troubleshooting rough start

Hey folks, I've gotten a lot of info on these pages, was time I joined.

I'm having an issue with a high mileage 2011 I recently picked up. It's in great shape, regular maintenance, and currently has 264xxx miles on it.

It would occasionally start rough, but it would go away and it would drive fine once it gets going. Recently though that rough start has gotten worse, and is nearly every time. Also rough getting back into drive after a full stop. It was particularly bad driving out of a car wash. Switching eco/pwr modes often helps. It is throwing codes, but the one that came up, when it first got worse, was loss of communication to steering, and that seems unrelated.

I recently got caught out in a monsoon storm, and I suspect I may have fouled a spark plug. Can't get it to the shop for a week or two though, but could maybe swing doing the work myself if I could pinpoint it. I'm thinking it might just be a good time to change spark plugs anyways, but if that doesn't sound likely I might as well wait. I'm not sure when they were changed last. It's also near due for an oil change, I do them every 5k.

Advice is appreciated. I'm sure I'll be a regular here now.

 

It's received regular maintenance. Was a fleet vehicle, I bought it from a guy I'd been leasing vehicles from for a year. I know they get regular care, but I don't have specific records for this one.

264xxx is high mileage, but this is a work car, and I expected to get another 100k out of it... and expected a repair or two. I can do some work on my own, but generally prefer to take it to a shop.

However, The problem seems to have progressed. The rough start was getting better, so I was starting to think maybe it was just bad gas or something. Temperature warning light flashed on for a minute, then went off. Thought it odd, so I checked anyways, and the reservoir was nearly dry. Threw some coolant in and kept driving. It kept driving better.

Today however... Doesn't seem to be driving as well, but not really anything specific. MPG dropped. Popped the hood. Coolant reservoir is empty again. And the oil looks muddy as hell. Got a friend coming over to do a compression test tomorrow, but I'm dreading the results. JC91006 may have called it. I don't know what I'll do if it's the head gasket.

 

Compression test was good, all 4 cylinders around 150 (though two a bit weaker).

Oil looks better today, in the light of day. No idea why it looked so terrible last night, but I've seen muddy oil and that was what it looked like then.

Changed the spark plugs while we had them out. Fired up much better after than it has been. No idea when they were last changed, but I doubt it was 24k ago.

Still not out of the forest, no idea where it's leaking coolant, and that was like half a gallon in a day. But it doesn't seem to be the head gasket.

 

Didn't see any smoke, white or otherwise.

Say 100 or so? I live in AZ, so it's a good chance there's a bad hose somewhere.

 

My normal parking is on gravel, and it's been either stupidly hot, or pouring rain lately, so I hadn't noticed anything, even when I'd look.

No techstream. Until business picks up (month or two) I can't really afford specialty tools and such.

Put some cardboard out, after we put it back together today and I took it out for a spin. I can see it dripping from something on the passenger side, but not from where. I don't think it's anything I can get at, if it's not something I can see from on top of the engine.

And unfortunately I have to keep running it. It's my work car, so if it doesn't roll, it doesn't make the money to pay for repairs. Figure I'll have to just keep pouring coolant in it for at least a week.

 

So, there is definitely a leak, but not like I was thinking. I'm pretty sure the reservoir tank is leaking, but unsure if there are other leaks. Starting to wonder if the whole issue was super low coolant. I don't specifically check the coolant as often as I apparently should, so it could have been low for awhile. It hasn't given overheat warnings, except that brief one, so I'm wondering if maybe the coolant got so low I've developed air bubbles in the system. After dumping a bunch of coolant into it, it's not disappearing as fast, which suggests it's a problem I've let go too long.

What is the coolant capacity of the reservoir?
What is the full capacity of the engine?
What would the symptoms of air bubbles in the coolant system be?
Can you point to a good video for bleeding the system?

 

Just heard from the mechanic, tests show it is the head gasket. Hasn't blown yet though, and compression in all cylinders is good.

Anyone have experiences with head gasket sealer type repairs? Particular brands? Blue Devil seems to have good user reviews. It's not a great option, I'd be looking at it as a temporary fix. Mechanic estimated $4000 for the head gasket fix, or he found an engine to swap and estimated about $5500.

 

What's the difference? One works, the other doesn't. Heh.

 

One in the process of failing. At the moment, replacing the gasket is an option. I don't have the tools, time, or confidence in my own knowledge to do it myself. If the gasket fails, engine replacement sounds like the better option. This engine is strong, even with 265k miles, but a lower mileage engine will still likely last longer anyways, and at a similar cost to having a shop do the head gasket.