal which had broken in 2. I replaced it with an AC Delco filter and tightned it to Spec, Filled it back up with oil, and then statred it. The oil pressure went immediatly all the way up to spike the gauge in the dash and then blew the O ring right out of the side of the filter and shot another 2 quarts of oil on the floor. We already checked the radiator and the lines going to and from it. Any ideas are welcome please help

Thank you in advance


  • stickmandadof3stickmandadof3 Member Posts: 3
    I have a 1993 Jimmy 4X4. I had been running around town today and after my last stop. It seems like it would not shift past 2nd when you had it in drive or over drive it would move but at very high RPMs. The speedometer would not register at all, transmion level is fine and dose not feel gritty any ideas :sick:
  • curlytopcurlytop Member Posts: 5
    Sounds like your OPRV (Oil Pressure Relief Valve) has jammed closed. This is an internal engine component and will necessitate sump removal to rectify.
  • rfletcherrfletcher Member Posts: 25
    Original sensor failed last April. Had been reading 40lbs. for about 165,000 miles.
    Oil pressure indication recently became erratic. Up, down not related to RPM. This was the replacement of the original sensor, which failed last April. Changed sensor again. Pressure stable at 40 lbs. for about 5 days [approx. 150 miles ]
    Last night engine started normally and drove about one mile. Suddenly pressure went to 0, digital warning flashed, check engine light came on and engine died. Sensor has a fuel pump cut out switch. Today I, found the oil level full. [ about 600 miles since change & new FRAM filter ] I removed sensor, checked with air pressure and found it to be OK both pressure and cut out. Observed there was very little if any oil on sensor and was not to the top of the open port. With the sensor removed, turned engine with starter. No oil came out of open port.[ may not have turned it long enough. was sitting over night ] I then added a small amount of oil into tho sensor port. It took very little to over flow. Again turned the engine. Bad idea. Blew oil all over the engine which ,by the way, I had just cleaned. Re installed the sensor and started the engine. Started instantly with 40 lbs. oil pressure

    My questions are; Since this is the second sensor change this year, am I buying defective sensors? [Auto Zone Duralast PS168 ]
    Could I have temporarily cleared the problem by putting air into the sensor or oil in the port?
    Do I have an oil pump about to die? Now at 176,000+ miles but running great until now.
    What else can I check to determine the cause? It seems totally unreliable as is.
    There is an unused port above the oil filter. If I install a mechanical gauge at this point in the loop, will it read correctly?

    Thanks for any suggestions
  • greensb94greensb94 Member Posts: 2
    Check the VSS! Located on the tailshaft of transfercase. Sometimes the Check engine light will come on and flash a code 24. Sometimes if you take it off-road they get hit and unplugged. Just a suggestion, mine did the same thing.
    GM Part# 15547452 @ $154.00. Hope I could help I own a 2DR 92 4x4 s-blazer & 4DR 94 4x4 s-blazer.
  • greensb94greensb94 Member Posts: 2
    How many Qrts of oil did you use?
    Was the old o-ring from prev. filter still on engine when new filter was replaced?
    The oil pressure guage only spiked do to oil filter blowing off.
    Try pulling coil wire when you change oil filter on start up to build pressure up in the lines. check for leaks before it actually starts.
    Are you adding oil to the filter before screwing it onto engine?
    Sometimes you can overfill. Try this and see if this helps.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Well, I buy some of my parts from Autozone, but not sensors. Find a Delco parts house, or one that carries Standard brand. The Delco will cost more, but hey, how long did you say that first one lasted???

    Good luck,

  • rfletcherrfletcher Member Posts: 25
    AC suddenly went completely dead. Found 25 A fuse open. Checked blower, clutch etc for shorts. AOK so replaced the fuse. Worked perfectly for about ten minutes and again went dead. Opened control circuit at pressure SW, clutch and control relay to isolate the wiring . Found 2 ohm to ground on wire leading to ECM. Now, if I could only find the ECM, might be able to fix it. Chilton said, " If it's not in the engine compartment then it might be behind the glove box or some place under the dash or behind the kick plate". Easter egg? The truck looks like it had been parked over night in a ghetto and I still can't find the ECU.

    Can any one be a little more specific as to where I might find the ECU?
    Can any one explain why the AC control even goes through the ECU?
    I prefer to replace the ECU, if necessary, but what would happen if I bypassed it and went directly to the clutch?

