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.
Hi all,
ive been struggling trying to figure out the overheating issue that i have in my turboed Honda civic. I have a fully built block/head B18C. PWR rad with FAL fan, new OEM water pump and OEM thermostat. i gradually overheat even on the highway with light load and when i park the car aside the fan just stay on forever. If i start up the car when cold the fan kicks in On/Off normally, but once i take the car for a drive the temps start to go way up. i think i reached to 212 MAX. The temp needle doesnt hit sky rocket.
Tests that i have done and got checked:
1- Leakdown test (after engine warm up) = Good
2- Pressure test (170-175 psi all board) cold and warm conditions = Good
3- pressure tested the coolant system 16-18psi. Thats the same rating of the rad cap im using = Good no leaks
4- Double checked my dist and made sure it was synced= Good
5- Checked the tune and the timing isnt aggressive. Timing is still stock GSR timing
6- Checked timing belt and timing belt didnt skip a tooth. All TDC marks are aligned.
Other info about the car:
1- car uses OEM coolant/oil heat exchanger
2- have an aftermarket engine oil cooler right under the passenger side front fender for the engine
3- 13 year old Garret GT35R turbo (practically been used for 5 years since most of the time the car was garaged)
4- turbo is water cooled and is connected to the coolant system
5- fuel used is 91 OR
6- Temperature here is around 93 - 120 F
7- 5 spd dogbox with twin plate
8- ATI crank pulley
9- engine head ported and polished, 5 angle job
10- JDM OEM CTR cams
11- CP pistons 9:1 CR with Manley Turbo Tuff rods
12- Moroso oil pan upgrade
Where do you guys think is the problem? what did i miss checking?
Last edited by IntegraTypeR; Jun 4, 2020 at 09:18 AM.
Are you pushing coolant into the reservoir? Even a little bit? Is there any oily residue on the bottom side of your radiator cap or inside your coolant reservoir? If so, it would likely be a blown head gasket, even with good leak down and compression numbers.
What pressure radiator cap are you running? Higher pressure caps will raise the boiling point of your coolant.
Are you running a wetting agent (water wetter)? If not, you may want to try it.
What temperature does your thermostat open at? Verify that it is opening when it should be.
Is the FAL fan a pusher or puller? What CFM is it rated at? Are you using the OEM wiring or are you running a relay and larger gauge wiring? I haven't done a comparison test, but I've read that puller fans do better. I'm not sure what FAL fans are rated at for airflow, but you can get some pretty powerful SPAL fans. Running the fan circuit with larger wiring, a bigger fuse, and a relay will allow the fan to draw more current and run closer to it's top performance.
How is the airflow to your radiator? How bad does the intercooler block the radiator? Do you have anything blocking the left side of the core support off (assuming no AC condenser)? The radiator needs airflow across it to cool down. An intercooler will reduce airflow if it blocks the radiator. Nothing blocking airflow where the AC condenser was will allow air to bypass the radiator.
What are the fan settings in your tune? I've got mine set to come on at 185F and not turn off until 90mph. I think this had the largest impact on me getting my coolant temps under control.
Post a picture of the front bumper? I bet your not getting enough air flow. Your temperature is warm but not enough to blow it up. Like you I would also want it a little cooler. The outside temperature is pretty extreme but I think with better air flow you will cool down.
Are you pushing coolant into the reservoir? Even a little bit? Just a little and its sometimes not always. i did a coolant pressure test and my pressure doesnt drop. In other words there are no leaks. with the rad cap open the coolant isnt bubbly when using a coolant flask.
Is there any oily residue on the bottom side of your radiator cap or inside your coolant reservoir? If so, it would likely be a blown head gasket, even with good leak down and compression numbers. I do see some copper spray oil residue. I used copper spray on my HG. I can try flushing it and see if there would be any more left
What pressure radiator cap are you running? Higher pressure caps will raise the boiling point of your coolant. using the cap that came with the PWR rad. I cant remember the pressure, could be 1.1bar but I shouldn’t worry as I’m using what the rad manufacturer has supplied. i can confirm later when i get my rad back.
Are you running a wetting agent (water wetter)? If not, you may want to try it. yes I was running two bottles of water wetter mixed with distilled water. yesterday I used some flush chemical and ran the engine for 10 mins as directed. drained the rad completely and flushed all coolant inside the engine by pressurizing water into the rad cap. took the rad to a shop to do a leak test and get flushed professionally. waiting for the results tomorrow!
