92z28tpi

OK, like this topic hasn't been beaten into the ground enough already. Thanks to those who have given suggestions and I've followed them but the problem persists.

If the car is moving (92 Z28 5.0) temps stay fine-not over 220. Get stuck in traffic-temps soar up to 260+ (this is verified with a scan tool).-with or without A/C on, doesn't matter.

Here's what has been done:
piggyback chip programmed to turn primary fan on at 205 (works)
A/C blows cold and secondary fan operates as it should
new water pump
180 t-stat
new coolant mixed 50/50 with distilled water
new lower rad. hose
air dam is fine

-no water in oil
-no coolant loss at all...added dye and checked for leaks everywhere with UV light
-no white smoke
-runs fine otherwise, very well maintained
-radiator has flow

out of ideas, every f-body I've owned has been a cooling battle! none of my other cars have these issues.

very frustrated because I have a car I don't want to drive for fear of being stuck in a traffic jam...I live in NY and spend a lot of time in NJ, traffic jams never happen, yeah right!

Please HELP!!!!!!!!!!!!!!!!!

safemode

iTrader: (1)

Since your secondary fan works when the ac is on, does the car stay cool in traffic if you have the AC on? If not, there may be something wrong with the relay that the ECM powers off that controls the fan when going over 40mph.

I would say with fair certainty that this is a fan issue, either they're not spinning fast enough (low voltage or high resistance due to aging), or they're not turning on when < 40mph and at certain temp.

92z28tpi

as long as the car is moving, ac on or not, temps stay acceptable...get stuck in traffic...temps climb and climb. 80 degree plus weather, it will hit 260 within 10 minutes of being at a standstill. the fans are kicking on at the proper temps. example, car idling in driveway. fan(s) kick on, but once the temp gets around 240...even with the fans on, the temp will not go down just keeps on going up.
i'm out of ideas at this point.
i see mention of different fan assembly's but can't see why this is neccessary. went through the same crap with my 91 Z. same mods too and problem solved, but not with this 92!

dippo6

do you have the right water pump? as our cars use reverse rotation? and i thought my fans worked to.. and im a full time tech.. i work for mercedes.. but little did i realize that my temp switch for my secondary fan was only working sometimes.. as in when ever i was checking it and the fans it worked.. but it was the cause of the same problem for me.. i put a 180 degree switch in off summit and the car has never run cooler along with the 180 stat, its located on the right (passenger) side of the block is a one wire switch and only accessable from under the car altho sounds like u have checked its operation with a scanner?

kooga

Maybe its a longshot but , a friend of mine had problems with overheating and it turned out to be the egr stuck open or malfunctioning..
When you did the scan did you take a look at the air intake temperatur? If its very high this could be a symptom of egr failure.Friends car had an intake air temperature of as high as 190F ( on the highway)....Changed the egr and no more overheating and the temperature went down to 100-110F

Reid Fleming

iTrader: (2)

Partial plugging of the radiator a possibility? Works good enough most of the time, but can't keep up when you really need it?

You say your 2nd fan is turning on with A/C....what temp is your fan switch? The stock fan turn on temp for the passenger fan is about 235° when the A/C is off (too high in my opinion).

Do you have a ton of leaves and branches between the radiator and the condenser?

I'm in Houston (FL style heat & humidity), running 50/50 with one bottle of water wetter. Mine will sit on 200-205° when sitting in a traffic jam. Of course I have the first fan on at 190 and the second fan on at 200. Stock radiator and fans.

When I had my transmission cooler put in, I bypassed the radiator. Made a nice difference in radiator temperatures. Also protects the transmission oil in the event your radiator is too hot. Transmission coolers are cheap insurance on our cars.

92z28tpi

bumping my own thread because I desperatly still need help.
I saw the mention of a stuck EGR but I don't suspect it because I'm not getting any codes??
There's no debris in front of the radiator.
NOW, the coolant in the overflow is boiling.
Same deal, drive the car and keep it moving everything is OK, but get stuck and have to sit at an idle....bad news..260 within 10 minutes.
Out of ideas and realistically preparing myself for the worst.
Fans run fine, oh the reprogrammed primary fan is set, on at 210 off at 180. Kicks on like clockwork, second fan on with ac. This running too hot condition is present with or without the ac on.
I can let my grand cherokee idle till it runs out of gas and it stays at 210.
if I start the Z28 cold and let it idle for 20 mins., it'll hit 260 and start boiling.

kooga

[quote=92z28tpi;3793367]bumping my own thread because I desperatly still need help.
I saw the mention of a stuck EGR but I don't suspect it because I'm not getting any codes??
quote]
Well , he didnt have any codes either? thats whats so strange...
We scanned the car and saw that the intake air temperature was way high and tried another egr and the problem with overheating went away...

