Mystery overheat (with solution)

[JWSmythe]

I was driving up I-75 last night, trying to get from Tampa to Gainesville. I wasn't trying hard or anything. Cruise was set to 70. It was a nice leasurely drive. It was cool out (maybe 60F).

In the middle of nowhere (and there's a lot of it on that road), the check gauges light went on. I had a problem with the belt breaking in the past (broken idler was eating them), but that's been fixed for a while. I glanced down at the gauges. Temp is very hot. voltage is fine. oil pressure is fine. I pushed it up to 80, threw it in neutral and shut it off.

When my belt broke before, with the engine off, rolling for a mile or two let the engine cool down. I had slowed down to about 50, so I threw it into gear and popped the clutch. The temperature had barely dropped. I got back to 80, threw it in neutral, and shut it off again. I repeated this maybe 6 times to get to the next exit.

In my head, I was going through all the possibilities. Belt broke again? No, my voltage was fine. Hose leak? Radiator leak? Heater hose? Thermostat? Head gasket? When's the last time I changed my oil?

I got to a truck stop (yippie!), and rolled into a space with the engine still off. I went inside and bought a gallon of antifreeze and a flashlight. This is a good start.

There was a little water underneath, but I drove through a puddle on the way in. I filled it all the way up with most of the gallon of antifreeze. It can't be a big leak. I started the engine, and it was boiling over within a minute. Well, the engine is hot, that must be all this is. I could see flow in the radiator, so it's not the water pump.

I shut it down again (obviously). A "helpful" guy came over. "You blew a head gasket."

I told him the engine sounded fine. No rough running. Nothing unusual other than the overheating.

He was insistent, and started showing me things. Thanks dude, I've built cars, I think I know how to diagnose things. But, I humored him. He pulled the oil dipstick. The oil was clean, and there was no water in it. There was no sign of oil or debris in my antifreeze. He still insisted it was a blown head gasket. I agreed anyways, and told him I would let it cool down, and limp it home. I was only about 50 miles out.

Why do helpful people come up and tell you the worst case scenario when you're stuck somewhere?

As it cooled, I topped it off with water, and overfilled the overflow tank. Unfortunately, it was dark, and I was trying to use a flashlight and a water bottle, so I spilled water all over. That'll make a leak harder to find. I started the car again, waited for it to burp up the rest of the air, and then put the cap back on. 2 gallons total, even with the water that had spewed out after I stopped.

I let it run. It sat right at 210, just like it normally does. I let it idle for about 15 minutes. No boiling. No temperature change. I revved up to 2000 RPM, and held it for a couple minutes. No change.

Ok, the trip to Gainesville is off. I'm going home. The person I was to meet in Gainesville came down to meet us at the truck stop instead. We left the car idling for about an hour. No change in temperature. No change in water level in the overflow tank. Nothing weird at all. It was running perfectly. I was checking the whole time for water dripping, leaking, spraying. Something's got to be wrong. No water anywhere, except where I spilled it. That's spilled water, right? I hope so.

Maybe I was stupid, and I hadn't checked the water lately? I always do when I change the oil. It shouldn't be that. Did I remember to check last time? I can't remember.

While we're doing this, I had my running and fog lights on. One of the fog lights burnt out. Dammit.

So, we get back on I-75 to come home. I take it easy up to 70mph. The temperature goes up a little bit. I back down to 65, and the temperature settles to just over 210. If it stays there, I fine with it. People are blasting past us the whole way. One guy in a riceburner blows past, moves over in front of us, and slows down to 50mph. {sigh} I move over to pass, and he speeds up with me. Great, a riceburner that wants to play. I'm just trying to get home. I speed up to 70, and he takes off. I slow back down to 65, and set the cruise again. Kid, go play with someone else.

The whole drive home, I'm asking myself what could be wrong. Maybe it is a head gasket. dammit.

The engine had thrown a code, but the SES light went off while I was driving home. I checked it, and it said something like "Low Engine Coolant. Fuel Disabled"

So I hop on here last night at like 1am, and start looking for answers. Almost any problem I've had, someone here has posted about. I love this place. Sure enough, another guy had the same situation, almost exactly. and the reply. "It could be your thermostat, or something blocking the radiator." He replied the next day "Ya, there was a garbage bag stuck to my radiator. I peeled it off and everything's fine."

I looked. Maybe I didn't look well enough with a flashlight in the dark. So I went out in the daylight and had another look. A big paper towel was covering half my radiator. Part of the drive had been foggy. I must have picked it up in the fog when I couldn't see it. Problem solved!

The moral of the story? Don't assume the worst, and don't listen to the random stranger at the gas station. He's not as smart as he thinks he is.
And, if the car is running hot, don't forget to check the front of the radiator carefully, even if you are wearing nice clothes.

[c5z28]

Glad it worked out for you, same problem but mine ended up being a sticking thermostat.

[JWSmythe]

I was ready to bust out the thermostat so I could get home. If it had been that, at least I would have had a real solution, rather than just wondering the whole way home if it was going to overheat again.

[02transamce]

dude,i'm glad it was just a paper towel.i was going home form work back in june and the freakin temp shot over to 260 i was like wtf and stopped on side of the road and found the water spraying from behind the water pump.i am a former ford technician so i'm like,great water pump gasket failed.then this dude stops and is like your block is cracked that's where the water is coming from,i politely went on my way,home was just 3 mile from where i was stopped, and replaced the water pump and gaskets the next day,block was just fine,thank you,mr.roadside auto tech.

[astyles]

same thing was happening to me so i changed the themastat........the next oil change while i was under the car i felt water drip on me.....i looked up and saw the water coming from the weap hole........but next time i'll check for radiator blockage after reading this....

[JoshieDoom]

Remember only the 98 guages are actually accurate. No telling the actual temperature you guys were running. Im paranoid when mine gets over 200. It always stays around 190-200 even on hot idle.

[02transamce]

Remember only the 98 guages are actually accurate. No telling the actual temperature you guys were running. Im paranoid when mine gets over 200. It always stays around 190-200 even on hot idle.

my second car 1986 thunderbird had cooling "issues" and since then i'm always paranoid about the temp gauge no matter what car i'm in.