What temperature does your thermostat open at? Verify that it is opening when it should be. Well the thermostat is OEM new. it starts to open around 160F I believe when I check my hondata sensor display. Once the engine reaches operating temperature the fan kick in i notice the lower hose is warm just like the upper hose. thermostat closes and open as its supposed to.
Is the FAL fan a pusher or puller? its a FAL Flexalite x-A-Lite 125 Single 12 in. Electric Puller Fan which is shrouded.
What CFM is it rated at? Manufacturer claims it flows 1250CFM.
Are you using the OEM wiring or are you running a relay and larger gauge wiring? I’m running OEM wiring. OEM uses a relay too and the voltage I’m getting at the fan is 13.7-13.9v which is pretty good.
I haven't done a comparison test, but I've read that puller fans do better. Yes true puller fans supposed to be better.
I'm not sure what FAL fans are rated at for airflow, but you can get some pretty powerful SPAL fans. used to have a 13" SPAL fan but wasn’t shrouded and it used to draw a lot of amps as I can see my interior dash light and front headlights brightness get affected.
Running the fan circuit with larger wiring, a bigger fuse, and a relay will allow the fan to draw more current and run closer to it's top performance. I believe stock wiring runs a relay in the fuse box. I see 13.7-13.9v at the rad fan connector. Hondata says i get 14v at the battery. As long its above 13v then it should be better than the battery constant 12v.
How is the airflow to your radiator? its good. when you check by hand behind the rad there is good airflow with no obstruction. The shrouds makes sure the whole front of the rad surface area cooled by pulled air
How bad does the intercooler block the radiator? intercooler is small and only blocks 1/4 of the lower rad and there is 2-3 inches gap between them.
Do you have anything blocking the left side of the core support off (assuming no AC condenser)? Nothing blocks the rad from the front or the back. the turbo inlet is close to the rad but not blocking anything. No AC condenser. Did a complete AC delete on this car long time ago.
The radiator needs airflow across it to cool down. An intercooler will reduce airflow if it blocks the radiator. Nothing blocking airflow where the AC condenser was will allow air to bypass the radiator. I’m running a half sized PWR rad with FAL fan and since I deleted AC on this car there is no blockage other than the small intercooler.
What are the fan settings in your tune? its stock OEM setting until now. 202F I believe. As a tuner the cooling system should be noticeable when cruising on the high way as the fan works less during that time and has enough airflow to keep the temps down. Rad fans are supposed to help cooling on low speed or at stops where the rad gets no moving airflow.
I've got mine set to come on at 185F and not turn off until 90mph. I have mine set at OEM 202F and I think it should stay on no matter what speed until temps are down.
I think this had the largest impact on me getting my coolant temps under control. what’s the weather like where you live? Over here summers are hot and temps fluctuate during the day from 93- 120F Max. I just realized something recently that my oil temps spikes quickly than normal and since I’m running a coolant/oil heat exchanger hot oil temps gets transferred to the coolant. FYI I do have an oil cooler installed too.
Overheating on the freeway is usually a sign of bad airflow, or water not circulating through the engine - clog or bad water pump.
i used to have a b16 on this car with this exact cooling system and it was perfect. Temps go down dramatically on the highway. i think the water circulation is fine but since its 3 years old i might consider changing the water pump and since i need to change the timing belt and Alternator belt that would be a good time
Post a picture of the front bumper? I bet your not getting enough air flow. Your temperature is warm but not enough to blow it up. Like you I would also want it a little cooler. The outside temperature is pretty extreme but I think with better air flow you will cool down.
running stock OEM 99-00 Honda civic front bumper. Will take a photo soon
Half size. Was efficient when i was running a B16A
I followed the same path you have so far and had the same exact issues in Texas heat. I think you have 2 main issues, other than the radiator is really just undersized for a turbo setup and high temps. You need a better fan (SPAL hard wired to the battery with a relay). a fan shroud and ducting.
My path:
B16, Koyo half rad and FAL fan: Worked great
B16 turbo, Koyo half rad and FAL fan with shroud: Wanted to overheat on the highway but idled fine. I could push in the clutch and coast then temps would come down on the highway temporarily.