92z28tpi

kooga,
was your friends car overheating all the time or just at idle?

NoMoFoMoCo

What you might want to check is the radiator cap.

Honestly, they are so cheap, just get a new one. With out the right pressure in the radiator the coolant thinks it is hotter than it is, boils faster, overflows and then makes the coolant level lower from boiling. So driving will be fine, idle will be hot.

What is the size of the engine?

92z28tpi

Well, I'm on rad. cap #3 now as I suspected it as well. I have a lev-r-vent on there now as opposed to a regular cap. Should I ditch the idea of using one of these caps...had one on my vette with no problems.
The engine is a 5.0L (305) TPI and absolutly bone stock. The only perf. part is 2 K&N air filters. I like it stock because gas mileage is good and I drive about 500-700 miles a week (highway)...well I was, but now I fear getting stuck in traffic so I've been driving the gas-guzzling Jeep

NoMoFoMoCo

Were all three caps lev-r-vents? Or just the latest attempt?

92z28tpi

I'd even be willing to take the hit on less gas mileage if this thing ran too cool....at least I could drive it without fearing that it's going to explode! I've never had so much cooling problems with an F-body before.
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2 out of 3 were lev-r-vents.....should I avoid these? I work for carquest so whatever I need is sitting in the building pretty much.

NoMoFoMoCo

Honestly, I have never had good luck with em. I would just go for a normal run of the mill 15psi rad cap. Also, might want to look into wetter water.

http://www.redlineoil.com/products_coolant.asp

How long ago was your last tune up?

naf

iTrader: (7)

What's different at idle and highway speeds?

Check your timing. Let it idle for a while and pull some of your plugs. What's the scan tool say about the mixture at idle?

kooga

It was overheating all the time , couldnt stay at idle for more then 10 minutes . On the highway it kept below boiling point but as soon as he came to a stop or was in slow traffic the temperature started rising.
Try to disable the egr , I think that the easiest way is to remove the vacuumhose and plug the hose not causing a vacuumleak ,see if it helps your overheating issue.
If you have got a vacuum(sucker) you can test the egr function by applying vacuum to the egr at idle , the engine should almost stall doing this.
Hope you understand my bad english grammar because I myself got problems with that

90fbrdprgt

I have the same issue with my 90 bird. It heats up bad when I am stuck in traffic or idle but when moving it cools down just from the natural amount of air hitting the engine. I heard a little squeal today so I assume that is the water pump bearings going. Replacing them this weekend hopeing that will do the trick.

Good luck

hotrodln

My 87 IROC used to run hot when pushed. I figured the radiator was fouled becuase of it's age.SO I bought a new one. When i pulled out the old radiator, I found a bunch of leaves between the radiator and the a/c radiator. even though my fans worked fine, there was NO air getting through there.

92z28tpi

Update:
So last ditch effort. The radiator in the car wasn't old, but it was the last thing to check. I had gotten it from work and it was some el-cheapo china made product. I took it out and brought it over to a shop around the corner that does flow testing, well, this next to new rad. had almost no flow. Didn't even bother with a warranty replacement and got my money back. I bought a different brand and installed it. So far so good If anything it's running on the cool side. Nothing like junk parts
So cooling issue solution seems to be resolved for now. Basically replace everything and reprogram the fans. That seems to work!
*Thanks to everyone for their help*....oh, the EGR checked out fine.
Now for the brake problem (seems to be more simple)..dives under hard braking to the passenger side.
And a moaning noise when taking slow speed sharp turns only after car has been driven to operating temp. Strange that it only makes this noise when the car is moving. Can't duplicate it if turning the wheel with the car parked??
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Update:
So last ditch effort. The radiator in the car wasn't old, but it was the last thing to check. I had gotten it from work and it was some el-cheapo china made product. I took it out and brought it over to a shop around the corner that does flow testing, well, this next to new rad. had almost no flow. Didn't even bother with a warranty replacement and got my money back. I bought a different brand and installed it. So far so good If anything it's running on the cool side. Nothing like junk parts
So cooling issue solution seems to be resolved for now. Basically replace everything and reprogram the fans. That seems to work!
*Thanks to everyone for their help*....oh, the EGR checked out fine.
Now for the brake problem (seems to be more simple)..dives under hard braking to the passenger side.
And a moaning noise when taking slow speed sharp turns only after car has been driven to operating temp. Strange that it only makes this noise when the car is moving. Can't duplicate it if turning the wheel with the car parked??

