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

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.

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

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?

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

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

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

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.

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

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

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

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.

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

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.

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

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.

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

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.

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

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.

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

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?

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

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

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?:chevy:

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

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.

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

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.

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

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

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

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.

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

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

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

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.

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

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.

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

The radiator does also have the automatic tranny cooler on it. Maybe installing a separate tranny cooler would help a little, but might help the tranny live longer.

I know you just have to be careful of running a BBC hot as the stock heads may not hold up long term to the extra heat input.

What about those aluminum radiators. I have talked to a few suppliers of them, they all claim about a 15-20% decrease in temperature just by swapping to one. They are expensive and I really don't want to spend that kind of cash if the gains are really small. If it could get me back to 190 degrees, I might would take the plunge for one.

Idea's? Thoughts?

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

Let's think about this. Water boils at 212 degrees F -- and 233* at 8 psi, and 242* at 12 psi.

Non-pressurized 50% antifreeze boils at 226* -- and 248* at 8 psi, and 259* at 12 psi.

I really don't believe you have anything to worry about.


http://www.heat-transfer-fluid.com/p...ling-point.pdf

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

Maybe one or more of those suppliers would agree to accept a return if it doesn't back up what it claims. It sounds to me like you'd be more comfortable with it lower than it currently runs at.

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

Yea, I guess most are right with not having to worry about boiling over.

I don't think that the radiator shops/vendors will say for positive that they would take it back if it doesn't work.

Think I am going to install a tranny cooler and get that out of the radiator. Every 20 degrees cooler a tranny can run will make it survive longer.

Who knows, maybe that might lower it 3-5 degrees too.

Thanks everyone for the replies and suggestions. Much appreciated.

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

There is this sort of thing - http://www.redlineoil.com/Products.aspx?pcid=10,
and this looks interesting! http://www.evanscooling.com/

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

210 is normal....I would never let my truck idle for one hour with the AC on during the summer!! I know you said it was just for a torture test but naw man I wouldnt do it. With AC on 210 is normal. Stop worrying and enjoy your truck. Lol.