[aventuragrun metallic]

Everyone:



Since this my first post, I wanted to thank the creators and all the contributors to this site. The info on this site is worth a million.



My temp guage has started to act funny. I think it has to be electrical since it will rise to hot and then drop down to cold in a second or two. I don't think the car is runnig hot. Fluid level looks normal and the fans do not kick in. Also, my speedo will not register until I am rolling at about 5 to 10 mph and then it jumps up to speed and then performs normally.



Has anyone else experienced this issue? Do you think there is a connection between the two?



Thanks.

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[flash]

most likely either a bad ground at the cluster, or a loose multi-pin connector - there are 3 at the back of the instrument panel

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[Tom in Austin]

Another thing worth checking are your ground points. Bad grounds cause bizarre effects on our electronics. Good news is, they're easy to clean up (check the wiring diagram for locations) and can solve a variety of odd behavior.

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[rustech]

The problem is definately going to be with the grounding at the cluster. You will have to remove it and clean all the contacts. I've had to go into my cluster for my temp gauge already, but now have to go in there again to fix the fuel level gauge. Use an eraser on the back of a pencil to clean the contacts. A small film of dialectric grease afterwords will help reduce oxidation. Good luck.

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[968Z]

I had the same problem in mine. I just gave it a good "whack" with my fist and it has worked fine ever since! <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[Anchorman]

I also am suffering from a crazy temp gauge. At times it will go to the bottom of the top red line, and then drop instantaneously to the 8:00 white line. Really bugging me. I'll have to get around to the R&R.

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[S_Cal968]

Re: temp: Keep in mind before the thermostat opens the gauge will indicate a high reading in the 10 or 11 oclock position. When the thermo opens the temp will drop rapidly - this is a normal cycle with most water-cooled engines.



Also most speedo's are not accurate @ ~5 mph and tend to bounce. This condition may worsen if the cable is not properly lubricated.

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[flash]

some "cycling" is "normal" but the thermostat point of the stock thermostat is much lower than the "10 o'clock" position - it is actually at just above the 8 o'clock line, but the needle may get a tad higher before it starts to come down until a bit past that - 9 to 9:30 is ok - if you are regularly hitting the 10 o'clock line under normal driving conditions, in normal climates, there is a problem with the effeciency of the system, and it should be looked at - that would equate to 212 degrees, which is well beyond the normal operating temp - flushing the system, replacing with phosphate free coolant and distilled water, and bleeding it properly may resolve it - this should be done every year - also, check the reservoir cap - if it no longer holds proper pressure, the system will run hot



what cable?

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[S_Cal968]

[lol] Bob that was an approximate position - I didn't think he'd go out and index his temp gauge - sheese... To re-emphasize my point, the temp gauge will go up before the themostat opens. Some may see this as an issue when it really isn't. Hmm I think mine transitions at 9:38 and 30 seconds <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" /> Actually mine does go past the 9 position which is well within the operating range and before the 2nd line on the gauge. And, I never claimed it stayed up there...



Perhaps I was thinking of one of my other cars when I mentioned the cable[?]. And, now that I think of it, I don't recall a speedo-cable when I pulled the cluster. However, I still doubt that it's accurate at ~5 or 160mph regardless of design.

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[flash]

lol - no worries - my point was really because of the 11 oclock reference - it should NEVER go there under anything resembling normal driving, and really should not even hit the 10 line - if it does, there is a problem, and it is usually the above mentioned items - a small bit of clogging (no, not wooden shoe dancing) or a weak reservoir cap (no, not your fishing hat) can easily result in an increase in guage swing



no worries there either - i thought perhaps you had found something i needed to service - everything i had found said the speedo was purely electronic, with no cable



no, it is likely not accurate at either one of the ends of the guage - i even have one magazine's test which showed it quite a bit off by the time you got to the top end (over 10mph off)

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[aventuragrun metallic]

Thanks to all for your input.



Maybe I'm not running as efficiently as I thought. I live in So Cal so the temperature is normally +/- 70 degrees. If I sit in traffic, the guage sometimes hits 10 o'clock but returns to 9 o'clock once I get rolling. Also, on warmer days, the fans will kick in for about a minute after I shut down.



I think I will have my cap and thermo checked out and get the system flushed. One mechanic that I spoke with told me that the radiator should be completely replaced periodically. Is this true?



Do I need to remove the instrument panel to clean the ground points or can it be done by sticking my head under the dash? Of course, I will try 968Z's "good whacking" solution first.





Thanks again.

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[flash]

perhaps rolling it by here makes sense - i could certainly walk you through it - besides, that would give me a chance to twist your arm to come out to some of our events

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[sbobosi]

I have a similar issue. My temp gauge bounces around like a pinball for a few minutes upon start, alternating between a moderate temperature and pegged deep into the danger zone. Then it levels off at a nice comfy temp around the 8:00 position for the rest of my drive. I am going to do a coolant flush and fill today and see if it helps. If not, time to yank the instrument cluster, I guess.

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[prj24149]

I have a similar issue with my volt gauge. It has been dropping slowly over the last few months. Use to be always at 3oclock or about 13volts now it stays at or just barely above 12v. I've check the battery terminals with the car running with a DVM, it reads 13.5v.

Sounds like I need to clean the contacts on the instrument cluster or clean the ground point also. Anyone know which ground point and were it is?

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[sbobosi]

Ok, so I have cleaned five grounding points, including the two found under the fuse box. Still, my temp gauge is haywire. Also have cleaned the contacts behind the instrument cluster. All this after my mechanic replaced a sensor. Still at square one. Starting to think I may need a new cluster. Thoughts?

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[flash]

if this problem is limited to one guage, then i tend to think it is in that circuit somewhere - likely a defective part



in the case of the temp guage, i would suspect the thermostat or the sender, new or not



in the case of the voltmeter, it is likely battery, alternator, or ground related - progressively dropping voltage readings are usually a sign of either a low specific gravity in the battery, or a shorting field in the alternator - it can also be building resistance in a ground or main power cable, but you should see signs of it either in brittle cable, or corrosion - i would carefully inspect the cables, and replace any showing cracks or breaks in the housings - i would also hydrometer check the battery and then load test the alternator if those do not indicate the problem

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[sbobosi]

So I also suspected it would not be the cluster. However, the garage that I bring my car to and initially diagnosed the issue as a sensor, proceeded to say it was the cluster when the sensor didn't fix the issue. I declined to have the work done, as I was unconvinced of their diagnosis. Looks like I need to find another mechanic to take a look. I really like this garage too. They are very fair and have done solid work for me. Still, no one is infallable.

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[flash]

true enough - aslo, many shops just aren't good at diagnosing stuff like this



i'm not saying that it isn't the cluster, but i would tend to suspect either the items in the circuit that are talking to the guage, or the thermostat - a sticky thermostat will do what you are talking about



the first thing to do is use a laser temp guage to determine if the guage is reading accurately or not - this wil tell you if it is in the cooling system, or the guage circuit



if the former, it's likely the thermostat - if the latter, it's likely the sender (these things are sometimes bad right out of the box) or more likely the wiring to it - apply either voltage or ground (i haven't looked to see which this one wants) to the wire to find out

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[sbobosi]

Interesting stuff. I know the garage used temp gauges on the engine when I brought it in buried in the red, and the engine temp was perfectly fine. I will have to check the wiring tomorrow.

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