Heat issues ... intermittent... ?

[defiance]

I was working on the a/c this afternoon, with the car idling, and after a bit of time charging up, I realized that it was getting hot.  It should be noted that I'm running off of a calibrated sensor into my ECU, and it does read correct ambient temp, so it's pretty well dead on.  After about 20 minutes, I'd gone from 95* ambient temp to 230*!  This worried me, so I checked everything real quick then shut it down.  Timing was at 14* advance at idle, water was full, gas was fine (I've got a wideband oxygen sensor - I run slightly rich at idle as recommended everywhere I read, it was a/f of 12.5, which supposedly helps to cool at idle as compared to 14.7).  The car has a 3-year old stock-style 'hd' radiator, correct shroud.  It does have a 'flex' fan, and believe me that I'm considering changing that, but before you say that's my problem, I don't think it is - the flex fan has issues, of course, but I've never heard of one of those having issues cooling at idle. Oh, and it's got a new thermostat, too, and the water pump looked fine when I had it apart a week or so ago.

Plus, here's where things get odd.  I left the car for a few hrs to cool and pulled the radiator cap, then started it so I could see if water was flowing.  It seemed to be...  but here's the trick...  I kept waiting for it to heat up, but it got to 190 and stopped.  After 2-3 times the time it took to get hot before, it was still hovering right at 190.....?

My first thought was that maybe the thermostat was stuck, but it was just replaced (just because I had it apart and the old one looked pretty old)... 

Any thoughts on what this might be?  Maybe just the thermostat needed to be 'broken loose' and it'll be nothing to worry about?  Or is there something that having the radiator cap off might have changed???

Any insight welcome!

[Chryco Psycho]

what brand T stat did you install ?
I have 4 bad ones in a row all Chinese made
Buy a STANT US made T stat

[defiance]

Hm...  It was a duralast (Auto Zone) 180*.  But hey, I've been itching to check out the new Advance Auto that went in here, and it looks like they carry stant, so I'll switch that in this evening.  Advice MUCH appreciated!!  Hopefully that'll get rid of this problem.

As for the fan, I know the obvious option would be to drop the flex and replace it with a clutch, but what about electrics?  I love the look of an electric fan, if it would keep up.  Plus, I could kill two birds with one stone; I've read a lot about a/c performance being enhanced by putting a pusher fan in front of the evaporator; I could do a push there and a puller (or even a pair of pullers) on the radiator.  I did a quick search on summit and came up with these... I could use two of these, one push-one pull-
http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2DG4904&N=4294924500+4294839058+4294838842+4294891681+215+4294775279+115&autoview=sku
they're each rated at 2010 cfm.  Would that be enough?  I really have no concept of CFM in comparison to cooling an engine; How much CFM does a good stock clutch fan with a good shroud pull at idle, for example?  If I needed a bit more I could replace the puller with this pair:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=DER%2D16928&N=4294924500+4294839058+115&autoview=sku
for 4,000 cfm pulling...?

I know some of you HATE flex fans, so help me get rid of mine!

[BrianShaughnessy]

     I'd rather run my clutch fan setup but if you're gonna go electric,  get as much electric fan as you can...  at least it gets that flex fan outta there  This is especially true if you're going to be running AC .   
I have a couple friends that have or need to upgrade their electric fan setup from 2500cfm to 4500 cfms.          One has a 502 BBC Chevelle and the other has a 572 HEMI 68 Road Runner.     Both were or are having problems wih smaller units.
    I have a Mancini aluminum rad w/ their shroud.    Highest I've seen it is about 200 in stop and go for an extended period.   Usually it's pegged at 180.

[defiance]

Ok... So, tonight I'll grab a stant thermostat, install it, and I just ordered a set of fans - 4,000CFM pulling behind the radiator, 2,000 in front of the condenser - which I think should probably cool perfectly, and clean up my underhood appearance quite a bit (hopefully).  Probably enhance a/c performance a lot, too.

Hm.. Just occured to me, I can set my ECU to turn on the fans at a particular time... heck, I could even stage it if I wanted...  I think I'll probably just set the puller fans to come on when coolant temp hits 180* and the front pushers to just be on any time the a/c is on.  Anyone see any reason that would be a bad idea?

Oh, just to be sure I"m on the safe side, I don't really know a lot about the reasons for different temp thermostats; I just picked 180* because it seems to be the 'standard'...  Is that right, or is there some reason I might want a different temp thermostat?  I assume the same applies to fan turn-on temps...?

Incidentally, thanks for reading and giving your opinions; they're MUCH appreciated!!

[Just 6T9 CHGR]

I have a silly question to add.....if your t-stat is stuck closed how could you tell except by the temp gauge reading higher than normal?

Would a rock hard upper rad hose be a sign? (when the car is at full operating temp)

If the stat was indeed open, wouldnt the hose be soft due to the flow of coolant?

[dodge freak]

The hoses get hard because of pressure in the system, if you have a leak then the hoses are soft. This is why the rad. cap says never open when hot. The cap controls the pressure, well limiteds it to 7-20 lbs depending on the cap. Most are 13-16 lbs, race motor might take a 20 lbs cap, don't know what takes a 7 lbs but I have seen them for sale, maybe a old leaky rad. When it comes to T-stats I just get the Mildon brand high flow, I never had a problem with them.

[defiance]

Stupid neighbors    Can't really test anymore, too many annoying neighbors nearby.  I did the the thermostat switched out, but I'm not really feeling good about it...  I tried the old one first (right after work) and it was getting hot again in no time...  When I pulled it out, though, and it wasn't stuck at all.  As for airflow, I could easily feel the air being sucked back from in front of the condenser, so it seems like air is flowing pretty well.  Maybe the old thermostat was opening, but not letting enough water flow or something...?

Guess I'll find out tomorrow if it worked...

[defiance]

Hey, here's an issue that just occured to me.  What are the chances my timing mark is incorrect on my harmonic balancer??  Can that happen? 
I'm thinking about maybe bumping the timing up so that it reads 20* on the timing light and see if that helps with the temps.  If it does, then I guess I'll actually pull plug one and all the accessories off the front and manually determine where TDC is, but I don't want to go that far until I'm sure I'm going the right direction...  I won't be TOUCHING the gas for this test for fear of detonation, but I'm thinking there's probably no harm in trying it out (since it's REALLY acting like the timing is set too low).  Any thoughts?  Good idea, bad idea?
Are there any good 'rules of thumb' to use to get a better idea of where the timing actually is?  (i.e., it's usually going to start stumbling at around 2x degrees, or idle will usually start slowing at 1x, or whatever?)

[Chryco Psycho]

i generally shroten the curve in the dist , the easy way is to disconnect the vacuum advance & set total timing around 38* at 3000 rpm this will give you more initial advance & often will cause the engine to run significantly cooler

[BigBlockSam]

hey
you need a minimum of 4500 cfms for a v8, i have 5600 cfm's on my 440 and it works well. plus you need a big alt and batt. so the fans don't slow down when you idle for a long time. like stuck in traffic. are you sure you don't have air in the cooling system? here's a site that helped me figure out how much fan i needed. Rene

http://www.perma-cool.com/faq/efans.html#cfm