jppettis

Hello, I recently have developed a few issues with my vehicle.

1 - Overheating. My car began to overheat while I was sitting in a parking lot at idle. Gauge was just over the middle line when I noticed. I was 2 minutes down the street from my house, so I drove it home. This was definitely a bad decision, and I have probably permanently damaged my vehicle because of this.
2 - Vibration. On the way home, I noticed my temperature gauge rising quickly, but only when accelerating. At idle, their would be no rise in temperature. My car was vibrating slightly as well. The vibration didn't begin until I was about a minute into the drive home. When I parked it at home, I noticed white smoke coming out of both sides of the engine.
3 - Coolant low. When I got home, I realized my coolant reservoir was completely empty. I initially thought that my car had a leak that I was unaware of. I filled the reservoir with water, and I turned the car on. It ran fine, but I didn't let it run for long or drive it around. Just let it sit parked for about 5 minutes. The next day I checked my reservoir and it was completely empty. Unfortunately the night before it had rained, so it was extremely difficult to spot any puddle or leak. A few days later, I came out and opened the coolant cap on the front of the engine. Totally empty. I filled it to the brim with water, and I filled up the reservoir with water. I turned on the car to move it into the driveway for repairs.
4 - Vibrating and drop in RPM. When I attempted to park my car, the vibration from a few days ago had returned and it was much worse. When I attempted to accelerate the vehicle, my RPM would drop almost to 0.

I have ceased work at this point, as I only think I am making things worse. Low budget and fear of potentially high prices keeps me at bay.

From what I have researched, the worst case scenario is I blew a head gasket when I drove the car home. This is most likely the case. I hope this isn't true, and I believe it is unlikely because I only drove the vehicle for 2-3 minutes before parking it. The temperature never red-lined, but it came close.

I recently changed my spark plugs. A possibility I believe that may explain the vibration and drop in RPM is that one or more of the spark plugs may have a problem. I am unsure how to diagnose this further, and I am not sure how this would attribute to my loss of coolant and overheating.

I apologize for being so wordy. If anything needs clarified, please let me know.

jppettis

I also just noticed that the actual RPM of the vehicle doesn't seem to drop. Rather, the RPM gauge needle drops but the vehicle seems to be accelerating somewhat smoothly besides the vibration and somewhat loud idle noise that can be heard through the exhaust. Also, no white smoke pillowing out of the exhaust or milky oil seen in oil cap.

aptoslexus

The coolant capacity of the car is over 11 quarts, so if it had a leak and ran down you're going to need to fill it. A couple of fills of the reservoir isn't going to be enough. Pull the plugs and do a compression check on the engine. If one or more cylinders is significantly lower, you might have a head gasket issue.

Bylan

I once thoroughly overheated my 97, like I didnt notice it was hot until I came to a stop light and the engine idled horribly due to the temp needle being pegged. I had a clear leak at my Heater control valve, fixed it and havent had any head gasket issues. Its hard to blow a headgasket. I would fill it from the proper fill port, the large bolt on top of the thermostat housing, and let it run and get up to temp. If you see no leak, and lose coolant, then do a compression and leak down test.

timmy0tool

iTrader: (7)

what year and mileage is your vehicle?

as already stated, it's unlikely you damaged anything by driving it for such a short time running hot. i've also driven my LS with the needle pegged at H only to cool it down by cranking the heater to max (air in the coolant system caused this). no issues with HG.
proper air bleeding is key to get all the air out, and yes it takes a lot more coolant that you think. no oil in the coolant is a good sign!

i suspect the vibration is caused by the ignition system as you mentioned a spark plug change. make sure the wires are seated all the way down and routed correctly.
could also be your cap/rotors if you have a 90-97 vehicle.

low idle plagues these vehicles so diagnose 1 problem at a time since it sounds like you have multiple.

jppettis

This is comforting to know.

1994 170k.

Why would the vibration only have started after the car overheated though? Also at the same time the tachometer started acting weird and still does. It only reads RPM's from 800-ish and below, but if you accelerate past that the tachometer drops down to 0. However, the vehicle does accelerate, although extremely slowly and sluggishly.