    Thanks :sick:
  • rfletcherrfletcher Member Posts: 25
    Reference my last post, Aug 05, 2009 [12:37 PM]
    Never mind, I found the ECU /ECM. It was not the problem but by tracing the grounded wire back, found the problem in a connector that does not show in the manual. All systems are now GO.

    For any one interested, the ECU / ECM is installed [ hidden ] behind the glove box. In this model the box appears to be a rigid part of the entire dash. Below the dash there is a shelf that runs from the passenger side kick panel just beyond the 4X4 shift lever. Even with all the screws out, it is difficult to remove. The kick panel comes out easily. A single screw, now visible, secures the mounting bracket. With that screw out, the entire unit slides down from it's hiding place. The cable harness is rather short and tangled so a little care should be taken. I had to remove the two small plugs on the inboard side before it was free.

  • jlflemmonsjlflemmons Member Posts: 2,242
    Glad you got it fixed. On the second generation Blazer, the ECM is mounted on the right side (passenger) fender well under the hood. The BCM (body control module) is mounted under the dash to the right of the accelerator pedal.

    What did you find that was blowing the fuse?
  • rfletcherrfletcher Member Posts: 25
    The 12V line was shorted to ground.The 12V line leaving the evaporator pressure switch goes to a connector, which does not appear on the diagram in the manual, where a second line is spliced in. One 12V line to the contacts of the compressor control relay, the second to the control module and back to the relay solenoid. The connector also contains a circuit ground wire. I can only assume that the problem was in the connector because the short disappeared as soon as I opened the connector and never came back. I removed the wires in question from the sleeves, in both directions, looking for damaged insulation but found none. I will also assume, as Murphy so eloquently states, the problem will come back and at the worst possible time. Most likely, when my wife is out shopping in 95 degree weather. I shudder to think about it.
    This sort of issue came up in a general discussion page elsewhere on this site. The question was, why are there never problems, in this forum, with the ECM. As I remember, the opinion was that the trouble is almost always in the peripheral circuit and the ECM is so well hidden that a stupid mechanic, such as myself, can't damage it. Well, I tried really hard.

  • jlflemmonsjlflemmons Member Posts: 2,242
    Good catch, hope it is a longterm fix. It may be that just moving the connector around cleared a short somewhere down stream in the harness. Connectors [Usually] don't short, but stranger things have happened.

    Regarding ECM failure, they are very rare. As any failure can cripple the car, a lot of attention is paid to these, and typically they are built using MIL-SPEC parts. Higher temp ratings, greater voltage tolerance, etc. The second generation S series ECM has a heat sink mounted to it. I have been told that many of the ECM that are replaced will test good. Either a harness problem, or bad contact in the mating connector. In a manufacturing environment, these are very easy to test and confirm good before installation.
  • rfletcherrfletcher Member Posts: 25
    Thanks, and I agree on the fault clearing that way. It's going to be a lot of trouble but I think that I should take a more extensive look inside the two sections of harness at least near the connector. It's working fine now, but a truck with almost 200K miles probably has arteries that look a little like mine.

    I need to correct myself on accessing the ECM. It was not the shelf under the dash but the kick panel below that was removed. Still a miserable job, out and back in. Also, the other wire in the connector was not circuit ground. Still more reason to look further down the line. Intermittent problems can make you crazy.
  • allen30allen30 Member Posts: 1
    I have a 99 blazer the gas gauge doesnt read right {just what ever it wants to).`Oil gauge reads according to rpms, speedometer moves up some while in park as to rpms. Is the a bad ground?
  • odaatodaat Member Posts: 1
    recently when i start the engine i hear a slight ticking noise from the engine,and the oil pressure climbs to @ 60, (it is normally@40) /after a few miles the pressure will return to normal / speculation is perhaps the oil pump is bad, or i should try a different viscosity oil perhaps 5w/30 / anyway this is a baffling problem, do you have any suggestions, thanks
  • jlflemmonsjlflemmons Member Posts: 2,242
    What are the outside temps? Not likely the oil pump, try an oil change with Castrol or Valvoline 10W30 and AC Delco PF52 (high capacity) filter.

    How many miles on the engine?
  • norblazernorblazer Member Posts: 1
    My sisters '91 Blazer does the same thing. The gauge kinda act like a RPM gauge.
    Did you find out what your problem was?

    Her also seem to just stop for no reason. It will stumble and die. A day later it's fine again like nothing has happened.
    It seam to come and go. Sometimes she can only drive for like 5min before it start to stumble and want to die. Others it will be fine for a week.
  • paultiberiuspaultiberius Member Posts: 1
    I am having EXACTLY this problem on my 2001. Did you find any answers?
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