Can an AC Installed make the engine run hotter than before?

[CST10]

I torture tested my truck cooling system yesterday. I placed it outside in the sun idling with the truck in drive and emergency brake set. I also had the AC blowing wide open with all the windows open to keep the AC running at maximum.

So, Over the winter installed a vintage air system in my truck. Prior to the AC installation the BBC 462 CI engine would run around 180 F degrees. Now, I can't keep it under 210 F degrees. I know 210 F isn't quite overheating yet but it doesn't leave much room for error.

I have a 165 f degree thermostat, new 4 core radiator, new water pump and twin electric fans pulling 4600 CFMs. Hoses have springs, so hose should also be good.

Can the condensor for that AC being in front of the radiator add that much additional heat to the cooling system?

Any ideas what can be done to lower the temperature a little. I know 210 F degrees isn't overheating. I am just not comfortable at that temperature,don't really know if I should be worried or not.

[Mike C]

Absolutely. The condenser blocks a significant amount of air and in addition, it puts hot air into the mix not just ambient temp and you also have additional load put on the engine from the compressor itself.

How does the truck work with the AC shut off? Is it still running hotter than before? Anything else been changed?

[Lee H]

How are you measuring the 210? Have you verified with another source?

[Stocker]

Agree with MikeC's post above. Also agree that 210 is a bit higher than I'd like to see, but as you said, the system was being torture tested. How hot does it run during normal use? Also, do those electric fans have any shrouding? Lastly, it's possible that 165 t-stat might be doing more harm than good. If coolant circulates too quickly, it doesn't spend enough time in the radiator to transfer as much heat as it could with, say, a 190 or 195 t-stat.

[volksworld]

my 93 big block motorhome has run at 210 since it left the factory...it has over 100,000 on it now...a higher than stock pressure cap can prevent it from boiling over

[67ChevyRedneck]

Mine has a 195* t stat. It runs 195 on cool and cold days. On hot days sitting it traffic with A/C on it will get to almost 210, then drop to 195, then back up to 210, then down to 195. We're talking 96-98*+ outside temps with high humidity.

Sometimes those fancy electric fans dan't do what their advertised to do... do you have them in a shroud or just attached to the radiator?

I run an old fashioned thermal clutch fan. Can't remember if it's 6 or 7 blade, whatever was stock for A/C trucks.

[Fitz]

Originally Posted by 67ChevyRedneck

Mine has a 195* t stat. It runs 195 on cool and cold days. On hot days sitting it traffic with A/C on it will get to almost 210, then drop to 195, then back up to 210, then down to 195. We're talking 96-98*+ outside temps with high humidity.

Sometimes those fancy electric fans dan't do what their advertised to do... do you have them in a shroud or just attached to the radiator?

I run an old fashioned thermal clutch fan. Can't remember if it's 6 or 7 blade, whatever was stock for A/C trucks.

And sometimes those fancy electric fans actually do as they were designed to do...keep an engine at the proper running temperature regardless of the outside temp. Here in the desert there are usually more than 30 days with temps above 105. A/C is a must and my fancy electric fans keep my engine cool while idling in city traffic with the air on when the temps are 115.

[67ChevyRedneck]

I have no doubt there are electric fans that work, and work well. I installed a 3.8L Taurus fan on my S10. I have the "Jeep fan" upgrade for the C10, but my electrical system is crap, so it's sitting next to the AAW harness awaiting install.

However, time and time again, on this forum and other car forums I'm on there are A LOT of AFTERMARKET fans that do not run/work as advertised.

I can't remember what brand I bought, but years ago I bought what was a "3,000 cfm puller fan" and I've farted harder than it pulled air through the radiator. Did some research, bought a Taurus fan, and there was a damn hurricane pulling through the radiator.

Also, as I mentioned above, how they're installed is important as well. Just sticking two fans to the radiator is nowhere near as effective as using a shroud to pull air through the entire radiator.

Electric fans are also not necessary for these trucks. *IF* one is necessary, something is likely off. People had A/C when these trucks were new and people have A/C now. It was 115* back then, it's 115* now. A properly set up extreme duty (or whatever they called it) factory cooling system will work.

[Fitz]

Originally Posted by 67ChevyRedneck

Electric fans are also not necessary for these trucks. *IF* one is necessary, something is likely off. People had A/C when these trucks were new and people have A/C now. It was 115* back then, it's 115* now. A properly set up extreme duty (or whatever they called it) factory cooling system will work.

Really? Not necessary? Something likely off??? The assumption you made is that we all drive stock trucks with a few trinkets slapped on them so we can say "custom".

