Touge/Wangan

I wanted to start by saying that I've spent a couple days searching for a solution and I've come up short, I have a 1996 Honda Type R (from japan) and it's having the weirdest issue, I bought the vehicle as a rolling shell and recently put a 98+ spec ITR engine and trans into it, seemed fine for a while but after installing the hondata I've noticed that the CEL is tripping intermittently as I drive, when I plug in my laptop it shows that the CEL lights when the coolant reaches 212f.

here's the weird part, when the climate control is set to "cold" and fan being anywhere from off-to-4, the car will overheat if I drive on the highway for an extended period of time (tripping the CEL @ 212f) or if I drive and come to a stop, I've witnessed the temperature going from 202f to 216f rather quickly but not surpassing 216f.

If I turn the heat on the climate control to "hot" and fan being anywhere from off-to-4, the car runs, heats up and drives PERFECTLY fine, after highway, in town, stopping and so-forth the temp. never passed 202f and ran 195f until I came to a stop, the rad fan works like clockwork as well and always turns on.

I've changed the thermostat with a Gates unit, and replaced the radiator with an OEM style rad, new rad hoses and meticulously bleed the system when I have issues like this, unfortunately to no avail. after I shut the car off it seems to push some coolant out of the rad cap and sucks it back in once the vehicle warms up but I'm certain this is normal.

any idea guys? I'm lost!

KevinEF7

The car runs fine when you switch the heater to hot because it opens up the valve on the firewall that allows the hot coolant to start circulating in the heater core and its hoses, which apparently is, as an entire unit, efficient to keep your car cool enough.

Long story short you need to either make your current setup more efficient or buy a more effective/efficient radiator.

Is this a full size or half size radiator? Is your coolant temp readings coming from the thermostat housing?

Touge/Wangan

it was an OEM full sized radiator, the coolant mix is 60/40 water to coolant.

the reading is coming from the ECT being read through Hondata with my laptop.

cafrog

You have already done things that I'd of done.

If I'm going to get picky....

The rad fan kicks on consistently/properly?

When you bled/burped the system, you verified it's circulating when thermo opens?

You've periodically check coolant level and it's not eating up coolant in any way? Doesn't need more? Reservoir stays at optimal level?

When CEL pops, have you tried to verify that it's that hot? I'm just wondering if it's a faulty sensor....

Any of the hoses hotter or harder than others when CEL pops?

Radiator cap is the old one or a new one? I know guys sometimes have issues with rad caps being bad. I know a guy who had coolant pushed into the reservoir. Weird. New rad cap fixed it.

Touge/Wangan

cafrog

When it spikes after the highway....fan is running then?

Will it spike with no AC and climate system turn off?

I own a lisle funnel. It's a nice tool...especially for my Kswap EG. It allows me to see coolant level as thermo opens. Easier than looking down into the radiator. But I don't think air in the system is your issue.

Coolant passages inside block flow appropriately? I'm kinda lost...sorry. Weak thought....flush the block and try again.

Touge/Wangan

yup, after the highway the fan is running. I've pulled over and immediately opened the hood to confirm just before the temperature spikes. it will go from 202f-206f and jump right to 216f (give or take) when I come to a stop tripping the CEL.

I do not have AC in my Type R, it has been removed. it will only spike with the climate control on the "cold" setting and not on the "hot" setting, fan speed does not change a thing, only temperature.

the coolant lines on the block are OEM and untouched, the engine had just shy of 100,000km on it when I purchased it, from a running donor vehicle.

I'm pretty stumped, I purchased an NTC (OEM) thermostat and I'm going to confirm that my friend (who kindly helped me when I was sick) to change the thermostat the first time, to confirm that he had done it correctly. regardless, the new one will be installed and tested but I doubt it will be the problem.

I'm pretty stumped.

cafrog

Maybe a lower temp thermo?

cafrog

Water wetter but I have no experience with that additive.

Touge/Wangan

yeah, the one I installed was a 180f thermo, the new Honda one is a 172f thermo.

I didn't think it would make that big of a difference, but we will see.

VegaS10

Clogged radiator maybe?

KevinEF7

Tired, inefficient rad, buy a new one, the oem style replacements are dirt cheap under $60, problem will be gone

holmesnmanny

How many fans do you have ? Actually watch the fans when it tries to overheat and see if both/all fans come on.

ojasia

Re-do your thermo stat with a new one 170* something. 180* seems high seeing it just starts to open at that range prolly why you seeing a spike. I was having a similar issue but it was spiking to 196-204 and it had a 172* stat in there but like 140k old. Anyways swapped it with what auto parts store had 170* stat and tried out this German stuff called Pentofrost I mixed it 50/50 with distilled water made a world of difference, I have used water wetter in the past but now that I see numbers every day on Hondata app I base my conclusions on factual avg.es my ECT remains in the 170-180 highway, city 180-185. Although straight Distilled and water wetter might work as well although I dont think it could be better at the numbers its running now it would just be to cold then, the Pentofrost gives you a better chance with boilover, and anti freezing additives whereas the water wetter is just a blah blah blah something for the water to retard the forming of bubbles something blah blah surface tension Lol, and I think it helps the water not to totally corrode your engine. Anyways, GL hope this helps. Sometimes it helps to just do it again. If you do try the Pentofrost dont forget to open up your heater core to try and get some of that coolant to drain as well, it says not to mix with coolant. Then flush with water and fill according to directions. Idk if it matters or not but when I swapped my stats there is a little hole and a pin thing dangling in it and said up mayeb you have same and friend put down idk just trying to help. GL!

mr. Grind

try a .9 or 1.1 radiator cap sir
the 1.3 increases the boilin point of your coolant/water.
Good luck

holmesnmanny

The Honda cooling system works just fine without trying to trick it into working correctly. All it takes is making sure you use Honda products which guarantees you get it right the first time and making some necessary checks.

No thermostat out there will work as good as the $20 you spend on an OEM Honda thermostat that has a builtin failsafe for when it finally does fail, years down the road. Or you can spend $10 on a cheapo which does not have a failsafe and will only last 30k, tops, which will fail in ONLY 30k and you won't catch it in time before your head warps.

Do the math. It's not rocket science.