Alright...well i've always had issues of the gauge telling me i'm running hot...but it seems to have gotten worse, and i'd hate for me to just be ignoring it, have it actually run hot and blow a head gasket...so i was hoping you guys could give me some ideas on checking various things

How can i check the actual temp of my coolant without dropping a stupid amount of money on a laser thermometer?

What is the RIGHT way to bleed air out of our coolant systems? ive read about a billion different ways...tried a few but didnt seem to do a whole lot for me

How do i make sure my water pump is working? i dont see any weeping from the bleed holes on the water pump...but i feel like they could fail without leaking fluid right?

How do i check my coolant temp sending unit?

Every once and awhile my car has a surging idle, which leads me to believe theres air in the system...but i just dont know how to bleed it out correctly...

If you have any other ideas on stuff to check or how to check it let me know, thanks!

 

Sounds like you need to download the manual.

 

actually, i already have. in fact, i printed it out, and have it sitting right here in front of me. I have it opened to the cooling chapter, and it really is of NO help to me other than offering one of MANY ways on how to bleed, one of many ways ive tried and i still get the same results. It offers no help on how to test my ECT sending unit (at least not that ive seen) or how to check if my water pump is working other than at removal of timing belt, which at that point you might as well replace it anyway....

In the manual it says to have the car off, open the bleeder valve till a stream comes out, and close it, ive read elsewhere to leave it closed, and open the radiator cap and let the engine run, ive also heard to open both the radiator cap and the bleeder valve with the car on and off, the on one is ALOT more messy as it bubbles horrendously out of my radiator onto EVERYTHING

So...if anyone can give me the right way to do this, that'd be fantastic

 

Also, i grabbed a candy thermometer and stuck it in the radiator cap hole while the engine was running and i never saw it quite reach 200 at idle for a hour or so...it got right under it a couple of times, but never actually hit 200....i'm not sure how accurate of a reading that is, but does that sound about right? The whole time my gauge was reading in the red

 

Could it be your Thermostat, or maybe a clogging radiator?

 

Buy an aftermarket Water temp gauge and check its reading against what it should be.

 

if your radiator is heating up your water pump is working. with the cap open do you see water flowing? pump is good then

when you look in your radiator do you see any chunks of stuff that could be clogging it? Sensors are not ridiculously expensive, so you could always just replace it and see what happens, just to rule that out.

 

well, i replaced the thermostat, and actually pulled it out twice over the last couple of months to check if its opening at specs and it is, i also replaced my upper and lower and bypass coolant hoses, and while doing that i hooked a garden hose to the top of my radiator to see if water was coming through and it came out the bottom hose so i gotta imagine its not clogged... i'm actually not entirely sure if i see fluid moving because i have my radiator filled to the very top of the neck so i cant really see anything move. When i was trying to bleed it i would burp the hoses and i would see like tiny pieces of leaves come up every once and awhile but couldnt figure it was causing too much of a problem since i saw water coming out before when i ran it through the radiator...

i do notice that my coolant hoses all become pretty stiff, not necessarily rock hard or anything, but definitely alot firmer after its been on for a few minutes....originally i assumed that, that means my water pump is working...but if its getting really hot then wouldnt the boiling fluid create that kind of pressure too?
I would buy an aftermarket gauge to check the reading against, or even one of those laser thermometers, but i dont really have the money to spend on that since i have to buy two new upper control arms....

Thanks for the advice and help so far guys...keep it comin, i'll check again in a few to see if the coolant flows after the car cools down and report back....anything else i can check to help you
help me? haha

Just a quick note...when i was trying to bleed the coolant with the engine on, filled the radiator left the cap off, turned the car on and opened the bleeder valve, and nothing came out of the bleeder valve...but it started bubbling HARDCORE out of my radiator...i thought the coolant was supposed to come out of the valve? It does it just fine when the engine is off, but as soon as its on its a completely different beast

 

Flush your radiator.

You can buy a cheap *** water temp gauge from ebay for like 15 dollars shipped. Its only going to be used once, or hide its uglyness in the ash tray or something.

My hoses arnt stiff after running, just hot, But it depends on the hoses i guess.

 

Alright i'll give'er a good flush and see what happens...i've been trying to bleed all day, eventually i wrapped a wide mouthed funnel with electrical tape untill it was thick enough to fit securely into the radiator, poured water into it till it was almost about to spill out, started her up and massaged the hoses as the car ran. saw lots of big bubbles...nothing very consistent though...

