ShotnVA777

As the title says.... Not sure what's going on here, but I'll tell you what it's doing and what I've done to try to fix it!

My make and model are in my sig....

SO, I noticed today that the overflow was "boiling". Or atleast I THOUGHT it was, once I got the overflow cap off, I realized it was the radiator just blowing hot air in there via the hose. If you pull it out, just steam (car off! )

*NOTE* Not once did the car overheat, or even COME CLOSE (unless my gauge is wrong?) I never passed the center line on the gauge!, With that said, I did the easy stuff first....

- drained the radiator and ran COLD water threw it after it cooled down. Letting it flush out of the drain hole.
- then I filled it with 50/50 (more like 70/30 *70 being H20 AND 30 being pure coolant*)
- I then added some radiator flush and topped everything off WHILE bleeding the thermostat housing (a MESS without a hose!) Lol
- then I installed a brand new radiator cap

OMW from the Parts Store, I stopped to see how it was doing, I was baby'ing it the whole way. Pop the hood and it seemed like it was FIXED! WELL, I decide to get on it a couple times, about a mile away from my house, ONLY to see if this made a difference...

... get home... Same things happening! Boiling (overflow practically overflowing!!!)

Back to sqaure one, as I stated! So NEXT...

- I did a compression check and ALL the cylinders AND EVERY ONE landed on 150psi EXACTLY, on the compression gauge. Except ONE (cyl. 2), which was a little UNDER 150 (I'll attach a photo)
- Looked at all the spark plugs and they're kind of whitish. (too hot?)

SO.... While I was at the auto parts store, I grabbed me a new thermostat ONLY because it was ONLY $7! I plan to install tom - i guess! Lol!

SO! WTH ithe oing on here? I've never had a problem with the radiator putting out hot AIR into the overflow AND my gauge never say I'm overheating!

ANY HELP OR GUIDANCE would be GREATLY APPRECIATED!!!!

I'm just not sure where to go from here.... ESPECIALLY if she's doing it AFTER I install a new thermostat!!!

*NOTE* - Also, when you leave the cap OFF of the actual radiator and crank it (cold/warm) it'll spit the coolant everywhere out of the radiator fill?! Then it will act normal and slowly drop, I guess as the thermostat opens up! Theres NOTHING in the radiator blocking air flow, I just put a BRAND new radiator cap on, so I know THAT'S good. I'm confused!

HELP!!!!

ShotnVA777

Anyone?

ShotnVA777

Well... Heres something odd to add to the equation!

IT STOPPED DOING IT?! I drove it like a Grandma for a bit and checked it... Nothing. All looked fine.

Then I got on her a lil bit omw home!

I popped the hood and THOUGH hotter (obviously), still nothing!!!

I think I'm going to do head gasket, timing belt, water pump, thermostat (since I've already bought it) and some new sparkly wires, along with a dizzy while I'm in there.

JUST A COMPLETE 200K TUNEUP ON A RARE CAR! WOULD HATE TO SEE THIS GO TO WASTE!

holmesnmanny

why are changing out the head gasket ? never use aftermarket thermostats...they dont have the failsafes that OEM have built into them

ShotnVA777

The reason I would do the head gasket, is simply so I KNOW its fine. Same with a timing belt and water pump. Aren't those things YOU do before they ever have a CHANCE to fail???

I know I do... Especially if I'm not sure if its EVER been done to my DD!

ShotnVA777

Ok... I figured out when it does it! ONLY AFTER A HARD DRIVE!

I also found out something ELSE about it, that may help me diagnose the problem....

... It's heat works ON AND OFF. Like, it'll be warm as ish one second and then COLD the next! It sucks.

I NEED HELP!

ej7attack

how much actual coolant do you have in the car, or is it mostly water?

ShotnVA777

I've got it at about 40/40/20 right now... (PURE Coolant/H20/Radiator Flush). Hoping there was something just caked up in there or something.....

That said, I keep the rad filled to the top and the coolant overflow is about halfway....

I was thinking thermostat or headgasket. I've already bought the thermostat but someone told me not to change it???

I also tested the compression last night and EVERY piston was hanging RIGHT ON TOP of 150psi (+- a cpl psi, but nothing over/under 2-3 PSI)

I'm sincerely thinking about doing a headgasket change, along with timing belt, tensioner, water pump, etc. SINCE I HAVE NO IDEA how old they all are on 215k motor!!!

GhostAccord

When you did the compression test was the engine hot or cold?

Sounds like you may have a hot engine HG leak... try doing a coolant pressure test vs an engine compression test.

Remove the radiator cap and bring the engine up to operating temperature. Shut the engine down and attach the coolant system pressure tester. Apply pressure and wait for the results.

A HG change is not part of the Honda regular maintenance. It's not like changing the timing belts and water pump. I have seen them go as far as 300k-400k+ miles without issue. Now if you want to do it for piece of mind, give'er I wish you the best of luck.

IMO the HG is one of those things that if it ain't broke don't fix it. In your case you still don't know if it's broke or not.....

holmesnmanny

The only time a head gasket is going to fail on a Honda is if it overheats. Period. End of story. It will outlast the motor.

It sounds like your thermostat is failing intermittently and/or your fans aren't working.

You need to isolate that instead of just imagining the worst and changing the head gasket just because.

19Accord97

You need to get that radiator flush out of the system ASAP. Radiator flush is meant for just that - to flush the cooling system. It is NOT Meant to stay in the coolant.

Since it has been in the system for much much longer than it should have been, it could have cleaned/removed so many containment/rust that it has started clogging things like your heater core.

Turn on the A/C - does the fan kick on?

