RS-Chevy-SS

Ok maybe I can explain myself Better.

The picture above was while I was driving down the highway at about 55MPH fan/ac off while it was 68Degrees outside. The car has a history of overheating in the 120degree summer climate we have in my home town. The car would constantly overheat with the stock single fan whenever the AC was on. In order to correct this I swapped in a 160tstat and swapped the stock fan with a dual speed fan+shroud combo from a ford taurus, we bypassed the stock switch and just run it off of a toggle switch. Now in 110degree weather I can run the AC with the fan always on and it will run about 210 in the city but on the freeway it will climb up to about 240 and ill have to turn the ac off for a couple miles to let it cool down, this is even if the fan is running. Also when I drive down the freeway regardless of the AC being on the car will warm up if it has any other car in front of it. As soon as I get back in clean air(or turn the fan on) the car will cool down. The lower air dam is in place but my dad cut about a inch off it back in the day.

JamesC

iTrader: (5)

Sorry, I'm having a difficult time deciphering the above. Some cooling issues can be attributed to the air dam. Have you determined that it's in place?

I don't recall ever seeing the particular "Bat" gauge (but I haven't seen them all) .

JamesC

CamKid1992

what is happening is the same thing mine is doing. with the 160 stat teh coolant is flowing through the engine alot faster then normal so at highway speeds and when its hot the coolant does not have enough time to "cool" down in the radiator and pretty much passes right through without disapaiting the heat. i also have a 160 stat with a 165 fan switch. my coolant barly goes past 100 unless im on the highway or its hotter then hell outside. i know this is my problem maybe it will help.

JamesC

iTrader: (5)

Oh, I see. I'd say that 160 is much too low (195 is OE). The following link has info that you may find interesting:

https://www.thirdgen.org/forums/cool...hout-chip.html

JamesC

naf

iTrader: (7)

Looks like you're about to run out of gas.

Not sure how a 160 stat would increase coolant flow? The opening on the stat is the same size, it just opens up at a lower temp.

Don't confuse those wavy, pointy things in the dash as anything that actually relays information about the actual state of nature at the end of the sensors. They're notoriously inaccurate.

Like James, I'd go back to a stock 195. Your engine will like it better.

camaronewbie

160 stat is too low. The engine never warms up enough, and thus the computer may have it running somewhat rich, decreasing your mileage. 180 is the lowest you should run. If the car actually boils over at anytime with a 180 stat, then you have a cooling issue that needs resolved. If the fan is running, and the air dam is in place, then might look at a coolant flush and a new radiator cap.

Your car is designed to run at 200 - 220. Now that is real temps, not what the gauge says - these gauges are often very wrong.

RS-Chevy-SS

Ok maybe I can explain myself Better.

The picture above was while I was driving down the highway at about 55MPH fan/ac off while it was 68Degrees outside. The car has a history of overheating in the 120degree summer climate we have in my home town. The car would constantly overheat with the stock single fan whenever the AC was on. In order to correct this I swapped in a 160tstat and swapped the stock fan with a dual speed fan+shroud combo from a ford taurus, we bypassed the stock switch and just run it off of a toggle switch. Now in 110degree weather I can run the AC with the fan always on and it will run about 210 in the city but on the freeway it will climb up to about 240 and ill have to turn the ac off for a couple miles to let it cool down, this is even if the fan is running. Also when I drive down the freeway regardless of the AC being on the car will warm up if it has any other car in front of it. As soon as I get back in clean air(or turn the fan on) the car will cool down. The lower air dam is in place but my dad cut about a inch off it back in the day.

RS-Chevy-SS

The battery gauge was taken out of a 84Z28 i believe. I tested it along with the original gauge that came with the car and determined that the gauge in the picture is very accurate

camaronewbie

OK - so nothing has changed - what I stated above is still true ...

