The fan comes on at the said 220mark, I just put a new 180* thermo in her Fresh radiator flush(No corrosion on the inside, fins are all straight) The heater return hose has tons of flow) When I drive she stays down at the cool 140? ish mark(First 1/4 line after 100) and when i sit in traffic or just around time driving it will get upwards of 240-260. The Air dam is also still their. Any Tricks. When i turn my A/C on the other fan does not come on. Can i wire them together so they both come on? Please help!
Also non-related, My FP went out. Do i need to remove the rear axle to do it. Im not cutting a hole in my car. I am willing to take a longer time to do it right. Also could a bad FP cause a car to overheat?

 

ITs a 1992 Z28 5.7. She sat for 7 years. In the last 2 days ive done: Oil change, Air filters, cap, plugs, wires, rotor, fuel filter. Car purrs GREAT! Untill it heats up.

 

Read this thread - Post %15 will also direct you to GREAT Tech Article too.

https://www.thirdgen.org/forums/cool...erheating.html

 

my car sat for about 8 years, got it running late last year, and it does good until i leave it idle, then it starts to heat up and i have a new rad and thermostat. what i would check is your heater core (mine is bad because sometimes my heater does not work) and a bad headgasket (changing mine at the moment). My car doesnt heat up until i drive it around then idle it, it will heat up but then i drive it a but and let air get in and it cools down.

 

Sounds like you have weak fan motors and a secondary fan/relay/switch thats bad.
If you plan on keeping the car, buy a factory service manual from HELM INC.

 

if the fan might be a problem wouldnt a good way to check it would be by putting it in diagnostics mode ( since the fan kicks on alone)

 

Yeah possibly. The fan doesnt seem to move too much air. (As opposed to other cars ive had with electric fans) Im thinking a nice Aluminum radiator, and a single big cooling fan!

 

You just need to fix the factory setup and you'll be fine.

 

I think you should pull both fans and replace the motors on them both. Then bring it up to temp and make sure she stays below 210. Mine stays around this point all the time and I have an aluminum radiator and a 185 thermostat. You then need to check out why your AC fan doesn't come on or hopefully the motor change on it fixed your problem. Also remember that these motors run hotter due to emissions equipment as well at least so I've been told

 

New motors sounds good. Now question my fans feel like they are pushing air out of the engine bay(I.E not blowing on the engine) What direction are they supposed to go? Also why would they be spinning backwards?

 

They should pull air towards the engine. The polarity is switched.

 

Just switch the two wire on the fan plug to reverse the flow, May also have an issue with the relay when the ac is on. Relay is right at the firewall on driver side.

On the other hand, did you make sure to burp the system good? Any bad bubbles in the system through the heater core could cause a lock in fluid movement. Double check the vac line on the air control valve (think that what it is called.) it is the plastic connector thing that the coolant tubes run through in between the heater core and the intake and the steel coolant tubes. Should be right up front on toward the pass. side.

 

Alright Ill take a look at that stuff.

 

Alright I took both fans out and tested the motors . The main motor sounded like a bearing was about to go out(But it still spun up super fast) so i swapped the less used one(Air Cond.) to the main fan spot. Both of them work. Now I started the car cold last night. Like i said when cruising at night she usually runs at the 1/4 line when i stop it will keep going up untill i move again. As she was warming up the fans did NOT kick on untill Halfway between 220-and the red. (I dont think that is right) Do temp switches go bad? Is there a better fan i can buy along with a lower temp Switch. She has a 180* thermo the one i took out was a 160*.

 

[quote=89newfun;5257973]Just switch the two wire on the fan plug to reverse the flow, May also have an issue with the relay when the ac is on. Relay is right at the firewall on driver side.

On the other hand, did you make sure to burp the system good? Any bad bubbles in the system through the heater core could cause a lock in fluid movement. Double check the vac line on the air control valve (think that what it is called.) it is the plastic connector thing that the coolant tubes run through in between the heater core and the intake and the steel coolant tubes. Should be right up front on toward the pass. side.[/quote]

I believe you are talking about the heater control valve. I just replaced mine.

