S13 Blacktop Overheating

[HotCarl]

So I took my friend to school yesterday and while sitting in traffic I notice my temp creeping up. Started getting high so I turned on the heat full and tried to get going so I could see if it would cool down. So I started driving and it cooled down so I headed on home and did fine for a bit. Couple lights down it started to creep up again. Almost home it cools down again sit in the parking lot and it starts to creep up again. So after reading around I decided to swap out the thermostat and bleed the coolant.

[HotCarl]

Ok so I've just about had it over something that should be so cut and dry...I picked up a KA thermostat today. Bought hi temp rtv. So I went ahead and pulled lower hose off, removed the three bolts, pop off the hard pipe and woohoo no thermostat is in the car. So I go ahead clean everything up pop in the new thermostat. Run a bead of rtv along the hard pipe and bolt it on. I go this afternoon to hook the lower soft pipe on and fill it up with coolant. oh f'n great coolant is running from the bottom of the hardpipe right behind the lower bolt. So I pull everything out and clean it all up again and second attempt. So I get everything ready to put the hard pipe back on with the bead of rtv and I drop a bolt. its getting dark I put the two bolts in I have and search franticly for the third. Roll the car back look around, look around the fascia, behind the intercooler, etc....Cant find it. So I stole a bolt off the AC system and put it in...I think it was the correct length it compressed the rtv and feels tight. So has anyone run into this problem...did the thermostat slide down and not allow the hard pipe to completely screw down...So now I just fill with coolant tomorrow and turn heat on full blast and open radiator cap and let it burb after I fill it...
Thanks

[eazye2000]

I saw your IM late last night bro. I sent you a text. I'll come check it out if you're still having problems.

[zachattack_5491]

I just did my thermostat the other day. When those bolts fall they are GONE haha. I've dropped them a few times, and every single time they are no where to be found. Usually what I do when I install it is put a little bit of sealant on the rim of the thermostat, and hold it in the correct place for a few minutes. That way it gives you a minute or two before it slides down and makes bolting the tube impossible. Make sure you put the jiggle valve facing up also.

[HotCarl]

Haha your right I couldn't find it for my life. I thought about putting some rtv on the stat just to hold it in place. So I tried to bleed the system today. Jacked up the front turned on the heat full opened bleeder valve got it up to temp. Started filling waited for coolant to stream from bleeder. Once it was flowing clean with no bubbles I closed it left the rad cap off ran for a while hitting the throttle occasionally and adding coolant as necessary. Then my car started running above the hot level felt the lower rad hose and it was cold to the touch. So I turned the car off just to be safe. I don't know if it's the tstat or air still in system. I'm getting pissed something so simple is giving me such a headache.

[Lobo240sx]

Gotta be either thermostat or not bled enough. What I do is put some radiator fluid in the reservoir overflow(to the full line not fill the whole reservoir in case it still overheats) and drive it around for a few then put some more in if needed. Seems to work out the best. Did your fluid go down in the overflow?? Check the PITA heater hoses going in the heater core in the firewall. Sometimes those leak and it is hard to see when the engine/bay is hot.

[HotCarl]

It's funny because the temp shot up pretty quick. There is fluid I'm the overfill from when I filled it a couple weeks ago before this became a issue. I have just glanced at the heater core lines. I haven't spent a lot of time there. It definitely seems like the thermostat isn't opening. But because it got so hot so quick I think there is a pocket of air still.

[Lobo240sx]

Did you take out the bleeder screw on the water neck?? Sounds like you might have just checking for little things.

[homeslicej2]

Make sure you're using an OEM thermostat. I ran a Motorad (O'Reilly's autoparts) brand thermo for about the first 5,000 miles and that first winter the car would run super cold (~150 degrees on the hot side according to the temp gauge with it's sensor placed in the hot side water neck) and right on the Motorad thermostat was stamped the 170 degree opening temp. Once I installed an OEM Nissan thermostat, this cold running issue went away. I think your thermostat isn't opening bc it sounds like you're bleeding the coolant properly. Also, running a motor (esp. an SR) without a thermostat and still getting hot running temps in stop & go traffic most likely means that your fan setup is not adequate and/or you have a bad headgasket. I would perform a leak down test. You can rent the kit for cheap from the parts store and they'll refund you once you return it. What fan setup are you running?

[HotCarl]

Hey thanks for the info. I have a s13 koyo with dual electric fans. This only happened this one time. But i don't drive the car that often but I don't know the prior history that well so who knows. It hasn't showed any signs of headgasket. No smoke, weird oil, bubbling in overflow.