1) 160 stat is too low - 180 is still lowest you should go

2) unless it boils over, it's NOT overheating - regardless of what your junk factory gauge reads (I say junk because these gauges are just that - pretty to look at, but useless for real diagnosis)

3) if it does boil over with a 180 stat, then you have a cooling issue that needs resolved with something other than a 160 stat - a lower than needed stat is just a bandaid fix and a poor one at that - I don't care what planet you drive on and what the ambient air temp is (as long as the ambient air temp is below 220F) - ambient air temps have very little (if anything) to do with engine operating temps. Given that you have an exhaust manifold/headers on each side of your motor that reach 800F+, and that heat is trapped under the hood and getting transferred directly to your engine, do you really think that any 120F outside temp is going to matter much?

If the stock air dam was hacked, I'd replace it - especially since your issues arise when at highway speeds. That air dam is really way more critical to the cooling operation than anyone wants to give it credit for - it's vital, and was designed the way it was to properly cool the car. Talk to any C5 or C6 Vette folks - they know for a fact ... any improper air dam means a significant loss in cooling! Those folks will park at the other end of the shoppoing center if it means not scraping their air dam on a speed hump.

ALSO, when at highway speeds, you having a cooling fan running all the time totally defeats the cooling characteristics designed into these cars! You cooling fan running at highway speed actually lessens the amount of airflow through the radiator - because it is spinning at a rate not equal to the airflow speed that the air dam is trying to create, thus your fan is acting as more interference and restricting the airflow possible. That's most here agree, and look badly upon, those folks that insist on rigging some wired to run constantly or toggle-driven fan operation, instead of having a correct method of controlling the fan. With a constantly running fan, you do more harm than good on tyhe highway.

Have you ever replaced the radiator cap? This is a simple thing, and because such, no one ever suspects it's part of a heating issue.

Definitely grab a non-hacked air dam, and look into a fan controller that will turn on/off the fan as it should be - that way you save your butt because 1) you don't forget to turn it on (which overheats in traffic), and 2 you don't forget to turn it off (which overheats on the highway).

RS-Chevy-SS

1) Originally had a 180 in it and it was still overheating/boiling in the reservoir
3) I HAVE to run the fan while driving down the freeway IF it is summer with the AC on. During the winter/mornings when its still cool its not a problem. If I dont run the fan and just let the air from the speed try to cool it will start to heat up pretty quickly. Again this is all in ambient temperatures above about 85 with the AC on. Yesterday I was driving down the freeway coming from out of town(its considerably hotter there) it was about 75-80 degrees outside and my AC has lost its charge so I was running without AC and the fan off. It ran about 190 constantly. As soon as I got behind another vehicle it would creep up to 220-230 quickly then when I would get out from behind the car it would cool back to about 190. GUARANTEE if i had the AC on I would be REQUIRED to run the Fan. The whole cooling system has been replaced. Radiator,Water pump, cap, tstat, fan. As I said before its been overheated twice to 260 and it had compression tests down and it was fine.

torque_is_good

here's a question

with the 3rd gens, are there model years that the computer will shut off the cooling fan based upon vehicle speed even if the A/C is on ?

naf

iTrader: (7)

How's your mileage? If it sux I'd look to your tune.

Later models controlled the coolant fan with a pressure switch for the AC instead of a switch through the AC control head. This would allow the fan to run only when it was needed by the AC and could theoretically shut it off when air flow was sufficient at highway speeds. I've never looked into whether it actually cycled the fan in everyday conditions. Likely they erred on the side of caution with the pressure set points.

camaronewbie

OK - one more thing to re-emphasize ... are you saying it's "overheating" because of what the gauge reads, or is it actually boiling over?

Everyone knows the 3rd gen gauges are far from accurate - they are just "pretties" installed on some cars to get a higher price tag - they are by no means accurate - ask any 3rd gen owner.

We don't care what the gauge reads ... it could read 100 and boil over tremendously, or it could read 300 and not even have the stat open yet. So - forget the gauge - is it boiling over or not? If not, then it ain't broke, so stop trying to fix it.

