Higher than normal temp

[1988ma70supra]

Hi, My car has been showing higher than normal temperatures when idling. It never overheats but comes about 3/4 of the way up the temp gauge. The temp doesn't just spike up when i idle but gradually goes up after it sits for a min or two. What i have noticed is that when it does this and i gradually step on the gas to raise the RPM's the temp goes back down to its normal temperature. I personally think that this is the thermostat sticking but wanted to hear from you guys for some feedback. :biglaugh:

Thanks in advance

 

[DBN]

Do you have a fan shroud?

 

[Zumtizzle]

Highly Doubt it's the shroud.

Things to check; Radiator, Thermostat, Fan Clutch/Fan, Leak/Air in system, Coolant Mixture, Water Pump.

 

[mkt]

havin the same problem. ill check into those suggestions

 

[jdub]

Highly Doubt it's the shroud.

Things to check; Radiator, Thermostat, Fan Clutch/Fan, Leak/Air in system, Coolant Mixture, Water Pump.

No shroud and a bad fan clutch will do it

A sticking T-stat will cause a pretty rapid spike in the 1st 5 min of driving. It could be sticking partially open, but not likely.

 

[noel]

thoses dam t-stats! i wish we didnt need them

 

[92nsx]

I vote bad clutch on fan or bad T-stat. When I finished My build this past spring I had the same thing. It would go 3/4 full temp gauge then bam, it would drop, right to normal in 2 seconds.

To fix it, I went to toyota and bought a new OEM t-stat & gasket ($21) then replaced the auto zone special one with the OEM and problem fixed. Temp sits right about 7/16 (just under 1/2) way up and dosent move now.
I learned (if that is the right word) the hard way not to cheap out on a thermostat.


<------ no fan shroud or under tray ***hides from flying objects headed my way***
Maybe some day they will get installed, stupid IC piping takes up to much room, lol.

 

[jdub]

Most of the problems I've seen with a T-stat is with the guy that owns the car

BTW - cutting the jiggle valve off the T-stat (leaving a small hole at the 12 o'clock position) is a very good thing to do.

 

[1988ma70supra]

To fix it, I went to toyota and bought a new OEM t-stat & gasket ($21) then replaced the auto zone special one with the OEM and problem fixed. Temp sits right about 7/16 (just under 1/2) way up and dosent move now.
I learned (if that is the right word) the hard way not to cheap out on a thermostat.

I did check for leaks and don't seem to have any. I do remember changing out the thermostat a while back and i think i might have gotten one of those Autozone stats. :nono: I do have a fan shroud and I have changed the fan clutch before. I'm don't remember if it was an Autozone part:dunno: How can you tell if it has gone bad?

Thanks for the quick replies

 

[jdub]

The problem with places like AutoZone is you might have got a GE vs a GTE fan clutch...there is a difference. The GTE clutch is much more beefy to drive the 10 bladed fan on the turbo cars.

On a cold start, you should here the clutch howl for 45-60 sec until it gets to the correct temp.

Get a Toyota or Stant SuperStat...cut the jiggle valve off and install with the hole up top.
I test every T-stat (even new ones) like this before I do anything:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=CO&P=8

 

[1988ma70supra]

BTW - cutting the jiggle valve off the T-stat (leaving a small hole at the 12 o'clock position) is a very good thing to do.

Just out of curiosity what would cutting the jiggle valve do?

I just took a look and it was the thermostat. Changed it out with the super stat and everything seems to be back to normal.:icon_razz

 

[jetjock]

It opens the hole to better allow air to pass. On the other hand with it gone there's no jiggling action. In either case if it's not at 12 o'clock it's useless...

 

[1988ma70supra]

It opens the hole to better allow air to pass. On the other hand with it gone there's no jiggling action. In either case if it's not at 12 o'clock it's useless...

I installed it the without the jiggle valve and at the 12 o'clock, like advised, and i also noticed that the temp takes a little longer to reach normal temp. Does this make it run cooler too? :dunno:

 

[noel]

the t-stat houseing does that come with a gasket or something mines likes

 

[jdub]

I installed it the without the jiggle valve and at the 12 o'clock, like advised, and i also noticed that the temp takes a little longer to reach normal temp. Does this make it run cooler too? :dunno:

It does take a tad longer to reach ops temp, but that is fine. Your car should run close to the T-stat rated temp, assuming the rest of the cooling system is in good shape.

 

[1988ma70supra]

Thanks for all the help and new info :bigthumb: