i know this topic has been covered numerous times but i've done as much as i could and i'm still overheating. here's the background.

95 ls special auto 148k
-changed timing belt and water pump at 121k
-newly machined head (not even 300miles) due to previous overheating
-new thermo
-new radiator and ALL hoses (even heater hoses)
-no leaks (that i know of)
-no mixing of oil and coolant (and vice versa)
-no loss in coolant
-fans are good (tested both separately by connecting to the battery, also jumped the fan switch connector to test and one turned on)

i'm thinking that the fan switch is bad since it only overheats when stopped. however today i let the car idle from cold then the fans turned on after 10 mins and kept turning on whenever i would rev for 5 secs at 2k. it's really tripping me out. it won't make up it's mind! could it still be the fan switch? and/or could it be a bad radiator cap (since i still have the original one)? HELP! tia

 

check the fan relay. the fans work when u jump them 2 the batt. but make sure the relay is kicking on when its supposed 2. if that dosent work check the temp sensor

 

Try a new head gasket

 

how do i check the relay to see if it works? how do i verify that the temp sensor works as well?

the head gasket was replaced when the head was machined.

 

Temp sensor/ECT sending unit test:
*Disconnect the wire that connects to the ECT sender
*Grab a voltmeter(w/an option to measure ohms) or an ohm meter and measure the resistance the resistance between the positive terminal (post that the wire connects to) and a ground.
*RESISTANCE should = 137
*Now, run the engine till it warms up to normal operating temp. The rad. fan should kick in at least once.
RESISTANCE should now equal between 30-46 ohms. If your readings are nowhere near these, change it.

 

By the way, I am presently having the EXACT same problem you are.........I 'm still kind of stumped.

 

Anyone know if Oil pressure or Engine Timing can cause a motor to overheat?

 

wne i had my integra i had the same ******* problem, only at idle tho. it would so straight to hot. i changed everything form thermo to fan to radiator. my gf's dad suggested i should change my head gasket because i was also blowing BLK smoked from my muffler so wen i did change it it still kept on overheating. i was going to change the radiator cap but i crashed it the day before i was going to. it sucks i wish i knew what was wrong.

it seems to me that overheating is VERY common amung integras

 

checked the fan relay today. the heater relay (which is next to the fan relay) was very hot to the touch compared to the fan relay. is that normal?

 

Not sure which relay you're talking about...

...But relays in general should not be so hot that you cant hold them in your hand for a prolonged amount of time.

<U>My Rundown is as follows</U>
1994 Integra GSR
Removed A/C couple months ago, Overheated even with it in the car.
<U>Replaced:</U> Radiator, thermostat, cap, Upper/Lower Hoses, 2 coolant hoses that connect behind the head of the motor, Overflow tank and cap, Water Pump, Fan Switch.
I've also: Bled the radiator after every re-filling of the radiator.

*Overheats while driving hard, will cool down when you turn up the heater in the car to MAX settings. Will act the same after driving for 30 mins or so in day time temperatures, then sitting at idle. DOES NOT shoot all the way to H, but will climb up to the 3/4 point of the guage.
*Radiator cap keeps falling apart. The fat o-ring held down by the lil metal clasp keeps seperating from the cap.
*Overflow tank doesn't fill up to the top anymore though.....just a lil over MAX, but wont go back down to MIN
*No leaks or loss of fluids
*No white,black, or colored smoke shoots out the back (Unless I downshift and hit it hard into vtec, but thats normal.)

I dont know timmy, do you have the same probs I do?


Modified by EnjoyTheRideDC2 at 3:01 PM 1/24/2005

 

shove a paperclip in the coolant fan temperature switch.. my teg was overheating because the fans wouldnt kick on. so i just jumped the switch, then it ran cooler than it was supposed to so i replaced the thermo and it ran perfectly

 

the relay should click when energized, when your fan is running try tapping on the relay to see if the fan cuts out. The coolant temp sensor should fluctuate in resistance when temp changes, buy a repair manual and have fun

 

If the thermo opens too soon it can cause it to overheat aswell. Take the thermo out and test it in water w/ a thermometer in the water and watch the temp and see when the thermostat opens.

 

If a thermostat opens up too soon, it can cause a car to overheat? Then lets say someone were to pick up a spoon or mugen T-stat, their car is more prone to overheating than cooling faster?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by I eat Pho &raquo;</TD></TR><TR><TD CLASS="quote">If the thermo opens too soon it can cause it to overheat aswell.
</TD></TR></TABLE>

Not even close.

If the thermostat opens early, then coolant begins to flow throughout the system sooner and it will cool it more. Therefore, it will NOT overheat. My thermo froze open before and the car wouldn't even reach operating temp.

