Here is whats going on.

basic stock GM 350 crate.
Northern 31x19 (dual 1" tubes)
Stock Dual Fans (working fine)
170 stat
Stock replacement pump
Timing set at 4* initial, carb is set at ~30 dwell.
using stock O2 sensor shows not lean, less than 8K

On a warm day (read 80F) i have a hard time keeping the thing cool. Cool to me is below 220, i hit 240 in basic city driving. Stoplights every 1/2 mile or so, 40mph speed.

On the freeway or open roads, its fine (air dam is intact).

Coolant not being lost, 60% water, 40% coolant with water wetter.

Any ideas?

 

im having similar problems (though i have a 305 TPI). i have an 80 degree thermostat

maybe you should get the JET fan switch, i might get it. it turns the fan on at 195 degrees and off at 185 degrees

 

i have an adjustable switch comes on at about 180. Of course with the temp staying up, they dont turn off unless im on the freeway for a little while.

 

wow...maybe its the radiator?

 

Brand new, Northern radiator. The summit brand one basically, no mangled fins. Tranny cooler in front of it, tranny stays at 180 or so...

 

maybe its your temp sensor reading incorrectly

what could it possibly be....

 

Fans pushing instead of pulling?

JamesC

 

Does "stock" mean "standard" or "1985 original,on car since new"?

 

Pulling, i verified many times
New fan motors (2 months)
Temp sensor for gauge (6 months), CTS 3 months
Reading at thermostat shows about 10* below gauge temp.

Fans are within 1/4" to 1/16" from radiator surface, some places closer than others

 

doesnt combustion chamber temperature increase if you are running too lean?

maybe there is some kind of blockage in your cooling system

 

I use a 180 T stat, mix same as you, and a fan switch (pass side head) that turns fans on at 189, off at 182 keeps motor cool and very even temp.
240 will cook the tranny fluid if you have an automatic.
Is the "undercar" air dam there and complete?? I often ask people and they say yes as they look at the car, most dont even know theres a cooling air dam underneath.
fan switch fs-158 echlin (napa)

 

Need to read the post a little better.

Carb was just readjusted (by me) NOT lean (O2 sensor reading)
Idle at 620+/- in drive (external measurement)
Tranny is not that hot, seperate cooler at 180 or so (In pan)
Air dam is intact. (verified x2)
Fans are working, on at 170-190. Dont usually have chance to go off with this problem.
Radiator blocking is highly inlikely. New block, new pump, new rad, new heatercore, new hoses.... Upper hose holds pressure no problem (16lb cap)

Today as about 80F, with fans on, small drive (3 miles) temps stayed from 200-230. That was fans on the whole time. Trans 170-185*



Thanks for the suggestions thus far guys.

 

are you SURE you have the coolant mixed right? if the cooling system is running perfectly like you describe then there is no way it would be getting this hot

does it have any trouble warming up in the winter?

you just might have to live with 220 degrees

you must be overlooking something because you have stated a perfect cooling system...in theroy its not possible it is getting that hot. also, just because something is "new" doesnt necessarily mean it works....

i really hope a solution can be found because i keep thinking about this lol

 

Air in the system??

 

Have you checked the voltage at the fan connector with the fan running?
A voltage drop would make it spin slower,moving less air.

 

Positive, on the mix. Much more distilled water than coolant. Done myself

I do have voltage drop, but a little 63 amp alt has some troubles with these. When first started, beginning of drive, voltage goes from 14.4~ to 13.5~, but after its been on (hood temps up), voltage will be at battery (12.5), sometimes less!

Im pretty sure the radiator is clean, when i first got it i flushed it with water (it was kewl i wanted to play with it .

Gonna grab an external, mechanical gauge to check it a little more.

 

Ok, here are few things to look at.
1st. Where does the needle on your gauge sit when the car has sat overnight?? If it sits anywhere between 100-220 than your gauge is off. They sit quite a ways back away from 100.
If thats not the case...
2nd. You replaced everything and it seems to me that you ought to eliminate quite a few things. If your car is staying at normal temp (I am assuming 180 because of your fans... probably thermo) than there is a problem with adequate cooling at idle.
Third gens are notorious about overheating when they idle. This is because the fans are not pulling enough air to cool the motor down. This is the first main reason for overheating in stop and go traffic. Second would be water pump or cloggadge.

