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While I think I'll be fine, I'm pretty sure TPI just runs hot and there's not much I can do about it. It reaches approximately 220* at the computer sitting in traffic with the fans on and doesn't come down. It's an 86 car with a recently replaced water pump, a Cold Case radiator and the twin fan kit to match. I also have an edelbrock base, which has the rear coolant passage that the factory TPI does not.The car has a 180* degree thermostat in it with the first fan on at 190 off at 183, the second fan on at 195 off at 185, and a functioning air dam. Today I went for a nice long drive and while it stayed around 185-190 above 40mph, below that it just wanted to heat up, and I wasn't driving it very hard at all. In fact I still have the 2.77 factory gears so I was cruising below 2k rpm for the majority of the drive. I was using the AC, which I know adds some heat to the system, but is there any way to get this motor to stay below 195 in traffic or will it just run hot by the design of the car with no grille? I know my timing is good as well, I have checked that.
Keep in mind these factory gauges are almost always wrong .Ive had a half dozen thirdgens and like one had spot on gauges My current car reads 20 deg higher than actual temp.
Keep in mind these factory gauges are almost always wrong .Ive had a half dozen thirdgens and like one had spot on gauges My current car reads 20 deg higher than actual temp.
How are you reading the actual temp? I'm plugging in a computer and looking at it as raw data, not the gauge
3rd gens with electric fans run hot when running a/c. The only one I have had that ran cool was a clutch fan car. The 4th gen fan upgrade or Chevy City Express/ Nissan NV200 fans do cool better than the stock fans though. When it is 110F even with those upgraded fans the engine will still run ~220-230F when stopped for any length of time. Lack of airflow is a big part of it.
3rd gens with electric fans run hot when running a/c. The only one I have had that ran cool was a clutch fan car. The 4th gen fan upgrade or Chevy City Express/ Nissan NV200 fans do cool better than the stock fans though. When it is 110F even with those upgraded fans the engine will still run ~220-230F when stopped for any length of time. Lack of airflow is a big part of it.
I had 4th gen fans for some time. Decided the stock rad didn't cut it so I went Cold Case with their aftermarket twin 12" fan kit. Seems way overkill for my little 355 and it's not running much cooler.
A lower temp fan switch, cooler thermostat and blocking off the TB coolant flow will help. Since you’ve done that, the only thing I can think of is air is still in the system or maybe a blockage/restriction somewhere. I had those mods listed above when my car ran and I had no problems sitting in traffic with the A/C on in high ambient temp conditions.
My 1986 TPI single fan runs Low for a while then moves to 220 to 230 then 210 then 220 to 230.
I just begun to live with this. Sad but it drives fine. I was going to do what you did upgrade my radiator to a 2 row and put Dual Fans with fan and temp direct to radiator to run the fans that way. So, yours is still going there to 220 with what you did?
I'd like to make my temp range 190 to 205 MAX.
Funny my current radiator has a 4/11/1986 manufacture date its clean on the inside "woman driver" previous owner.
I want to Show you these 2 things this will explain your options below.
( My 1986 does not have screw in fan sensor switch I bought one from Hawks 185 temp it doesn't have that hole) on the Passenger side. Why I do not know)
2nd Now I had a 1985 TBI Trans am that overheated a lot back in 1989 we rebuilt the engine.
In 1989 Pontiac dealer tech said cut out the lower 1.5 feet-ish of the Trans am Air Dam and blot in the IROC AIR DAM in that GAP he said it going to Ram more air into the Engine... We did it and the car stopped over heating crazy but true.
Behold Below Punny Pontiac air dam vs IROC Dog Tongue Air Dam Deflector. Same Car Same Bolt on. Which one Pushes more Air up? Take Care
If you don't want to cut your Air Dam then just remove the whole thing and keep it to the side while you try this, I can't remember which we did 35 years ago cut part of it or remove it, but IROC Dam Fixed it the moment I started driving temp fell quickly. I was not overheating at stop and go traffic either I believe it balanced out the air flow before it was like a closed oven door not much air flow at all was getting in so it just baked in the engine bay.
Last edited by Extrafitkid; 06-20-2024 at 11:25 PM.
Does the TB help that much? I already have a180 stat and matching fan switch as well as PROM changes
Yes, the off-idle throttle response is much better. You will feel a difference. Stuck in traffic in a triple digit day with the A/C on, maybe not that much. However, the less heat soak you have going through the TB/plenum assembly is a good thing.
An aftermarket pusher fan might help. I had that in another vehicle, not my GTA, and it really helped cool it down in traffic. These cars do get hot when stuck in traffic with the A/C on. Once you start rolling, they should cool down rather quickly. I’d go through cooling system again and double check everything. Have you replaced the radiator cap?
