breathment

I want to make a FAQ sticky post so we dont continue to get the SAME post everyday. such as what temp thermostat should i run and stuff like that. I went through and found some post that have already been made. but if anyone has ANYTHIGN to contribute to what u think should be in the FAQ post, any ideas or thread links etc, then please reply. This is only a temporary FAQ and once we get some more info i will make a new post and put all the usefull information into that. So feel free to reply to THIS post with any info u wish to contribute to the sticky.


1. What temp thermostat temp. is best?
https://www.thirdgen.org/techbb2/sho...hreadid=148577

2. Is it true that if you don't use a thermostat you will run hotter? (NO but read for yourself)
https://www.thirdgen.org/techbb2/sho...=no+thermostat

3. Want to use an electric water pump?
https://www.thirdgen.org/techbb2/sho...hreadid=142784

4. What is a good mech. water pump to use?
https://www.thirdgen.org/techbb2/sho...hreadid=118670

5. Cold air intake, Ram air intake post are NOT allowed. you will get better exposer and help out more people by posting these in the appropiate forum for your intake type. (TPI, TBI, CARB, AFTERMARKET PRODUCTS etc..)
-------------------------------------------------

Tech Articles
General Tech Article Written by Willie, (VERY good)
A\C Sealing Strips
Thermostatic Theories
Derale Fan Switch Install
Single Fan Schematic
GM Cooling Systems
Coolant Temp Sensor
Cooling System Mods
Dual Fan Conversion
Overheating Car

breathment

this should help u guys who wanna hook up a fan switch or to diagnose a problem with ur dual fan setups. Single fan setups are very simular, just combine everything together with the exception of the secondary fan temp switch.

breathment

explanation of the connectors in the relay.

ctandc

How 'bout the BASIC first?

Like......

"My new 350 overheats, and my 305 ran fine......"

1. What's the condition of the radiator? Are there leaves and dirt caked in front of it blocking air?

Is the front air dam broken or missing?

Has the cooling system been backflushed with the HEAT ON to clean the crap out of the block, heater core, heads etc?

Is the lower radiator hose collapsing? Was a hose used with an internal support spring?

IS the thermostat WORKING.....doesn't matter if it's new or not...

Are the fins on the radiator bent and mangled?

What's the coolant to water ratio?

IS the radiator cap new and the correct psi for the cooling system?


I think this would cover 90 percent of all cooling problem posts......





HTH

mdr211

wow great timing this thread is just what i needed

psycomaross

you should put in the normal operating temp for noobs like me

Randy82WS7

190-220 is about normal, depends on driving habits and rad and system condition and temperature including humidity and on your thermostat condition/rating

Z383

Breathment, do you have the diagram for the fuel pump relay?

Jim 86 Bird

Breathment:

From what I can tell reading my '88 manual, the switches added in the dual fan wiring diagram you posted can be BOTH added at the ECM. The same wire that is tapped into on the left side of hte diagram can be picked up at a pin on the ECM also.

Would you agree, or should I post more info? I figured I'd get a second opinion before I go ahead.

breathment

your saying making it where the ECM controls turning both fans on at once?

Jim 86 Bird

In my case that's what I'll be doing, but I meant to say that you can find the wires where you can tap into either fan circuit BOTH at the ECM plug.

Brett Gutshall

How bout some torque specs, for example water pump to block and pulley to water pump. It seems my water pump took a dump thursday night out of nowhere so i put a new one in yesterday. Havent torqued it yet though cause i have no specs. Just a suggestion.

mw66nova

iTrader: (13)

what about aftermarket electrical fan size? i have a 305 that is street driven with a blue racer cam, forged bottom end w/ 9.2:1 compression, intake, holley 4bbl, headmen headers, ect, ect, ect. what should i look for in fan size. the motor is not quite together yet, i have the stock electrical fan from the v6 on a 305 radiator. what should i expect from this combo, and should i upgrade and to what size/brand.

maybe also suggest aftermarket fans for 2.8/3.1/3.4/305/327/350/383/400/and so on. keep in mind streetability factor.

thenick

All that is really helpful, But what is the correct way to just run the fans off a switch direct.
I.E. just a switch, a fuse, and some wire. Bypassing all relays and other OE components.
Im asking because i cant find out why my cooling fans wont turn on, and I really want to drive my new (to me) GTA.

MrDude_1

the "correct" fan bypass switch mearly runs from the relay to the switch and from the switch to the ground.

CrazyGTA

Which wire do we splice into, to make the switch work?

carfixxer

This is for two fans: If you splice a wire (with keeping the relay connected)to the green /withe stripe 1st fan
green w/yellow stripe 2nd fan.
So I repeat, splice a wire into that green w/ stripe to a good quality toggle switch (without lighted **** etc) and the other end to a ground. By grounding that green/stripped wire turns on the fan.
OR go right to the fan motor and look for the heavy red wire at the connector cut and and run power to it.... but the first way I listed is best.
Do your fans work when you jump the a-b terminals on the ALDL?

thenick

No they do not turn on with the ALDL jumped.
Also the engine harness has been cut into at many points, such as the TPS, low coolant sensor in the radiator, coolant temp switch on the left head.
I did have the right side fan run off the the parking lights, but the fuse started to blow last week every time I turned the lights on.
So your reply has come at a good time.

intruder

iTrader: (1)

my car came with a clutch fan, i have put a electric fan on but it runs all the time how do i hook it up so it starts and stops on its own?

berlinettakid

buy the "painless" kit for 60 bucks. Jegs or summit, super easy to install and looks pretty professional

88IROK

If I'm not mistaken, breathment's 2 diagrams contradict each other in their naming of the functions of terminals "D" & "E".

The 12v+, always on and the 12v ignition switched+ are reversed between digram #1 and digram #2.

If I read them correctly that is?:hail:

Green92RS305

just FYI the single fan on my car is only operated by two things, the a/c relay and the cooling fan switch located on the passenger side of the engine block. the ECM doesn't even touch this one for some reason, so if you have a 91 or 92 RS with a 305 and your fan runs all the time or not at all then i'd look at the cooling fan relay and then the fore-mentioned cooling fan switch. replacing the CTS on top of the manifold will not affect the cooling fan.

and if you don't like the stock cooling fan switch's operating temp of 242-228* (something close to that) and don't want to pay for an expensive $40 hypertech or jet fan switches or whatever here's a link to a corvette site where the switch is just over $20 shipped and fits right in.

http://www.madvet.com/shop?frame=1.138.944
You want part #609-106

and here's a write up that ben91RS did (hope you don't mind me posting it ben )

1.) Disconnect negative battery cable and wait for vehicle to cool down.
2.) Raise and support vehicle on jackstands.
3.) Disconnect electrical connector from coolant fan switch. It's located in between the #6 and #8 passenger side cylinder head, right next to the dipstick tube. To remove the connector, press in on the 2 longer sides and pull. It should slide off. Take your time, it may be stubborn. DO NOT use pliers on the connector, it will break.
4.) Drain and collect the coolant from the engine block. You can either remove the drain plug (not the oil drain plug) above the oil pan on the driver's side engine block or remove the knock sensor. Either will work fine. Reinstall drain plug or knock sensor once coolant is drained.
5.) Unbolt the stock coolant fan switch (should be 21mm, IIRC) and remove it from the cylinder head. Collect any coolant that might come out.
6.) Start the threads of the new coolant fan switch and hand tighten it until snug. Then tighten it down with a ratchet. I would not suggest using teflon tape.
7.) Plug the electrical connector back into the new fan switch.
8.) Lower the vehicle
9.) Fill the vehicle back up with coolant and watch for any leaks.
10.) Reconnect negative battery cable, start the car, and let it sit and warm up for about 2-5 minutes and confirm that there are no leaks.
11.) Test drive the vehicle and make sure that the fan turns on and off at the right temperatures (on at 200* and off at 185*).
12.) Enjoy!


Ben's a really smart guy and has helped me with both my a/c and smog delete's and even fabricated a block off plate so i could remove my a/c evaporator and not have all that ugly crap on the firewall. good job ben

HorseflyDF

I have a question about my single fan on my car.
Its installed towards the engine
side of the radiator and its a pusher.
Is this good or bad or the same as a puller?
One other question
Dual fan setup (if I decide to go with it)
Can I splice into the existing fan wiring to get
both fans to run together? and is that ok ?
I am running 170 degree thermostat and hypertech 200-185
fan switch. I put on an air dam and when Im moving she
runs cool, in stop and go traffic she gets hot quick.
After shutdown the fan wont cut off even after 5 minutes.
My temperture gauge is off also by 20 degrees.
said 220 when the hypertech switch starts the fan.
Im not sure what coolant temperture sensor to get since
this was an engine swapped car 305 to 350.

HorseflyDF

Ok sorry for all the questions
I reversed the wires and now she pulls and she shut
off after a few minutes.

Green92RS305

you want the fan to always pull air into the engine. trying to push against the wind is gonna get you nowhere. and i wouldn't really take the stock temp gauge by heart. if you really wanna see what temp your actually running then i'd get an aftermarket guage. and have you checked your condensor/radiator for any debris, that'll stop you from cooling no doubt.

HorseflyDF

The radiator is relatively new. I drained the coolant
when I changed the thermostat and the fan switch.
The coolant was very clean.
To bad I didnt see the switch for the vette it is alot
cheaper then hypertech.. it all adds up.
The person who owned this car did an
engine swap from 305 tp 350 and I got a good buy
because of all the problems he ran into I guess he had
enuff. I fixed alot of things with the help of people here.
Thanks for the reply.

Green92RS305

its always a work in progress, but if you do it yourself and do it right then you have that security of knowing that that particular part isn't gonna go out.

Fire"Dutch"Bird

iTrader: (1)

Redline Water Wetter helps (a little).
www.redlineoil.com

HorseflyDF

Yeah I try my best to do things right.
Sometimes its hard when your doing a job for
the first time and you dont have a good guide.
Or your in over your head but thats the learing
curve and getting experience.( on the job training)
Its the little things that can kill ya.

I dont like strangers touching my car and taking
my money
Thats why I started working on my own cars.
Then when I did learn enough to understand some
basic principles, I would discover that mechanics
sometimes wouldnt be on there best behavoir towards
my cars. oh what a world.

DENN_SHAH

iTrader: (1)

dirty coolant & what can be done about it.

say the cooling system on your car is dirty, i don't mean where you just need to do a standard flush or 2 & then its clean & stays that way, i mean where you flush it 10 times & after a few minutes its back to looking like rust again & looks like you haven't even touched it, that nice dark brown color.
what can you do so it stays clean?
do endless flushes on it? take it to a shop & let them fight with it?

go to the auto parts & get a remote spin-on oil filter kit. you want 1 that uses a common one quart oil filter.
mount it & run the heater hoses to it. you want to mount it so the filter goes on just like on the motor, the open end of the filter up toward the top, & you want it so you can change the filter from under the hood. you want to leave the heater core hooked up so coolant flows through it. hook the hoses up in the proper direction, you want the water coming out of the motor to go into the inlet side of the filter. if you have a heater control valve you'll need to remove it. if you don't want hot coolant flowing through the heater in the summer then bypass the heater core, just be sure to get some 50/50 antifreeze/water mix in it, it doesn't need to be completely full, just pretty close to full & then cap it off. its best to do this in the winter, when your heater seems to not heat as good as it should, you know its time for a fresh filter. if you by pass the heater core, flush the core before you hook it back up.
run a 180 degree or hotter thermostat, the heat helps break up the sludge.
fill the radiator with your preferred mix of coolant (not just plain water) & drive it. it does take some time but it does work, on the vehicles i have done this to, normally by the time 6~8000 miles have been put on them the system is running clean & will stay clean.
the systems that are already over heating from the build up in the block will probably need the freeze plugs knocked out & the block flushed out though the freeze plug holes.
while you have this set up on your car, be certain you have atleast 1 new filter with you at all times, you never know when the one on the car will need to be changed, i have seen some clog the filter up in less than a 100 miles.
do not change the filter with the motor hot, remove the radiator cap before you pull the filter. carry some extra coolant in the car with you in case you have to change the filter when your out somewhere or need to top off the system.

PhLaXuS

Huh...never had this problem, but I like the idea...

Bill Speed

I have a schematic in my Chiltons, but prefer a physical, visual, or photo image means of showing where these various components are. For the underdash hookup ALDL, for example, I have no idea the pinlayout as I have no device to read codes and never used it for anything. If I keep this car for some years still, I need to get more acclimated but sadly, I've neglected that end.

No mods done on my engine, been running stock since 38/39K miles when I got the car. I do plan performance mods but my engine is likely pretty well worn for those at present. I plan to try VMAX and ProLong in my high mileage engine (now 124,700 miles IIRC) to see if these really aid a high temp engine.

EDIT: I think the above link to Willie's assessement and work (same guy?) was the link that was broken in the other sticky... I think. Anyway, that's alot of info to quickly print out but I think it should help me for sure. I have my lower front shroud removed to replace my bumper and energy absorber as well...so that cuts cooling effectiveness down some. Also my antenna fuse is removed under the drivers dash as it's stopped in operating full extended mode and I heaven't dealt with that problem as of yet...but it's at the top of my list. Does that fuse affect cooling sys at all?
Bill

coolram62

iTrader: (2)

Something I've run into before( and did today - it looked as if a mouse could have been living there)when you remove the upper fan shroud.You'll be surprised how much dirt,leaves and various other things get pulled thru the condensor.This crud gets trapped between the radiator and the condensor greatly reducing airflow thru both.If you're having cooling problems and have done the usual - check the lower air dam,check the thermostat and cooling fan(f) for proper operation.Just a suggestion that may prove helpful to someone.

