rb20 cooling system help

[glitched]

Previous owner said he replaced the water pump a couple years ago when he did the swap, and found that the blades had rusted away. the radiator is also only a couple of years old. He said he flushed the system clean and never had any cooling problems afterwords.

Now, I'm flushing the system again, but the car has been sitting for about 9 months.

I've found that the coolant is very rusty again, I've flushed 3 gallons of distilled water through the system, each time letting the car run for about 15min with the radiator cap off to burp any air bubble blocks. then put the cap on and let run for another 5 minutes. and the water is still really murky looking.

but with all that, the water is cold coming out the bottom. while the radiator cap is steaming hot to touch. The top radiator hose is at 170 degrees according to my laser thermostat, the bottom radiator hose is cool to the touch.


So, I'm thinking there's got to be something up, could it be the radiator, the water pump again, or am i not getting all of the air blocks out? or maybe some other sort of block somewhere? what do you guys think?

I've got 3 more gallons of distilled and a bottle of coolant anti-rust flush stuff to use yet...

[wv240]

I just went thru the same deal with my rb20. I let it sit for allmost a year without doing anything with it and the water was murky looking like that. I drained the water and coolant from the radiator and engine and refilled it using water a couple times while running the engine. Then I refilled everything with water and coolant mix and ran the car for a while and drove it around for a little while and let it sit overnight and then drive it again the next day. Then drain everything again and put coolant and water mix back in it and it should be good to go. Im using a greddy swirlpot with my system so its a pain in the a** to clean everything out.

[Sil240]

Ok next time you flush your engine use Vinegar with the regular water.
When you are done use 50% coolant and 50% distilled water or another ratio depending on where you live.
More water for a hotter climate, less for the opposite.

It sounds like your Radiator is clogged.
Pull the Rad out and flush it from the COLD side to the HOT side.
Use a hose with a gun on the end to get some good pressure behind it.

Then Pull out the Thermostat and Flush out the block with the hose as well.
Make sure the Thermo is good or just replace it, its only a couple bucks.

Also I would double check that there are blades on your water pump.
Make sure that guy didn't just throw that old broken pump back in.

[glitched]

yeah, the plan is to keep flushing using gallons of distilled water until it starts to clear, then actually go with the coolant/water mix with some watter wetter and some anti rust stuff. Going on the fourth day of flushing.

I think I'm gonna pull the radiator and thermostat, flush the radiator with a hose outside of the car from the other direction

[Sil240]

You don't need to use distilled water to flush it.
Just use the hose.

Definitely sounds like your Rad is clogged

[glitched]

yeah, dont have hose access in my garage, and i had bought distilled water in bulk cause it is cheap, like 60 cents per gallon.

I'm gonna have to take the radiator out of the car and bring it to a hose to flush it that way.

[Genpac]

My RB coolant was rusty as well. I replaced the radiator and removed the thermostat. Using a pressure nozzle, I pushed water through the block and all of the lines until the water came out clear. Just a note, if you do this, the asphalt/concrete you're on will be rust stained.

[Yellow4g63]

Use the bleeder valve on the intake manifold to get rid of the air bubbles in the system. If it has an aftermarket intake manifold buy one of those swirl pots and hook it up.

[glitched]

Some updates. took the radiator out of the car and flushed it using hot water, the whole radiator got hot from the water, so i dont think it was a clogged radiator.

Took the thermostat out, turns out prev owner put in a nismo thermostat that opens up at 62 degrees c. I dropped that in some hot water and tested that it opened at the right temp and did.

I didnt take the water pump off, but i reached in from behind from the thermostat hosing and felt and found that the blades indeed were still intact.

I'm now even second guessing myself that there was something wrong in the first place.

[RustspecS13]

Like I said on NRR I think its just doing a really good job at idle. There's a low enough amount of heat that the rad can cool it down to the point where you might think coolant isn't circulating.

~Alex

[SullivanRacing06]

id have to say if the previous owner "changed" the water pump it wouldnt of rusted out like it did..

take caution on what the prev owner told you on what he did to the motor

[Yellow4g63]

is it the stock KA radiator? if so it won't do a good job when it's hot outside. Modine makes a replacement that's for auto S13's that's a little bit thicker.