scooter500

iTrader: (1)

After some old message digging, saw that balanced thermostats work much better than common one, so am upgrading to a Milodon 16401 (180 degrees). My water pump is leaking. This car is stock w/ exception of hypertech fan switch and thermostat & purpose for now is work n back (4,000 rpms max). Since I have to replace water pump anyway, would there be a big advantage to a higher flow water pump? Also, I'd really appreciate any recommendations on reliable water pump brands - thanks

jimdutro

iTrader: (1)

Scooter, my `88 Iroc runs at 200 max in traffic when the temps are 90+ outside. I use a Jet part # 60600 fan switch, 200 degrees on, 185 off, a Stewart part # EMP-301 180 degree thermostat with 3 3/16ths bypass holes, 30% anti-freeze, 70% distilled water, 1 bottle Red Line water wetter and the parts that made the most difference in cooler temps was installing a 4th gen dual fan shroud and fans. I got the shroud from Hawks, the fans and everything else from Summit or Pep Boys. The fan shroud is the key.

scooter500

iTrader: (1)

The dual fans & shroud would be a big step up. I will check bone yards around here. my water pumps going any thoughts on stock water pumps or something better?

GutSmack

Just did an engine swap on mine.. from 305 tbi to 305 tbi.. needed a motor fast, mine was toast from overheating.. and still driving it. (stupid, I know) I have been researching the cooling quite a bit. A new radiator made a HELLUVA difference! They are about $100 from Advance Auto and I am having great luck with it. Also, I am running a 180* thermostat. My fan switch does not work I have found. The fan wouldn't turn on and it would overheat idling, so - I took off the connector to the fan switch and made a wire to ground it to the block. This will tell you both that the motor is grounded and that the fan and relay are working, but the fan switch is not! I plan on getting a fan switch that turns on at 200 and off at 185. The stock ones scare me as they don't turn on until the gauge makes me nervous from being so high. I can drive it with no fan with no problem and it doesn't seem to reach 220 until after sitting for more than 5 minutes. Also, if your fan switch is bad, then you can turn your AC on max and it should turn on your fan. I'm doing this until I can find a lower fan switch. My dad swears on a 160* and the guy I bought the motor from swears by 195*, so I am going with 180* as the summers here in South Carolina have been in the high nineties, and our winter hasn't been very cold. Hope this helped!

jimdutro

iTrader: (1)

I`ve never had cooling issues with the changes I made in my last post except I forgot to mention the Stewart stage 1 water pump I also installed. I run a toggle switch for each fan to the console so I can turn them on manually too. Works pretty slick. I`ve tried every radiator out there and not one made a difference in cooling temps. I now have a single row plastic/aluminum for the past 2 years, I like it. Cheap and works great. My temps never go past 200 unless I want them too.

iroc-z1988

running a 170 degrees from gm delco yes they do exist !

Gallileo60

My single fan on my 89 runs all the time, the dual fans on the 92Z do the same thing..My 89 barley moves the gauge...170 therm, new radiator, and hose, with water wetter...I can turn them off, if I need to have the key on for any length of time, but rarely do so..the 89 has been this way for about 5 years with no problem...Had a 160 in it for a while, but it just ran too cool in the winter time...

seaniboy

Hi everyone,
Never had a problem with my 89 RS but just bought a 91 Z28 and feel the temerature pain. Put in a high performance, new waterpump, a 180 deg thermostat and still see the temps rising over 1/2. dual fans kick in just before the redline and seem to control it. I put in midrange gas, hoping it keeps he engine a little cooler...
Thanks for sharing all the info about fan switches ! Will work on that next.........

jesse1957

i have a 82 z28, i rebuilt the heads with suregrip springs, eldelbrock cam and lifters, performer manifold, headman headers going on next,, every thing is emission legal and it runs strong.. i,ve noticed it runs about 220 degrees,, it never overheats and never pings,,, is it normal for 305,s to run at this temp?

jimdutro

iTrader: (1)

No,it sounds like you may have a low temp fan swich. My Iroc runs at a consistant 200-220 max. I have never had any problems getting the car smogged here in So. Cal. No chip and no reprogramming anything, only some mods to the cooling system.

FireDemonSiC

Personally I have ran all three thermostats. stock 195F when I got the car, then went to a 180 for about 8 months and now I'm at a 160.

To be honest with everyone here, the only difference I noticed was on the temp gauge. In the real, real cold winter months, my engine will never get above 140 - 150F on the 10 minute commute to work and longer periods of driving are normally in the 160 range with the 160 stat. Now that summer is ruthlessly bearing down upon us 180 - 195 is normal operating temp partly due to stock radiator with a single fan and no fan shroud.