I recomend you check your fan motors and possibly replace them since, if they are stock, they are getting old and slow. I prefer changing the fan to the most powerfull one you can find. Check summit, they have great deals on fans.
Traped air could also be a problem alongside with not enough water/coolant in the system.
There is a cooling line coming from the back of the block. You cut that line and insert an "Engine Flush Kit" T fitting in it. Than hook up a hose to it and flush the whole motor with it. The coolant will start coming out of the radiator "flushing" the system. This will eliminate the air pockets and possilbe clogg problem. When you are done the block will be full with water. This, roughly, equates to half of the system. So fill the rest with coolant and you will have about 50/50 or 40/60 mix. This is a good thing to do to any cooling system.

I personally think that your fans are the culprit. You can replace the motors, but for the price of that you are probably better off getting a 2800CFM fan from summit. Our stock ones are about 1300 all together. I know, its WEAK.
Its the WEAK LINK OF THE THIRD GENS.

 

Im going to the junkyard today to find a taurus or intrepid fan.

Fan motors are brand new maybe 2 months (Siemens)

 

Update:
Gauge sits at 220-240 when off. Resets to below 100 when ignition on.

Picked up the 2-speed fan from a 4.6 Thunderbird V8, wholly crap that moves a lot of air! Even the lowspeed kills my 16" fan (not on my car)!

 

just wondering what temp you run at on the freeway

 

I agree on the air flow. If you're cooling fine at highway speeds like you say, then the fans must not be pulling enough air through the radiator.

What heads/cam are on your 350 and do you have hedders? I'm running the LG4 radiator (2 years new) and fan and mine stays cool. It's a long wait in the line at Sonic in the summer before my one, lonely fan comes on.

Carb still doing good?

 

Ok, get a temp gauge and a thermo housing that has provisions for the sending unit for that guage. hook it up and you'll see what you're runing. New fan will defenetly help you out. So, get that one from the Thunderbird and you should defently see the change.
I still prefer those 3000cfm+ fans cuz they sound soo cool when on. The car sounds like a jet. Keeps that sucker cool like no other.

If the fan does not fix your problem look into cloggs pump and thermostat. GOod luck.

 

Some people need to remember to read the whole thread, carefully. As stated, freeway temps are fine.

Goodwrench crate motor, really mild. LG4 manifolds budget sucks.

Carb was just adjusted (by me, bought a dwell meter) and runs a lot smoother than before but no noticiable difference compared to before in temps.

Tomorrow im going to get the other fan installed (had to find a 40AMP fuse assembly) and will see if it helps... it better im almost out of ideas...

Next will be replacing it all (Thermo, cap, new Stewart pump, intake gaskets (not leaking, never now)) and that will suck, as all of this is new already...

 

hey...did you check to make sure there was no paper stuck in the ends of your rad, heater core or water pump....i work in a body shop and alot of our aftermarket rads have paper in them for transport....if you forget to take it out it can be a hudge prob....just my 2 cents...good luck

 

FIXED: Stock dual fans suck.

Here is how i wired mine incase someone search for installing these

Relay one (High speed)
SPDT relay 40AMP
30 - Battery +
85 - Switched + (Ignition)
86 - Manual Switch (to ground)
87a - To second relay 30/common
87 - Fan (high speed)

Relay two (low speed)
SPDT relay 40AMP (Can be a SPST 4 post relay, no 87a)
30 - from relay one 87a
85 - Switched + (Ignition)
86 - Adjustable Thermostat (to ground)
87a - No Connection
87 - Fan (low speed)

This thing is awesome, while waiting in traffic it actually cycles on and off!
Using low speed cools from 220-230 down to 180~ in less than 2 minutes at stop and go. High speed haha about 1 minute. Its louder than my engine at idle, could probably move the car itself!

31x19 northern radiator this covers about 7/8 of the surface, bottom to top is covered. There is about 3 inches from the fan motor to the waterpump.

Using 10g wire for all connections. 14g fusible link from battery to main distro point (about 50 amps before link dies). Voltage drop is LESS than i had with the duals. Stop up amps look to be about 45 or so amps, when running about 27.

Thanks for the help guys.

 

FINALLY thank heavens lol

it was starting to sound like some twilight zone story about the car that wont keep cool

 

This is a CLASSIC third gen issue! I am glad you got it fixed.

 

So if anyone is interested in stock dual fan setup let me know

Im sure on a stock setup car, stock rad it would be fine. I think it just loses some potential with a radiator that is over twice as thick as stock.

After more testing the new setup works great. Now if only the adjustable thermostat was as stable. Sometimes it works at the 220, then sometimes 235, 200, etc. Maybe get the screw in type...

