usdm_ED7

ok few lil details about the car. EF Si with b20vtec (stock block and head) and bolt ons. Its been pretty hot lately in So Cal so i decided to throw the AC back in. Car runs fine when the AC is off but once its turned on, the Temp gauge rises.

edit - only happens while driving on the freeway or side street. hasnt happened while in idle....yet at least.

heres a few things ive tried
swapped radiator to C&R half size dual core with spal fan
bled out cooling system
propped hood up to let heat out

i dont know what else it could be? some say head gasket but wouldnt it overheat even if the AC isnt on? if anyone has suggestions or anything please help me out. THANKS!

661rex89si

t-stat opening up? no leaks? coolant in oil? smoke?

usdm_ED7

Sorry ya t stat opens, no leaks, no coolant in oil and it's not smoking.

Ludehrt

It's about 115+ here in AZ and I have been fighting overheating issues with the AC on for a couple of years in my B18C EF hatch. It's to expect when you try to fit 10lbs worth of $hit in a 5lb bag.

After trying various setups, the following worked for me today in 118 degree weather
-DA Radiator
-6 inch Spal pusher fan in front of condenser
-10 inch Spal (thin) puller on manifold side
-Stock DA puller fan with shroud on passenger side
-Running water with Water Wetter
-Re-installed underbody plastic panels (helps direct incoming air)

I am still running the stock heat shield with the stock manifold. Sometimes I think it acts more like a heat radiator which does not help with radiator heat soak. I might try header wrap if my current setup does not work.

usdm_ED7

Hmmm that sounds like a good setup. How thick is the da radiator? Reason I ask is because I'm running toda knockoffs 4-2-1 and with the stock EF radiator one of the ac lines was super close to the header. Is there any I'll effects of running straight water instead of antifreeze mix?

Tyson

I am currently going thru this as well here in socal. Interestingly, I JUST recharged my system with FREEZE-12, basically R-134a but supposedly ok to use in the old system.

What refrigerant did you guys use?

What I am noticing when the temp needle starts to go up is there's a slight change in throttle, I think the compressor clutch is engaging on and off.

I have a feeling this is a side effect of using the wrong refrigerant, and the pressure sensor needs to be changed, as typical for a proper R-134a conversion.

I also am considering the possibility of over charging the system. I used two 12 oz cans, which is 1.5 lbs where the system specs are only 2 lbs.

I'm not sure its a matter of heat soaking the radiator. It could be as simple as that. But then I dunno what else I could do to fix that... Both fans turn on. But the 105 degree heat surely doesn't help.

Ludehrt

-A DA radiator is thicker and longer than a stock EF radiator (nohomo). I would say its about 1/3 thicker.

-Make sure you use heat reflecting wrap on the AC lines that go close to the exhaust manifold. Ive heard of alot of swapped civics and CRXs turning into car-b-q's due the lines catching fire.

-Nothing beats water in taking heat away from your engine and exchange it in your radiator. The Water Wetter stuff helps break the "tension" of the water to help it carry heat away from internal engine parts. When I swapped the fluid out of my cooling system, I didnt do a complete flush which helped keep some of the radiator fluid (green stuff) flowing through my cooling system. This helped maintain some anti-corrosion properties in my water / Water Wetter mix. Now, if your demographic sees freezing temperatures, I would use the appropriate mix of antifreeze.

Tyson - I am running R134 but I let my mechanic do charging / evacuating. It's always a good idea to get the old freon vacuumed out when re-charging due to moisture that could build up in the system.

usdm_ED7

Tyson - i wish i used r12 but couldnt find a shop that had r12. so i switched over and converted to r134. on my old DA i converted to r134 also and never had an overheating problem. i had a shop vaccuum, oil, and refill the refrigerant.

ludehrt - i learned the hard way. i busted two of the lines til we figured out to finally wrap it! LOL
- i might have to try out water with water wetter. have you tried Royal Purples royal ice?
- so you are running 3 fans all together? i was thinking of adding another pusher in front of the condensor or maybe a pusher behind the condensor, in front of the radiator (like a sandwich) since i am running only a half size dual core radiator.


edit - maybe it could be my compressor is cycling on and off too much?! i dont know at this point. im to the point i want to throw my stock motor back in

~sp33~

Is the fan cycling on and off ok?

My OEM system runs 2 fans, and i was having trouble keeping the temp down in hot temps with the A/C on, turned out the second fan motor had died.

I know you don't have a full size rad, or two fans, but the point is you're probably not getting enough air flowing past your radiator.

Does it only start getting hot when you're not moving much? If so you need a bigger/better fan. If it's overheating while you're on the freeway you need a bigger rad.

ef-dallas

got the same problem.... changed coolant temp, thermostat, heater core, a/c fan... still stunmped... if found out let me know

usdm_ED7

yes i am running two fans with a half size (EG) dual core radiator. both fans turn on as soon as the AC comes on. i dont know what other radiator i can fit while still keeping the AC lines away from the header. it overheats when i am driving.

are you swapped or have a stock motor?

ef-dallas

im running stock but have the exact same problem... i live in texas so its also hot in the summer.... if i dont turn the a/c on then dont have a problem getting hot but as son as i turn my a/c on give it 10 min and its starts to get hot and the idle increases.... stumped and would really live the solution to the problem

4drEF

I think you could narrow it down even further.
Just a practical idea with no auto-tech anything to back it up.
When you flip on A/C at idle it adds some load to the engine and the idle bumps up.
What if you not put the A/C on and just rev the motor a little to get the same idle as if the A/C were on?
I think it would start heating up anyway. Only to further show that your water cooling system is not working well.

