My temp gauge hit max for like 1 second, whats the go?

[Jackel]

I was driving along after filling my car up and looked at my temp gauge and it bounced from 1/5 to over 4/5 max temp for like one second and went back down. What the go with this? i shat myself when it went up cause i just put ron98 fuel in for the first time since i've had it a though that could of been the only reason or just a voltage spike for some random reason.

Tell me not to worry it won't happen again?

[leso]

if it's an electrical temp gauge..??? when the wire to the sender unit is earthed out, the gauge will read max...thats how we used to test if it was the gauge or the sender causing the gauge to not work..same applies to some fuel gauges etc.. Well at least the ones they made 20 years ago... so possible you have a intermittent short in the wire that runs to your temp sender... cheers leso

[Bananaman]

The only time i've seen this was when i had airlocks from just changing my coolant, but if you haven't just changed anything this is unlikely

[Dale]

I think leso is on the money. The wire is probably nicked somewhere and earthed onto the motor or chasis when the wiring moved a bit, ie. with acceleration or braking

[Jackel]

the gauge is the oringinal sitting in the dash so would be electrical, hope thats the problem, does anyone know where the sender for the guage would be? block?

[leso]

try the thermostat housing

[limmy]

, this is intersting, my mz21 done the same thing when i first filled my car up with 98 octane fuel, soon as i turned it on, the temp shot right up , it stayed hot for about 20 seconds, befoire comming back down to normal. i freaked out seeing the p00 doesnt like those sky rocket temps? after filling up again it didnt do it again. but soon as i turned it on after filling it up , it shot right up. but my problem had nothing to do with my gauge maybe just the fact sitting and idleing in really hot weather for 2 long. good luck

[CrUZida]

I've had a 7MGTE that would reach the top of the gauge after parking the car for <5mins.
After 30 secs of idling it would come down to normal.

But that was heatsoak.

[Talasas]

Mine did it a little while back for a second as well, I only noticed it with my eye on when the needle was on the way down. My vote is also for either air pocket or sudden earth.

Hasn't done it since.

[Negative Boost]

Yeh, i've had the same thing on a many of times during hot weather. Turn engine off for a few minutes. Turn ign back on and you can see the temp guage at the top! Turn on engine, 20 seconds later it was back to normal. Just the coolant getting extra hot after you turn your engine off.

[Jackel]

well i guess it was just the wire getting bumped, cause it hasn't happened again, i'll fill my car up with 98 again and see if it does it again, doubt it?

[H1TMAN]

yup mine did that, well actually it went insane.. up and down like a million times shortly after i got home the car was fine and didnt do it again... it just boiled lol

[o_man_ra23]

Could be a dodgy sender, dodgy wire, or a bit of crap in your coolant which is shorting the sender out. Try draining and backflushing the radiator and block (if you cant find an electrical problem - good maintenance to do this occasionally anyway). Also try replacing the sender (if you cant find an electrical problem)

Cheers, Owen

[Jackel]

ok it's done it about 5 times in the last two days and it's getting annoying. It will do it when i start the car early in the morning or when i i finish work or just driving. Would having worn valve stem seals cause this problem?

also is the temp sensor the one pointing towards the radiator cause i had a look at the thermostat and it's pretty dirty might squirt it with some degreaser?

thanks

[CrUZida]

Which ever the single wire one is.