[HotCarl]

So I attempted to bleed the coolant again. Jacked the car up and let coolant run through the bleeder to make sure. Turned the heat on put a large funnel in at the rad and everything is topped off. Started the car held it around 2500 rpm while squeezing upper hose and I did see some bubbles held that for a couple minutes. Went to check temp and it was at normal range. Held throttle a couple more minutes and some more bubbles. Let it idle for a bit. Went to check temp and it was sky high. So I messed with it for another min then shut it down because I don't want any damage. I felt the air from the heater and it's definitely warmer then the other day. The lower rad hose is cold to the touch doesn't feel warm at all. So I went to feel the heater core hoses and they are hot but I never noticed they are quite pinched. If they get blocked will that keep the motor from cooling? I don't know. I just feel like i can't run the car long enough to get all the air out. Any help would be great thanks

[ciscos13]

So I attempted to bleed the coolant again. Jacked the car up and let coolant run through the bleeder to make sure. Turned the heat on put a large funnel in at the rad and everything is topped off. Started the car held it around 2500 rpm while squeezing upper hose and I did see some bubbles held that for a couple minutes. Went to check temp and it was at normal range. Held throttle a couple more minutes and some more bubbles. Let it idle for a bit. Went to check temp and it was sky high. So I messed with it for another min then shut it down because I don't want any damage. I felt the air from the heater and it's definitely warmer then the other day. The lower rad hose is cold to the touch doesn't feel warm at all. So I went to feel the heater core hoses and they are hot but I never noticed they are quite pinched. If they get blocked will that keep the motor from cooling? I don't know. I just feel like i can't run the car long enough to get all the air out. Any help would be great thanks

check all the radiator clamps and make sure they are tightened well. do you have a overflow tank?

[HotCarl]

Yes sir, and I've got it filled just below max level. Nothing is leaking anywhere that I can see I even looked at the heater core hoses to see if anything is wet or obvious.

[USMCgetsome]

try a new tstat that has to be your issue.

[HotCarl]

The tstat I installed is brand new.

[ciscos13]

Yes sir, and I've got it filled just below max level. Nothing is leaking anywhere that I can see I even looked at the heater core hoses to see if anything is wet or obvious.

all i could tell you is to try a different radiator. it may be clogged.

[HotCarl]

Yeah I dont know. When I removed the thermostat coolant just flowed from the lower hose fine. So who knows. Anytime I run into something its never a quick fix. Haha..Thanks everyone.

[240life]

Try bleeding the cars coolant system while it isn't in the air. If that dont work try another t-stat.

[HotCarl]

So I went ahead and picked up another tstat today. I did do the boiling water test to make sure it opens correctly. I've read so many different opinions on this so I decided to try one out. One suggestion is to cut off the jiggle valve and drill it out with a 1/8 bit.


The other thing I finally got around to was tapping and threading my upper radiator hose hard line for my temp gauge.




I ordered a spill free funnel through NAPA today that was on sale that I'll pick up tomorrow. So hopefully tomorrow I'll be able to fill the cooling system, bleed it and be good to go.

[HotCarl]

What ratio do you guys mix your coolant/h2o. I'm in North Florida so we see low 20's sometime teens during the winter. Thanks.

[HotCarl]

So I picked up the "Super Funnel" today that everyone keeps saying you have to buy.It is nice and very convenient to use. I ran coolant through until it was a nice even flow through the bleeder screw and replaced it. Then topped the funnel off until it finished filling the radiator. Then I filled the funnel about halfway and turned the car on and held it around 2500 for about 5 minutes and then backed off and let it idle. I would occasionally squeeze the upper hose during the process just to aid the bubbles. Let it run for about 10 minutes and it looked good for a bit then of course here comes the temp creeping up. I let it continue idling until the stock gauge read H. The heat in blowing cool and the upper heater core hose is cold to the touch. So its cooling down now and I'll go out in a bit and try again. I didn't jack the car up this time.

[Lobo240sx]

What ratio do you guys mix your coolant/h2o. I'm in North Florida so we see low 20's sometime teens during the winter. Thanks.

Use straight coolant. No water. Less corrosion occurs, less likely to freeze up when you forget when it is below 25.

Look at the radiator for damage and hoses make sure you don't have any kinks.

[240life]

Are you running a temp sensor from a 91-93 240? Until I replaced mine the car would read all sorts of funky temps. The car might not actually be over heating, see if you can get a digital thermostat to take temps at the hoses. Other then that you might be in the market for a new water pump.

[homeslicej2]

What ratio do you guys mix your coolant/h2o. I'm in North Florida so we see low 20's sometime teens during the winter. Thanks.

Use straight coolant. No water. Less corrosion occurs, less likely to freeze up when you forget when it is below 25.

Look at the radiator for damage and hoses make sure you don't have any kinks.

