Overheating still, and new A/C and electrical issue (probably heat related)

So my system just doesn't seem to be rejecting enough heat. The ambient is around 110*F (greater Pheonix Metro), and my watertemps sit around 230-238* (checked via autometer gauge, plumbed in waterneck, stock gauge reads right edge of L).

Fans set to 184/180 low, 200/196 high (on/off-hysteresis).
Summit Aluminum Radiator
stock fan reshrouded to fit
stock waterpump
decent hoses
66%water, 33% coolant (so far the best out of the various blends)

I know the fans are engaging, if you open the hood while the fan is on high, you'll instantly regret the decision to lean in and over. Its rejecting heat, but it is incredibly hot under there.

Also, two other issues that are related: 1st is the A/C will no longer blow cold air sitting at a stopsign (is that an eec controlled deal to save the car's butt?), once moving its very cold. Refridgerant charge checks out as good, and its not over-filled

2nd more sinister issue is once the car is so hot, its hard to start the car if I turn it off in that temp range. Today I was stranded for 30 min out in this heat, as when I went to engage the starter, the whole car just seem to shut down/felt like a fuse had blown, but everything checked out. I checked the battery voltage, 12.6V, checked it at the alternator charge point, grounded to multiple points, and the system reads ok. I can't check it under a load, but once I took the posts off and put them back on, the car started.

Before when it was hot, it would just start slow, and I thought it was from a baked starter, but now I think its something more sinister.

If its motor related (I've heard certain fel-pro gasket sets might not have the proper water passages, and I don't know if this is a stock waterpump, seems to flow), I really will likely just bench the car and drive my other vehicle, as spending money on the 302 when I have a 351W block in the garage isn't something I want to do.

However, if its the summit radiator causing issues (it is narrower than stock width), I think might try a mishimoto drop in 2 core aluminum one and a new stock fan/shroud. I might go as far as a new waterpump, but I don't have interest in investigating the headgasket coolant passages. If I do pull it down that far, I'm just going to part that motor out.
 
Chris,

A couple of first blush thoughts (again. I think you were stuck with me posting on your other thread too).

The AC kicks off at about 242*F (per the ECT) as I recall. The tuning guys who see such values can confirm this value. Given any miscalibration in the ECT, you're in the ball park for that to occur. Once you start moving, the AC might kick on since you should start running just a little bit cooler.

Be very sure high speed is coming on. Low will blow enough to make your face feel like it's melting when you lean over, but it will NOT keep the car cool in your Phx temps. Several of us have had the PCM stop switching from low to high speed.

FWIW, if your radiator is of 26x19 (2" thick) or greater, you should be doing much better than this.

I would once again go over all of your battery cable connections. Also add an extra motor ground if you havent. Resistance obviously goes up with temp, and temp causes greater resistance (and so it snowballs, or in Phx, anti-snowballs). :D

This might help with your starting issue, and get some extra performance out of your E-system (read the cooling fan might work a bit more efficiently).

Good luck bud.
 
I don't think 66/33 will give you the results you want. I live in Florida and run distilled water and antifreeze ( not the premixed 50/50 crap) and a bottle of waterwetter. I don't believe 33% antifreeze is enough and waterwetter won't hurt things.

Do you have good flow? Let the engine cool off, take the radiator cap off and start the car. When the fan comes on check and see what kind of flow you have. When the fan shuts off you sould have some coolant over flow but not a lot. If you have no or little flow you have a restiction some place.

Good luck

Transmission cooler?
5 speed of auto?
 
FWIW, water rejects heat about 2.6 times better than E/G coolant. We just use coolant for the rust inhibition, lubrication and slight elevation in the boiling point (which is offset IMHO by the fact that the coolant is displacing water that could be in the system, and the system runs a little hotter as a result).

That all said, I'm not super big on playing with the stoichiometry when it favors water content of over 50% by volume. If it takes that little bit extra, there's something else wrong with the system.

Just my take/perspective.
 
what temp stat? what kind of stat? A cheap attempt would be to put a Mr. Gasket high flow style stat in, it can help a little bit sometimes...

How thick is the summit core? Didn't think they made smaller than 1" single?