I want to see you install a shroud and clutched fan on this motor! No Room. There is exactly 4.5 inches in front of that serpentine belt at the crank pulley and 3 of that is radiator. This truck has 15,000 miles on it since finished and all of those are in the middle of the Sonoran Desert where there are at least 30 days every year when the temps are over 105. This truck has never overheated. Twin Be Cool Electric fans and a Be Cool Rad rated for 800 horsepower. Does it "need" electric fans? Youbetcherass if you want to run that motor. Is there "something wrong" with this truck? Only if you're the local sheriff and you're trying to catch up to me on these back roads!.

[Stocker]

Originally Posted by Fitz

Is there "something wrong" with this truck?

There is something wrong with that truck. It needs an air cleaner to keep the desert grit out of that big bad beautiful engine.

Other than that, nothing wrong. Well, maybe the gas bills, but some things are worth it.

[Fitz]

Originally Posted by Stocker

There is something wrong with that truck. It needs an air cleaner to keep the desert grit out of that big bad beautiful engine.

Other than that, nothing wrong. Well, maybe the gas bills, but some things are worth it.

Like this? I don't always pick the latest pic! Believe me when I tell you, I never notice the gas bills. Pressing the loud pedal is just too much fun.

[67ChevyRedneck]

Originally Posted by Fitz

Really? Not necessary? Something likely off??? The assumption you made is that we all drive stock trucks with a few trinkets slapped on them so we can say "custom".

Yes, I was referring to stock trucks. Even ones that are mildly hopped up should run just fine with a stock set up. Time and time again people use electric fans to mask the real issue as to why they're overheating in the first place and never fix the real problem.

I know lots of guys with LS swaps that use e fans, but most of them use a form of OEM fan, and not an aftermarket one. Again, I mentioned I was burned by aftermarket fans (and have read about many others that were as well) and will use an OEM Chrysler fan on my C10.

I was also just burned by a pile of crap "aftermarket" flywheel. I installed a T5 in my 65 mustang and it's vibrating like crazy in N and all gears at the same RPM. Turns out quite a few people had the same problem with that brand. Expensive (and time consuming) lesson learned. Going with an expensive Ford Racing one now (didn't know they offered one for my set up at the time).

Nice looking motor!

[Fitz]

Originally Posted by 67ChevyRedneck

Yes, I was referring to stock trucks. Even ones that are mildly hopped up should run just fine with a stock set up. Time and time again people use electric fans to mask the real issue as to why they're overheating in the first place and never fix the real problem.

I know lots of guys with LS swaps that use e fans, but most of them use a form of OEM fan, and not an aftermarket one. Again, I mentioned I was burned by aftermarket fans (and have read about many others that were as well) and will use an OEM Chrysler fan on my C10.

I was also just burned by a pile of crap "aftermarket" flywheel. I installed a T5 in my 65 mustang and it's vibrating like crazy in N and all gears at the same RPM. Turns out quite a few people had the same problem with that brand. Expensive (and time consuming) lesson learned. Going with an expensive Ford Racing one now (didn't know they offered one for my set up at the time).

Nice looking motor!

As with most aftermarket stuff you get what you pay for. I wouldn't use anything but a Griffin or Be Cool rad and fan IF I need to go with an aftermarket unit. They are expensive but if you install them correctly they are reliable and always work. The 1320 race club I am in has six cars using LS motors and they all use electric fans. The ECM has the switched output for the fan relay built in so there is no need for a thermostat specifically for the fan.

That motor will take this truck through the traps at SIR in 11.3 sec. with the AC on! It's a bit faster with it off.

[Andy4639]

I'm running a 6.0 LS in the 71 now with 2 electric fans with no shroud. The fans themselves have a small flange with them but I want to make a shroud for them to pull more air through the whole radiator. I'm also looking at the new LS radiator by Griffin.

[brown7373]

You are not anywhere near boiling. Pure water, with a 15 lb. cap won't boil; until about 250. Add the proper 50/50 coolant, and the boiling temperature rises even more. Most vehicles with idiot lights, the light doesn't come on until around 250.

[MARKDTN]

Originally Posted by brown7373

You are not anywhere near boiling. Pure water, with a 15 lb. cap won't boil; until about 250. Add the proper 50/50 coolant, and the boiling temperature rises even more. Most vehicles with idiot lights, the light doesn't come on until around 250.

Yep, I used to worry if if went over 180. Now 210 is no problem. It will actually get better mileage the hotter it gets. On 90ish Corvettes and F-bodies the second fan didn't kick on until 230 unless you were running the a/c.

