Another overheating thread :(

[lxfiveoh]

Hello!!

My car has started to exhibit some strange overheating behavior.
It has been gradually building up.

It has ALWAYS run near the bottom of the gauge, perhaps right above the first line or around the "A" in NORMAL. In the last few months, it started going up past the second line, or half way up the gauge. This is mainly afternoon (HOT weather) and evening driving.

I usually drive it only for a little while on Friday nights to meet
with the club I'm in. They are city miles, and the gauge doesn't get very high at all.

Now, when I get on the highway, this is when the gauge creeps up. This past weekend, I drove about 30 miles in the morning (not too hot, yet) and the gauge went all the way to the "R" in NORMAL. I was driving around 70-75mph.

My car has the stock radiator and stock water pump. It has a 160
thermostat & underdrive pullies. These parts have been on the car for several years of hot South Florida summers with no problems, so I'm not quick to blame them.

I partially drained my radiator and it didn't look corroded to me.
When I cranked up the car the water seemed to be flowing through it just fine. I let the car sit idling for about 30 minutes and the temp gauge never got past the bottom...maybe around the "A" in NORMAL.

Any suggestions at what this might be?

To surmise, it seems to run about 'normal' in the city, but the gauge quickly rises on the highway.

Thanks, MustangWorks!

[fiveohpatrol]

my suggestion is to buy an autometer water temp guage. You can't rely on the stock guage's for anything other than what they say, which is "normal"

other than that, i'd try putting a new radiator cap on it, and maybe a new thermostat if yours is very old.

but you really need to see exactly what the temp is doing with a good guage.

hope this helps atleast a little

[PKRWUD]

4 things:

1) get a real gauge. The factory gauges sucked when they were new, but yours is going on 13 years old, and is worthless.

2) Ditch the 160 t-stat and get a 180. There is absolutely no reason at all to use a 160 t-stat in a daily driver.

3) Replace your radiator. You may think it looks fine, but it's not. The only time an engine runs hotter on the freeway than it does in stop and go traffic is when the radiator has clogged passages. You can't tell without taking it apart, but I can.

4) When you refill the system after putting in your new radiator, temp gauge, and t-stat, make sure you don't use more than a half gallon of coolant! Your mix should be at least 80% water.

Take care,
~Chris

[302 LX Eric]

Good info above.

fiveohpatrol - I'm curious how a new radiator cap would help him. Can you enlighten me? Thanks.

E

[PKRWUD]

Originally posted by 302 LX Eric
Good info above.

fiveohpatrol - I'm curious how a new radiator cap would help him. Can you enlighten me? Thanks.

E

As the cap ages, the spring loses tension, and the pressure it can hold becomes less. The lower the pressure, the lower the boiling point, and the sooner it will overheat.

Or something like that.

Take care,
~Chris

[lxfiveoh]

PKRWUD,

I've known about the evil 160 thermostat for years, now, but it was installed by my 'tuner,' Unlimited Performance Racing, at the time they did some engine work and burned a chip for my combo on their dyno.

Not knowing if the car was 'programmed' to go into closed loop at the lower temp, I didn't bother to change it for a 180.

FWIW, the temp after the 160 was the same as before (w/ stock thermo) on the stock gauge.

I was thinking radiator, myself, but wanted to hear some other opinions. I did get a couple of "votes" for bad radiator, and some that I would NOT have thought of, like bad radiator cap!

Thanks, everyone.

[302 LX Eric]

Thanks, Chris.

E

[ByrdPE]

Originally posted by lxfiveoh

Now, when I get on the highway, this is when the gauge creeps up.

To surmise, it seems to run about 'normal' in the city, but the gauge quickly rises on the highway.

Thanks, MustangWorks!

Is your "Air Dam " still intact??

[lxfiveoh]

Hmmm....I'll have to double check, but I haven't hit any parking bumpers or anything lately, and I don't think anyone has stolen it from my car.....I'm 99.9% sure it's still there.

Good suggestion, though.

[jimberg]

I don't think he's talking about the front air dam that covers the bumber. There is a black plastic one that is just behind the front air dam. It is supposed to divert air to your radiator when you are moving.

[jimberg]

You have it in your first users' rides picture.

[Hozer 88GTConv]

I think your 160 thermostat could be causing you more trouble than you think.
Since it is basically open all the time your water just continues to flow throughout your system, thus not having sufficient time in the radiator to cool.
As your system has lost efficiency over time, it is finally catching up to you in the form of slowly increasing water temps.
Perhaps all you need at this time is a 180 thermostat. You will probably need a radiator in the near future but maybe not right away.
At least it's worth trying before you drop the coin for a radiator.

[Old Guy with 87 GT]

mine was doing the -exact- same thing .......turns out most of the culprit i think was the fan clutch

i pulled my hair out on it for a while ......i think it was a combo of stuff that was causing my problems .........i did everything that everyone suggested above and it helped ,but mine still seemed like it wasn't working like it should ..........i changed the fan clutch (witch was only 1 year old )....and it made a big difference....now the car runs at 180 witch is where my thermostat puts it .....even while running it hard on 100 degree days

fan clutch seemed fine ,felt fine but it made a big diff after changing it