When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It seems these third gens are always running a little hot. Back when I was in Arizona, my car seemed like it wanted to overheat constantly. I added dual electric fans (from a TPI setup, I had the TBI one fan), but it didn't seem to make a big difference really.
Before, when I had the 305, I added an Edelbrock intake manifold. I believe I used a 1/2" NPT to 5/8" hose barb fitting from the intake manifold to route to (or from, I'm not very familiar with the direction of flow on these motors) the heater core. I don't remember what the stock intake manifold heater core fitting looked like, but I thought I had things correct. With my 350 I put in, I also have an edelbrock intake manifold (for vortec heads), and used a 1/2"npt to 10an fitting for the heater core line.
However, I read somewhere recently that the stock heater core fitting on the intake manifold is actually restricted somewhat. The reasoning given was to prevent coolant from flowing too much through the heater core (in turn bypassing the radiator to an extent). The person who said this mentioned that you probably would have cooling issues if this wasn't done.
I can't seem to find this post, or any other mention of this but I was wondering if anyone knew if this actually is the case. If this is so, I'll have to try and find something to restrict the flow at the intake manifold port I have because I feel like my car still seems to get a little warmer than it should when I have a 180 degree thermostat in. (as in my temps are usually in the low 200s with AC running, and it's not super hot out here in Wyoming.)
I know these engines run a little hot so it's not super concerning for me, but I think something may be off still. I did forget to mention some adjustments I made for my car. The stock wiring/sensors for the fans were in horrible shape on my car, so I got rid of that system completely. I just rigged up both fans to turn on by a switch in the dash (one switch powering two relays) so that I know I can turn the fans on. So it's either they're fully on, or off with the switch.
Back in Arizona, even with both fans on at idle, if I had the AC on, the car temps would climb pretty high. I have an aftermarket gauge cluster with a temperature sensor, so I'm not sure how accurate it is, but it would go to 250 sometimes at idle with the AC on and both fans running. It would get warm enough that the AC would stop blowing cold. My radiator is relatively new, and there isn't and junk stuck in front of that or the condenser. I do have the little air dam as well, but that shouldn't make a difference when idling. Both fan motors have been replaced as well and the fans seem to be running pretty strong.
I never had temp issues when driving, just idling. I don't know if the stock fans on these cars aren't very good, or if I have something wrong with my setup. Here in Wyoming, it doesn't get nearly as hot outside so I haven't had that issue yet, but I feel like the car should never get hot enough where AC stops blowing cold at idle. I may look into getting a different fan setup, but that may be a little while in the future. Winter is coming here in Wyoming and it's gets a lot colder than I want it too..... The 350 I just threw in has a block heater on it though so I suppose I don't have to worry about the engine ever being too cold!
You could test your theory by removing the hose and using a flat washer (with about a 3/8" hole) on top of the fitting, and then putting the hose back on.
See if it makes any difference.
That looks like the fitting I have on my old non-vortec edelbrock intake. If that's the stock fitting, then I assume I had the correct piece. I currently have 10an fittings for the coolant flow now. I was considering putting a washer or rod in the fitting (they are angled fittings so a long enough rod would be wedged where it couldn't go anywhere) so that way it would somewhat block flow. I don't remember where I read about the restriction being necessary to the heater core but it seemed to make sense when I read it. I don't really see why the engine would get as hot as it does when I have a 180 thermostat and two fans running (when the AC is on) unless the fan design wasn't built to handle that much cooling (when it's 100+ degrees with the AC on).
With the temperatures in Wyoming now, I won't be having an issues until probably sometime next year unfortunately (as in it gets way too cold for way too long here....). It would be nice to know my cooling system is working the best it could be though.
The hole in the restricted heater hose fittings is about 3/8" - certainly no smaller than 5/16".
Are you going by the stock gauge with the sender mounter in the driver's side cylinder head?
Those stock gauges are anything but accurate and shouldn't even be called a gauge. They are a slight step above an idiot light at best.
Keep in mind that the temp where the gauge sender is located and the temp where your thermostat is can be at very different temperatures.
Last edited by NoEmissions84TA; 10-03-2019 at 02:52 AM.
The hole in the restricted heater hose fittings is about 3/8" - certainly no smaller than 5/16".
Are you going by the stock gauge with the sender mounter in the driver's side cylinder head?
Those stock gauges are anything but accurate and shouldn't even be called a gauge. They are a slight step avove an idiot light at best.
Keep in mind that the temp where the gauge sender is located and the temp where your thermostat is can be at very different temperatures.
Thank you for the input! I have the intellitronix digital gauge install now, so it's not the stock gauge. I also purchased a harbor freight infrared reader (a few years back in AZ when I was having more of the extreme cooling issues) and the temperatures seemed to match very close to what my gauge cluster was reading. The gauge set I have came with a sensor that I put in an aftermarket thermostat housing with a bung for the sensor. 3/8" seems like it may be smaller than what I had previously, but not by much if so. The stock electric fans on these cars (dual or single) don't really seem to have much of a shroud at all. Maybe an aftermarket electric fan would make a huge difference. The cooling issues really only seemed to be at idle, when it's hot out with the AC on. I think I mentioned I haven't had cooling issues here yet in Wyoming, but I don't want them to come back up in the future.