After i got done i put the cap back on and turned her off for about 1 minute, turned her back on and it was at normal temp again...at idle the temp started climbing again, it took about 3 min for it to start, but once it did it went from 3 bars to hot in about 1 minute...if i rev the car up to 2k rpms it'd go back down, and if i brought it to 3k it would go all the way back to normal operating temp....

I'm not very familiar with cooling systems, but to me it sounds like the water pump may not be pushing enough fluid....am i right or is it something easier (cheaper?) maybe just a clogged radiator like suggested before? haha

 

Hey guys....still havent figured out what the problem is... i bought one of those preston backflush kits, bought some radiator flush and ran it through, hell i even disconnected the lowe radiator hose, taped a garden hose to it and backflushed my radiator that way. It STILL says i'm overheating...i found a test for my temp sending unit with a multimeter, and it checks out still...so NOW i'm starting to worry that it really is overheating...

When i drive it about 10 miles to work, i pop the hood just to check out whats goin on, my lower hose is ALWAYS much much much cooler than my upper...i know its supposed to be cooler, but its more of a, my top hose i can touch for about 1 second before i have to take my hand off, and the lower feels like its probably at or below ambient temp... also both hoses are VERY VERY firm. even if its just sitting there without driving the hoses will get firm enough i cant squeeze them enough to make one side of the hose touch the other

I pulled my thermostat again, just to check if maybe it gave up randomly, but the boil test showed its still working correctly. When i squeeze the lower hose, i can hear the little metal piece in the air hole of the thermostat jiggaling, even when the car is hot,i'm not sure if that means anything or not

I'm not seeing it boil over, and as of yet, i havent seen any extra coolant in my reservoir...but i can only assume that doesnt always mean anything.

When i take my radiator cap off and turn my car on and stick a thermometer in the filler neck, i notice that around the temperature where my thermostat should open, instead of the fluid level in my radiator dropping, it actually rises and starts to bubble out...it seems completely opposite of what it should be doing...

Any ideas on what to check next?

 

take the tstat out and see how it runs, you'll be able to see the coolant flow immediately.

 

confirm t-stat ground and valve cover ground wires

 

Pulle dthe thermostat and now both hoses feel warm, and now i can squeeze the two sides of the hose together

Ok...so...if its my thermostat...why ius it opening in the boiling water, but not opening in my car?

**edit found the valve cover ground, and its hooked up, as is my thermostat ground

 

First of all, the temp won't go above 212 deg F with the radiator cap off as the water will boil off as fast as needed to keep the temp at 212.

1. Does the heater get hot while the engine is running? If not, you may have a water pump problem or low water level.

2. With rad cap off, let engine start to warm up. Make sure radiator is still full as the temp valve opens - which you will know because the hoses will suddenly get much warmer as soon as water starts moving in any volume. Now, put cap on. Note that the hoses are kind of squishy. The cap will begin to let off pressure at around 15 psi (as I recall.) The hoses will be quite hot and much harder to squeeze.

3. With the airconditioning off, the fans should only come on occassionally. The flip side of this is to make sure the fans DO come on. With air conditioner on MAX fan and Cold, both fans will cycle pretty frequently if the outside temp is above 85-90 degrees. Above 100, they will only shut off after the inside of the car cools off and you are moving 30+mph.

4. On my car, it started behaving like you explained when the water level was low... which was frequently until I found a leak on a lower hose that would only loose water under pressure.

5. There are TWO temperature sender units. They are located very near each other. I think that they plugs are interchangeble. If things have been running OK, then it is unlikely for both to fail at the same time. If the dash sender was bad and the computer sensor not, switching them will make the dash work, but the engine will run very lean until you fix it. (not a good situation, but you can tell if the sensor was bad without spending money.

I have never really "Bleed" my radiator. I just let the engine start to warm up and then rapidly squish the top radiator hose to "knock loose" air bubbles. Then just top off radiator, make sure you have fluid on overflow tank and put the cap on tight.

Finally - there are some legitimate reasons for this happening. If the head is cracked, you can get a hot spot that will dramatically raise the temp. If the engine is running too lean, the valves and head will be much warmer than they are supposed to be. The radiator could be plugged. The water pump could be bad (but normally, it will leak because the bearings are worn). In the old days, it was possible for the engine block to build up calcium deposits in the engine. This would slow water flow and insulate part of the block. The temp difference in a small area will eventually cause the wall to crack.

