[Shotimes] Re: Overheat - Problem solved?

[Steve Tatro]

Well, I *may* finally have my overheating problems solved.  After hearing the talk of people saying to make sure it wasn't the ECT, and that the plastic NAPA ECT is no good (which is what I had in the car), and realizing that I had actually installed the plastic ECT last spring (it seemed like just a few months ago), I decided to head out this morning to buy an OEM brass part.

10 minutes (and 1/2 a gallon of coolant) later and I was finished.  Started the car up and held the throttle (around 2k rpms) to get it to warm up faster.  After just a couple of minutes the t-stat opened properly and the upper radiator hose got warm.  Sweet.  I kept waiting and waiting for the fans to come on, but they never did.  I checked the gauge and it was only up to the "M" in NORMAL.  Decided to take the car out and flog it around some back roads, as that always gets it hot in a hurry.  Still never got the gauge to read over the "R" in normal.  Got home and parked the car.

The real test was a long interstate jaunt this afternoon, the same scenario which has been causing the overheating the past 4 days.  I tried everything I could to get it to run hot, but it just wouldn't.  On and off the gas, repeated runs up to 100mph, "drafting" closely the car in front of me to disrupt the airflow, etc.  No dice, car stayed right in the middle of NORMAL (which is more than I can say for myself).

So, I just wanted to say thanks for the advice and ongoing banter on the list.  If not for all the guessing and related cooling comments and stories I wouldn't have figured it out.

Oh, I went and test drove a '94 MTX this morning.  It had flowmaster mufflers, the Jr. S.S. clutch, the S.S. CAI, some junk tires and 104k miles.  Kid was asking $4000 for it.  Decent car, paint in pretty good shape, but it would've been like starting over with a whole new set of problems: a/c clutch, antenna mast, EATC buttons, brakes, sensors, etc.

Lessons I've learned this week:
1. Flush out the coolant overflow reservoir each time the radiator is flushed.
2. Don't think the plastic ECT from NAPA is as good or reliable as the OEM-style brass ones.
3. Dealing with a bit of aggravation from an old SHO is better than spending a bunch of money every month on a car payment.

Thanks again to everyone,

Steve Tatro
Red/Black '93 with 178k miles
Monroe, Ohio

-----Original Message-----
From: Steve Tatro <stevetatro_shotimes@earthlink.net>
Sent: Jul 29, 2004 6:54 PM
To: shotimes@autox.team.net
Subject: Overheat - Part II

Thanks to everyone who responded with advice.  I had the system pressure tested, everything there was fine.  I also had a pressure test done on the block, at least that's what they told me, and there's apparently no head gasket problem.  Sort of what I expected since it seems HG failures are so rare on the SHO.  For the heck of it I paid them the exhorbitant amount they demanded to do a chemical flush/refill of my coolant system.

On the way home, same thing.  Temperature goes waaay up to the "N" in NORMAL, even a bit past a couple of times.  This was on the highway going anywhere from 65 to 80 mph.  It seemed to help a *bit* if I made sure to get in some clean air instead of "drafting" the car in front of me, but not much.  What did help (and kept me from overheating) was switching the EATC to FLOOR and turning the heat all the way up.

Does any of this help anyone make a long-distance guess as to the problem?  Theoretically the car shouldn't even need a cooling fan at that speed, right?  So I should be able to cross that off the list.  Besides, even putting the EATC in full AUTO didn't help, even though it forces the fan on (AFAIK).

I guess there are three things I can think of: thermostat, radiator, water pump.  Thermostat replaced a couple of years ago, radiator about 5 years old (but always with plenty of fresh green coolant), water pump about 2 years old (went bye-bye suddenly one day).

Ideas?  I appreciate it.

Steve Tatro
Red/Black '93 with 178k miles
Monroe, Ohio