hdhype

What I have: S13 chasis w/ s13 SR20DET, Aluminum Radiator, Dual Electric Fans, Colder Thermostat (I don't remember open temp); New Head gasket, new water pump. 40% coolant & 60% Water (Rad, fans, thermostat, head gasket, and pump installed < 50 miles ago, also head was hot tanked and decked)

Problem: After about 15-20 minutes of driving (Seems to happen when I go at a constant speed, and not stop&go), engine heat starts to rise while both e fans are on. I can usually offset this for another 10-15 minutes if I turn on the heat in the cabin full blast. (I keep my rpm between 2000-3000)

What I have done: I've tried bleeding the coolant, raising the front end and massaging the top hose, along with turning the bleeder screw. I've ran the engine with the rad cap off, and I don't see any bubbles, but the coolant level rises a little bit, I'm guessing from the pressure from the water pump. I don't notice any white smoke coming from the exhast.

Edit: I've also searched for another thread with possibly the same symptoms and came accross one with some guy who started posting a bunch of pictures of cars he worked on, and that SR20's arn't ment to cruise 3500+ RPM or they over heat... That thread turned to shit really quick.

What was mentioned in this thread:
1. I have dual shrouded e fans. One is toggled to turn on with temp, the other is connected to a switch that I control. They both work. they both are on the engine side of the Rad. They both pull air through the rad, and towards the engine. This was tested by using a sheet of paper to show direction of air travel.
2. I made a make-shift air scoop underneath my bumper to direct air flow.
3. My resevoir went from max to min in 2 weeks, either I have a leak (Doesn't look like it) or I didn't correctly bleed my coolant all the way.
4. I did what aga said to do, and hold on to my rad intake hose, and rev the engine to feel for pressure to check for a hole in my gasket. (Later determined to not be an effective way to test that)
5. With the air scoop, it appears that I am able to keep from busting the max temp, as long as I have the cabin heater fan on full blast, and both my e fans are turned on, this however is very inconvenient, and was tested by driving conservitively.
6. I could switch back to the OEM clutch fan/shroud, but I don't want to spend the time/resources to do that.
7. My rad temp at the rad inlet hose was 198 degrees F.
8. My resevoir doesn't smoke.
9. My Rad Cap is in working condition.
10. New Nismo colder t-stat

Update: 6/21/2019 - I have since gotten rid of the car and moved on years ago, but let me tell you what happened because this is the second result to pop up when searching "sr20det overheating."
I purchased a coolant leak test kit and it showed that my coolant was getting exhaust gasses. I come to figure out that a couple of the head bolts where stripped when installing the head. it wasn't enough of a blown head gasket to cause white exhaust smoke. I ended up pulling the whole motor apart, and re-tapping to 12mm head bolts instead of the stock 11mm. I don't recommend this for DIYers, instead I'd recommend buying a new bare block and starting from there. What looks like was happening, is that while the head was on tight enough to stay cool under idle, boost would cause the gases to escape and enter the coolant system. After I corrected the head-bolt-stripped issue, I didn't have overheating issues anymore.

The best advice I can give anyone trying to chase down a problem is to not ignore gut feelings, and don't keep yourself from finding the problem to the issue out of denial. Also, one of the most liberating things I have ever done was getting rid of the burden of a project car. (I have since picked up another one, albeit it is daily-drivable, and I pay others to do the hard work for me now)

ultimateirving

hey man i remember that thread, and you really should not have overheating issues with what you have stated.
Two things can be done to help, One ditch the Efans lots of people complain with issues on overheating and they are not the best set up.
Second get a fan shroud, That is the number one thing I think that will help you to keep your temps down.

Most of the other things you tried is the basic troubleshooting..

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Turb0wned

I had issues with electric fans as well. Went back to stock fan and shroud, problem gone. Try driving your car without the bumper and see if it's the FMIC not allowing enough air to come throw. I also had that problem.

If that fails.... Take out the thermostat and test drive it like that.

ZenkiKid

Switch back to clutch fan and shroud.

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SLiDe_WaYz

Are you using a real fan controller like a DIF, or do you have it ghetto rigged to a toggle switch.