Orr89RocZ

iTrader: (20)

heres an update for this thread. alot of threads mention what wires to cut for manual fan switchs but not the location of the relays. alot say the drivers side firewall but thats not always the case.

the fan relays can be located on the firewall OR next to the battery. find the lines coming off the fans and follow them out is the easiest way to find the relays.

my car is a dual fan car, an 89 irocz L98. the fan relay was in between the battery and radiator.

Talon

Where Can I buy new relays,, I've got one with a broken prong, and the other one looks like it has over heated and has melted a little, plus the one wire looks like it has over heated also... I have two fans and someone has wired in manual/automatic switches, they attached the relays onto the side of the fender right beside the battery, so everytime you have to mess with the battery the wires are in my road...

Orr89RocZ

iTrader: (20)

I think you can pick them up at Auto Zone, Pep Boys, etc... other car parts stores

just bring in the relay part number and tell them you need a relay

else try to find a parts car

Talon

The relays I'm talking about I think are after markets... These are about 1 and a 1/4 inch square in size,, I don't think they are factory...

Killergrl

Ok so i've done all the checking on the site and gone through the engine looking at all the suggestions and such and find nothing at all wrong here.
I recently upgraded my 305 tbi to a 350 tbi, just purchased new radiator also. when im on the highway OR just driving around town it does fine at first then just out of no where starts to go up BUT the thing is it doesn't go to redline, it stops about 240 or so, just enough to when i stop, bubble a little. it doesnt go higher, i know that's too hot for her but im confused here! yes the thermostat is in working order nothing that i can see is wrong.
i had a person say maybe the belt was getting loose after driving awhile......making the waterpump not run like should, BUT how exactly would i check if that's right or is that even possible?? like i said it never redlines, and it doesn't immediatly heat up, i drove clear across my town today (city stop and go for about 5 miles) and it didn't even reach 200 barely.........but on the way back it went to 240......?!?!?!?!?!?!?!?!?!?!?

Killergrl

just thought i would throw in that i didn't change to a duel fan set up when we switch to a 350........still has the stock 90 RS 305 fan.....................................would that make a difference????

PhLaXuS

Wow...that's really strange. Since it happens in city and on the highway, the fan isn't to blame. That fact that it's heating slowly and consistently is what's so confusing. It sounds like the cooling system is just not up to par. If the coolant doesn't get get hotter than 240*, then the cooling system IS working, just not well. Doesn't sound like there's an actual problem on a component-by-component basis -- just the sum of the entire cooling system is not good enough for the engine. One very distinct cause could be a partial blockage in the cooling system somewhere. Could even be that someone filled the water jackets in the 350. Aside from that, I don't know. Is the thermostat in the proper orientation? Is the problem still around with no thermostat at all? I'd recommend measuring the belt deflection to make sure the tensioner is good, removing the thermostat and then getting the engine up to temperature. Once it's ~220* or high, get it on the highway at a sustained speed of 55+MPH. If it doesn't cool down to ~200* or so within a few short minutes, then this will indicate a cooling deficiency: either a blockage somewhere, bad radiator or even a reverse rotation water pump. If the water pump is a reverse rotation type and the belt is stock-routed, that's your problem.

Also, the ECM temp sensor is a totally separate unit from the one which sends the temp to your dash. Could be that everything is cool, but the dash gauge sensor is going out. Are you going off the dash temp gauge to ascertain the coolant temperature?

-Luke

Killergrl

yea we took the thermostat out to see if it would help at all, and it did nothing!! i just drove around town now at night and this time it drove about 220 in town but the second i got on the interstate it heated up again......... so now im at a loss. i was thinking maybe i needed dual fans to go with the upgraded engine since im still running a stock single fan, but wasnt sure if that would even matter or not. wouldn't think going from a 305 to 350 would make that big of a difference in that area.

Killergrl

im going by the actual coolent temp, after it sits for a min it starts to boil up so i know its getting warm. how would i know if it's a reverse water pump? its an old style chevy 350 that was in a truck...would that make it just not quite pull enough fluid through?
got brand new radiator in her already. so far all the obvious checks out......i just really feel like im missing something right in front of my face!!! that water pump makes me wonder though....let me know if theres a way to find out with out swapping it all around.