Like the others said, replace the thermostat with an OEM one and make sure it is not installed upside down. Same with the radiator cap, probably should stick with OEM unless it is an aftermarket radiator and it came with it.

ShotnVA777

Fans kick on fine... I've changed the radiator cap, I'm going to change the thermostat this weekend. As well as flush the heater core, as I have TERRIBLE heat! It DOESN'T overheat, ever! (Atleast it doesn't say it is on the dash and the car never feels HOT AS ISH when u pop the hood)

BUT the coolant overflow will be "boiling" after a hard drive (so bad that I lose coolant out of the overflow cap!), and its not that its SO HOT that its boiling, if you take the cap off and lay it aside, you'll see that its just the hose from the rad cap (that goes into the overflow) steaming/releasing air????

I don't know.... But the cleaner HAS been in for a few days! I'm going to go flush it and put 50/50 back in now!

What do y'all think?!

GhostAccord

Have you tried the coolant pressure test yet?


Also if you remove the rad cap, start the engine and you see air bubbles.... it's probably a bad head gasket.

ShotnVA777

If I start the car while warm and punch the gas it WILL spit antifreeze everywhere, IF the Rad Cap is off? Sound normal? Lol....

Other than that!

Well... Just need to flush my heater core and replace the thermostat this week and everything should be good to go! All I did was flush the entire coolant system with some cleaner for a couple days, drained it, flushed the rad AGAIN and AGAIN until I saw crystal clear water.... I also pulled the overflow out and cleaned the hell out of it and the hose that connects it to the rad! Filled it up with 50/50, bled the thermostat housing and she's behaving thus far! We even have a LITTLE HEAT! Haha.... And I haven't even TOUCHED the heater core yet! BTW the heater cores inlet hose is HOT, and the exit is COLD - so she needs a good ol cleaning!

It hasn't "boiled" the overflows coolant yet and I DOGGED it on my trip here (10 mile drive) - checked it immediately after and no lose of coolant and everything looked fine! Hell, even the fan cn for me when I was checking everything!

GhostAccord

That's what can happen when your thermostat is open. are there air/gas bubbles in there?


Sounds like the flush and fill may have solved your issue.... Remember if you are going to flush your heater core that you push the air/water in the reverse direction to the coolants normal flow.

ShotnVA777

I usually do it both ways, multiple times, on the heater core thing. I like to flush it out the best I can using a water hose w/ pressure and then blow it out using the air pressure method, at 10ish PSI. Then I'll use a cleaner, let it soak in there and repeat until I can drink the water going either direction! Haha....

Then maybe the thermostat IS bad... I've honestly never seen bubbles? Though once the initial "blast" of coolant comes out (after I punch the gas in nuetral), it just blows steam(?) after that, everytime i hit the gas... Ha!

I have a replacement from O'reillys, but someone ON THIS THREAD said not to use it? Um, why??? Lol.... Its just the thermo that popped up when the guy put in the make/model/trim?

Lemme know what y'all think...

PS: heater air is still cold... The core DEFINITELY needs a good flush, everything else seems to be working fine now. But I AM going to replace the thermostat... Once someone explains that comment about NOT using it! Lol

GhostAccord

Some times when you are not able to get warm air in the car but the engine is up to temp that can be a head gasket as well. I would keep an eye on that after you clean out the heater core and replace the thermostat.

As far as generic parts store thermostats go. As long as it is a fail safe and it is rated for the engines operating temps, I don't see any issue using it. I think what they were trying to say was not to use a cheap thermostat that doesn't have the fail safe feature.

cschlick

An OEM replacement from a parts store is fine, get the $25 dollar one tho, not the $7 bottom shelf brand.

If I understood that post correctly, what he meant was don't get the "performance" one

holmesnmanny

Considering the fact that your compression test said it was all 150, it would make sense that your issue is a blockage which instead of circulating coolant around the engine is pushing it out of the radiator overflow. This is the only logical explanation, unless your compression test results are somehow flawed.

ShotnVA777

Compression test were not flawed, whatsoever! 150 across the board!

I'm thinking its ALL that heater core backing stuff up. BUT since the flush, she's been behaving somewhat and not boiling over. I still don't get GREAT heat...

The inlet hose on the core gets BLOODY hot, the exit, not so much... I will be "blasting" it out today!

ShotnVA777

Btw. .. here's were my temps STAY and the thermo I got? Is this fine?

ShotnVA777

Annnnnd she's "boiling over" again!!! It never overheated though, EVER!

I really need to flush this heater core IMMEDIATLY!

GhostAccord

You guys do realize that they heater core is a coolant bypass system right. You could completely remove the heater core and all of it's hoses and components and the engine would run at the same operating temperature.

If there is a blockage causing this issue. It would be somewhere in the head or one of the rad hoses. When your coolant is boiling over are both of your rad hoses hot or just one?

ShotnVA777

If you mean the upper and lower Rad hoses than yes they're both warm/hot....

The ones going into the heater core is hot in and cold out.... I think THAT'S causing the pressure build up. Sure you can bypass one, but can you PLUG ONE?!

GhostAccord

That usually indicates that there is flow through the engine and rad.

Yes you can plug one.

If you look closely there should be a flow control valve in the heater core inlet hose. When you turn your dash temp control to cool. That valve closes completely and no coolant flows through the heater core. I highly doubt that is the cause for your coolant system high pressure. However, you might want to check that valve now that I mention it. Make sure that it is in the open position when the temp control dial is turned to hot.


So lets go to basics here; what are some things that can cause a cooling system to over pressurize?

Bad rad cap
Coolant boiling (230°C) Engine gets pretty hot!
Leaking Head Gasket (exhaust gasses getting into the cooling system)

Have you had a chance to run a cooling system pressure test with the engine hot?