Overheating issue, not sure what it is.

[zoneoneoni]

Hey guys,I recently installed a Nismo thermostat, new radiator hoses, and a new water pump to my SR20DET'd 240sx, along with the dual FaL fans because I've been having a overheating issue for quite some time now. Anyways, after installing these parts, I went for a drive last night only to find that my overheating issue had not been solved. I'm assuming the only thing left on my list to replace is the radiator, but the one thing that bugs me is that there are no leaks and no visible signs of fluid loss.

I'm pretty much stumped as of trying to figure out what it is, and I don't want to buy a nice racing radiator right away. Does anyone else have any ideas?

[exhsturbine]

did you replace the jdm temperature sensor with the usdm one?

[zoneoneoni]

Yeah, it's the correct one.

[zoneoneoni]

I guess it's safe to say that it's just the radiator then...?

[240trackjunkie]

I had the same issue a while back. After replacing all the same stuff you listed, it turned out to be the radiator. Got an aluminum Mishimoto (excellent quality for the price imo) and now I'm gonna have to change back to an oem thermostat because my temp won't go above 160F while cruising with the Nismo unit.

[zoneoneoni]

Hm, alright, sure thing. I'll start saving for that same one then. Thanks for the advice.

[Neil]

Ductwork! I would personally recommend making sure enough air is getting to and through your current radiator first before spending the loot on a larger one. After all, there's thousand of stock silvias running around today with the oem radiator with no problem whatsoever.

I would also get rid of the Flexalite fans as well. I don't much like that rig because it actually prohibits a lot of air from flowing through the radiator while cruising at speed, and it restricts what flow there is to two openings.

Are you using a FMIC? if so, that only makes it worse, because most kits require that you you cut out the "tongue" of the bumper opening to fit the intercooler. That tongue being gone means A LOT of air that should be flowing through the radiator is flowing underneath it. Even if the fans are cranking full boar when you're cruising at 60mph, their flow pales in comparison to the amount of air that usually flows through the radiator if all the appropriate ductwork is in place, and the shroud around the flexalites only means that much more air is not flowing through the radiator.

you can most likely get away with using a larger radiator, but if anything I mentioned rings true to your setup, then it won't be fixing the actual problem. I would recommend at least rigging up some sort of pan underneath the car to make sure air is being forced to flow through the radiator if you did indeed have to cut up your stock bumper.

[zoneoneoni]

Yeah, you're actually 100% correct, I have that exact setup. I don't exactly want to just "ditch the FaL fans" because they cost a large amount of money, etc, whatever and I don't know what radiator fan would be better to use. I do have a FMIC, so I'm guessing I'm having some type of Airflow problem... Is there any other way to fix this? Anyone else have this problem and a alternate solution how to fix it?

[zoneoneoni]

Alright, well, I was looking at the radiator cooling plates and whatnot on various sites and was wondering really how effective a cooling plate would be in my situation? Obviously I'm not getting enough airflow and that's what my problem is I guess, so how much will this help or will this solve my problem?

[exhsturbine]

i know its on here some where. where someone actually did a test with various radiators, fans etc.... and also in that test they applied the upper aftermarket cooling panel. as well as the oem lower panel that many of us take off. it actually made like a 20 degree difference at all levels of driving. where most fan\radiator setups only did that sometimes, if at all.

the thing about the air going through your front air dam is that it will take the path of least resistance, which is going around, below, over etc. with the duct work it directs air into the charge air cooler as well as the radiator. and with the lower panel i believe that physics will actually "pull" air from the engine bay and pass it below the vehicle.

i wish i remembered which thread it was on. but i know it was like two or three months ago. hijacker might know how to find it...... but it had very convincing results.....

so these panels will help, and it may or may not solve your problem, depending on whether or not you have some faulty equipment. which ive been meaning to ask.... have you replaced the head gasket? if so what kind? and im sure you have done it but i have to ask... did you bleed the system properly?

on another note, an aftermarket radiator wouldnt hurt!

[exhsturbine]

AHA! i finally fu***** found it after a long search. http://home.satx.rr.com/nissan...t.htm

that was the tests performed. read through it, and towards the bottom is the information regarding the panels. hope that it helps!!

[zoneoneoni]

Damn, thanks a lot man, I think what I'm gonna do is get a aftermarket rad, then do a silvia conversion along with the GT-R grill. If this STILL doesn't solve my problem which it better, then I'll get the cooling panels.

No, I haven't replaced my head gasket, when we took a look at it before we put it in, it was in surprisingly great condition.

[Neil]

^^ wow, that's very thorough

[zoneoneoni]

Yeah, for reals, I just finished reading that whole thing and it was pretty intense the lengths that guy went through just for the SR20DET community, lol. What a stud.

[exhsturbine]

cooling panels are a little bit more cost effective than replacing a front end and radiator. but whatever floats your boat : )

[zoneoneoni]

Yeh... Long time project car... Just want it to be what I dreamed of :]Plus, my front end panels aren't in the best condition... Hahahaha.

[Frankz28]

HiI had an over heating problem back in May '08I had a Flow test on the radiator - OKChanged the water pump and the thermostatStill overheating.Removed the thermostat.Car stopped overheating.But I had a problem last winter.The temp gauge barely moved. So I had no HEAT.The fan clutch spun about 3 times when pushed manually and didn't feel sloppy.So with the advice of other membersI changed the thermostat, which I bought from Nissan (w/jiggle valve),I had the fan clutch so I replaced it also.So far so good. The car is not overheating.I went through the hottest days of the summer w/AC on.Still not over heating.My Problem Solved!Good LuckFrankz28

[Neil]

what is this jiggle valve you speak of? some sort of bypass? curious that the first thermostat replacement didn't fix the problem.

