Overheating, knock (kinda long, sorry)

[SHOGIRL1994]

I blew the upper radiator hose yesterday afternoon, which I replaced. I let the car cool down enough before driving it again about 5 miles, where I left it at my boyfriend's dealership and took his truck to work. He checked the coolant level and added a little bit (presumably because of some air pockets that were in it after I filled it the first time) and drove it home last night about 8 miles, which it was completely cool by then, and didn't have a problem with it. We left later to go out to dinner and drove about 15 miles. When I'd stop at red lights, the idle would dip down just a tad (not enough to feel like it was going to shut off), and the oil light would come on. Once I gave it gas, the oil light would go off and the car would run fine. About another 3 miles up the road, I started hearing a slight knock, combined with the voltage, low coolant, and oil lights all on at the same time. I went to exit the highway and check it out, and as I went down the off-ramp, it started knocking loudly and shut off. The knocking all happened within like a 10-second period before it shut off, I didn't continue to run it under that condition. My first thought was oh great, rod bearings. However, I haven't put more than 20K on it since I replaced them. I coasted into a parking lot, let it sit for about 20 minutes, tried to restart it. It started right up but was still knocking so I shut it off and had it towed home.
I did notice that the cap to the overflow bottle had popped off twice, once after my boyfriend got home after he drove it, and once after the knocking situation. So I thought maybe the thermostat was stuck and causing it to build up pressure and overheat. Coolant was sprayed all under the hood and was dripping down the back above my computer, so then I thought maybe it shorted the computer and that's why I was getting a voltage light, and it could have been spark knock I heard. (My exhaust is too loud to hear exactly where the knock was originating from.)
This morning it started right up with no problems, no knocking, and no lights coming on. I just realized that my fan is taking too long to kick on, and when it does kick on, it runs for about 3 seconds and turns off. This would of course be why it is overheating and shutting off, but still does not make sense to me why I was getting the voltage light and possible spark knock unless the coolant really did get to the computer and it was trying to (unsuccessfully) compensate. I still don't know why I was getting an oil light, but I really don't think it would be rod bearings at the same exact time as the cooling problem. I want to eliminate the cooling problem before I have to drop the oil pan and check.

So my questions are:
1) which is the fuse for the fan
2) does it sound like the fan has gone kaput, or the wiring (nothing is visibly wrong with it)
3) any thoughts on the knock and/or the oil light
4) any potential for severe damage, considering it only ran this way for a few seconds

 

[DigDeez]

I can't help much on this one!

However, as hot as it's been here in Chicago this summer, much hotter than last summer, my car hasn't really been getting too hot as what the thermostat reading indicates. Last summer, it stayed at the tip of the NORMAL, as that was very frustrating! The only difference that I can think of is that this summer I've been using Murray's Auto Store 50/50 Diluted Antifreeze. Yeah, the cheap stuff!!!

For whatever that's worth.............

Good luck!!!!

 

[SHOGIRL1994]

Thank you.

And I guess I should add that my temp gauge has never worked in this car...

 

[Racer X]

And I guess I should add that my temp gauge has never worked in this car...

Well, I'll go ahead and state the obvious. Drain and strain the oil, drop the pan, look for glitter, and so on.

But also, check your transmission. If your car overheated significantly, it can also raise the fluid temp of the tranny. Or worse yet, if your cooler circuit in the radiator has a leak, you can contaminate your ATF with coolant, which would be monumentally bad.

On the fan issue... how do you know that it's turning on too late if you don't have a Temp gauge? A quick 3s cycle could be a bad ECT sensor, a weak relay at the IRCM, ground issues, voltage issues, or any combination thereof. That fact that the fan spins up rules out a fuse.

In my experience, an oil light followed by knocking indicates either a bad rod bearing, or a bad oil pump.

Good luck with it all...

 

[SHOGIRL1994]

On the fan issue... how do you know that it's turning on too late if you don't have a Temp gauge?

Just a guess that it's coming on too late when driving it... I know it definitely doesn't come on any sooner than 20 or 30 minutes when I let it sit and idle. That issue seemed to have worked itself out this afternoon, it seems to now be coming on and running an appropriate amount of time when it's idling in the driveway. Maybe due to a relay that was wet with coolant and has now dried out? I drove it for another 10 minutes this afternoon and it did fine until the cap to the overflow tank blew off again. Something is causing it to build pressure and pop open and spray coolant all over the place. No more knocking or voltage light, so I'm now assuming that it was spark knock from the computer trying to adjust the timing when it was going wacky. I don't have a leak anywhere, and it's obviously pumping so I know it's not the water pump.

 

[Racer X]

Have you tried to replace your radiator cap yet?

 

[RAYJAY]

how does the oil look ? and how over heated did it get (cracked head /head gasket )??????


Jeff