90fbrdprgt

Almost as bad as the 70 Nova I used to have. Couldn't figure out why I could only get a little fluid in the radiator until the dead mouse fell out! Usually the simplest thing that causes the most problems.

C305

iTrader: (2)

I have a 91z 305 tpi and im having the same problem. Guy I bought it off removed the a/c and it has a pulley, I changed the water pump but my fans didn't run at all.When I unplug the fan sensor it runs consistantly on the driver side but still overheats at idle. What does egr stand for??

C305

iTrader: (2)

I have replaced the cap and replaced t-stat 180 aslong as I give it a little bit of gas it won't overheat and stall.

ikeepitreelz

E.G.R=Exhaust Gas Recirculation

91camaroRSx383

dude ive had all kinds of cooling problems i replaced everything related to cooling even took my thermostat out, and nothin worked. my father works for us airways and he works with some old school mechanics who can tell you anything about cars as if someone were reading the newspaper to you. Finally a solution, they told me that my timing was retarded( by this i mean slow not challenged) so little that i couldnt realize it but just enough to make my car run hot. They said i should advance my timing ever so slightly cause it would not burn as much feul as quickly. And now my 91 RS hasnt had a cooling problem since. Lets put it this way, on a hot SC day(about 104 degree) my camaro sometimes gets up to 200degrees no matter what im doing sitting or moving. Your performance will drop very little but its nothing a few modifications cant overcome. Just try it, worked for me, my car got to about 240 everytime i drove it before.
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Also if there is setiment in your radiator, it most likely came from your engine because the person who owned the car before you or perhaps you only used water in your radiator, in that case flush your radiator every 100-150 miles, for the fluid cost you can just buy staright fluid and mix 25% fluid, 75% water.

naf

iTrader: (7)

Advancing your timing should IMPROVE performance unless you're advancing it too far and the computer is pulling the timing back out due to spark knock. The reason this solved your overheating problem (and retarded timing causes overheating more times than you'd think) is that the engine was running less efficiently with retarded timing. It was burning MORE fuel than it needed for the same amount of power. That extra fuel was producing additional heat for the motor without assisting in the power stroke.

Romilin

Let me start by saying I had the SAME issue with the SAME attempts on resolving them, new thermostat, hoses, radiator, waterpump etc...... I believe a combo of 2 things resolved it for ME......

1. There was alot of trash inbetween the radiator and the AC ( I looked mult times but did not see it till I pulled the radiator). (This helped about 15-20 degrees)

2. And no flaming on this..... My front suspension was going bad and my car was awfully low to the ground, so I thought about the possibility of it "sealing" heat in when stopped. All that heat from the concrete and the engine with nowhere to go....... So I replaced my front shocks which lifted the nose up a couple of inches...... BAM problem resolved. The air had no place to go, it was like an oven. Now my car runs steady at around 160 average


Hope this helps SOME!

Steve

b4ccamaro

There is something to be said about using factory parts. I live i Phoenix and have had the worst time with overheating at a standstill. I talked with a trusted mechanic and he pointed out that GM uses a single core radiator because it has the greatest surface area contacting outside air. He also showed me that factory radiators have the most fins per inch accross the radiator. That also helps a lot with cooling. I counted when I got the new radiator and sure enough, the generic radiator had 6 fins per inch where the GM one had 10. So word to the wise, use GM parts whenever possible!

GodSpeedGTA

iTrader: (1)

You should def upgrade your radiator to sustain these cars. You can pay $600 for a griffin radiator or you can simply buy a 100-300 dollar summit aluminum radiator. I bought a 19x31" radiator, its too big but will work. It sticks out of the radiator shroud but it cools like none other. I also used an aftermarket flexolite fan that blows high cfm.

Try a better radiator and if youd like to try something cheaper first then id suggest a really strong SINGLE fan (Pusher not puller) and mount it on the front. Then you have two fans pulling air through the radiator and a optional switch controlled fan to push air when you are at a stand still.

My car doesnt overheat at all if im moving. Once I stop for more than 5 min or so (traffic or whatev) then i hit my fan and it says around 200.