I noticed absolutely no difference in closed loop operation (In fact according to my A/F gauge the engine would enter closed loop as low as 110F after the 60 second window upon starting the engine), no discernible difference in MPG and no performance increase (At least nothing that I could say without ANY doubt wasn't placebo). This was running a JET chip at the time which to my understanding only adds 2* of timing at WOT and kicks the fans on earlier.

I think the big benefit of running a cold stat would be possibly a degree or two of timing on an engine that was best suited to take advantage of it.

Chris Reese

What if you only drive it a few hundred miles a year

z28cmr83

hey everyone I read this entire post but didn't see anywhere what the factory fan switch on/off is... only that the thermostat is 195. I have an 84 L69 and im running a 180 with a manual on/off switch and i just want to switch back to factory settings but i no longer have the factory fan switch.

JRODRS

nice im ordering two of the hypertech 160 for my LB9 and L98

Ron U.S.M.C.

Anyone running a 160* stat. must have a fan that comes on at at least 170* to make it work.

Running a fan all the time is very hard on your charging system and along with the manual fan switch should be at the very least a temporary fix.

Seriously start learning how to install a fan circuit that either is controlled by a temperature sensitive adjustable fan switch or a fan switch in the heads stock location.

Heres a very simple circuit that uses a $ 20.00 adjustable temp. controlled fan switch.

no new tires

Those of you still relying on the stock water gauge while "playing with thermo stats".

Are asking a blind man to paint a Picasso...

JRODRS

im going with the hypertech 160 t-stat and installing a new fan switch 185-200, at idle my car hits 220 then finally the fan kicks on and lowers it to about 190. Im going to do do the switch and tstat and later get the hypertech chip.

antman89iroc

LOL yes the stock dash gauge is not accurate. Some may be but mine was way off. I put resistors in series with the sending unit to get it close.

Still, datalogging is the only way I know of to get accurate temps. Or at least know what temp is being reported to the ecm.

Anyway, I do have fuel injection but don't have emission so power and economy are my main objectives with engine (& component) life being high priority.

I run a 195* t-stat with both fans wired to respond to the ecm command. I set my on at 95*C and off at 89*C. My objective is to run at 195-205*F coolant temp which should result in approx. 220 oil temp. I do tune my EBL ecm via TunerPro but I have found that while it is possibly to retune everything to run at a lower temp it really isn't worth the hassle, for me. The factory set everything to operate ~200-210 so that's where I run it.

Lots of people like lower temps and I am one of them. But I can't find any hard proof that temps in the 160-180*F range are any better for engine wear or performance. In fact, slow warm up times may cause more wear and inconsistent temps make tuning more difficult. So while a lower temp may be better for performance maintaining that temp is more difficult, especially with the design of these 3rd gen cars. In the end it is more practical to target 190-210*F temp range and I can find no evidence that is causes problems.

greg812003

Have a quick question for you gents/ ladies in here and your limitless knowledge base. In regards to the 1991 L98 platform are fan operational temps fully controlled by ecm or is it based on fan switch? I have a feeling it is 100% ecm. If it is are there any decent chip programmers / manufacturers with any real quality focused mindsets around any longer. I noticed Fastchips has called it quits. I would like to keep my ol girl fairly stock, in the least retaining the TPI system. I will likely be stroking out the block to a 383 and doing some minor valve train & head upgrades but will definitely be retaining the stock TPI system, as well as the EGR system.

Also what is the efficacy of lowering temps whilst maintaining an EGR? Is it even a viable option?

I am looking to achieve stable and consistent operating temps in the lower range preferrably around 160-190 however am comfortable with operating temps around 180-210.

My current upgrades thus far are swapping the OEM radiator to an aluminum radiator w/ dual 1" cores and a dual electrical fan setup with shroud that mirrors the OEM style, Also I have invested in functional hood louvers from Trackspec to assist in venting the under hood heat and create a negative pressure zone to aide in incoming air flow, as well as a new front air damn to aide in assuring air flows correctly.

I do believe; please correct me if I am wrong on this that these adjustments should be of null issue with the functioning EGR as the EGR system is completely temp based and should continue to operate accordingly with minimal issue. I would think it will mostly just lie fairly dormant as a whole since the vehicle would be operating cooler than its operational range. I am still running a 195 therm for the time being as my fans are triggering at 220 & 240, please dont ask me how I know this lol. Needless to say underhood temps has been one of my primary issues with this ol gal getting her back on the road after a 20 year hiatus. One step at a time many small gremlins have been fished out. Thankfully they have not been costly however more so frustrating and damn good at hiding in their simplicity and multitude.

All in,
What do you gents/ ladies think? Is it viable? What do I need?
Feel free to pick me to pieces on this and help me figure out this little idea. Besides any assistance, to include criticism will be truly appreciated. I am still learning so opinions and information are always a positive thing.

Tuned Performance

iTrader: (92)

Wells sw555 or search summit racing for a single wire temp switch 3/8npt.
A few choices for tuners or goto moates.net and diy