Hey everyone... I'm looking at buying a 2000 Blazer LT with 107k miles. After taking it for a test drive the guy told me 'he forgot' to replace the crank sensor after I said it would not shift under heavy acceleration. Is the crank sensor the problem or is this a more serious transmission issue?

** I think the crank sensor is unrelated?.. so maybe I heard the wrong sensor. Either way, he told me it was a magnetic sensor and its located towards the front and bottom of the engine.

Secondly, I was told the oil cooler lines should be replaced... is this a job I want to do myself? I'm fairly mechanically inclined but I have limited tools. Is this a rough job to do?

Thanks for your help, hopefully these issues get sorted out and I purchase another Blazer.

 

What makes you think that the crank sensor is faulty? Do you have a code for it? Are there any codes which might point you in the right direction?

It is highly unlikely that a bad CKP sensor has anything to do with the transmission.

As far as the oil cooler lines go, they aren't bad, but it can be a pain in the but to get the lines off the oil filter adapter on the driver side of the block if your truck is 4wd. A few extensions with the last one having a wobble end on it with a deep socket and you should be able to get it. To put it back together, use some grease or a piece of shop towel to wedge the nut in the socket to keep it in place while you get it back on the stud. Everything else is pretty easy to work with once the air damn is removed from under the radiator in the front.

One thing to note is that when you disconnect the lines from the oil cooler in the radiator, check if the e-clips are bent before reusing them. They should lay flat. You can bend them with a pair of pliers if they are not flat. The new lines should slip right into the radiator with no tension on the lines. If there is tension on the lines, they can leak. You need to bend/twist/adjust the lines to get them lined up for the port in the radiator.

 

Thanks for the reply! I only test drove the car for 15 mins and noticed the horrible shake and refusal to shift under heavy/full acceleration. The seller (claims to be a mechanic) told me it was 'xxxx' sensor that needs to be replaced.

He said he will be replacing it and calling me back. I've just never heard of a sensor causing a refusal to shift and violent shaking? I feel that he is full of it, but the rest of the car is extremely clean and well taken care of. I'm worried he might be covering up the issue for when I come back?

I don't want to buy a car and then have to put a new transmission in though! Any ideas or recommendations on what I could check or assume it is?

 

If you are looking at this with these problems, I'd probably move along. I wouldn't consider buying a vehicle with unknown issues especially from a "mechanic". Chances are, he's selling it because he can't figure out what the problem is.

 

Thanks Swartlkk, I was really impressed by the car but that's exactly what I was afraid of... an undiagnosed issue. The guy called a bit ago saying he replaced the 'crank sensor' and everything runs smoothly now. I do not understand how the crank sensor fixes that... I don't even know if it's worth my time going back to check it out (It's only two miles from my house)

 

The crank sensor could cause the engine to cut out if it weren't sending the proper signal to the PCM, but I would be very skeptical. If i were you, I would want to drive it for at least a 30 minute ride, making sure to run through a complete OBD2 drive cycle (a quick google search should give you the steps). Then on the way back, stop in at an Advance Auto, Napa, or Autozone and get the codes read to see if there are any active and/or pending codes.

 

Sounds like a great plan... can't believe I have not heard of the OBDii before. If I understand correctly it will allow all error codes to be checked, and then I can check if any came on at the auto parts store? I don't need a special diagnostic tool plugged in before the OBD right?

 

Running through a complete OBD2 drive cycle (make sure the engine is completely cooled down when you first start it) will allow all systems to run through their checks. Most autoparts stores can hook up with their scanner and read codes as well as look at the emissions monitor states to see if there are ones that are ready, pending, or failed.