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CRX ECODiesel Ram
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Discussion Starter · #1 ·
I have been running for several years without a problem at 12.5:1 with an oem gasket and stock headbolts. This summer though i started pushing coolant out, and a test kit confirmed exhaust in the coolant. I pulled the head, sent it off to be surfaced and tested, bought head studs, and put it back together with a new headgasket. I also replaced the radiator with a new oem style unit, along with an aluminum fan shroud, 2 slim line fans, and mishimoto radiator hoses, and all new honda coolant.
Prior to headgasket failure, i was seeing 183-189 degrees coolant temp all the time. Now with the repairs and "upgrades" I am seeing 185 creeping up to 203-205 when driving for longer periods. I have the radiator fan on all the time while the condenser fan is still wired to run with the ac. I am not pushing coolant out anymore. I am concerned that I am running too hot still and am replacing my thermostat this week just in case.

It has also been hit as hell this summer, I am looking at high 90s on a daily basis with heat indexes up around 110 daily.

Should I be concerned about the temps I am seeing? Do I need more coolant capacity (larger radiator)? what else can I look at?
 

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92 cx
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It could definately help lower temps to run a larger capacity radiator, straight water with water wetter or the amsoil stuff. You could duct the airflow so it goes thru the radiator and not around it. Do you have more info on your build? Report back after thermostat install. I dunno if it's a great idea to have the fan run the whole time if that's what you were saying.
 

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Check for slow leaks or pressure escaping.

Sometimes the thermostats don't open enough. Drill it.

I prefer hot side mounted thermostats.

Full size rad.

More important. Make sure air isn't going around the Rad.

Probably is more now with new rad
 

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CRX ECODiesel Ram
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Discussion Starter · #4 · (Edited)
d16a6 .5mm over bore, pg6b pistons, rebuilt stock head milled (need about 5 degrees of advance to time properly), oem z6 headgasket, arp head studs, arp rod bolts, stock rods, new oem retainers and clips, Isky valve springs, Rocket Stage 4 cam, Edelbrock intake manifold and TB, S2 alpha 2 header, h22a45 injectors, aem rail and fpr, s300.
exedy sport clutch, lightweight flywheel, mfactory lsd, mfactory 4.7 FD, synchrotech built trans.

I am running a full width radiator, but it is one of those aftermarket ones with the trans cooler on the bottom. Currently running Honda blue coolant. I will take a careful look at the gap around the radiator and between the radiator and aluminum shroud, and make good use of foam weatherstripping tape to make sure airflow is going where needed.

I THINK my current thermostat is a Honda OEM one, I am swapping it with a new Gates one on Wednesday, and am going to test it and if opening at the right temp will see about drilling it for more flow.

I have had the same results with water wetter as I have with a few drops of dish detergent, will probably look into doing that to see what happens...

With the high temps and humidity I am seeing would a larger capacity radiator be even worth looking at?
 

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Integra DB9
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Are you reading the temperature while running or just when you stop?
If the former, does the temp go up and down with airflow over the car, ie: traffic versus open road?

205 degrees is still 20-25 degrees below boiling point at typical coolant pressures, so depending on conditions, if you see no higher than this, you may not even have a problem in the summer temperatures you're talking about. What happens in cool night air?
 

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Discussion Starter · #6 ·
Any driving load causes a creep up in temp over half an hour. I have not had a chance to be out longer to see how high it will go but it appears to stabilize at 205 to 210. I am not seeing any real cool night air, 80s with 80 to 90 % humidity is as good as it gets.
I have the next 3 days off and will try for longer rides though and monitor more, though i am going to really look at gaps and air flow through the radiator.
 

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Brokedick Millionaire
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What are you using to measure the coolant temps? Maybe something there might have changed at about the same time the head gasket went.
 

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Discussion Starter · #8 ·
Hondata s300 readout from the stock sensor.

Hopefully some cooler weather will come through so I can see what happens then. I may be just plain old paranoid since i never monitored this closely before the head gasket...
 

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Brokedick Millionaire
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Was the OEM gauge still working???

Once OEM dash gauge moves above 1/2 way mark, time to shut it down....

Have you checked base timing setting since the HG issue?
 

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Discussion Starter · #10 ·
OEM gauge works, it has not budged between reading 180 and 195, then slightly goes up and is still under half at 210. I can see that I marked the base timing and it is the same as prior to head being resurfaced. THe shop said they took off as little as possible since they knew the head had been surfaced before.


fitment of radiator is pretty snug not much gap, coolant levels are very good and not changed at all.

At idle on a warm day (air temp of 89 with moderately high humidity) i am seeing steady 183 degrees while idling for sustained periods of time.

Going for a drive shortly
 

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CRX ECODiesel Ram
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Discussion Starter · #11 ·
after 25 minutes i am seeing 187 degrees ECT while idling
 

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Discussion Starter · #12 · (Edited)
at half an hour seeing 192. IAT is 120 degrees. idling. short drive around the neighborhood, temps shot to 198 then dropped back to 192.
 

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Discussion Starter · #13 · (Edited)
This morning in front of the tropical storm coming in temperatures dropped about 10 degrees so I was looking at air temperatures of about 75 with nearly 100% humidity. Went for a test drive and I'm saying 179 - 185 coolant tabs so I guess I am just being overly paranoid especially on days when I'm looking at 100 degrees with 90% humidity.

later in the day i was looking at low 90s and about 60% humidity, and with ac on and spirited driving saw no higher than 208 degrees. Stock gauge still below the middle. I guess it just comes down to me being overly cautious and that my cooling system is adequate for a drag race and daily driving but road racing will need more...
 

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you are not close to boil over...

At sea level, water boils at 212*F

Now for every pound of pressure the radiator cap holds , allows 3* above boil point

Most import come equipped with a 13lb cap

so 212*+(3x13)= 251* is when you will truly hit over heating

Now rad caps need to be checked and/or replaced every other year.

as long as your cooling system hold proper press and has no leaks, you are doing fine
 
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Discussion Starter · #15 ·
I think I am just overly paranoid cautious after losing the headgasket once this summer already.
 

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Brokedick Millionaire
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Simply put, if WT (water temps) climb above 220 in the early laps, you have a problem.

If you can see 210 while leading the race, but it creeps to 240 while in traffic or 260 while in second and drafting the leader on his bumper for the lead, that is normal. You need to step out into clean air and drop those temps. Also need to watch OT (oil temps) to be sure they don't get above 275-300 range...this is where $$$$ in GOOD fluids pays off.

SCCA 2017 Runoffs at IMS, this is gonna be a blast!
 

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anything below 200 is fine, 205-210 i would start looking for problems. i suspect your water pump might have failed and the impeller is basically freewheeling on the end of the rod but no good way to test that without pulling it off.

i live about 150 miles from death valley and daily drove my crx. i know all about the struggle of keeping these motors cool. however suprisingly the oem size radiator is enough to cool a turbo b18 without issue even under hard pulls.

i highly suspect a mechanical failure of either the thermostat, wrong installation or a bad waterpump as the stock radiator has more than enough surface area to reject the heat your engine is putting out at idle. also, check and make sure the fan is spinning the correct direction, ive made that mistake before.
 

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If you're running a 195 thermostat, swap it for a 180. That would get the coolant running through your radiator sooner. Other than that...
 

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Discussion Starter · #20 ·
afaik 180 is stock on the Si.

I have been tracking IAT and coolant temps though, looks like at 80 degrees or less IAT i see 181 on ECT always. Around 95-110 IAT I start seeing 195 ECT and 110+ ECT creeps up to 200-210 depending on the day. I guess after losing that headgasket I was way paranoid.
 
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