BlueOval23

First off, Im new here thanks for having me. Im a big Ford fan and own a 2003 Focus and a 90 Bronco. On to the questions...

My mom has a 96 Mustang GT 5spd convertable. It was leaking coolant out of the intake manifold (plastic WTF?) gasket so I pulled it off and replaced the gaskets and everythings fine, no leaks. I put in a new thermostat while I was in there and put in a 180 degrees. I was wondering what the stock thermostat is and if the 180 is OK. Reason I am concerned is that the Temperature fluctuates as your driving from the "O" in NORMAL to the "M", the fan comes on at "M". Is this fluctuation ok, or might it affect something? This car is BONE stock and my mom drives it every day so please answer this question with stock reliablity in mind and not performance as I dont think shes every floored it.

Second question: When I finished everything I was driving it around and after about 15 minutes the check engine light came on. It has been on for about 2 days now of normal driving. The engine seems to run fine. Any ideas? Ive checked all the vacuum hoses and wiring I disconnected. I replaced the spark plugs while I was in there (they were stock with 90,000 and were gapped at .080").

Thanks ahead for any help!

KillSwitchNY

First off, I beleive 190* is stock for the 4.6's. so a 10* cooler thermostat will not hurt it. figure this... on my 5.0 i change the thermostat twice a year. i put a 190 in the winter and 160 in the spring/summer. being that the car will never run exactly what the thermostat is. it depends on climate.

second. im not sure about those spark plug gaps. On a 5.0 the stock gap is .054 you should look into that huge gap you have. they are definetly in need of replacement with 90k on them!! and while you are doing plugs get either the Motorsport 9.5mm wires or the MSD 9mm's they should provide a noticeable difference with throttle response and the car will run better overall. MINE DID.



good luck.

BlueOval23

Im pretty sure the 190 is stock too, im just wondering if there are any negative things that could come from the 185. I did change the plugs, I put in Motorcraft Platinums gapped to .054, what I was saying is the plugs that came out were .080 meaning they defintely needed to be replaced. Im not going to bother with the wires since its my moms and she has no performance expectations from the car. Thanks for the input.

dothack

I can help ya with the thermorstat info. Yes, dont worry..the 4.6 SOHC LOVES 190 F..thats the temp they are design to operate both the engine and drivetrain. Yes, the stock temp gauge ****ing sucks since it reads from NORMAL since the "M" of NORMAL can either mean 190F or 210F...so u dont know exactly. What I did, I bought a mechanical one and took the electric stock one. The new mechanical one has actual numbers so u know exactly what the engine temp is running on. I remember that it run from M to A, with the mechanical one it shows from 180-190F so Im good to go. Yes, about the thermorstat..its good to go down up to 180..as long as your engine temp is between 180-200F..u r good to go

BlueOval23

so no one can give me a good reason not to run a 180? for emmisions, smog, mileage, longevity, etc? Thanks for teh respsones so far guys.

P.S.I.cho

the 180 will work just fine i cant see it hurting anything as for your check engine light go to checkers get the code read do NOT erase it though, once u have the code it will give you a general idea of what is wrong but dont think that fixing what the code says will fix your problem sometimes the code will say"02 sensorreads rich" how ever its a stuck open fuel injector sending too much fuel. so be careful, untill u are 100% sure u fixed the problem dont erase the code. if u cant figure out whats causing the code take it to a shop this is why u dont erase the code...with their scanners they can do a lot more then what checkers can do