 

That is the correct "factory" normal settings.

put this in the pass side head if your running a 180* t-stat
http://www.jegs.com/i/Hypertech/533/4028/10002/-1

 

Yea this part broke on mine too, was a pain to replace due to heavy corrosion, due to a great deal of neglect from prior owner.

Worst comes to worst.. you could ground the relay via switch for you fans to come on when you want them.

 

No never do this. Im so sick of buying cars where people cant figure out how to get the fans to come on like factory and throwing a toggle switch on it.

 

Sweet. I ordered the Switch cause i drove the maro around today and It got very close to the red and would only cool to 220. Do these switches go bad? The new pump is VERY VERY VERY loud under a 1/4 tank.

 

No I agree with you 100%. The car overheats, that means there is a problem, not going to put a band aid over it and hope it holds. I put a switch on my old firebird cause all the wires where F'ed up and it was 500times easier! Im hoping this switch works!

 

Would definately change the switch in the head because it sounds like your ecm is what is kicking on your fan to save the motor. Its a fail safe that they built into the ecm. I would check your wiring and relay to the AC fan. I have spares if you need them. I'd rather send you a new relay then have you put a toggle in. Whether or not your wirings messed up you should fix it....

 

If coolant isn't boiling out of the radiator it is NOT overheating.

If you're relying on the dash temperature guage as an accurate indication of the true state of nature at the temperature sender, the initial conditions for all other suppositions are flawed.

Don't simply swap the temp sender in the passenger head. Do a little troubleshooting. Does the second fan come on when the lead to this sender is grounded? If it doesn't, work your way back. If grounding the lead engages the fan, verify the ACTUAL temperature of the motor. Don't rely on the wavy thing in the dash panel. Discount what it tells you. It wasn't accurate when it was new and it certainly hasn't improved in accuracy and precision in the years since.

 

Just another thing to check is your air damn..

 

Get an aftermarket temp gauge. My factory gauge is very inaccurate. I tested it with resistors, aftermarket gauge, 2 sensors and an IR temp gun and it is off 20-40 degrees at any point in time.

BTW I got that pigtail from autozone

Brand: BWD part# PT770 pigtail $10

Also SW555 makes at 210 and is $9

 

I bought a aftermarket temp gauge. I let the car idle till it was in the "Red" I shut the engine off and i filled the overflow tank with hot coolant(I have the radiator cap with the little red relife valve) and stuck the new gauges probe in it and it went up to 185-190 is all i could get it to go to. I only paid about 30$ for the gauge from checkers but I have one in my blazer and it seems to work fine. I think this one would be more accurate!

 

Was that an accurate way to measure the temp?

 

If fan does not come on when ac is on than your fan switch relay is bad. You can check it by grounding the switch wire to a body ground with the key turned on position. You'll here the relay clicking if it is working.

 

Best way to check temp is with a laser temp gauge. These cars fans are not designed to come on until 220-240, unless ac is on.

 

Also, check your fan sensor switch wire connection. These are known for melting and braking easily. Could be a bad connection.

 

This

And if it is boiling out of the radiator, try changing the cap first.

 

To replace fp properly, the rear axle will have to be dropped as far as the brake lines will allow, along with the exhaust, and shocks. I cut the whole myself and am very pleased with the outcome.

 

I've had the same problem. New radiator, new water pump, new thermostat, new fan motor, no $$$ left, burped the system. Next up is a mr gasket radiator cap with the built in thermometer.
Unless I switch to putting all aftermarket gauges in, not really a fan of having the same gauge in the car at the same time.

 

REally? Man We almost had the tank out only another foot to go and then we noticed the hole already in the floor. One more question i guess, Do you also have to cut the metel tubes coming out of the tank and bend towards the back? cause there is no way in hell the fuel pump is coming out without cutting them. (My tank was already lowered a little bit so it was "fairly simple")