I had issues with my dual fans, went to the clutch fan and Sr shroud and my issues went away. Hopefully your using the Nismo tstat and not a auto parts warehouse pos.

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cotbu

Everything thread starter post is irrelevant,WHY?
No actual temps(numbers)!

Coolant level is rising stated by OP during bleeding process
What did you do after that?
What you should have done is have the heater on full blast.
The bleeder screw! You're bleeding air out, after air rushes out close the screw, continue with bleeding(squeezing hoses) etc. return to the bleeder screw, crack it open again let more air out, just because coolant comes out of the bleed doesn't necessarily mean all the air is out! that's why we repeat. turn heater off and let the coolant flow. Check the cap make sure it's functioning. when you shut down the engine, and it has cooled enough to remove the cap, add more coolant/water. fill reservoir to the desired level.
Get an actual temp gauge or use a consult program to read engine temps.

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hdhype

The e fans I have are built into a shroud, but I also read that the clutch fan and shroud are better. Kinda dont want to hunt some down. :/

I was thinking my FMIC/bumper might not be letting enough air through. I've actually finished fabricating an air scoop on the bottom of the bumper to direct air flow through the FMIC and though the Radiator.

I have one fan hooked up to turn on once the rad gets hot. The other is a toggle switch. Both of them work. I am using the nismo t stat.

I didnt think about getting actual numbers. Please forgive my ignorance. I pretty much bleed my system every day after work, but according to your post I may have a faulty technique. I haven't been turning the heater on in the cabin while I bleed, and I only do it once at a time.

I've also noticed this morning that over the course of 2 weeks, the amount of water in my reservoir as gone from MAX, down to just above the MIN line. According to the internet, that could mean that I have a small leak somewhere. AGA mentions to try to grab the hose with a glove and rev the throttle, I will also try that, along with re-checking for leaks.

I wish to thank everyone for their help. I greatly appreciate it.

aga

try this:

with the engine running and at operating temp, grab one of the coolant hoses (with a glove, if it is too hot) ...hold it tightly and rev the throttle.

if it gets hard, you have a compression leak from a cylinder to the coolant system. could be a tiny hole on the side of a cylinder, or gasket (Since you ve had your head checked)

cotbu

The missing coolant, could also mean you didn't bleed it correctly, And or you don't understand how the system works. OR it's just hot as Fuhhg outside! Because the coolant has to go somewhere, you don't see any white smoke
and.... that's what the reservoir is for.

Don't use this method it is flawed! WHY?'
Operating temp is 80c/176f
The coolant system is under pressure if working correctly. Rubber hoses would get hard, end.

If you truly think the engine is leaking combustion into the coolant passages, they have real tests for that.

Adding external pressure to the coolant system will help find leaks, quickly!

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LoverTechnologies "Half Broken Things!"

hdhype

Alrighty,

I stuck a chef's thermometer inside my radiator fin where the coolant enters the rad. Filled the resevoir a little under max. After I was done driving it said 198 degrees F. While I was driving around town the temp started with being just a little under half. After about 10 minutes (it ws hot today) the temp gauge started rising. I turned the heater air on full, and my car was able to regulate itself between half and 2 bars away from top. Once I parked, I did was aga said, and I put on a glove and held onto my inlet hose for the rad, and pulled on the throttle cable, there was no change in pressure. I did notice that my resevoir had a little bit more coolant in it before, but it was not smoking. I take it that my rad cap is in good condition. Normally putting heater on full can only postpone my car from eventually going to max heat, but it seems that it was able to keep itself from busting the max. I wounder if the make-shift air scoop under the bumper directing airflow through the fmic and rad contributed with keeping my car from busting the max. After I stop sweating, I'm going to go check for leaks under the car.

hdhype

It also very well could be that I didn't bleed it enough. If that is so then I very much underestimated how much air is in the engine. This is pretty much a fresh start after being in pieces.

I also wondered how much merit there is to checking the hose pressure like aga said, because I have noticed the hoses being under pressure before. I'm guessing when they get warmed up, but not quite opening the rad cap to the resevoir. However, I'm still in the proccess of correcting my ignorance, and thought meybe aga was on to something.

whitey240

I am assuming your fans are positioned closer to your engine then the bumper. Are the pushing air at the radiator or pulling air away from the radiator?