B16 turbo, Koyo half rad, SPAL 13" fan with shroud and ducting on the front: Solved my issues on the highway but was not capable for 20 minute track sessions
I switched to a custom dual pass tucked radiator, full ducting, shroud, oil cooler and have not looked back. I can run on track all day at temps over 90 degrees and it stays perfectly cool
Are you pushing coolant into the reservoir? Even a little bit? Just a little and its sometimes not always. i did a coolant pressure test and my pressure doesnt drop. In other words there are no leaks. with the rad cap open the coolant isnt bubbly when using a coolant flask. To me any coolant pushing is a sign of head lift / slightly blown HG. I would personally replace the HG. You may find other ways to get the temperature somewhat under control, but if the HG is blown even slightly, replacing it will put you in a better spot. Definitely consider replacing the HG if the car starts pushing coolant regularly.
Is there any oily residue on the bottom side of your radiator cap or inside your coolant reservoir? If so, it would likely be a blown head gasket, even with good leak down and compression numbers. I do see some copper spray oil residue. I used copper spray on my HG. I can try flushing it and see if there would be any more leftI use a Lisle funnel when bleeding air from my coolant system. I could see oily residue float to the top of my funnel right when the thermostat opened when my HG was blown.
What pressure radiator cap are you running? Higher pressure caps will raise the boiling point of your coolant. using the cap that came with the PWR rad. I cant remember the pressure, could be 1.1bar but I shouldn’t worry as I’m using what the rad manufacturer has supplied. i can confirm later when i get my rad back. You're probably OK.
Are you running a wetting agent (water wetter)? If not, you may want to try it. yes I was running two bottles of water wetter mixed with distilled water. yesterday I used some flush chemical and ran the engine for 10 mins as directed. drained the rad completely and flushed all coolant inside the engine by pressurizing water into the rad cap. took the rad to a shop to do a leak test and get flushed professionally. waiting for the results tomorrow! OK.
What temperature does your thermostat open at? Verify that it is opening when it should be. Well the thermostat is OEM new. it starts to open around 160F I believe when I check my hondata sensor display. Once the engine reaches operating temperature the fan kick in i notice the lower hose is warm just like the upper hose. thermostat closes and open as its supposed to. OK.
Is the FAL fan a pusher or puller? its a FAL Flexalite x-A-Lite 125 Single 12 in. Electric Puller Fan which is shrouded.
What CFM is it rated at? Manufacturer claims it flows 1250CFM.
Are you using the OEM wiring or are you running a relay and larger gauge wiring? I’m running OEM wiring. OEM uses a relay too and the voltage I’m getting at the fan is 13.7-13.9v which is pretty good. I would definitely run a relay and large gauge wire. We're more concerned about amperage than voltage here.
I haven't done a comparison test, but I've read that puller fans do better. Yes true puller fans supposed to be better.
I'm not sure what FAL fans are rated at for airflow, but you can get some pretty powerful SPAL fans. used to have a 13" SPAL fan but wasn’t shrouded and it used to draw a lot of amps as I can see my interior dash light and front headlights brightness get affected.
Running the fan circuit with larger wiring, a bigger fuse, and a relay will allow the fan to draw more current and run closer to it's top performance. I believe stock wiring runs a relay in the fuse box. I see 13.7-13.9v at the rad fan connector. Hondata says i get 14v at the battery. As long its above 13v then it should be better than the battery constant 12v. The relay isn't what helps - it's the larger gauge wiring. The relay just allows you to use the stock circuit/wiring to switch on the circuit with the larger gauge wiring.
How is the airflow to your radiator? its good. when you check by hand behind the rad there is good airflow with no obstruction. The shrouds makes sure the whole front of the rad surface area cooled by pulled air I agree, a shroud is a good thing.
How bad does the intercooler block the radiator? intercooler is small and only blocks 1/4 of the lower rad and there is 2-3 inches gap between them.
Do you have anything blocking the left side of the core support off (assuming no AC condenser)? Nothing blocks the rad from the front or the back. the turbo inlet is close to the rad but not blocking anything. No AC condenser. Did a complete AC delete on this car long time ago. You may want to block off the left side where the AC condenser used to be. This will help direct airflow through the radiator when the fan is off instead of around it.
The radiator needs airflow across it to cool down. An intercooler will reduce airflow if it blocks the radiator. Nothing blocking airflow where the AC condenser was will allow air to bypass the radiator. I’m running a half sized PWR rad with FAL fan and since I deleted AC on this car there is no blockage other than the small intercooler.
What are the fan settings in your tune? its stock OEM setting until now. 202F I believe. As a tuner the cooling system should be noticeable when cruising on the high way as the fan works less during that time and has enough airflow to keep the temps down. Rad fans are supposed to help cooling on low speed or at stops where the rad gets no moving airflow. I highly recommend you drop this down to around 185F.