I even saw a guy that had split the side of his block (chevy 350) big enough to put your finger in after he ran dry and overheated the engine and then sprayed it with the hose while trying to refill the radiator.

 

Have you ruled out that you have a blown head gasket yet? When was the last time you changed your oil?

 

The heater does get hot when the engine is running

My upper hose gets hot, but my lower hose always stays MUCH MUCH colder

I cant do any kind of tests involving the fans because apparently whoever had the car before me hardwired the passenger side fan in, and my A/C is completely empty, and since our cars are equipped with pressure shut off switches which wont let the A/C system even attempt to turn on without the proper pressure...the drivers side fan wont come on.

I only see one sending unit on the head, theres a temp sensor next to the sending unit but it is an ENTIRELY different connection

I havent ENTIRELY ruled out a blown headgasket...but i dont see any signs, i dont see any milkshake substance on my oil cap or dip stick, no oil loss, no white smoke from the exhaust, i pulled the plugs and didnt see any greenish tint on any of them, but i have not done a compression test or one of those coolant checks to see if exhaust has been mixing

I pulled the thermostat and ran without it all day (i know i know, its not good, but id rather it run cold than run hot) and it ran at either just under normal, or at normal all day. Both hoses are near the same temp with the lower being slightly cooler, i can now see coolant moving in the radiator, rather than it bubbling out, and i can squeeze the two sides of either hose together, though there is still pressure after running for awhile.

So....i'm pretty positive i have a bad thermostat....but it opens up fine in boiling water....so i'm nervous about spending money (i know they're cheap) on a new one. I'd hate to spend money on a new one and have it not open for whatever reason the other one isnt. Is there any reason a thermostat wouldnt open in the car but would open in a boiling pot of water?

 

Make sure you buy Honda.

 

You need to work your way up from the cheapest fix and go up...Check your radiator cap, temp sending unit, tstat, and on...You could drill a few holes in the tstat too to allow it to run cooler (a trick from my mechanic that races) I found that the best way to fill and bleed the system is by taking the top radiator hose off that connects to the radiator and fill it that way till the radiator fills up, then bleed it for a minute via the bleeder valve located by the vtec solenoid. I just bought a new temp sending unit from autozone for 24 bones, and will be installing it this weekend, because I've had the same problem that you've had with overheating, even after blownin my headgasket!! Not cool...So I watch my temp gauge more than the road!! I'm hopin that this new temp sending unit fixes my problem because my car only seems to flex in temp when my A/C is off...so...

 

ok....well, all the hoses are new, i dont see any leaks, i'm not losing fluid anywhere...oil or coolant... with the thermostat out i dont see any bubbles with the radiator cap off... so i can only assume my head gasket is fine. fluids moving so water pump is good... i boil tested the thermostat i have again...this time i brought it up to about 220 instead of just 190...it opened QUITE a bit more...so...do thermostats normally open further after whats listed as fully open? (stupid question but comon....parts manufacturers do crazy crap)

Also what do honda genuine thermostats look like? i dunno if the one i have is OEM or from some parts store

 

sounds headgasket'ish to me.
1) temp sending unit is dirt simple and works or doesn't is 99% of the cases.
2) tstat seems to be operating.
3) water pumps work or break. they even work fine if there seeping you just loose fluid and the bearing will fail soon after. but your radiator heats up so that confirms its working.

is the bottom of you radiator corroded?? hard to see, but can caught mildly high temps like you stating.

 

yeah did we rule out a radiator?

could be your radiator

 

something else i noticed....with my t-stat in, the bottom half of my radiator was cold, and the top half was hot as all hell...took the t-stat out and its hot top and bottom, with the bottom being a little cooler

seems like the radiator is doing it job, or at least as far as i can tell by feel...i dont see any corrosion and i flushed the holy hell out of it...but hell...who knows....could be something i cant see... i'm gonna get a honda thermostat tomorrow just for peace of mind.

I'm trying to find someone with a compression tester so i can see if my head gasket IS ok...i really have seen NO indications of a bad headgasket, other than pumped up radiator hoses which only pump up like that if the thermostat is in there... but i do want to eliminate it as a possibility on all levels...