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Discussion Starter #1
I currently have a 1990 Honda CRX with a built d16y8.

I've been having serious issues with the car running really hot (temp gauge goes to Hot pretty quickly).

Notes:
Car idles fine at normal operating temperature (50% of time)
Car goes hot under boost / under idle same
Coolant system has been drained and refilled
Coolant system has had bubbles and air pockets removed
No leaks or spewing coming from motor or radiator
All coolant and radiator hoses are new
All clamps are tightened
Block deck and head have been checked with straight edge for deforms (both fine)
No cracks visible in block (extensive searching)
Cylinder head has been replaced (switched y8 cylinder heads just to double check for cracks - still same overheating issue)
Cylinder head gasket HAS been replaced (Stock - MLS)

More info for diagnosis:
Do not have coolant temp gauge or external electric thermometer
Do not have EGT Gauge hooked up
Radiator mounting has been modified / fabb'ed to sit to side of engine bay because of the Holset mounting
Downpipe is open (not connected to exhaust yet)
Bumper has been taken off to further access to intercooler
Overheating issue is same with and without hood on
Turbocharger does not have turbo blanket
Downpipe is wrapped with Lava heat wrap
Sparkplug wires are stock
Sparkplugs are gapped at .18 for e85 (sparkplugs are standard NGK BKR6's)


Have changed:
Thermostat (now running stock Honda thermo.)
Coolant Temp Sensor
Radiator (half-size from civic)
Added two electric radiator fans (1 is pushing 1 is pulling)
y8 Cylinder head
Headgasket


Okay, here is my full setup:

(Listed everything just to make it easier and to clear up any questions)

  • Full D16Y8 Motor
  • YCP 75mm Vitara pistons (8.5:1 comp)
  • Eagle H beam rods - crankshaft has been balanced
  • ARP Headstuds
  • ARP rod bolts
  • Golden Eagle blockguard
  • LS throttle body
  • FIC 1050cc injectors
  • Walbro 255 fuel pump
  • Custom-made exhaust manifold
  • Tial external wastegate
  • Turbo XS, dual stage boost controller
  • Mishimoto front mount intercooler and piping
  • 7 blade Holset Hx35
  • 3" downpipe obx, full exhaust
  • Streetfire ignition box, and msd external coil
  • 6 puck sprung clutch disc
  • act extreme hd pressure plate
  • ECU is chipped and tuned on CromePro for e85
Cylinder head is stock.
 

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So you've replaced everything, except for the radiator cap and water pump. I'm putting my money on the water pump. If it's not that, i'd say that your temp gauge is wrong. Does your coolant boil in the overflow?
 

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Discussion Starter #3
So you've replaced everything, except for the radiator cap and water pump. I'm putting my money on the water pump. If it's not that, i'd say that your temp gauge is wrong. Does your coolant boil in the overflow?
Radiator cap is new as well. I haven't gotten around to water pump yet. Coolant does boil in overflow.
 

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do you have both fans on at the same time? what CFM are the fans you are running? try changing out the water pump. possibly hardwire the fan to be on to make sure it is working and trying to keep the ECT's down. also try and swap out clusters with someone elses just to test it, maybe the gauge is messed up.

is there a way you can do a datalog on your car and see if the temperatures you are seeing on your gauges are the actual temps your sensors are seeing?
 

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Discussion Starter #5
do you have both fans on at the same time? what CFM are the fans you are running? try changing out the water pump. possibly hardwire the fan to be on to make sure it is working and trying to keep the ECT's down. also try and swap out clusters with someone elses just to test it, maybe the gauge is messed up.

is there a way you can do a datalog on your car and see if the temperatures you are seeing on your gauges are the actual temps your sensors are seeing?
Both electric fans are from Godspeed I think? Both are working. One is pulling, one is pushing.

I think I'm going to replace water pump next. Then cluster.

I'm not sure if I can data log or not.
 

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honestly, both of them being on there is prob causing a restriction than helping, i would just use one or the other.

are they 10" or 12" fans? i looked them up and they are 1250 cfm fans which isnt bad at all.
 

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1988 Honda CRX
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Is this a new set up, or did it run fine but now overheats after some changes.

Are both top and bottom hoses about the same temperature to touch with the engine running.

What does "Car idles fine at normal operating temperature (50% of time)
Car goes hot under boost / under idle same" mean.

If you start it and let it idle isit OK like forever, but once you boost it and overheat it under boost, it then also overheats at idle.

Does it overheat when moving at highway cruise speed.

Is total actual timing correct.

If you start it cold with the cap removed can you see water flowing in the header tank once the thermostat opens.

As above, do gas bubbles erupt and blow water out.
 

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1988 Honda CRX
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Are both fans moving air from in front of the radiator to the engine bay.

How are the fan shrouds arranged.
 

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Discussion Starter #11
honestly, both of them being on there is prob causing a restriction than helping, i would just use one or the other.

are they 10" or 12" fans? i looked them up and they are 1250 cfm fans which isnt bad at all.
They are two 12" fans. I don't think having the one of the front is causing much of a restriction due to its placement in the bay already...
 

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Is this a new set up, or did it run fine but now overheats after some changes.
Setup ran for a year fine in another chassis (EK hatch). Nothing has changed other than chassis (crx now) and cylinder head (switched out heads to rule out possibility of a cracked cylinder head

Are both top and bottom hoses about the same temperature to touch with the engine running.
Both feel like same temp while idle after normal operating temp has been reached.

What does "Car idles fine at normal operating temperature (50% of time)
Car goes hot under boost / under idle same" mean.
50% of time car can idle without overheating. Rest of time car goes hot. 90% of time car goes hot driving around normal (in and out of boost) and highway speeds.

If you start it and let it idle isit OK like forever, but once you boost it and overheat it under boost, it then also overheats at idle.
No it's not. Overheats under normal conditions. Overheats under conditions of boost.

Does it overheat when moving at highway cruise speed.
Read Above

Is total actual timing correct.
Yes. And timing has not been adjusted

If you start it cold with the cap removed can you see water flowing in the header tank once the thermostat opens.
Yes you can see water move in radiator once thermostat opens (so obviously thermo is working correctly.

As above, do gas bubbles erupt and blow water out.
Yes, it boils like normal once temp is reached.
 

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So if the water is moving, the water pump is probably OK

It does have sleeves. They where fitted by Honda as OE.

I suspect insufficient airflow over the radiator due to the different chassis.
 

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Discussion Starter #17
So if the water is moving, the water pump is probably OK

It does have sleeves. They where fitted by Honda as OE.

I suspect insufficient airflow over the radiator due to the different chassis.
I just meant aftermarket sleeves. We've already looked for cracks.

The radiator setup has been ran by other holset users in crxs and civics before without issues
 
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