2001 Buick Century coolant sensor

Tiny
WOODSTOCKBIRD
  • MEMBER
  • 2001 BUICK CENTURY
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 98,000 MILES
My Buick had the low coolant light on intermitently. After three times in the shop (the catalytic convertor also went out) it is still on. Problem is the mechanic replaced the head gasket on that third trip, an expensive repair as oil was leaking into the coolant from the engine. He actually gave it back to me with the light still on. I gather he did not replace the sensor which was gummed up, so I took it elsewhere and they switched out the sensor. Now after a month the sensor is back on solid.

So my question is, since the sensor was replaced, could there have been residual oil still in the coolant which is now gumming up the new sensor? Is it even possible to replace the head gasket without draining off the old coolant? I hope it would be very unlikely that they could have screwed up the repair in such a way as it is still leaking.I can't afford any more repairs. I would appreciate your input.

Thanks
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Tuesday, May 20th, 2008 AT 12:00 AM

5 Replies

Tiny
LEGITIMATE007
  • EXPERT
Your supposed to drain and replace the coolant when doing a head gasket. Your coolant temp sensor may not be the problem anymore. Take it to autozone or advanced autoparts/checkers for a free computer scan, so that you can get the trouble codes and bring them back to us. We'll take it from there
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Tuesday, May 20th, 2008 AT 12:13 AM
Tiny
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Thanks for your reply. Yeah, well I would have thought they would have automatically flushed out the coolant, but it turns out they did not. It was flushed prior to the repair when he tried some sealant, but the light came back on within a few weeks, so clearly the oil was still leaking in. Now after the fact he tells me he didn't want to have to charge me for flushing it out since it wasn't so bad that it would effect performance. I assumed they had.

Of course this left the low coolant light still on. Granted I suppose it makes no difference, but I think they should have flushed it, or at least discussed the options. So now I have a second sensor that I had put in that is gummed up. I'm sure the second mechanic assumed that it has been flushed also and they had just tried cleaning the sensor and had not replaced it.

I thought I would have the coolant flushed somewhere else and then figure how to put a new sensor in myself. It looks to me like the input is a few inches down on the engine side of the radiator, but I'm going to pick up a manual to get the exact procedure. Do you think that would be a good course of action? Also I imagine a flush might not get all the residual oil out and the problem could possibly recur anyway. Would you personally even bother?

Thanks for the help man.

Tony
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Tuesday, May 20th, 2008 AT 7:56 AM
Tiny
LEGITIMATE007
  • EXPERT
Oh yes its worth it. Go ahead and flush it and put the new one in. But first go to autozone and have them reset the engine light for free. Drive it and see if it comes on again if it doesnt then everything is ok. If it comes on then do your flush and change the sensor
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Tuesday, May 20th, 2008 AT 9:49 AM
Tiny
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Thanks for the response. I gather you have to build up some points before you can leave a feedback, I will when I can. Tried to give you one, but I have oly 0.1 points thus far.

I'll take care of the coolant light issue this week coming.

By the way, another odd thing happens sometimes on this same Buick. I've had the brakes checked several times and they tell me they are fine. Occasionally the car makes a small groaning noise when braking at very slow speed. When this happens the ANTI LOCK, TRAC OFF and SERVICE VEHILE SOON (not check engine) lights all come on at once, but go off again when the vehicle is restarted. The only code that ever registers is that the wheel has slipped, like when it spins on gravel, but of course that is not the case. Odd that, I've always assumed there was some sort of sensor malfunction there, perhaps intermitant. Although the noise sounds like something straining or humming, which I gather could be the anti-lock motor? Never happens when a mechanic looks at it. Ever hear of anything like that?

A while back I whacked into a baby deer and although there was no damage to the car, this happens a bit more frequently since. (Both this and the coolant issue predate the deer incident).

Thanks again,

Tony
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Wednesday, May 21st, 2008 AT 9:24 PM
Tiny
LEGITIMATE007
  • EXPERT
Yeah its probably the actuator motors, but you should check the tone rings on all of the axles to see if some of the teeth are chipped. Or if the sensors are loose
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Wednesday, May 21st, 2008 AT 9:31 PM

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