Killergrl

im at a loss here
i cant figure out what the prob is with my baby!! i swapped my 305 out for a 350 tbi, been overheating ever since........read the previous posts to see more! i installed a new radiator with the engine swap, we put new thermostat in it it's working fine, i just put a new water pump on her, and that didn't help, we made sure timing was on. it was. mixture is fine. air dam is good. my only thing (other than head gasket) is that maybe i needed to convert to a dual fan set up with the upgraded engine?????????? will be checking tomorrow for head gasket i guess. the motor had been running in a truck right before we put it in and that truck never ran hot. so i was hoping that couldnt be it! i'm pulling for the fans though........what u guys think??

PhLaXuS

As long as there is no disruption in the air flow path through the air dam/ducting/radiator/etc, then fans should not help the issue because at highway speed, you're getting more airflow through the radiator than the fan(s) can account for. In any case, if you want to do it just for peace of mind, nothing wrong with that. I should do the same, too.

I still think there's some internal blockage in the cooling system. If the engine never overheated in the former vehicle, then it's not the engine -- it's the cooling components in the current vehicle. I believe you said the radiator was new, but even those can be bad straight from the factory. Can you get anything (even if it's old or doesn't fit well) to test with?

Jays92Camaro

I would agree. I am experiencing a similar issue and I actually have a 160* thermostat so one would expect it to run cool. I'm running a 305 TPI setup and it was originally a TBI so it only had the single fan. I have the dual fans from my parts car which was an IROC-Z. Car runs cool at first and gradually warms as one would expect but stop in traffic or shut it off and back on and it heats up and has trouble cooling down, hovering around 240 or so. I have been researching hooking up the dual fans as I believe pulling more air across a larger surface area of the radiator should solve my problem. If that doesn't work, I'll investigate a larger core radiator. The 160* therm is also getting switched up to a 180 to back to the ECMs expected operating temp. Some good post that should make the dual fan install a breeze. If you don't have the stock duals, I believe BECOOL would be able to provide them.

PhLaXuS

I'm running a 180* thermostat with four 1/8" holes drilled around the mounting flange. Temp stays right around 190* during the summer whenever the fan is on or if I'm moving >~35MPH. In the winter, the heat sucks, but it was eeh even with the stock one, anyway.

Killergrl

checked today for head gasket problems but it's all good.
yea after i thought about it some more the fans dont seem like the prob.
it takes a long time for it to start heating up but it does eventually get up to 220 then just goes up from there to about 240 and stays. it cools down though when im idleing or in park. which is odd. i drove it today and was out for about an hour or so it stayed about 190 for awhile then just slowly went to 220, if i got on her at all she would get hotter. would a heater core cause it? i've only had one heater core go out and it was leaking fluid on my floor board of the car i had so is that the only sign of one going bad? or are there other ways of checking it? i do have a 87 iroc that has the radiator that was in my 90 in it now i was thinking maybe just switching and seeing if that helps it out. hopefully i find it out sometime soon!!

PhLaXuS

NOTE: Just a side note -- something to think about, but don't give it too much thought right now:

You sure this thing has a good Air/Fuel mix? Slightly lean mixtures usually give themselves to a bit more power at the expense of extra heat. I don't know if it's enough heat to cause what you're seeing. Someone else may have to follow-up on this particular post to confirm if lean mixtures will cause this much overheating.

This may be one of those strange consequential problems. For instance, I had a spark knock error that I absolutely could not figure out. I replaced parts, verified all wiring and NOTHING was wrong in the spark knock system. Turns out someone had advanced the distributor timing so much that it was inducing spark knock once the engine came up to temperature. I retarded the distributor and have not had a problem in almost a year, I guess. In the same vein, a lean AF mix could possibly be causing this crap you're dealing with.

Killergrl

that's possible i believe, my boyfriend thought the same thing and took it into his shop and put her on the scanner and the mixture was reading rich lean rich lean just like it's supposed to. i'm going to check that radiator and make sure that isn't the problem. other than that i have baffeled everyone i ask! it's almost gotta be that radiator!! will be doing that today so i will let ya know what i find out!

Killergrl

ok so i've come to the absolute last thing with this!! we changed the radiator to a 4 core and it still does it....mainly when i get up to speed or get on her......so we thought MAYBEEEEEEE posssibbblyy it could be the PROM since everything in that area is still for a 305 not a 350...could it not be advancing the timing enough at higher rpms?!?!?!!?!?!?!? this thing is making me
let me know what ya think?? and maybe what i should expect to pay for one of them!?