2001 Accord automatic (ULEV). Quite certain I have a blown head gasket. I have no idea for how long.

I have had a coolant leak somewhere for a while now (over a year), and I've just been topping it off once a month or so. Never noticed any coolant in oil or vice versa.

Last week the car went into limp mode with a p1254 or something like that (vtec malfunction). Checked my oil and it had gotten to about 2 quarts low, also looked milky and maybe even a little curdled...Assumed it was the head gasket so I put one of those coolant additive sealants in and topped off the oil. Ended up having to do a full oil change to clear the code (I guess the oil filter had gotten clogged).

In addition to that line of problems, I recently got the "catalyst efficiency below threshold" code, though I replaced the cat and both o2 sensors less than a year ago. I'm guessing coolant and oil have been getting into the exhaust?

So that's all the backstory. Then today as I pulled onto the highway antifreeze sprayed everywhere. After checking it out, it's not even a hose that is busted, its just spraying out of the top of the radiator (see picture).

Clearly I need to replace the head gasket, and most likely the cat though I'm less concerned with that. I'm just wondering what else I should expect to replace. Once the head is fixed and pressure isn't building up in the coolant, would my radiator be fine? Do I now need to replace that too?

 

It's $55 dollars for a Denso radiator at rockauto plus shipping so maybe $65 bucks. Any idiot(not saying you're an idiot but I'm using the reference) can replace a radiator in under an hour. It's really easy.

There are really only two things that you absolutely have to pay attention to, oil level(oil changes) and coolant temperature. Outside of that and anything engine related is minimal cost(outside of timing belt change at 95k replacement).

You should confirm just to be sure, compression test the engine. Report back the results. It's likely an overheated head gasket will result in the number 4 cylinder being the first to show bad results.

 

Yeah I looked that up and was surprised at how cheap they are. So replacing it isn't a big deal, just wondering if it's necessary.

So you think it's still questionable that it's the head gasket? I was under the impression that anytime the radiator becomes an antifreeze squirt gun, it's 100% the head gasket. Like don't have to warm the engine up or anything, just start it, rev, watch geyser of coolant erupt.

I was actually planning on doing the full head gasket kit (Victor Reinz) and timing belt kit (Aisin), along with balance shaft seal/retainer and vtec solenoid gaskets. I've had various oil leaks for years, also no idea if the timing belt has ever been replaced (currently at 220k miles).

Edit:
I just cranked the (warm) engine with the radiator cap off and the coolant rose/bubbled. Enough for me to see it from inside the car.

 

I've had a tell tale of a Head gasket with the overflow puking. Turned out to be the radiator cap. Saved myself time and money.

 

So I went ahead and did the compression test, all 4 cylinders are consistently between 185 and 190 psi.
Cylinders 4, 3, and 2 tended to be between 187 and 189.
Cylinder 1 was slightly lower, from 185 to 187.

Now what? What else could pressurize my radiator fluid to the point that it squirts out of the top seam in a stream?

Update:

I realized that I wasn't cranking the engine long enough to get to maximum compression. Here's the new results.

Cylinder 1: 220 psi
Cylinders 2,3,4: 225 psi

Another update:

I measured the compression for each cylinder on the first cycle. They were 120, 124, 122, and 124 for cylinders 1, 2, 3, and 4 respectively.

 

It's likely your radiator cap is bad but if it's leaking then you should just replace it.

 

Can you explain how the radiator cap would cause this? I would think it's irrelevant to the coolant bubbling on crank, since the cap is off for that test.

 

When the other guy posted about the reservoir overflowing I thought they were referring to something you said about the radiator overflowing. The radiator cap can cause the overflow to overflow.

But if you just got a leak out of the radiator and it's spewing what would make you think there is anything wrong besides the radiator is leaking ?