I've got mine set to come on at 185F and not turn off until 90mph. I have mine set at OEM 202F and I think it should stay on no matter what speed until temps are down. Hondata has a setting where the fan will shut off above X mph. I believe this is set to around 30 mph in the stock tune. Bump this up higher.
I think this had the largest impact on me getting my coolant temps under control. what’s the weather like where you live? Over here summers are hot and temps fluctuate during the day from 93- 120F Max. I just realized something recently that my oil temps spikes quickly than normal and since I’m running a coolant/oil heat exchanger hot oil temps gets transferred to the coolant. FYI I do have an oil cooler installed too. I'm in the south, so hot and humid. We don't see over 100F temperatures, but regularly get 90's with very high humidity during the summer. This past summer I was able to keep coolant temperatures under 195F (mostly stayed under 190F) even while running AC. This included some long trips (3+ hours) going over some mountains.
I followed the same path you have so far and had the same exact issues in Texas heat. I think you have 2 main issues, other than the radiator is really just undersized for a turbo setup and high temps. You need a better fan (SPAL hard wired to the battery with a relay). a fan shroud and ducting.
My path:
B16, Koyo half rad and FAL fan: Worked great
B16 turbo, Koyo half rad and FAL fan with shroud: Wanted to overheat on the highway but idled fine. I could push in the clutch and coast then temps would come down on the highway temporarily.
B16 turbo, Koyo half rad, SPAL 13" fan with shroud and ducting on the front: Solved my issues on the highway but was not capable for 20 minute track sessions
I switched to a custom dual pass tucked radiator, full ducting, shroud, oil cooler and have not looked back. I can run on track all day at temps over 90 degrees and it stays perfectly cool
so you are running a full sized radiator? its nice to see photos of the shroud setup on a full size aftermarket radiator.
do u have a picture of coolant line from ur turbo? cold water goes from block to turbo, from turbo to upper direction of radiator.
i welded a -6an bung on the OEM water neck pipe and the another line from the turbo to the cylinder head. There was a stock OEM plug there which i removed and used an o ringed metric fitting to -6. Will take photos soon
The radiator is not there since i send it to a shop to leak test and flush it, but as you can see where the radiator goes and the gap between them
Originally Posted by b16racereg6
Post a picture of the front bumper? I bet your not getting enough air flow. Your temperature is warm but not enough to blow it up. Like you I would also want it a little cooler. The outside temperature is pretty extreme but I think with better air flow you will cool down.
Last edited by IntegraTypeR; Jun 5, 2020 at 11:07 AM.
I would recommend heat wrapping your turbo manifold to cut down on engine bay heat , you might want to also check and see if your fan is still blowing full strength. I was having the same issue with the same setup and I went to a stronger fan and all was good afterwards
Have you tested the ECT sensor to make sure they are not giving a faulty reading! I recently helped someone who thought the engine was over heating when it was actually just a faulty ECT sensor.
I would recommend heat wrapping your turbo manifold to cut down on engine bay heat , you might want to also check and see if your fan is still blowing full strength. I was having the same issue with the same setup and I went to a stronger fan and all was good afterwards
i will upgrade to a 12" SPAL fan and aluminum shroud hopefully soon. i wil use it on the FAL shroud. which puller fan model would you recommend from SPAL?
i was looking at these models:
my current setup is capable of 1250 CFM. so all of the above pull more air.
dont you think it could be a bad turbo bearing? well the reason why im asking because the turbo doesnt sound smooth when i hear it spooling down when the engine is shut off.
Last edited by IntegraTypeR; Jun 7, 2020 at 02:36 PM.
Have you tested the ECT sensor to make sure they are not giving a faulty reading! I recently helped someone who thought the engine was over heating when it was actually just a faulty ECT sensor.
im considering replacing the ECT sensor, Fan switch and thermo unit
i will upgrade to a 12" SPAL fan and aluminum shroud hopefully soon. i wil use it on the FAL shroud. which puller fan model would you recommend from SPAL?
i was looking at these models:
my current setup is capable of 1250 CFM. so all of the above pull more air.
dont you think it could be a bad turbo bearing? well the reason why im asking because the turbo doesnt sound smooth when i hear it spooling down when the engine is shut off.
Can you make a cardboard duct and try to force more air down the throat of that intercooler/rad? I bet with a bumper trim it will fix it. You’re not getting enough air flow. You can always go into the engine management and make the fan turn on around 185 deg.
Troubleshooting: Overheating issue @212* - B18C turbo