I don't think the rad cap is to blame here. If the cap were failing and not sealing, then most likely you would notice a loss of coolant. Either the thermostat is not functioning properly anymore, which I think is to blame, or the thermoswitch, which is what controls the fan, may not be activating correctly. But I doubt it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by timmy0tool &raquo;</TD></TR><TR><TD CLASS="quote">checked the fan relay today. the heater relay (which is next to the fan relay) was very hot to the touch compared to the fan relay. is that normal?</TD></TR></TABLE>I don't think that's normal.

The fan switch is on the thermostat housing. Unplug it & jumper the wires with a paper clip. Key on, that should make the fans run. If that works, you've just verified the fuses, relays, wiring, & motors. In '95 the radiator fan control has nothing to do with those other ECT sensors that are near the upper radiator hose.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by I eat Pho &raquo;</TD></TR><TR><TD CLASS="quote">If the thermo opens too soon it can cause it to overheat...</TD></TR></TABLE>That's interesting. Where were you during heat transfer class?

 

I still cant figure out my problem. KEEP IN MIND, everything has been changed regarding the cooling system. Nothing is leaking, there is no coolant loss, and the fanswitch/fans do work and kick in.

My car will rise up to the 3/4 way point, which is when I'll turn on my heater to MAX settings, and then the car will operate normal. SOMETIMES, when I attempt to remedy the overheating by turning on the heater, cold air blows out for about 30 seconds, then hot air comes out. The thermostat has been changed 2 times due to everyone and their mom speculating the problem is the t-stat. barely 2,000 miles on it, and it's installed correctly. ANY IDEAS?

 

Enjoy...DC2:
Everything points to a bad thermostat, but you've already changed it twice. That also sorta rules out the T-stat being backwards, or blocked by its gasket being farbed up.

Is anything non-stock (besides no AC)?
T-stat has to see the HOT water on it's sensing side, before it'll open up. What about all those little hoses between the oil cooler, FITV, crankcase vent, etc.? If those are scrambled, maybe the T-stat never sees the hot water?

 

update:

i tested both relays and they click on when given power to the coil. i was at the dealership trying to get a new radiator cap and the tech told me that the cap can not be culprit in my case. i guess it wouldn't hurt to replace the fan switch.

all is well so far. i drove it for a full tank of gas and no overheats. i even let the car idle (while i was reaiming the headlights for 30mins) and the fan kept on turning on every so often. the needle never passed the midpoint line. i pray that it would remain this way. i would hate to get stuck on the 405 fwy again. if you guys see a forrest green SE, come help LOL. thanks for the help.

bump for enjoytheridedc2. i want to remedy his problem as well.

 

Jim: Changed the 2 hoses in that general area.... one that shapes like an "S" and the fatter hose next to it. I see your point though....but there's no loss of coolant

 

timmy: Thanks....Slam through the gears down the 405....then see if it overheats. Half way point is "hot" IMO, since i'm so used to seeing my needle under half.

 

Did you fill the system correctly when you changed the water pump. You may have an air bubble ....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnjoyTheRideDC2 &raquo;</TD></TR><TR><TD CLASS="quote">Jim: Changed the 2 hoses in that general area.... one that shapes like an "S" and the fatter hose next to it. I see your point though....but there's no loss of coolant</TD></TR></TABLE>What I was talking about is taking all those little hoses off & getting them mixed up when you put them back on. (Or blocking off some of them.) If that stuff is scrambled it may be possible for cold water to flow into the T-stat housing. Then the T-stat never 'knows' that the engine is getting hot.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by timmy0tool &raquo;</TD></TR><TR><TD CLASS="quote">all is well so far. i drove it for a full tank of gas and no overheats. i even let the car idle (while i was reaiming the headlights for 30mins) and the fan kept on turning on every so often. the needle never passed the midpoint line.</TD></TR></TABLE>That sound just about perfect. The fan isn't supposed to come on until the temp gets a little bit above normal.

 

I never took out a hose without replacing it immediately after. I dont believe I mixed up hoses. I never really messed around that area a lot. I guess i'll look harder in that area.

adrenaline: I made sure to bleed the system and such by what the Helms manual suggests. I dont think I have an air bubble this time. I think it's something tricky, considering its been damn near a year that i've been trying to diagnose the prob.

to JimBlake for the info
to timmyt00l for getting his prob figured out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ScreaminTeg &raquo;</TD></TR><TR><TD CLASS="quote">

Not even close.

If the thermostat opens early, then coolant begins to flow throughout the system sooner and it will cool it more. Therefore, it will NOT overheat. My thermo froze open before and the car wouldn't even reach operating temp.
</TD></TR></TABLE>


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">That's interesting. Where were you during heat transfer class?
</TD></TR></TABLE>

Take a second and think about it, smart guys.

If the thermo is stuck open, coolant constantly flows. The coolant doesn't have time to absorb the heat from the engine what happens?

How about you go back to class and ask your teacher.