 

Well I saw milky oil at one point. That combined with my persistent oil leak, coolant leak, and converter going bad after only 1 year, points to a blown head gasket as far as I know. But like I said, I threw in some of that head gasket repair stuff in my radiator, so maybe that actually worked but ended up causing this separate radiator leak.

Maybe my source is bad, but I thought that the following was conclusive evidence for a blown head gasket: Take off radiator cap, crank engine, coolant shoots up due to combustion gases escaping.

I just made a video of this test here: https://goo.gl/photos/6JcDz6n4r2oQDcqMA
You can see that coolant shoots up a bit as the engine starts. If you're saying that's normal, then thank God I can just replace the radiator lol

 

If you're getting 225 consistently across all cylinders it's likely the head gasket is sealing but it could be leaking where a coolant jacket meets an oil flow spot. You should replace the radiator since you know you need to and then run a cooling system tester to see if it holds. It will just leak out of that hole if you try to use the tester with that leaking radiator.

 

I installed a new radiator (plus cap and thermostat) and did a couple pressure tests. First test was pumped to 17 psi, this fell to 15 within about 7 minutes. Second test was pumped to 16 psi, this fell to 13 after 20 minutes.

There is one small leak that I can see from the overflow tube where it connects to the radiator. Maybe I should just put a hose clamp on that?

I also spent about an hour doing some test driving, and letting it idle. No overheating. Occasionally saw a few drops of fluid under the overflow hose. Also occasionally saw a little steam around the hood, but this could just be from water splashing up (it's been raining).

In the morning I'll do a cold crank pressure test. If that checks out, I think I'll finally be satisfied that the head gasket is fine.

Update:
Pressure is slowly rising after a cold crank. I guess the head gasket is fine, I just need to spend some time searching around for more small leaks.
Could adding head gasket repair stuff to my old radiator have caused it to spring that huge leak in some way? It still just seems odd that right around the time I'm already suspecting a head gasket, my radiator busts.

Not so good update....
Pressure slowly worked it's way up to 20 psi at idle and was still climbing.

 

Are you sure you saw milky engine oil ? It doesn't sound like you have an issue anymore. Yeah, I would clamp off that hose.

 

Went on a 300 mile round trip and didn't have any leaks, granted I was babying it and never revved past 4k.

It was thick and whitish, almost curdled looking. Also about 2 quarts low at the time. This triggered a vtec malfunction which didn't go away until I changed the oil filter.

So it's not a concern that the coolant pressure rose to 20 psi while idling? I thought it was supposed to stabilize around 8.

 

Sounds like a swapped engine to me. Look at the front of the engine on the left side of the block near the tranny under the upper rad hose it should say the engine model stamped on there. I know my head was warped pretty bad. Hopefully the same for yours.

 

In my experience avoid head gasket fix liquids. Sounds like head gasket, like others have said such a small leak wouldn't let oil into coolant and coolant into oil but would pressurize your system causing a leak and defiantly will only fill your resirvoir because the coolants been replaced with compressed air(exhaust gas). Take the cap off with the car cold and warm it up, smell the rad neck for exhaust. Might not smell anything since the leaks so small. I would deck the head and get a new gasket.

 

the arrow on your picture, well that's the most common leak on plastic radiators, they leak where the metal is crimped into them from the plastic deteriorating due to old age, nothing weird there. if the cap is leaking get a new oem cap. I also can't tell how you concluded you have a blown head gasket other than milky fluid, which could be a coincidence being that your radiator has been leaking forever and you just ignoring it. also fyi if your radiator is that old you should be looking to replace the upper radiator hose and if you have extra money the lower radiator hose too. those would be the 2 giant sized coolant hoses coming from the radiator to the engine, also probably need a new thermostat and seal for it

 

If you had a blown head gasket and the bottle fix sealed it, the blown head gasket could have been the reason for your radiator leak. All of the excess pressure in your coolant system from leaking combustion gases is going to find a weak point to escape. If the bottle fix did seal a head gasket issue, be prepared because eventually that will fail, and most likely things will be worse than before.