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Mercury Cougar, Engine, Coupe
#52 of 156 2000 Merc Cougar & Check Engine Light/Issues
Jan 07, 2009 (12:40 pm)
I have a 2000 Mercury Cougar and about 2 months ago the check engine light came on – the OBD-II code was P0128 - Coolant Thermostat (Coolant Temperature below Thermostat Regulating Temperature). All seems to be well with the car.
I live in WI so it is very cold now (Jan/09) and overheating should not be an issue; the car is producing heat in a timely fashion and it isn’t running hot. I disconnected the battery to see if I could get it to kick out the trouble code again. The check engine light went away – but came back about 2 weeks later; I ran through all of the same steps and got the light to go off again.
On my way to work this morning as I switched the heat from defrost to deforest/floor and the check engine light came on again and as it came on I remembered that this was the same thing that I was doing (switching the heat) when the light came on a few weeks ago.
Could there possibly be any connection between the heater and the check engine light?
#53 of 156 Re: 2000 Merc Cougar & Check Engine Light/Issues [jjb009]
Jan 21, 2009 (1:50 pm)
The check engine light is it the one on the dash our the one in the head liner?
If it is the one in the head liner ( the shape of a wrench) it is telling you that it is time for an oil change, there is a spot in owners manual to reset it. If it is the one on the left side of dash is the you need to pull the heater controls out and clean them and see if that takes care of it
#54 of 156 Re: 2000 Merc Cougar & Check Engine Light/Issues [yankabilly]
Aug 06, 2009 (5:41 am)
This morning i got in my car and was a bit cold so turned on my heater for a few min...turned it off when i warmed up...but noticed shortly later my car was not having that smooth engine flow but rather a chugging without the physical jerking of the car. Anyway shortly later check engine light comes on...drove it home no problem other then the fact that ocassionally that check engine light was now blinking . Turned car off and back on started no problem. LIght was not on till i turned around the corner and came back on...same issue...has anyone had this problem and can tell me what it is and how to fix it?
#55 of 156 2000 Cougar Alternator surging problem
Aug 10, 2009 (3:32 pm)
I have a 2000 Cougar with a V-6 that I have been having a problem with the head lights flickering, a/c blower motor surging and alternator light flickering. I ordered a new alt. and replaced my old one. I'm having the same problem although its a little better. With no load, it shows 14V. As soon as I load it up, the voltage jumps from 12 to 14 to even 16 or 18. I load tested the battery prior to replacing the alt. and it was fine. So, I removed and replaced the main wire off the alt. that feeds the batt. and still have the problem. I then, completely disconnected the wires at the alt. and I have no issues, problem fixed, but of course I cannot operate this car without an alternator. I think I may have a "bad" new alternator. Can someone confirm my suspicions or give any input to something I may have missed or not thought of. Thanks!
#56 of 156 Overheating 2000 Cougar
Aug 20, 2009 (7:54 am)
I have 2000 Merc. Cougar, that the temp gauge shows it is overheating. When I check the resevoir bottle, the water is not boiling. I have replaced the radiator, water pump, coolant sensor, temp sensor, all of the belts, have flushed the engine, replaced the thermostat, even put in an aftermarket 160 degree. Still shows that it is overheating. I have also had the entire system pressure tested and it holds the pressure, so no leaks of any kind. Currently am running the car without a thermostat, but here is where it gets interesting.
When I removed the thermostat, I noticed that the hose that it is attached to is not to the upper radiator hose, like it is supposed to be, but to the lower radiator hose. The upper radiator hose bypasses the thermostat housing and connects to the back of the thermostat housing. My understanding is that the thermostat is supposed to be facing the radiator, and attached to the upper hose. Is this an error made by Mercury. Has anyone else had this type of problem and been able to solve it or had someone solve it? Please, let me know. Thanx in advance for help and advice.
#57 of 156 Re: Overheating 2000 Cougar [lmoreno3]
Aug 20, 2009 (8:08 am)
It obvious that your dashboard temperature gauge is bad, perhaps experiencing an electrical short. Mine was doing the same thing (reading hot), finally I just "bopped" it with my fist on top of the dash, then the needle went to the center of the gauge and stayed for a while then while I wasn't looking, it went back to cold, then again, way up to the red. I plan to buy a aftermarket MECHANICAL (not electric or electronic) and install it. I'm not going to worry about the one in the dash. . .it's cheap and defective.
#58 of 156 Re: Overheating 2000 Cougar [avp0713]
Aug 21, 2009 (2:40 pm)
Thanx for the info and advice. I went a purchased an Eqqus guage today, and am going to install it tomorrow. One more question though. Coming out of the water temperature sensor plug are two wires. One is green witha red stripe and the other is grey with a red stripe. The question is which one is the ground the green with the red stripe or the grey with the red stripe? I want to get this right the first time, since it is a tight fit to work in.
#59 of 156 Temperature gauge rewire
Aug 23, 2009 (8:59 am)
I am going to rewire the water temperature sensor to the original gauge, is this a diffifult fix. I do not currently plan to cut off the wires, just splice the new ones on. I think my problems is a short in the wiring, and am going to give this a shot. Let me know if any of you think this is a good idea or a bad one.
#60 of 156 Re: 2000 Cougar Alternator surging problem [protech1]
Oct 15, 2009 (6:57 pm)
Hope you can help, I own the same vehicle and I am currently having the same problems. I have also replaced two alternators and the battery. Someone advised me to change the electrical voltage regulator and that would take care of the problem. Just wondering if you had found out anything about your situation or to see if maybe my advise may help you. Please contact me with a solution to the problem if you found one. e-mail address natbear0104yahoo.com. Thanks, Crystal
#61 of 156 Re: 2000 Cougar Alternator surging problem [natalieisiahb]
Oct 16, 2009 (2:37 am)
My problem was, the temperature gauge was fluctuating between cold and hot (needle going all the way up to the red area). After checking all the obvious signs of overheating; bubbling or overflowing water bottle, bulging hoses, etc. I realized it was just a bad temperature gauge. It still fluctuates all the way up to the red (hot) area... I have not been paying it any mind. It is not overheating. We have been driving it like that with no problem. And no, I have not yet put in a different temperature gauge. At some point we will put in an after-market MECHANICAL temperature gauge, as opposed to an electrical or electronic one.
2 years ago, I DID replace the Alternator when it went bad.... by chance I found an unused alternator on eBAY for $30 and I paid a "sidewalk mechanic" $100 to install it right in my driveway - in mid winter no less. For comparison, this would cost approx. $500 at the dealer.