[Frankz28]

Hi Neil

what is this jiggle valve you speak of? some sort of bypass? curious that the first thermostat replacement didn't fix the problem.

The first thermostat I put in the car was from a local and reputable auto parts store that I deal with all the time.One of the members asked if it had a jiggle valve.Like you I didn’t know what he was talking about.So instead of going back to the auto parts store I went to Nissan.When I looked at the thermostat I saw the jiggle valve. If you shake it “jiggled”.It looks like a piercing.And the stud is capped at both ends.And the stud is not a tight fit.So it jiggles when you shake it.Now being that I changed the fan clutch also I’m uncertain which one or maybe both were the cause.So if your radiator and the water pump are OK I'd change both.They're not difficult to change or too expensive.A little background about my problem.When my car began to overheat it was an intermittent problem.Which leads me to think it was the fan clutch beginning to fail.After awhile it was constant problem. Fan clutch failed.Hope this helps.Frankz28

[Frankz28]

Neil

Also I did a flow test on my radiator.Which came out OK.A flow test can be done at a radiator repair shop for free.If the flow test is good the radiator is fine.If it fails to flow test ask the guy what it would cost to have it cleaned and rodded?Rodded is where they push rods through the core to clear it out.Then you have to decide if you you want to go for a new maybe over sized radiator(because of your engine modification) or getting yours repaired.Good LuckFrankz28

[Jadesr20det]

check your heater hoses...i had the same problem had a nismo thermostat, new waterpump, 14 fan, koyo rad and nismo rad cap and running water wetter still was overheating....turned out to be a pinhole in my heater hoses trust me it wasthe biggest sigh of relief of life...its worth checking

[bribot]

also check you radiator cap. the seals on it could be bad which might be letting air into the system

[zoneoneoni]

Hey guys, I've checked both of these things, and I'm really just going to say that the problem I have right now is due to airflow. Now that a member has already mentioned it to me, I have more than enough reason to believe that it is just my airflow problem. I'm going to get my aluminum radiator soon, but I'm so ****ed for money right now, considering how college is starting soon, I just got laid off, and I have no other means of transportation other than a overheating car. It doesn't feel too great right now, and I might end up having to trade my project, but I'm going to work as hard as I can to get this finished and running so I can just appreciate my project car.

On the other hand, if someone made me a legitimate offer (not sure what anyone would want to trade for a car that is having cooling problems) to trade me, I would most likely accept it because this is taking a toll on my wallet, free time, college-study time, and job app time.

[Neil]

You will definitely be fine with a Koyo or Griffin or something even if you don't do anything about the ducting.. because, hypocritically, i've got a cut up bumper for my fmic, no ducting, a koyo, and the stock a/c fan running on a thermostat switch and everything's been honky dory.

until yesterday, coincidentally, when it started overheating on the highway. I was really hoping it wasnt a head gasket problem since ive been running more boost recently. turned out a part of my thermostat had corroded so the valve shaft was binding and it wouldn't open fully. I bought a new one for a '91 Sentra from the dealership and an hour later everything seems to be okay.

I'm sorry about your financial situation.. i've been laid off for a couple months myself. unemployment helps but it's not the same. luckily it was a union job so i've got them working to get me back in.. I hope your situation gets better.

[zoneoneoni]

Thanks a lot man... I really hope it's not my head gasket of all things... If it is, I'd probably just trade off my car because this project is taking a serious toll on my time, wallet, and sometimes my family. Anyways, I'm sure things will work out, as soon as I get this radiator, I need to start looking for a smog guy because well... My tags expired this month also. Hah. But like they said in Harsh Times, "There's always a way out of every situation." so I think I can figure it out. Hopefully.

[Frankz28]

Hey Zoneoneoni

Sounds like rough times.Make the best of it.And good luck.

Frankz28

[Morph]

Hey man i've had some expierence with overheating. Have you gotten all of the air bubbles out of the system? Do you have an s13 or s14 sr? How long ago was the headgasket replaced, any oil in the coolant or vice versa? How bad has it over heated b/c the head could be warped. Also are the fans blowing the correct way? Had this happen after my headgasket was replaced and the tech wired it backwards. That will cause you to overheat no matter how fast you go.

Last time mine overheated, i changed the thermostat, bled the system and after 30 min or so i had a stream of tiny air bubbles that never stopped. I also had small black dots along with the bubbles and the headgasket was the problem.

[zoneoneoni]

Wow, holy **** dude, uhh, well, something really cool happened today and it's actually going to pull me out of my whole situation so for a update on that, everything is gonna work out.

I actually now have enough money to go replace the headgasket and whatnot so I'm going to go the whole nine yards on the cooling system. I'm gonna replace the headgasket and the radiator in a week or so, so I'll let you guys know how it goes!

BTW: No oil in the coolant.

[Neil]

Grats!

[SRspoolin]

Last time mine overheated, i changed the thermostat, bled the system and after 30 min or so i had a stream of tiny air bubbles that never stopped. I also had small black dots along with the bubbles and the headgasket was the problem.

this is what mine is doin so i did a compression test and came out fine?