Sergei

On my 5000CSTQW this light goes on after 20-30 minutes of driving. After next 5 minutes constantly blinking it turns off for a while, then once again. Temperature gauge shows normal range of temperature, there is no fault code in the system, car was never overheated, fan works ok on all 3 speeds. Does anybody have idea what's wrong? May be it's just a reminder to flush cooling system and change ab antifreeze? (Last time it was changed 1.5 year ago).
Thanks in advance.

Randolph

It sounds like you need to simply add a little coolant in the overflow bottle. I had a similar problem a few weeks ago and learned that the Temp sensor is VERY sensitive on these cars. Based on what your saying I'm about 99.9% that's your problem. As your driving and the thermostat and fan operate your coolant level in the bottle goes up and then goes down and, if the car is low enough on coolant it will cause the temp sensor to come on when the coolant gets sucked back into the engine causing the level to go low in the bottle.
Randolph
97 Cab (sold)
87 5KCS
93 928 GTS
98 Cadillac STS (for sale)

strungtight

Hey Randolph,

I am trying to figure out how to flush my '89 200tq radiator? Do you have any experience? I am not sure where to start and dont know which hose to hook up a T-fitting if I go that route...Any help would be greatly appreciated!

Dan

Randolph

Hi Dan. I haven't done the coolant flush yet because I ended up taking the car to the body shop to remove a dent and some scratches. (it's going to look awsome when finished) Anyway when I get it back then I'll get around to flushing the coolant. Hopefully in the next few weeks. I think what I'm going to do instead of using the T fitting is I'm going to disconnect the lower radiator hose and drain (as Stephen Clark suggested)as much as I can then reconnect and start the car and fill with water and let run for a little bit then drain again and refill with water. I'll do this a few times until I think it's all flushed then on my final fill I'll put in the proper coolant/H20 mixture. If anyone has a better way please advise. On these cars I think the less you have to remove and disconnect the better. What happend to the "oldschool" radiator cap and draincock?
Randolph
97 Cab (sold)
87 5KCS
93 928 GTS
98 Cadillac STS (for sale)

strungtight

Do you refill through the overflow tank? Thanks!!

tightcurves

I have this same problem right now. Has been coming on for the last few months, every time i start the car after fifteen second and stays on until i turn the car off. It started out just like you said 20-30 minutes until now when i start the car, it's right away. All my fluid levels are at or greater than maximum. It is very annoying. The mechanics that i go to told me that the grounding beind that instrument panel has gone bad. (I don't know if this is true). the cost he said was $500 to get it fixed. What i did was put black tape over the display. The cheap alterntive.

Adam Mowafy

be carefull if your going to use radiator flush, it must be safe for aluminum!

Will Ng

if you have enough coolant in the reservoir, then your MFTS may be faulty.

SteveAngry

Yes.

tightcurves

I unplugged the sensor and no warning light came on. This will save me a lot of money i don't have. Now only if i can drive with it unplugged. Thanks.