Yes, the off-idle throttle response is much better. You will feel a difference. Stuck in traffic in a triple digit day with the A/C on, maybe not that much. However, the less heat soak you have going through the TB/plenum assembly is a good thing.
An aftermarket pusher fan might help. I had that in another vehicle, not my GTA, and it really helped cool it down in traffic. These cars do get hot when stuck in traffic with the A/C on. Once you start rolling, they should cool down rather quickly. I’d go through cooling system again and double check everything. Have you replaced the radiator cap?
The radiator came with a new cap, so yes. I've been thinking about switching out the 120W fans that are included for a 180W set by American Volt. Should move more air and as we know airflow is the name of the game with our cars. Is there a special process for burping the heater core or something that I'm maybe missing?
The radiator came with a new cap, so yes. I've been thinking about switching out the 120W fans that are included for a 180W set by American Volt. Should move more air and as we know airflow is the name of the game with our cars. Is there a special process for burping the heater core or something that I'm maybe missing?
Nothing special that I know of. You just have to get the radiator to be highest point in the cooling system when burping it. With these cars, that’s not hard to do if you have the front end slightly higher than the rest of the car. Even level, I think the cap fill inlet (radiator cap) is the highest point anyway. However, I’d raise the front a little just to be safe. Maybe try burping it again to see if that helps. There might be a stubborn air pocket in there.
I was out for a long drive last Sunday, it was 96F. As long as the car is moving, it sits somewhere in the middle between the 100 and 220 mark. If I had to guess, 160F. This is with A/C on. Coming to a stop at a red light, it climbs a bit, lets say 170, but never gets near 220 before the light turns red. If I let it sit there for 20 minutes, yeah, it will reach 220. All air damns are intact, all foam gaskets around condenser are in place and force air thru the radiator and condenser not around it. Everything is where it was, when it left the factory. The car has always behaved this way, even when new.
While I think I'll be fine, I'm pretty sure TPI just runs hot and there's not much I can do about it. It reaches approximately 220* at the computer sitting in traffic with the fans on and doesn't come down. It's an 86 car with a recently replaced water pump, a Cold Case radiator and the twin fan kit to match. I also have an edelbrock base, which has the rear coolant passage that the factory TPI does not.The car has a 180* degree thermostat in it with the first fan on at 190 off at 183, the second fan on at 195 off at 185, and a functioning air dam. Today I went for a nice long drive and while it stayed around 185-190 above 40mph, below that it just wanted to heat up, and I wasn't driving it very hard at all. In fact I still have the 2.77 factory gears so I was cruising below 2k rpm for the majority of the drive. I was using the AC, which I know adds some heat to the system, but is there any way to get this motor to stay below 195 in traffic or will it just run hot by the design of the car with no grille? I know my timing is good as well, I have checked that.
a good rad and shrouded 4th gen fans worked best for all my setups. The shroud pulls air thru better than the tpi dual fans
a good rad and shrouded 4th gen fans worked best for all my setups. The shroud pulls air thru better than the tpi dual fans
I never had TPI dual fans, I went from the single fan to the 4th gen dual fans, then to the cold case fans. They wouldn't fit with the thick radiator and my V belts. I'm thinking I'll get the American volt 180W fans to replace the Cold Case 120W fans.
My 1986 TPI single fan runs Low for a while then moves to 220 to 230 then 210 then 220 to 230.
I just begun to live with this. Sad but it drives fine. I was going to do what you did upgrade my radiator to a 2 row and put Dual Fans with fan and temp direct to radiator to run the fans that way. So, yours is still going there to 220 with what you did?
I'd like to make my temp range 190 to 205 MAX.
Funny my current radiator has a 4/11/1986 manufacture date its clean on the inside "woman driver" previous owner.
I want to Show you these 2 things this will explain your options below.
( My 1986 does not have screw in fan sensor switch I bought one from Hawks 185 temp it doesn't have that hole) on the Passenger side. Why I do not know)
2nd Now I had a 1985 TBI Trans am that overheated a lot back in 1989 we rebuilt the engine.
In 1989 Pontiac dealer tech said cut out the lower 1.5 feet-ish of the Trans am Air Dam and blot in the IROC AIR DAM in that GAP he said it going to Ram more air into the Engine... We did it and the car stopped over heating crazy but true.
Behold Below Punny Pontiac air dam vs IROC Dog Tongue Air Dam Deflector. Same Car Same Bolt on. Which one Pushes more Air up? Take Care
If you don't want to cut your Air Dam then just remove the whole thing and keep it to the side while you try this, I can't remember which we did 35 years ago cut part of it or remove it, but IROC Dam Fixed it the moment I started driving temp fell quickly. I was not overheating at stop and go traffic either I believe it balanced out the air flow before it was like a closed oven door not much air flow at all was getting in so it just baked in the engine bay.
