Low coolant light and service engine light flashing.?

M

Mark

New member
I have a 1991 Buick Regal with a 3.8 V6 with 79.140 miles. about a week ago the low coolant light started coming on only when i would break. then a few days later it started flashing like a turn signal flasher. I checked the reservoir it was at the full line, so i checked the radiator its self and it was also full. now the low coolant light it staying on all the time, but now the service engine light is coming on when the car is idling like when i sit at a light, but as soon as i take off it goes out. I asked at a few auto parts stores and they said they don't know they never heard such a thing and one said they can't tell until the service engine light comes on and it wouldn't come when i was there.

Any Idea what is going on and how to fix or stop it?
The engine is running just fine, nice and smooth like always.
 
If the light is flashing usually means bad and I would recommend not driving it until it is checked or you risk permanent damage. Also I am not sure but it should have a on board computer and you should be able to go and get the code scanned at most any garages or part stores and get an idea of the problem. And with the age it could just be a faulty warning. but I would err on the side of caution
 
Service engine light could be related to low oil level or low oil pressure. Check it.

The low coolant light could be related to a bad sensor or wire going to the sensor (since the coolant levels are normal). The coolant level in the radiator should be all the way up to the filler neck at the radiator cap (just to the point of overflowing).
 
I think that 3.8 is a Mercury Marine engine = very strong.

That is an odd light sequence. Could just be an electrical issue giving false info.

You can "stop" it with electrical tape. Otherwise just let it happen until, like the auto parts guys said, the check engine light stays on. Then a code will be stored that they can read.

Or you can pay a shop to drive it around and check it out. But that may be an expensive way to find out it's just false readings because of 18 year old electrics.
 
Mark: First I believe you have two problems, since the ECM is hard wired separate from the low coolant light, the two problems are not related.
First, If you know for sure thar the coolant level is good, try disconnecting the LCL, it's located on one of the radiator tanks. It has a two wire connector. Since it's the least expensive part, replace it (do it when the engine is cool)
Second: I believe that you may have a shorted wire to the Emission
Circuit, probably to an O2 sensor (against the exhaust), look for any shorts in the engine compartment.
Good luck
 
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