[GCncsuHD]

Just reiterating what has already been stated.

Yes, the AC condenser will add a substantial amount of heat in front of the radiator, putting more of a load on the cooling system.

210 isn't bad at all, but as mentioned, it doesn't leave a large margin for error.

Do you have pics or details of the e-fan setup? Are they just strapped to the radiator? Or are they properly shrouded to utilize all available cooling area?

Originally Posted by MARKDTN

Yep, I used to worry if if went over 180. Now 210 is no problem. It will actually get better mileage the hotter it gets. On 90ish Corvettes and F-bodies the second fan didn't kick on until 230 unless you were running the a/c.

True to an extent, yes an internal combustion engine will run more efficiently and powerfully at a higher temperature until detonation becomes an issue.

[Andy4639]

I just drove the 71 all week at the beach and then to NC and back to SC. It was 95* most of the time and I drove the truck the whole time with AC running. 210 was what it ran just about the whole time and this is fine it's what the engineer's whant the truck to run at.
I think you have plenty of room for it to run hotter. Sitting still is the worst case senerio so what does it run at on the road?

[CST10]

Thanks for all the replies so far.

As I said, the torture test was about 1 hour in drive with AC blow wide open idling in the sun with the hood down except to verify the gauge readings. Outside temp was about 94 degrees.

I did second verify the temperature at several location on the engine and radiator using an accurate temp laser gun...........readings were with 3 degrees of each other. Engine temp sending unit is located in the front drivers side on the top of the intake manifold by the thermostat housing.

The fans have a shroud that covers 95% of the available core surface area. Fans blow so hard you can feel the air movement coming from under the truck by the doors.

With the AC off, it runs 200-205 degrees in the same conditions now since summer has arrived. On the road at 55 MPH the temp will drop to about 200 degrees then climb back up after you are idling for awhile at a stop.

I am using 50/50 anti-freeze/water mixture with a 15 lb cap. All of the air is out of the system also.

Should I add an additional pusher fan to the condenser unit? Would that help any? Should I look into an aluminum radiator to replace the new 4 core copper radiator? Should I leave as is and not change anything els?

Really at a loss of which direction to go forward with.

[FirstOwner69]

I agree with all the replies above that say 210 degrees is essentially normal. My 2006 Duramax fan doesn't even engage until the gauge reads 210 and antifreeze containers say a 50/50 mix protects from boiling to 265 degrees with a 15# cap. I would run it as is.

[Stocker]

Originally Posted by CST10

Fans blow so hard you can feel the air movement coming from under the truck by the doors.

Should I add an additional pusher fan to the condenser unit? Would that help any? Should I look into an aluminum radiator to replace the new 4 core copper radiator? Should I leave as is and not change anything els?

With the fans blowing that much air, I don't think a pusher would make much difference.

Being pressurized raises the boiling point, as does a 50% mix -- with both of those circumstances, 210 is quite a ways from boiling. If it were me, I'd leave it alone.

[stsalvage]

there is one more you can do.Go find your self a Small AC condenser from your home AC unit the one that sits on top of your Heater unit Plume it with attachments for a Trans cooler and you will watch your Heat drop a lot.I had a friend make me on From a House unit and boy dose it keep the trans cool in my 1 ton Box Van I have a Alanson trans in mine it was a 4 speed with a splitter and my box van is a 1966 Chevy 16 footer Box Van.I can reach up and put my hand on the pan and its warm but not Hot

[pweslaw]

I have the exact same set up but with a oversized be cool radiator and i havent seen it go over 180

[brown7373]

Most vehicles from this era had 195 degree thermostats as original equipment. The thermostat was designed to open at 195 and the engine was designed to run a little above that. Many people, myself included, change to 180 or 160s, thinking running at a lower temperature is better. First off, a lower temperature t-stat will not lower operating temperature UNLESS you have enough cooling capacity to maintain that temperature. But that begs the question...do you or I know more than the engineers who designed these vehicles? I doubt it. We are driving vehicles 30, 40 50 years old or more. Properly maintained, they still operate as they were designed many years ago.

Leave it alone. There is nothing to gain.

[Stocker]

Originally Posted by brown7373

But that begs the question...do you or I know more than the engineers who designed these vehicles? I doubt it. We are driving vehicles 30, 40 50 years old or more. Properly maintained, they still operate as they were designed many years ago.

Can't argue with that logic, except for these observations: 1) improvements have been made in the past few decades and 2) he's running a 462 BBC, not a stock engine.