My GTA has the 3 piece air dam from the factory. Hawks sells the one piece like in your top pic, but at some point GM changed the design before my '87 was made.
In my car the torque converter is really tight at idle (low stall speed) and that will generate a lot of heat that goes to the radiator. Maybe add a trans cooler?
In my car the torque converter is really tight at idle (low stall speed) and that will generate a lot of heat that goes to the radiator. Maybe add a trans cooler?
Believe it or not, I have one. It's stacked in front of my AC condenser and radiator. I wanted to make sure it would stay cool when I upgraded the motor with how fragile the 700r4 is under extreme temperatures and loads. It blew anyway a year later so now I have a built unit with an allison converter, but I left the cooler in.
My 1986 TPI single fan runs Low for a while then moves to 220 to 230 then 210 then 220 to 230.
I just begun to live with this. Sad but it drives fine. I was going to do what you did upgrade my radiator to a 2 row and put Dual Fans with fan and temp direct to radiator to run the fans that way. So, yours is still going there to 220 with what you did?
I'd like to make my temp range 190 to 205 MAX.
Unfortunately yes. I just ordered higher power fans. The ones that ship with the Cold Case kit are 120 watt fans, I ordered a set from American Volt that look identical but are 180 watts. They should move more air and they have great reviews. They get here Wednesday, but I'll update you when I get them installed. Got backed into in a parking lot a week ago so my car is in the body shop right now (ugh).
On a 90 degree day with moderate humidity my 406 never sees 200 degrees. This is currently with a Mark VIII fan/shroud and a upgraded radiator (can't remember which). Low speed comes on at 180 and high speed at 190. I have a condenser in front of the radiator but AC isn't functioning currently. When I get the AC going I will likely be upgrading to a brushless fan setup like a C7 Corvette fan setup. Brushless fans put out some incredible CFM numbers and use significantly less amps. Plus can be setup as variable speed if you want to get fancy with wiring.
yep, pretty much all 80s/90s GM cars were like that. If you're sitting at the drive-thru with the a/c off, you can see the temp gauge start to climb, then when the fan kicks on you can see it start to go back down. It can make you nervous for sure.
I replaced the fan switch in mine with one for a TTA. It took it from 238 down to 215. Of course that's just for the one fan though, the other one is still controlled by the ECM.
While I think I'll be fine, I'm pretty sure TPI just runs hot and there's not much I can do about it. It reaches approximately 220* at the computer sitting in traffic with the fans on and doesn't come down. It's an 86 car with a recently replaced water pump, a Cold Case radiator and the twin fan kit to match. I also have an edelbrock base, which has the rear coolant passage that the factory TPI does not.The car has a 180* degree thermostat in it with the first fan on at 190 off at 183, the second fan on at 195 off at 185, and a functioning air dam. Today I went for a nice long drive and while it stayed around 185-190 above 40mph, below that it just wanted to heat up, and I wasn't driving it very hard at all. In fact I still have the 2.77 factory gears so I was cruising below 2k rpm for the majority of the drive. I was using the AC, which I know adds some heat to the system, but is there any way to get this motor to stay below 195 in traffic or will it just run hot by the design of the car with no grille? I know my timing is good as well, I have checked that.
I have an 85 and in traffic it has eun hot since it was new. Ac would start to blow warm and t tops fry you head until i got covers. It has the air thing in front and it just has always been like that. But as you said driving around normally on open road, never an issue. Oh my 85 Transam has a carburetor.
Last edited by soldaustin; 07-03-2024 at 09:38 PM.
Reason: Missed a point.
While I think I'll be fine, I'm pretty sure TPI just runs hot and there's not much I can do about it. It reaches approximately 220* at the computer sitting in traffic with the fans on and doesn't come down. It's an 86 car with a recently replaced water pump, a Cold Case radiator and the twin fan kit to match. I also have an edelbrock base, which has the rear coolant passage that the factory TPI does not.The car has a 180* degree thermostat in it with the first fan on at 190 off at 183, the second fan on at 195 off at 185, and a functioning air dam. Today I went for a nice long drive and while it stayed around 185-190 above 40mph, below that it just wanted to heat up, and I wasn't driving it very hard at all. In fact I still have the 2.77 factory gears so I was cruising below 2k rpm for the majority of the drive. I was using the AC, which I know adds some heat to the system, but is there any way to get this motor to stay below 195 in traffic or will it just run hot by the design of the car with no grille? I know my timing is good as well, I have checked that.
I’ve noticed if the black plastic air dam under the front end is broken from a concrete Parker or something else it will overheat on you
06-20-2024, 12:57 PM
then 210 then 220 to 230.
its clean on the inside "woman driver" previous owner.
Which one Pushes more Air up? Take Care
