78westfalia

Today the outside temp was 80F. Drove 25 miles and the coolant and oil temps did not go up at all. 2 miles from my destination, the oil temp came up to between the second and third lines. Coolant stayed the same. When I got there, both upper and lower radiator hoses were hot and the fans were cycling. I pulled the cap off the reservoir and dipped a thermometer in. It read 195F. Is this correct? If the sensor or guage for the coolant is bad, why would the oil temp read low?

Occasionally, both guages read fine, but it stays cold much more often than not.

I've sniffed the coolant tank and no head gasket leaks detected. I've bled and burped the system umpteen times. I just recently replaced the thermostat with a Behr when I changed the WP & timing belt.

The car acted the exact same way when the temp was 5F. 5-10 minutes into my drive, the heater would blow very hot.

I'm trying to give as many details as I can. Any help would be appreciated. I like everything to be working the way it should.

Bmthorn

<a href="http://www.google.com/search?hl=en&client=firefox-a&channel=s&rls=org.mozilla%3Aen-US%3Aofficial&hs=MTL&q=90+celsius+to+fahrenheit&bt nG=Search">http://www.google.com/search?hl=en&amp;client=firefox-a&amp;channel=s&amp;rls=org.mozilla%3Aen-US%3Aofficial&amp;hs=MTL&amp;q=90+celsius+to+fahre nheit&amp;btnG=Search</a>

austinado16

Clearly, you don't have a mechanical problem, so you could say either the wiring to the gauges is the problem, or the senders are the problem.

But to me, it's unlikely both sendors (located in different areas) would be bad at the same time....and you do sometimes get a reading.

Might be worth buying a little dual watt soldering pensil from RadioShack for $8, pop the instrument cluster out, take the back off it, and remelt the solder connections at the back of those 2 gauges.

78westfalia

Not a bad idea. I did have the instrument cluster out last week to change the ignition switch. I checked the back of the coolant guage and it looked fine. I did not take the back of it apart though.

austinado16

Sometimes it would read smoking hot in a matter of minutes after starting the car, and other times it would be dead and have no reading. Finally cured it by cutting the plug-in connector and a couple inches of wire off, and butt splicing on a new connector. But I initially solved it by moving the wiring there at the sensor around while the engine was running and watching what the gauge would do.

Just Me

rarely guage, but possible.

Grant

rmccomiskie

I suspect the sensors. Operating temps seem to be okay. Climate control code 51c reads normal, 90C but gauge is very low. It's just the gauges that read incorrectly.

oilcan97

Currently experiencing something similar in my 97 A6Q wagon. Coolant temp sensor was replaced last week for 2nd time. Replaced 1 year ago due to unresponsive coolant temp gauge and gauge worked fine up until a month ago. After just re-replacing coolant temp sensor both coolant temp gauge and oil temp gauge remain malfunctioning, oil temp gauge won't ever go past "10 o'clock" marker, coolant temp gauge occasionally rises to ideal "11 o'clock" position but usually sits at 10 o'clock or below on gauge. Addtionally, a strange intermittent clicking sound beneath steering wheel that began last month will cause radiator fans to engage and they remain stuck on until further clicking beneath steering wheel will sometimes follow with fans disengaging, or sometimes not.

The clicking sound from beneath wheel also dims interior lighting on dash/climate control/radio display, headlights, battery gauge flops back and forth, climate control blower fan will weaken. Load reduction relay was replaced last week in hopes of fixing clicking+related issues, didn't work. So I posted a thread about those issues few days ago, was told likely cause was ignition switch failure---which makes sense after reading everything I could about similar symptoms others have posted that were attributed to faulty ignition switch.

But would igniton switch contribute to the malfunctioning of coolant temp gauge+oil temp gauge? The clicking sound beneath wheel has some relation to engaging the radiator fans, but unsure how it all relates to the simultaneous dual coolant/oil temp gauge malfunction.

This user described something very similar a few years back. He replaced the ignition switch and some of the electrical problems were fixed, but the coolant+temp gauges remained a problem. Unfortunately he never reported back on final solution.

https://www.audiworld.com/forums/aud...issue-2767453/

Any theories if all my symptoms are interrelated(ignition switch) or separate? And if separate as I suspect has anyone tackled the multi gauge failure aspect of what I'm currently dealing with?

computrtutr

It might be worth it to pop out the cluster and check the wiring from the connector pins to the wiring on the outside of the firewall- look for a pinched or partly broken wire. You might even check resistance along that wire and compare to a known good wire- if you can do it fast enough, do it when the engine is hot and do it when cold. Check along the length of the wire but you might also check against ground for continuity- this would tell you if something is pinched or shorting out and doing it when hot would give you a comparison between when working vs not. Check wire routing and looms for melting while you're at it.
I would also replace the ignition switch if nothing comes from the above testing- someone asked why the ignition switch, so here is what I think: it supples power to the cluster so if a region of the switch contacts is failing, maybe part of the cluster is not working due to no power- that would explain two gauges not working. If the switch were failing perhaps the heat coming up through the car causes it to expand enough internally to make contact, activating the gauges. Just a thought.