Thermostats.

[Hemet8]

Has anybody put a 3400 180 degree thermostat in a '95 3100sfi? I have completely went thru the cooling system and it still runs 210-220. I have the factory saying that is "normal" because they engineerd the car to have little thermal expansion because of the aluminum heads. That way, the machanic told me, there is no "hot and cold" going on between the heads and block, less stress on the gaskets too. I understand the properties of thermal dynamics when it comes to aluminum, and the fact the fans in my car come on at 225, so the "rise" never really exceeds more than a 15-18 degree difference. So.....it does not overheat, should i just put a littlee water "wetter" in it and forget it? Will the 180 degree thermo mess it up? (provided it fits/works) Is there any performance gain from running a cooler thermo?

[spacecadetz26]

if you put dexcool in it, it will run cooler. Have you thought of anything like a manual fan switch? The stock fan settings make it run 210-220.

[DEI37]

The only real problem with a colder thermostat (although 180* isn't cold enough, I believe) is that the engine won't lean out as it warms up. I think you'd be just fine with a 180* 'stat. Might pick up mileage a tick, and both the engine and trans will run cooler. If you live in a cold area, it will slightly affect the heater output. I run a 160*, and it's a fair bit cooler. Should still be alright in the cold days though. In theory, if you're modifying, a colder 'stat will help KR resistance, and thereby help you increase power.

[DEI37]

BTW, I wouldn't put DexCool in anything. I ran VW G-12 coolant for a while, but after a year or so, became unimpressed with the heat absorption properties. Run silicate free green coolant. It's cheaper, anyways.

[Manitcor]

Ive been running a 180 for years, on the hotest of days it doesnt make much of a differnence but delay the inevitable. On the coldest of days it doesnt make much of a difference because you dont even make it to 180 anyway. Id have to say it makes the biggest difference in mild temps where it will open sooner and keep the engine from even reaching 195+

[Hemet8]

Thermostats

yeah, i am going to go to a new, slim type fan with the switch set to 205. But i don't have the funds for that yet. So it seems i can run the 180, but will the 180 thermostat from the newer 3400's fit my '95 3100?

[Manitcor]

RE: Thermostats

yes, you wont find a part number on these very often so just look for a 44mm single valve 180 t-stat

youll most likely end up buying the gasket seprate but most autopart stores carry it. They just wont find it in the computer.

[spacecadetz26]

I bought my 180 from partsforyourcar.com I think it was like $15 shipped or something and it came with a new oring, I THINK Summit sells them too.

I have had no problems with running dexcool, I use it on EVERYTHING we own but the plymouth voyager turbo. Even the old 86 Fiero runs dexcool, just have to make sure the system is totally clean before you put it in. 90 GTZ with the Quad stays at 1/4 even in heavy Shitcago traffic.

BTW, you shouldnt have one bit of problem with KR on a 95 3100... When i'm datalogging with the DHP tuner, I have never seen an ounce of KR with either the 3400 or 3100. The stock timing settings are too conservative.

[TurboZ24]

Ask any GM tech, ask Colin or Scott. They both absolutely hate Dexcool. It's got poor rust inhibitors, and plenty of other issues. Prestone and several others make a "fits all" replacement these days, that's what I end up using. In fact, when Scott get's a new car, he immediately flushes out the Dexcool and replaces it.

[TurboGTU]

NPG watterle$$.

http://www.evanscooling.com/catalog/C_npg1.htm

http://www.evanscooling.com/html/npgPls.htm

Regular green stuff is good.

Waterwetter works OK.
You need to wire a external fan switch or get your PCM flashed to take advantage of the new thermo..as the fans will still kick in at 200+.

The idea is to keep the coolant a liquid. Lower than 160 and you can cause more rapid engine wear.

But anyway..

http://www.consumeraffairs.com/automotive/gm_dexcool.html

[spacecadetz26]

If it wasn't for dexcool, Colin or Scott wouldnt have anything to do at work. I used to hate dexcool too.

Before I worked on cars, the lower intake gaskets went on my car at around 85k miles. I was almost forced to pay a shop $600 to fix my car, then did them at school with a couple friends help. I find that dexcool turns acidic if you leave it in too long, I think they should have you change it every 3 years or 75k miles instead of 5 years or 150k miles. I found pitting on the aluminum of the lower intake manifold. You could also say it makes your heater core or radiator go bad, two other common problems it seems with GM vehicles.

My dads 99 Blazer experienced a bad heater core at 60k miles. I drove it from Las Vegas to Northern Wisconsin with just putting stop leak in it with the heater core leaking. I did not have to fill it once on the way. Later the $1000 repair bill and the crappy designed heater core left his wallet empty. It was leaking at the seam where the tube and the core meet.

My 96 Z26 (a car I have driven for 5 years and 100k miles) has experienced two radiator failures since I owned it. Both were from the plastic end tanks that ruptured, was it dexcools fault? No. crappy design of the radiator, the NEW aftermarket radiator I put in has been perfect not one crack. Same with the intake gaskets. So no I do not blame dexcool for all my cooling system issues, I still have the original heater core in my car and it has 155k miles on it and nearing 10 years old. I have kept my cooling system maintained, and had many other issues like a warped timing cover (from the replacement engine after piston failure) that have made me change my coolant more often. It had the "original" water pump with 150k miles on it until I changed that timing cover. I do not find dexcool to be at fault with any of my issues.

BTW, I used to be a Ford Tech. I now have my own business.

[TurboGTU]

Dexcools fault is that they advertise "Mainance Free". Meanning..no flushing needed for those "Advertised miles"...adding watter..yes you need to add watter. Only a moron would neglect not to add watter. SLudege depositing and formation from not changing it before those mile is false advertisment causing the unit to be less effective and over pressurise causing hot spots to boil out watter and causing failer. I will agree that the heater core and end tanks are caused by GMs low bid on part selecting to save for manufacturing..but as far as clogging and sluge deposits causing over heating and boil over...Thats Dexcool.

[geoffinbc]

Well again it is and isn't Dexcool. Dexcool seems to be very suseptable to low level paticulates and air introduction into the system. The worst vehicles were the chevy S-10's with 4.3L's. On the rad they had a hose to the overflow which had no clamp. This often leaked not only causing a loss of coolant but also an introduction of air. This caused huge problems once owners let it fall past the full line. If people were on top of things then this would never would have happened. But you know how car owners get.

So yea I would blame some of the problem on Dexcool because im sure they could have spent a few more years researching product formula. But also the vehicle owner is partly to blame.

On a side note I always use Prestone coolant and had 1 gm heater core fail after 10 years on my s-10. Now the new one I put in 2 years ago has failed. I am not going to use a GM one again because the parts store one was cheeper with my discount. We'll see what happens. So far it seems to be luck of the draw because the first GM core went 10 yeas but the second only went 2. The Rad is still original. I change coolant every year at the beginning of summer. I completly flush it with water then blow it out with air. This includes removing the block drains. You could eat off the inside of my rad it absoutley sparkles So contamination is not to blame for teh second core failure.

[Hemet8]

Thermostats

Thanks for all the guys. I put in a Hypertech powerstat 180 degree thermo. Part number is 1020. I had to look up the stant equivelent for the oringinal, then cross refence the size with the summit application catolog. It is for a 96-2002 chevy 454, 92-96 chevt 3.4L. Works great. I have an Air to fuel ratio gauge in the car and it added two more bars of fuel on the table. Engines runs at the first hash mark now, much better! Thanks agin for all your help.

P.S. I like the green stuff my self, just seems to run cleaner. ( buddy has an 01 alero, it always seems "dirty")

[Gangstgprix.]

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