Coolant light on after taking it for an oil change

[rfung]

So this morning I took it to my usual oil change place. Right after I drove out of the lot, the coolant light went on. I pulled over and popped the hood and looked at the expansion reservoir. I opened it (with a towel and glove) and a lot of water came out. I looked inside and it looked like the level was okay, so I closed it up and drove some more. When I got to my destination the light came on again, I looked at the reservoir and put some water.

After that, I drove around a bit in the city, and noticed that the temp would go about 3/4th of the way and the coolant light would turn on, and then the temp would drop back to the middle. This happened a handful of times when I was driving in the city.

On the freeway on the way back home (about 40 miles) the light came on 4-5 times, but the temp never moved.

I searched around, and found this thread:
http://www.audizine.com/forum/showth...-wondering-why

"The wire on mine was broken off and triggering the light.

I think a lot of people just push the reservoir aside when doing work on the engine and this fatigues the wires. That is how I got my car and I wire nutted it on...been fine since.
"

Since this happened right after the oil shop did my oil change, and they had to shove their hands in there to get to the oil filter, are the symptoms I just described a possibility that the wire is broken off? bear in mind I have no idea what this wire does or looks like. (if anyone has a pic, that'd be greatly appreciated - I will try to look for it tomorrow morning).

That wire aside, what are some other possible issues I may be looking at?

I read about fans working on idle, or turning on the AC/heat for the fans to run, but I'm not sure what exactly that achieves, or checks for. Again, an explanation would be appreciated.

Thanks in advance

[Dubsport Inc]

Definately the low coolant (reservoir wiring) is directly above the oil filter and if they put their ape arms from the top to get to the filter it might have damaged the wiring... You need to make sure you have the correct proportions of coolant/water on there now as you said you added water, you may also have a air bubble in the system as you said you opened the reservoir and a lot of water came out!

[Myst420]

It's possible they moved the reservoir and forgot to plug the sensor back in. I know I've done that plenty of times.

[ECS Tuning-Audi]

It's possible they moved the reservoir and forgot to plug the sensor back in. I know I've done that plenty of times.

X2 or if they didn't unplug it they tore a wire loose from the connecter.

OP remove the screws that hold the coolant tank down lift up gently on the tank to see if its still connected. Chances are it still is if it comes on and off, if it were unplugged it the light would be on the whole time.

See if you can spot a wire tear, and try to unclip the sensor with out causing more damage.

Good luck!

Jason

[Ricky Spanish]

It's possible they moved the reservoir and forgot to plug the sensor back in. I know I've done that plenty of times.

THIS... lol.. Literally every time I change my oil I forget to plug that damn thing back in.... Or they man handled it and damaged the harness..

[ZipMeUpJ]

the light will come on automatically if the temp reaches 3/4 (ask me how i know lol) even if the level doesnt change in the tank. It will change temp for air bubbles caught in the system as well, and will correct itself when the bubble is purged. Check that plug directly under the tank. you can see/feel it with the tank still in. they may have yanked on teh cord by mistake putting their arm in or when they moved the tank not knowing theres a sensor attached to it (ask me how i know). or they may have just not attached the plug securely. plug would be the easiest thing to check first then go from there

[rfung]

Ok I looked under the reservoir, the sensor looks attached fine. The two wires coming into it seem like they're connected ok. What can I do next to troubleshoot?

[ECS Tuning-Audi]

Ok I looked under the reservoir, the sensor looks attached fine. The two wires coming into it seem like they're connected ok. What can I do next to troubleshoot?

Unhook it and follow it back to where it connects to a main harness. Check for cuts and splices. If the wires look good, replace the coolant tank since it already has the sensor in it and you can't buy it separate.

Click HERE to order or for more information


Jason

[rfung]

Does that sensor failure result in the oil temp going up to about 3/4th before coming down to the middle again?

[Myst420]

Im thinking you have air in your system. Do you have any coolant leaks? Take a flashlight and look between the motor and firewall. Look for pink crusty stuff on top of the transmission.

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[rfung]

That may not work because I run a diluted coolant/water mix (plus, I had to top it off with water the past day). But the factor I'm at a loss here is why it happened right after the oil change. I would go back to them and complain but 1) It's about 35 minutes away and 2) time has passed where they could plausibly say it wasn't them (which, understandably, I can see their point of view). I'm merely mentioning it because it _had_ to have resulted from something directly related to it. That being said, this morning I was looking for anything wet but couldn't find anything. Will try harder.

[rfung]

So I looked at it this afternoon after spending the whole day trying to replace my brakes (post to come), and I looked under the hood and I found wetness on the far side of the engine bay near the fire wall.

Coolant leak? is this something I could do myself or do I need to get it to the shop? Planning a trip to Tahoe this weekend from SF, so I need to get this fixed asap...

[rfung]

Also, I turned on the heater to 80 degrees and it wasn't hot. Ideas? I researched some and that's a symptom of a leak....