Last edited by Bubbajones_ya; 10-04-2019 at 09:37 PM.
Reason: spelling
I'm with ya. Mine is a Trans Am - and they don't have grilles to easily let air flow through the radiator core.
I will be swapping to a Ram Air hood to try to let some underhood heat out. My car is an 84 that uses a belt-driven clutch fan.
How do you like the Intellitronix digital gauges? They will be going in my car also................Someday.
Why not use a set of these for decreased hot foot and better a/c performance to
block heater flow?
My carb. HO has no heater core shut off valve like my Cadillac.
Installed these:
Why not use a set of these for decreased hot foot and better a/c performance to
block heater flow?
My carb. HO has no heater core shut off valve like my Cadillac.
Installed these:
Do you have a link to that valve? It is a nice all-in-one piece that you don't have to assemble from 3 separate parts.
I'm with ya. Mine is a Trans Am - and they don't have grilles to easily let air flow through the radiator core.
I will be swapping to a Ram Air hood to try to let some underhood heat out. My car is an 84 that uses a belt-driven clutch fan.
How do you like the Intellitronix digital gauges? They will be going in my car also................Someday.
Yeah I ended up cutting holes in an IROC hood I picked up and dremeled out the louvers to make it a real venting hood:
This is a few year old picture but it looks almost identical now. The 350 I just threw in has a red powdercoated intake just like this one. These hood vents seemed to make about a 10 degree fahrenheit difference during summer months when it was 100+ outside in AZ. Surprisingly, I never had issues with rain water either (even during monsoon season when I was stuck in heavy downpour). It does make the engine bay a little messier sometimes, but I think it was worth it.
As for the intellitronix gauges, I do love them but I have had some issues. I did get them on ebay as a refurbished unit but they still offer a lifetime warranty. The speedometer stopped reading correctly and keeps resetting itself, and sometimes glitching out, and a bit of small LEDs have went out as well. I emailed them about a year ago about it and they said to send it back to get fixed (lifetime warranty), so their customer service seems pretty good. I'm going to get a GPS unit to hook up to the speedometer next time though so it won't have to be calibrated and will automatically be correct. I currently have a double din GPS unit so I've been using that for my speed and trip mileage in the meantime (since I've been too lazy/busy to send the gauge cluster back now.) I do love the gauges though so despite the issues, I'd get them again as long as there are no issues with the refurbishment.
Originally Posted by sonjaab
Why not use a set of these for decreased hot foot and better a/c performance to
block heater flow?
My carb. HO has no heater core shut off valve like my Cadillac.
Installed these:
I thought with the way the heater bypass valve is set up, when the AC is on, vacuum re-directs the coolant flow away from the heater core so it is no longer being recirculated. Having a shutoff valve like that would be significantly less hose routing for sure, but I've decided to keep the stock bypass valve for now. I may consider something like this if the stock bypass valve has issues.
Last edited by Bubbajones_ya; 10-04-2019 at 09:36 PM.
Reason: spelling
I can't tell by your hood pic, but is the weatherstrip there at the back?
I have read by other people that have also done this that without the weatherstrip, the hot engine compartment air gets sucked in by the heater box inlet, making the passenger side footwell hotter.
My 84 TA does not use a heater control valve. That's why I'm interested in the valve posted by sonjaab.
I actually went and got a control head and harness assy (which includes the vac lines) out of some later car, that used a heater control valve, and put that into my 83. Made a noticeable difference to the AC performance.
There's also cable-operated HCVs available for various other vehicles; you can leave a cable **** hanging under the dash or something, since it's not something you're likely to be using very often.
But I could screw this one directly into the water pump. https://www.supplyhouse.com/Uponor-W...alve-Lead-Free This fitting is lead free for potable drinking water. I'm not sure it will compatible in an automotive cooling system. Good to 250*F.
The NOT drinking water safe full-port brass valve is good to 250*F and The full-port valves are compatible with propylene glycol mixtures up to 50%. These ball valves are not for use with potable-water applications.
I suppose either style would work.
Heck they are brass so why would a 50/50 mix of hot coolant hurt them?
I have even seen them in plastic.
House hot water wont hurt them so I cant see hot coolant mix causing a issue.
Thanks for the opinions. I competely agree that using it with automotive coolant should not hurt the valve.
For < $20. it's worth a try.
I will use the valve in the second pic with the threads on one end directly connected to the water pump.
Yeah I think I've used something like the brass shut off valve before on a different vehicle. My car came stock with the heater bypass valve (the plastic 3 prong tube looking thing) so that it should defer coolant away from the heater core when the AC is on. I know my Bronco didn't come with something like that before, so I got an explorer valve (somewhat similar to the ones in the camaro) and it made a really big difference.
I read people don't like just using a shut off valve to block the heater flow to the heater core, but I don't think it would be too big of a deal since there is a bypass hole in the block (for non vortec blocks at least) allowing coolant to constantly flow anyways.
09-24-2019, 08:53 PM
