Sherrisbird

midias

Is your air damn still in place?

Have you done any investigation?

What is the state of the water pump / cooling system?

If you remove the thermostat will it run on the expressway?

84 1LE

iTrader: (9)

radiator cap.

TylerSteez

iTrader: (3)

boiling coolant is caused by the system not having any pressure, usually a loose/bad radiator cap

Ghettobird52

its funny because i used to always hear my radiator releasing coolant into the overflow whenever i would park/shutoff the car. Ever since i replaced my radiator cap with a 16psi Stant cap i havent heard it it release any coolant at shutoff.

Go Blue

The air dam from the front of car needs to be there for sure. I ran into that a few times. The radiator cap is another easy fix that definitely causes issues if it isn't putting out enough pressure. Also, radiators in Firebirds/TAs are really hard to bleed because they sit on an angle and there always seems to be an air bubble that just won't go away! Sometimes a pressure flush will fix that. Also, what kind of mixture of coolant/water are you running? If you're down south and it's always hot, more water in the mixture helps because of its ability to help displace heat with higher pressures. Or something like that. I can't remember the exact reasoning but I know there's physics behind it that will back that statement up. Also, make sure that the serpentine belt is routed correctly, because if it's spinning the water pump backwards, the impeller won't be pushing out the coolant as well as it should be. i know that sounds stupid, but I've seen it done.

NoEmissions84TA

iTrader: (1)

To add to what Go Blue said, are you running the correct rotation water pump?
Serpentine WP runs CCW, v-belt runs CW. If you swapped setups during the engine swap, and did not swap the water pump, then there is your problem.

GeneralDisorder

iTrader: (1)

The system must hold pressure because the factory thermostat and fan set points have the system above boiling point if it's not under pressure.

NoEmissions84TA has a good point about the water pump - especially if that's from the 305 and wasn't the right part to begin with. Must be for the belt system you are running. Which stock would be V-belt for that car.

The stock temp is really high and gives very little room for additional temp rise. I lowered my temp with thermostat and new PROM firmware to keep coolant temp around 190. If it's 100+ degrees out it will still climb into the low 200's on the freeway. Just the nature of the body design and it's airflow.

GD

Gilaad

Interesting points @ General Disorder. I have a 1992 Camaro Z28 that has just had its engine rebuilt and tends to overheat and boil over as well. Without ac on it overheats and with ac on it does not, such as I can see. Besides those points, what else could be responsible? I'm running stock dual fans in front of the engine and aftermarket dual thermostat controled fans at the rear. What could be the cause of this problem?

NoEmissions84TA

iTrader: (1)

So you have 4 fans then?
Are all of them turning to force air through the radiator in the same direction?
And I don't mean all the blades spinning in the same direction, I'm talking about the air flow direction.

Gilaad

@ @NoEmissions84TA, as far as I know the mechanic installed them in the correct order to make sure that was the case. I've hired another mechanic to examine the problem, hopefully he solves the issue. Thank you for your help.

midias

If your heater core bypassed

Go Blue

Gilaad,

You want the 2 fans in front of the radiator to be pushing fans and the fans on the engine side of the radiator to be pullers. This way the air gets forced through the radiator and then pushed away from it to cool the rest of the engine. Also, make sure that you have that plastic shroud under your front bumper, because somehow that little piece of plastic helps push air towards the radiator and does help keep it from overheating.

Gilaad

Thanks to everyone for the help, I'm in the process of replacing the master cylinder and reservoir. Once that is accomplished , I'll get the mechanic on the overheating issue. @ midias, not sure if the heater core is bypassed, that's one more thing to check among others for possible cause.

Gilaad

Update on my situation, the heater core is not bypassed, so that should not factor into the issue. The mechanic removed the air dam when he bolted the dual fans to the transmission cooler, he's a very unorganized guy and he still can't find the air dam and the aluminum distributor cover that bolts on the air plenum.

So the air dam for sure has to be added, also considering a 3 row performance radiator from jegs and a dual fan, thermostat switch kit to go with it. I also notice my ac is not pushing max cool air into the cabin, considering the whole ac system is new.

Does the size/capacity of the radiator factor into how well the engine is cooled and how cold the interior of the passenger compartment gets? Anyone have any recommendations and suggestions.

What number of rows on an aftermarket radiator give the best results on a 5.7 L 350 with a compcam 5 and headers? Thanking you guys in advance.

Go Blue

the radiator has no bearing on how cool the interior can get. Heat, yes, but not the air conditioning. The ambient temperature and what refrigerant you are using (i'm assuming R134a) has the most bearing outside of blockages and mechanical failures, and vent doors opening and closing correctly and fully. R134a can only cool the temp inside the car MAYBE 20 degrees from the outside air temp.

But, back to the overheating, a 3 row performance radiator and dual fans on both sides of it, should be more than enough to keep it cool as long as the fans are pushing or pulling the air correctly and not fighting each other. The fans in front of (on the side closer to the front bumper) need to be pushing air through the radiator. The fans behind the radiator (closer to the engine) need to be pulling air through it. IF you have that reversed, it will definitely not work well as the fans will be fighting each other for air and very little air will be going through that radiator. Your water pump, thermostat, upper and lower radiator hoses, and even the radiator cap are all still possible causes if the fans are working and helping the air flow correctly. When was the last time you replaced the hoses and thermostat? Or even the radiator cap? Have you noticed losing any coolant??

Gilaad

@ Go Blue, the engine was recently rebuilt. The radiator hoses and radiator cap are new, no coolant loss noticed. The mechanic deleted the thermostat at the water neck. So very few things could be the cause. Before I drop $ to add the 3 row radiator and thermostat controlled dual fans I'd just like to hear some comments/suggestions.

Go Blue

PaulyC

For sure you absolutely need to run a thermostat on the street no question. Without that you are non stop recirculating coolant through the system and it does not have enough radiator time to cool adequately before returning to the engine. When you are idle the pump is running slower and the coolant flow will slow as well enabling you to keep the temp under control.
You need to question the decision to delete it in the first place. What was he trying to accomplish? I also question the need for 4 fans, were the additional fans installed to try and remedy this overheating issue?

bigdaddyflo

Like go blue said above, test the temperature sending unit (TSU). If the car is not getting hot with the AC on, the fans are probably getting a signal (power) when the AC is turned on and are working correctly. However, with the ac off, the fans get a signal (power) from the TSU once the temp gets to a certain point. If there is no signal from either the ac controls (ac in the off position) or the TSU to turn on the fans, the TSU has probably failed. Once the coolant temperature gets to a certain point, a correctly working TSU will send a signal (power) to the fans and they will turn on.
The TSU we installed IN OUR CAR will turn on at 231* and turn off at 220*. These are above the boiling point of water (212*) , but not coolant (depends on the mixture) and it is important to have a good radiator cap.
To test the TSU...
You'll need a continuity tester and temperature gauge to test the temp sending unit. Place the TSU (not the cables) in water and start to heat up the water. Keep an eye on the temp of the water with the temp gauge. With the continuity tester touching both wires at the connector, the circuit will be open (no power flowing through the TSU) as the water is still cool. After the water gets to heating up/boiling, the TSU should open up and the continuity tester will show he circuit is closed (power can flow through).
This is how we found our problem with our car overheating.

Gilaad

PaulyC what you say about the thermostat makes sense, but with the addition of the compcam5 and the other performance parts this engine runs hotter than stock. I see a few people here on the forums add puller and push fans in addition to 3 row all aluminum radiators to solve overheating problems. All the parts are brand new, including the TSU; ill see about adding the thermostat to the intake manifold and see if that changes the situation. Thanks for the help guys.