91phoenix

iTrader: (5)

As Camaronewbie said earlier the air dam needs to be whole. Cutting an inch of the bottom will allow more air under the car and less through the radiator. If it isn't there how can it do anything in helping redirect the air through the radiator. As for the 160 thermostat it doesn't have more flow as such. It does not stop the coolant long enough for it to loose the heat in the radiator or absorb more from the block. For this reason it seems to flow more. It flows the same at any given time but flows more often. If the temps are at 190 actual then the thermostat will never close and the coolant has no time to stop in the radiator and cool more thus helping it to overheat.

crytical point

I use a 160 stat and have a air dam and it takes forever to warm up but I also live in FL and drive city 90% of the time so its nice to run cool in the summer gridlock.

Aldudley5

I had a 4th gen that ran hot with the ac on and I discovered a sheet of newspaper blocking the condenser. Pulled it off and it was fine after that. I'm sure you checked but just my 2 cents.

Reid Fleming

iTrader: (2)

I know at least some (maybe all) models shut off the fans at 40 mph and above. This appears to be the sweet spot as I've noticed that A/C performance at 38 mph is a little better than at 42 mph....but once you go above 45 and especially 50 mph, the A/C performance improves again.


Agree. It's amazing what gets sucked in there. I had a plastic bag. Just one simple grocery store plastic bag sucked under my car. Made a 15° difference that I couldn't figure out why it had been running hotter.

Disagree. Air inlet temps make a good sized difference. That's why cold air intakes improve performance. I notice a huge difference in performance in January (50°F) compared to August (100°F). Car warms up waaaay faster in the summertime than it does in the winter as well.

Getting back on topic, assuming that there are no leaves, bags, etc stuck in the condenser/radiator, I'd say the air dam is the culprit. If an inch has been removed and it's (guessing) 4 inches tall in stock condition, then you've just lost 25% of your air capacity going up the air dam and into the cooling system. In 120° weather, this is huge.

Another question. Since the fans/shroud are out of a Ford Taurus, are there any gaps on the sides that allow the air to bypass the radiator? If so, that isn't helping.

LAFireboyd

iTrader: (3)

Ask any thirdgen owner? lol Ok...

I've owned 4 thirdgens, and all the gages in all 4 cars have always been accurate enough and consistent enough to trust. And I'd doubt I'm in the minority.

I'm not saying there's nothing wrong with your gage, SS-P-RS, but you're the person who reads it regularly, so only you would know. But from what you've said about the temperature fluctuations you're seeing, it's my guess that your gage is ok.

Nextly(is that a word? lol), a 160* stat is definitely NOT too low. I have to think most of those people who think/say a 160* stat is a bad thing have probably never run a 160* stat, so they don't actually know if it works or not.

I've been running a 160* stat for many years. It's the BEST change I've ever made to the cooling system. No re-progamming of the PROM is necessary for a 160* stat; it works well with stock programming, just as it works with coordinated re-programming; my mileage has never suffered; and I've never had any emissions issues. So, SS-P-RS, unless your stat is sticking or failing, and I don't think it is, then your issues are most-likely NOT because of the 160* stat. In fact, you're your own witness to the fact that your operating temps improved after you installed the 160* stat.

I wouldn't necessarily recommend one for someone in a cold climate(although it would still be fine during their summer months), but in desert climates like CA, 160* works very nicely.

SS-P-RS, you mentioned your car heats up behind traffic, then cools down in open air. That's normal. But the amount of temp fluctuation depends on the difference between the stat, in this case 160*, and the primary "on" temp for the fan. The wider the spread, the more fluctuation you'll see. So when running a "low temp" stat(such as 160*), the fluctuation is simply more noticeable. And the fact that you're seeing that suggests your stat is working properly.

But you're not running a stock PROM, and you've bypassed the fan program, so the only way the fan will run is if you turn it on manually? That's not usually a good set-up. Human beings can be too easily distracted when driving(hard to believe lol), so it can be easy to overlook climbing temps... until it's almost too late. So you could be widening the range of temp fluctuation, which can make it harder for your fan to do its job efficiently.

But getting back to your non-stock PROM, it's always possible that your running issues could be because of the PROM. Or it could be a related sensor, such as the CTS.

Otherwise, it sounds like everything is operating properly(except the fan). So I have to concur that the heating-up at freeway speeds sounds like an airdam issue. I wouldn't think trimming-off an inch would make much difference, but the car has gfx, and gfx cars, I believe, do have deeper airdams than non-gfx cars, and the difference is probably about an inch. So there must be a reason for that.

