Overheating only while idling

I finally had a pressure test run on the coolant system today. They were unable to identify any external leaks in the system, and also checked the heater core and found no leaks there either. So it would seem the only conclusion to draw is the head gasket is leaking. For the time being I've just been keeping an eye on the coolant level and refilling every 2 or 3 weeks. I've been avoiding any of the liquid glass type of sealer products like K Seal since they can cause other problems like clogging the thermostat. It's all strange as I haven't seen any bubbles in the radiator coolant and have only noticed white smoke coming out of the tailpipe once, which was upon startup. The Midas guys were saying it is misfiring upon startup which they think is caused by coolant getting into the cylinders and on the sparkplugs.

Hi Joe,

I only saw actual white smoke once a couple weeks ago. It was a few puffs of white smoke when starting the engine. I've looked for it since then but haven't seen it again. So definitely wouldn't call it excessive. The more alarming fact is I'm losing 6 ounces of coolant every week or 2. And my engine is running slightly rough. So it seems like the engine is a bit of a time bomb with the coolant burning off in the cylinders. Still no sign of coolant in the oil. They said the coolant system was holding pressure well enough in their test at Midas, so I'm not completely messed up. A bit disheartening after all the work I've put into it this year though.

Adam

Hi Joe,

Does running the A/C on high all the time cause coolant to be consumed? I think I heard that running the heater causes a bit of coolant to be consumed, not sure about the A/C though.

I replaced the radiator cap 6 months ago or so just to be sure. It was a Stant which seems to be a pretty well respected brand. The radiator itself was replaced only 13 months ago. It was a warranty replacement from roughly 3 years before ( September 2016), it had a leak out of the bottom left front area, I never found out exactly where. I also replaced the radiator sometime in 2012 or 2013. I recall multiple times checking the radiator during all those years and having the same issue, where the reservoir area appears bone dry and I have to refill it. Anyway, the mechanic who replaced it the past two times told me he did a carbon monoxide test on the coolant and it tested positive, which is where the idea of the head gasket leaking started.

Is it also normal for the coolant to pool up on the rim of the reservoir filler area just beneath the cap? I noticed that happening and was curious if maybe it was getting really hot and evaporating. I thought about maybe trying to block off that area so that doesn't happen anymore. Thanks for your help.

Adam

Hi Joe,

I was referring to the radiator itself. I fill it up to the filler neck, and the pressure from the system shoots some of the coolant up into the rim around the cap area. I was thinking maybe with such a small amount in there, it could get really heated up to the point of evaporating. I also noticed the sticker on the radiator cap was rather damp. It did rain tonight but nothing else was wet in that general area, so it seems to have come from out of the radiator itself. I switched back in the old radiator cap, but noticed the sticker on that is completely worn out. So it may have had the same thing happening. I've attached pictures.

Also, yes it does shoot out coolant with the cap off and engine started. It seems to pressurize properly, and the pressure test at Midas showed it continuing to hold proper pressure. I don't fill up coolant in the reserve tank / reservoir, it is currently sitting maybe a half inch above the low line. It doesn't seem to vary much when I check it. Also the reserve tank is only semi translucent so it's hard to see the hose in there, but I pulled it out and put it back in, and it goes all the way to the bottom, doesn't seem to be bunching up or anything.

Maybe I should spring for an OEM radiator cap and see if that helps any? I do know switching to an OEM gas cap fixed my P0442 gas cap issue before, when an aftermarket one was still triggering the code.

Adam

What is the expected behavior for the coolant in the radiator with the cap off, starting the engine cold? Since it's being pressurized I would think it would shoot out, or is it only when warmed up?

I really don't feel comfortable with any major engine work. Supposedly some of the head gasket sealer products work, if you properly follow the directions and flush the system out multiple times, as well as pull out the thermostat so it doesn't get clogged up with the liquid glass stuff.

My mechanic, who has the best prices around, had said $750.00 for a head gasket replacement. At that point it seems like a complete engine rebuild or replacement with a low mileage or new engine would be the best thing to do IMHO. If I'm going to continue to pour money and time into it, I want it to get me the next 200,000 miles. The car had been so reliable for 200,000 miles that I assumed if I put in the proper work that it would continue to be so. I didn't realize the whole thing would fall apart at 200,000 miles.

Anyway, what's going to happen if I continue to drive it as is? I've seen the cars with fully blown head gaskets where the white smoke is billowing out of their tailpipes. I have already driven it a year since that mechanic said it tested positive for the carbon monoxide in the coolant. I've been topping up the coolant every 2 or 3 weeks and have had no overheating issues. If it doesn't get the point it's overheating, is it really a problem to keep driving it as is?

I didn't realize you guys have a YouTube channel. You have a video titled "Can You Fix a Head Gasket with a Chemical Sealer?" That says Blue Devil head gasket sealer works, it was someone named Ryan who did the test. So is this what I should attempt?

Hi Joe,

Supposedly none of the coolant is getting into the oil. There is a risk that if there's a leak directly on the engine seal, the sealer can seep in there and seize the engine. Evidently a gallon of sodium silicate can be used to take out a tank engine. If the leak is in the cylinder(s), I heard to remove the corresponding spark plug while doing the sealing process. I will admit I'm definitely paranoid about the risk of ruining the engine. There's no way to guarantee there isn't a tiny leak that isn't discoloring the oil that much but still has a bit of coolant getting in there. I think I'll ask the manufacturer about that directly. I'm also going to do more work to try and identify where the coolant is going before proceeding. Maybe I'll fill it up with coolant and run it with the heater on full blast again.

Thanks,

Adam

Well, it didn't spray out this time on a cold start with the radiator cap off. This time I had just filled it to the bottom of the filler neck, and when I started it, it began slowly expanding and rising. At which point I had to quickly put on the radiator cap before it overflowed.

The time it shot out coolant was back when I tested it with the heater on full blast, so perhaps that's what caused it to shoot out that time. In any case I'll probably have my mechanic check it out. I just had to put in another 6 to 8 ounces of coolant in there today.