Thanks again

 

Once you get your hedders and exhaust opened up, you'll be able to get more of that heat away from the engine. I added coated hedders and heads to mine at the same time and noticed it running cooler. Attribute most of that to the hedders as I was running stock lg4 manifolds like you. Glad you're good.

 

headers would be nice... even cheapies right now

Progress report

temps have been around 90 or so

Using just the thermostat to control the fans, temps stay stable. goes down after a short time running. Switch it over to Hi, and good god it cools fast. But am noticing i most likely will need to update the alt soon, as it takes a lot of power to run the fan. slight bog from idle, not fuel related as it works fine when the fan is off.

Anyone suggest a drop in for me? 100+ amps, vbelt setup.

 

gm temp gauges are known to be off , i suggest getting a mechanical aftermarket gauge

 

Im also going off of the "feel the side tank test". Before fan is engaged, fast touch burns, after fans on for a little i can hold for a few seconds. I dont have leparsy(sp?) so i think im ok.

Gonna pick up an iR therm one of these days... but i agree with you on the verification

 

Here is where aftermarket fans will help. They can flow around 2500-3000cfm and have a smaller draw than you stock fan! The stock fan I think takes around 30amps. The aftermarket fans usually around 9-15!

 

Yea i've been having the same problems with my car. Those stock dual fans wired on all the time do nothing for the cooling . I'm gonna have to try what you did. I was thinking about that derale set up. They flow i think like 3500-4000 cfm!

 

Well for $25 i couldnt have chosen a better setup.

it takes a lot of power (replaced with new alternator! 94 amps) but work great.

 

so what fans did you finally go with? they duals? Thats awsome you fixed the problem.i have been battling with this for some time.

 

Read the thread, lots of people helped with this one. Thunderbird 4.6 fan

 

I put this post on another thread but you may find it usefull

I'll tell my story for what it's worth. Ever since I bought my 87 camaro I had cooling problems, mostly related to the electric radiator fan. The temp sensor failed, then the relay burned out. This caused me to go through a couple fan motors. Over the years I kept having cooling problem, especially after installing my big cam, big head engine. I removed the air conditioning components, including the AC condensor which allowed more air flow through the radiator. I also set up the radiator fan motor on a dash mounted toggle switch. I had to watch engine temp closely. Not the best situation, but the car was not a daily driver and it got me by the next few years. Last year I was looking for parts at the junk yard and came across an 82 or 83 firebird. This car came with a belt driven fan. I had thought all third gens came with electric fans. The radiator shroud went home with me that day, along that car's non AC heater box. I installed the parts with an aftermarket lightweight flex fan. Now cooling problems are GONE. The belt driven fan gives all the cooling air flow I could ever need. Granted one advantage is that I have a manual transmission, meaning no trans cooler.

This is my long winded way of saying there are other ways of getting more air flow without creating special air ducting. My solution may not be for you if you are not a belt driven, 4 barrel, no AC, automatic power nothing, guy like me. TPI guys go ahead and build your air dams. If you're like me, search the junkyard for an early third gen car to pull parts from.

 

I'm about to try one of this fans, do you know what are the colors of the fan wires, for high and low speed? How can I identify them?
Thanks in advance.

 

Black ground typical

I dont have the car with me right now, i simply connected 12v to each other connector.

 

I wonder how much CFM's the Thunderbird fan pulls?

 

I just checked the fan wires and there is three of them, one blue and two black ones,

 

one black has a red/orange line through it

 

Forshock,
What year thunderbird did that fan come out of??

 

97 thunderbird 4.6l

 

No red line, just 2 solid black and 1 blue hope I didn't get the wrong fan. I got it from a late 90 Lincoln mark III 3.8 v6

 

Here’s what I would do to figure it out...

I would test the wire in different combinations on the battery terminal, this fan you be a pusher or a puller depending on how you hook the positive wire.
Just touch the wire to the post for a very short moment to see if the fan moves, and write down your results, call this R&D on a Lincoln Fan.

Good Luck!!

 

get a stronger fan...ive got a flexalite fan for about 80 bucks i think and it pulls or pushes 3000 cfm of air. I can let my car sit in the garage for 1 hour and come back and it will still be below 200 if even 180*...makes all the difference in the world

when i first upgraded my system...i got a 160 stat, 31X19 alum rad, air dam and new water pump...stayed under 180 as long as i was moving...but if i sat still for more than 3 min it was well over 220...got my flex fan installed and now its ALWAYS under 180* right where it should be

gl

 

umm we are talking electric fans, not mechanical. Rather off the point...