Sorry for taking the scenic route to get to such a possibly-simple conclusion, but 160* stats take too much "heat," so-to-speak, often getting a bum rap. They're good, but apparently misunderstood, so I had to address it.

goomaan

iTrader: (2)

How old is your radiator. I know this is a stretch but. I was having similiar problems with the car running to hot. After I changed the radiator (becuase to original one finally gave way) my cooling issues were over.

These are not new cars and no matter how much you flush that thing it full of build up that won't wash out.

Rickey_85TA

What temp is your car at when the coolant boils out?

I had a problem with my radiator boiling all of the coolant out, the neck where the cap screws on was wore out and wasn't holding back the pressure anymore. The overflow would fill up and boil over.

Problem solved after I replaced the radiator.

RS-Chevy-SS

It was boiling over before I swapped fans. The gauge is pretty accurate as I have cross checked with a temp gun

I can generally tell when this happens because even with the fan on this thing will over heat FAST! so yeah thats not it

No where near enough to make a difference, the shroud takes up almost all of the radiator. It almost doesnt fit

I had this issue long before I put the prom in it. Im leaning towards the damn too, I asked my pops why he cut it down way back in 1995 and he said it would hit everywhere. As far as forgetting to turn the fan on, in the summer I basically leave the switch on at all times(wont run unless ignition is on) because If i dont have the fan on at all times it will heat up fast! If it gets to 220 its not coming down even with the fan.

Maybe 3 years old but less then 10000 miles on it

Not sure hasnt happened in a while

RS-Chevy-SS

Im going to go outside and take a pic of the shroud/air damn will post in a minute

RS-Chevy-SS

As Promised. Now the shroud looks short on this side but on the other it goes all the way to the endtank. I did this to center the fan on the radiator as the design of the shroud is longer on one side.

LAFireboyd

iTrader: (3)

That airdam is pretty short, so it's probably not providing enough airflow to be effective. Fortunately it's an inexpensive place to start and a simple thing to replace, so I'd suggest replacing it as soon as you can. Even if it doesn't solve the problem completely, it should at least help a lot, which will make the situation safer if you have to continue dealing with a cooling issue.

RS-Chevy-SS

Like $40 to replace right?

LAFireboyd

iTrader: (3)

New ones aren't easy to find anymore, but it does look like Modern Day Muscle has one for about $40. But if you have time to go through a junkyard or two, you might find a decent one for just a few bucks.

RS-Chevy-SS

I thought hawks carries them for $40

ASE doc

One thing to be aware of for anyone who has AC: between the condenser and radiator is a 5/8 inch vacuum for every loose leaf and bit of debri you come across. When I deleted my AC this winter I found this space 1/2 full with all manner of garbage. This was cutting airflow to half of my radiators core surface. I would expect that most any of our cars with AC will likely be the same.

You cannot see the debri with the radiator in place. You need to remove the upper support and swing the top of the rad back to expose this area. If your car runs hot, definitely check this area.

LAFireboyd

iTrader: (3)

Hawk's, Modern Day Muscle, or whoever else might still sell it, check the shipping cost first(especially with Hawk's). Something like this, because of its size(length), might cost more to ship than its purchase price. But personally, I think I'd try to find one locally before ordering one to be shipped.

Your local GM dealer might even still be able to get it. Some airdams are still available, but with different part numbers than the originals. So you'd need a patient parts sales rep who's willing to take the time to cross-reference part numbers. As far as I know, they work on commission. It wouldn't be a big sale for him, but at least it would be something, so hopefully he'll spend some time on it for you.

And again, try junkyards, if you have time. I like this idea best because you can get one to use as a test piece. So it won't have to be perfect, nor anywhere close to perfect, just decent. Then if it turns-out to not solve the problem, at least you won't have spent much money on it.

90 camaro cj

u got the wrong water pump.... u have eathier A V BELT one on a serp setup or a serp. one on a v belt...

ASE doc

This would cause the car to overheat quickly even in cool weather.