Overheated my 4Runner. Any help?

[Clark White]

No good deed goes unpunished right? Well I picked up a half frozen guy on the side of the road today and when I went to pull away I caught something underneath. Didn't think much of it, but when I was almost home, the engine started knocking, still didn't think too much of it, no lights were on, I was only a few blocks from home, so I kept going. Check engine light came on with code P0115 and the engine died. At this point I was only a block from my house, so I started it up (almost didn't start) and parked it. By this time the knocking was very loud, but still no warning lights other then the check engine light, temp gage was normal. Just as I pulled into my driveway the temp gage jumped up and pegged out. This is when I noticed I had no heat. Turns out I had ripped off the lower radiator hose. At this point I was pissed. The gage read normal, I had no water temp light, and I hadn't noticed the actual temp on the scan gage, so I drove for probably 5 minutes with it over heating. Scan gage red 285deg F when I went back and looked :yikes:. Refilled the coolant, but the knocking is still very much there. I will change the oil tomorrow, but what is likely causing that knocking? I fear it is permanent damage, but I'm hoping not? Never had a vehicle over heat before, so I don't know just how bad this probably is.

Thanks!
Clark White

 

[maxama10]

Well the 3.4l has a cast block and aluminum heads. The bad news is you probably warped the heads. The good news is that the block is probably fine. Sorry man. Hope I'm wrong.

The knock might be the cam journals? If you didn't let it cool long enough then it might just be early detonation of the gas.

If either of these guesses are correct and nothing else is wrong you should be able to either pull new heads at a salvage yard or if the damage isn't too bad a good shop should be able to fix this.

 

[keezer37]

I will change the oil tomorrow

Well, the engine cranks so that's a plus.

If the knocking goes away, after changing the oil, I'd bring it up to full operating temp at idle and look for air bubbles in the coolant reservoir indicating compression gases getting into the coolant.

If the knock is still there, my guess is a damaged piston due to the detonation.

If the oil broke down due to overheating, the engine may never be the same. But probably not, as a former BMW owner, I am experienced with overheating engines. Oils today hold up quite well.

 

[Clark White]

I'm hoping it's something fixable. I really don't want to be putting a new engine in. Although, if the engine does turn out to be shot, maybe that's my excuse for a diesel?

Clark

 

[SilverBullet]

Clark, if I can be of any help locally, let me know. I know 2 good shops in PV.

 

[Clark White]

Thanks all for the advice! I have the knocking nailed down to the right side head only, engine still runs fine, however I have an excessive amount of vapor coming out the exhaust so we all know what that means.

Brian, I will likely be calling you for advice here soon!

Clark White

 

[Ludedude]

Temp sensor and lead wires may also have been damaged, making for innacurate temp readings, would make it run pretty bad. These parts are pretty cheap.

The water temperature sensor is meant to check the temperature of the water circulating around it. No water = no temp reading, so typically no overheating warning from the factory gauges or lights Since those are usually in or around the thermostat housing it's not likely that they were damaged by the unscheduled lower hose removal.