Leaving the hood open at idle may worsen the problem as air will not circulate around the motor properly and leave pockets of hot air.

My questions :
What coolant/water mix do you have? Running too much of either is bad... straight water is royal failure.
Is the fan CFM sufficient and is the fan sized properly to cover the radiator? Fan shrouds are awesome - a Spal fan doesn't cover the corners of the radiator so you do get hot spots where there is no air flow. This problem is magnified at idle.

Some aftermarket radiators are garbage and can not cool as effectively as a stock radiator. You didn't mention what dual core you went with. IF it's a used stock dual core, it may have old build up inside and could simply need a flush.

Also, how is you dual core mounted? This may have some effect as to how it cools.

Is the A/C evaporator mounted in front of the radiator?

usdm_ED7

-im using 50/50 mix of water and antifreeze.
-im using a dual core C&R radiator (mentioned in first post)
-i dont know the exact CFM of the fan but the fan does cover up the whole radiator. im sure its more then enough as my buddy ran the same one on his drag EG.
-the dual core is mounted straight up and down. i bought an innovative crossmember so i wouldnt have to "ghetto lean" it.
-as far as the evaporator i will have to go double check. im not too sure where its located. but the only thing in front of the radiator is the condensor.

4drEF

Ah - blew right over the C&R when I was reading the thread the first time. sorry.
and sorry again for mixing up the condenser and evap.

Shrouds are easy to fab up and will make a difference.
I think it would be a good investment.

Just throwing out more thoughts...
Considering how you have a side-by-side setup with the radiator and condenser, you can probably rule out any issues between the two. I'm thinking your problem has to do with the raised idle and load of the compressor creating more heat and then inefficient air flow through the radiator. You can feel around on the front of the radiator and check for hot spots (inefficient air flow) or cold spots (clogs).

Maybe check the water flow in the radiator to see when the thermostat is opening. It could be that it's opening too early and the water in the radiator is passing through too quickly so that it doesn't have a chance to transfer heat.

Deetz

My crx used to have this problem also, BUT............i solved it!

It was simple, i went and picked up this great product made by a company called Redline. It is called WaterWetter, which is a heat transfer agent, allowing your cooling system to become more efficient

usdm_ED7

4dref - no worries bro, thanks for the input though.
ill check the water flow to the radiator next. if the thermostat is opening too early what should i do? get a higher temp rating for the thermostat?

Deetz - tried that and it didnt help. heard great reviews though.

would a water pump going bad have anything to do with this? im new to this cooling system aspect of things.

~sp33~

If you were to rev it up, there would still be no load on the motor, and the coolant would be passing through the engine faster. A/C adds load with no increase in coolant speed which is usually why it causes this overheating.

Sorry i don't have any more suggestions OP, except a full rad which would allow the fans to be more efficient.

4drEF

You are correct.
The coolant would be passing through faster, but on a stock engine/radiator overheating does not occur.
Thinking that it might narrow down the problem by just simulating idle bump with no A/C load.


That is one option.
I was just throwing it out there to be checked.

I really think you have an air flow problem. If you put a house fan fin front of the car does it still overheat?
If it doesn't then I'll stress it again and point you towards getting a shroud.

usdm_ED7

im going to try the stock EF one again. This time im going to try with stock headers or dc so i can mount the fans at the stock location. ill try a 10in in front of the header and the stock fan on the passenger side. ill have my fingers crossed.

Ludehrt

Heat wrapping the header also helps keep heat away from the radiator. Every little bit helps.

Tyson

An update since its been another week.

Last week I did 3 things, changed out my coolant to mostly water PLUS water wetter, and fixed some of the fins on the condenser, and removed my front license plate. oh yeah, i also cleaned out my EACV/IACV but that was pretty much pointless.

I happened to drive up to Bakersfield once again this weekend and driving up to the Grapevine (a socal mountain pass) the temp needle started to wiggle, but never got me too nervous. was fine at the top, where it still continued to overheat last week, and wiggled again as i got closer to bakersfield where it was 100 degrees, instead of 110 last week. Still, very much different than last week so very much happy with the results.

driving around town the needle never budges. i'll put the license plate back on, hopefully it'll be ok. and no, the foglights in the corner are very insignificant to the amount of area the front license plate takes up. also, when i have time, ill finish straightening out the remaining row or two of the condenser (ran out of time last week).

btw, the radiator fin straightening tool from harbor freight is absolutely worthless! to fix the fins, you just need two small screwdrivers and A LOT of time, its very tedious work.

usdm_ED7

thanks for the update.

only update i have is that we pressure checked the cooling system and their are no leaks. also tried a new thermostat sometime last week but that didnt help. only thing we havent touched is the water pump. im running the LS water pump. might upgrade to the GSR water pump since it has more teeth. Im hoping this is it cause we have tried almost everything.

88waggy

Wat bout radiator cap!!!

ef-dallas

my car secondary fan doesnt come on till the car gets hot... then will cool back down but the idle the surges which messes it all up and constant hot... clueless