Never run straight coolant, especially on a car in the southeast where summer temps hit 100+ with 90+% humidity. It is not a good idea. 50/50 coolant/water mix is best for a street car, maybe a bit more coolant (70/30 max on every brand of coolant I've ever seen) in really cold regions, or a bit less (40/60 max) in hot, humid areas. I'm in NW GA and I run a 50/50 mix. My coolant bottle states that with a 50/50 mix, it won't boil until 265 degrees and won't freeze until NEGATIVE 34 degrees with a 15psi cap. WATER dissipates heat BETTER than coolant does, but yes, the coolant does protect against corrosion within the cooling system and is needed. HotCarl, that doesn't look like an OEM t-stat, get one of those and perform a leak down test with a rented kist (parts store) to make sure your HG isn't FUBAR. If you install (test it like you did the last t-stat) an OEM t-stat, get normal results on the leak down test, and replace the OEM sensor with the right one, but are still having this issue, let us know. Also, 240life makes a good point on the OEM gauge sensor, get the right year and replace the water pump if you haven't already. If you have cold heater core hoses after running it for some time, you've got blockage or a lot air in the system.

[homeslicej2]

Also, what temp is your aftermarket gauge reading in the upper coolant neck when the stock gauge reads hot? What brand is the gauge? It looks like the sensor for an Autometer Ultralight short sweep gauge. What temp do you have your e-fans set to come on at and what brand/style are they?

[Lobo240sx]

Never run straight coolant, especially on a car in the southeast where summer temps hit 100+ with 90+% humidity. It is not a good idea. 50/50 coolant/water mix is best for a street car, maybe a bit more coolant (70/30 max on every brand of coolant I've ever seen) in really cold regions, or a bit less (40/60 max) in hot, humid areas. I'm in NW GA and I run a 50/50 mix. My coolant bottle states that with a 50/50 mix, it won't boil until 265 degrees and won't freeze until NEGATIVE 34 degrees with a 15psi cap. WATER dissipates heat BETTER than coolant does, but yes, the coolant does protect against corrosion within the cooling system and is needed.

I've run straight coolant in all my cars in Texas were it gets 110 degrees sometimes in the summer NEVER had a problem with it overheating. Turbo cars, NA cars, even my 67 Mustang didn't have any problems. While on the subject I have talked to people who race at the track as well as mechanics who have been working on cars for many years. They all say use straight coolant no water. I've been doing it ever since I had my first car.

It is up to you and your car. Do what you want with it. I'm definitely going by experience. But don't come on here later down the road posting up wondering why you got rust floating inside your radiator.

[homeslicej2]

Glad none of you have issues with overheating or corrosion (not using a mix will increase corrosion btw). I'll go by the manufacturer's recommendations (both coolant and automotive) that state never run 100% coolant. As you know, SR's are aluminum, most of us run alum radiators too. About the only item that could rust would be the water pump impeller. Yes, I know aluminum corrodes, but it doesn't rust. If you service your cooling system properly; rust, corrosion, scale, sediments won't be an issue for the life of the engine.

Here are the links to back my claim:

This is a coolant brand of BASF chemical company.
http://www.glysantin-hosting.de/21-1-Fr ... tions.html#
All engine coolant concentrates must be mixed with water

Prestone's antifreeze FAQ's:
http://www.prestone.com/learn_more/freq ... aq-row-467
we do not recommend more than 70% antifreeze. This would cause restriction of the heat transfer capabilities, corrosion protection, and freeze protection.

PEAK antifreeze FAQ's and technically speaking:
http://www.peakantifreeze.com/resources-faq.shtml
http://www.peakantifreeze.com/resources ... king.shtml
Water is required to activate the chemicals in the inhibitor package. Furthermore, adding water to antifreeze actually increases the freeze-up and boil over protection provided.
Water is an excellent conductor of heat. Glycols are not as good of heat conductors as water. As the concentration of glycol increases, the heat transfer ability of the mixture decreases.

From Honda's American Service Express site. Not sure which car though bc it's a pay for access site (just happened to allow access to the PDF through google search):
https://techinfo.honda.com/rjanisis/pub ... 00160B.pdf
Never add straight antifreeze or plain water.

You will find this info on most any coolant manufacturer's website and most vehicle owner's manuals will tell you to never add pure coolant. Also, you can use tap water for mixing, but de-ionized or distilled water are best. So yes, as you wrote, it's your car, do what you want, but for this situation, I will go with decades of R&D and common automotive knowledge from the coolant manufacturers and automobile makers instead of the personal experience of a few.

[ciscos13]

on this water wetter that i bought from autozone, it says that straight water actually makes your car run cooler than antifreeze. just felt like throwing it out there.

[HotCarl]

Sorry I didn't get back quicker I never got a update from my email that posts were made. So I drove to my friends which is only half a mile and once i got there I left the car running and the temp was actually ok per stock gauge. So I bled the system again and let it run finally the heat blew warm. I do have autometer short sweep gauge. I drove the car around today and the stock gauge was reading hot while the highest my autometer gauge read was 180 at most.

[USMCgetsome]

well there u have it your stock gauge or sensor is boned. The autometer is a better piece of calibrated equipment. I'd also like to add that it was a great idea to drill that 1/8hole due to the fact that bleeding your cooling system can be a bish sometimes!