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hdhype

They are on the engine side, and they are both pulling air. through the rad towards the engine.

whitey240

Do you have a picture of your fan rad setup? What brand of headgasket did you use?

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hdhype

I used the OEM Gasket from This set

This is my rad setup

Attached Images

fan.jpg (524.0 KB, 35 views)

hdhype

I figured it out. It's fixed now.

cotbu

Good job!!

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LoverTechnologies "Half Broken Things!"

aga

well aren't you gonna tell us what it was? :P

TheRealSy90

Switch back to clutch fan and shroud. /thread.

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aga

well i have dual electric fans, a driftworks radiator, stock thermostat and pump, and i live in greece where summer is like 35c+ all the time, and i ofter reach my destination and the fans don't start at all , so the cluch fan and shroud is not the solution to everything (im not saying my setup is better, i just bought the car without a stock fan)

hdhype

thanks again

aaron240sx

What was the solution? sorry for bumping, didn't want to start a new thread.

bc.

he said it two posts above...

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aaron240sx

i must be missing something... Aga didn't start the thread.. hdhype did. hdhype never said what fixed it, unless i'm blind.

hdhype

It's embarrasing, but I'll write out everything about what happened, so others may save themselves the trouble of shooting. It was a long case of multiple problems producing the same symptom.

During a rebuild, I didn't take the time to chase the threads in the block for the head bolts. Because I didn't do this, and since I was using head studs, it's possible to have the stud not sit all the way into the block. What happens is that when you tighted the head down, you will notice that some of the studs sit higher than others. I didn't notice this at first, but this is important.

While torquing down the head, I don't remember feeling like I had stripped any of the threads, my wrench was clicking that I had reached the right amount. (I think it was 80lbs). Long story short, I decided to rebuild my engine to help fix/upgrade it. I noticed that a few of the head studs felt loose and easy to take out. This leaves me to believe that they had came loose(stripped the threads). This produced some weired symptoms.

While checking the coolant, I didn't notice any significant amount of bubbles while idle, or by simply tugging on the throttle. Just the random bubble every once-once-in-a-while, which I thought was just small amounts of trapped air. I imagine under load and boosting, it produces more bubbles.

The coolant resivior keept filling up and not going back in, which is also a sign of a blown headgasket. I kept telling myself that it couldn't be it, because I had JUST replaced it. (This is because the threads had stripped and I didn't know)

I finally decided enough troubleshooting was enough. I didn't want to be in denial anymore, and I want to find the solution to my problems and fix it. So I bought one of those coolant leak testers, and that sonofabitch changed colors on me, telling me that exhaust was getting into the coolant.

Another symptom I noticed that may have been effected is that my boost was all sorts of crazy while accelerating. It was jumping all over the place. Which I believe to be because it was pushing the head off the block while boosting. but that's just speculation.

I never noticed any white smoke coming out of my tail-pipe. Possibly because the headgasket wasn't broken, and the head was somewhat mostly tightened down, which allowed it to stay sealed until boosting.

As for the stripped threads for the head bolts. I'm fixing/upgrading it by going to the GTir 12mm head-studs, and tapping the threads to 12mmx1.75.

People who say that fixed the problem but don't tell you how they fixed it are the worst kind of people. Among other kinds of people.

Another thing I noticed is that the E-fans I had recieved for my radiator had the wires backwards. Because of that, it was blowing the wrong direction, which would allow my car to stay cool while not in motion, but overheat while driving. When I checked it first, I just put my hand down next to it and felt for the ait, and it felt like I was blowing the right direction. It wasn't until I put a sheet of paper in front of it that I noticed that it was spinning the wrong direction.

aaron240sx

Uh oh. I remember when building my motor, I hand tightened the studs like arp recommends and all of them weren't equal. I've been having non stop trouble of my engine getting stupid hot only when I boosted. I went back and retorqued the head gasket, but it didn't change anything. I'm pulling the motor out right now, taking it back to the machine shop that did my bottom end due to a crazy amount of shavings in my oil after every oil change, even 3k miles after break in. The tuner said there was no signs of head lift though. But later my, boost was acting strange. Like going in and out, half boost, full boost, 3 psi, 22 psi. Weird stuff