Ok, I’m stumped. I’m having overheating issues. It’s a 94 LS with JDM B18C swapped in. 95% of the time, it works fine. No cooling issues driving through traffic, stopped in traffic or at normal driving. So it's not a fan or a fan switch issue. But, when cruising at 80 mph or higher on the freeway, after about 20 minutes, the temp starts to creep up. Yesterday I was on the 91 and it went up to about 70% towards H. Our teg temp gauge is normally at 40%.

Before everyone suggests thermo or water pump, let me just say, I’ve done both; and I'm not losing coolant.

Could it be the radiator (clogged)? I did a flush already; and it's only 4-5 years old. I switched it in 2006.

The temp sensor?

Radiator cap?

Anything else?

Any help is appreciated. Thanks.

Ron

 

check your Thermostat....i had this problem i replaced it with the one from autozone it was not the OEM one it had a bit bigger hole and my engine runs bit more cool..

also did you a radiator cap break before ? might have a some parts sucked in the radiator might be blocking good flow

 

Wait, what are you saying? I need to get a thermo from Autozone, b/c it's bigger or get an OEM b/c it's bigger? When I changed the thermo recently, I got one from Napa or Kragen, I forgot. But, it was smaller than the one I replaced it with. So what you said could very well be true.

No my radiator cap had not broken before. But my suspicion is a clogged radiator in some way.

Thanks for the input.

 

get a mugen or spoon thermostat

 

OP, just SEARCH, there are a TON of threads about this!
But I am nice and have been there so let's go through some tips.

After it starts to overheat, pull over, is the bottom radiator hose hot or cold?
If it's hot your thermostat seems to be ok, if it's cold buy a new thermostat.

Once it cools down, take the radiator cap off, when you take it off is it like opening a shaken can of coke? If so then it's not relieving pressure and you need a new cap.

Once it starts to overheat turn the heat on full blast, does the temp go back down?

Did you recently change the cooling system, IE add a half core radiator?

I would say check all above then make sure you bleed the cooling system
(with rad cap off, start car and let run until thermostat opens and fan comes on, continue to top off with fluid through the process)

If it still continues to overheat but a legit fan for the radiator(SPAL 13")

 

so what happens if your turn your heat on and it stays at normal running temp? mine does this **** after i drive on the highway or its super hot outside

 

Well turning on the heat allows the coolant to flow through heater core, thus providing more cooling to the coolant. This in turn cools it slightly and helps to bring down the overall temperature of the coolant.
Normally one sign that the radiator fan is not up to snuff.

 

The fan has no effect at higher speeds, normally will not even turn on.

Most common overheating problem, [when driving hard or fast] is rad capacity, replace rad with full-size dual or triple core.

The above assumes that water pump and thermostat is good and there is no blockage. 94

 

Correct, because it's a simple fix.

And I have never seen a fan turn off at highway speeds???

It will stay on and yes it does have an effect, this has been discussed in the cooling thread. I even proved this correct as I was having a very similar issue.
Before I had an Ebay slim fan and when driving around my car exhibited the same symptoms. Replaced said fan with a 13" Spal and all the issues went away, even on hotter days.....

 

well i will do this. sucks now that its getting cold here so i cant even really figure out if its getting hot. But im just gonna replace it with a mishumoto full core raidiator. and 2 fans. If that doesnt keep a stock h22 cool then something is f'd up

 

BUTTTTTTTT like fcm mentioned, be sure to check everything else, fluid level, water pump and even flush out the system as well. JUST to be sure!

 

yea i flushed the system and fluid level is always full. always right on. one thing i will check though after i drive to school in a few is if the lower hose gets hot

 

If your fan is turning on at highway speeds there is something wrong, the fan is controlled by the ECT switch, [closed at 192-200 degrees F] a car moving at 50/60 MPH will move more air through the rad then any rad fan, take my word for it, it is what I do, [auto heat and A/C]... http://airwolfeautoair.com/ at highway speeds the thermostat will close a little if anything to keep temp. up.

With that said, on a blistering hot day and/or going up hill, [loading up the engine] the rad fan may turn on, it still means the rad does not have the proper capacity for the engine.

Rad fan issues, [not working or poor efficacy] will show up during stop and go/city street driving when air flow is low due to car moving slowly or stopped, the OP does not have this problem, "No cooling issues driving through traffic, stopped in traffic or at normal driving" 94

 

It's been hot this summer and issues like this have come up A LOT