Temp / Thermostat Q's

[Masterd]

Ok Ive got a question on a '93 EX. It seems that when I drive, the temp guage never reads above the first tick mark on the NORMAL sweep, if its a sunny day, maybe a little into the normal range.

My question is, does this sound like the sender or the T-stat sticking open, because even when the guage reads below the normal, I can still get heat from the heater.

Thanks,

Masterd

 

[ma96782]

Mine used to do that. Since I was doing stuff I changed the t-stat and anti-freeze along with the sender.....now it reads between O and R.

The below elec. tests are the, "cheap test methods"........there are more sophisticated tests with values, that can be run.

Test for the dash thermo gauge................disconnect the wire from the temp sender unit.........KOEO...........ground that wire.........it will peg the gauge on the hot side............disconnect from ground and it will return.

Sender unit.........if you suspect it..........replace, replacement is cheap.

Aloha, Mark

 

[BrooklynBay]

Those senders cost about $7 in AutoZone. I've replaced them before. Make sure that you get the correct one.

 

[Masterd]

Hopefully its either the sender or the guage, because I do get heat, but at 272k I dont think its ever had a Tstat

 

[marragtop]

You should replace the Tstat as it's part of normal maintenance. If it sticks closed on you, you will have an overheat problem with potentially bigger issues. Make sure you get the Oring gasket with the new tstat.

 

[pugsy]

Mine had same problem and still got heat but didn't read much past the first notch. I just changed the t-stat and it was fine after that, but now it's nice and cozy! The rubber o-ring came with my new t-stat. Didn't change the fluid or anything like that either.

 

[Masterd]

Yeah I agree that it needs to be taken care of. Its just that its been underheating so Ive not been too worried as of yet.

Is there a guide on how to replace it?

 

[pugsy]

There's some good threads on here on how to. It's really easy and just need regular tools. It's just in a tough spot, you have to take off the serp. belt and air hat to get to the 3 bolts. But that's all that you need to do, remove three bolts, take out old, tstat, put in new one and rebolt, just make sure the new one has the rubber gasket on the t-stat.

 

[marragtop]

Pugsy is correct. Make sure you take off the serp belt, as it makes it much easier to get to the bolt (10 mm I think) near the tensioner.

 

[Bruce Thompson]

Masterd,

Before you go and replace the sensor and Tstat you might want to check the coolant and pressure to make sure there is no leak. My 94 explorer did the same. Comes to find out I had a small leak. Do you have plenty of pressure and coolant in the reservoir?

 

[Masterd]

A few weeks ago I found a small leak at the top left of the rad. where the metal line goes into the top, but I tightened it and its gone, I haven't leaked any coolant since.

But as an example, if the truck is heated to the first notch of the normal sweep area, and I go down a hill using little throttle, the gauge goes back to cold, until I start putting load on the engine and it slowly heats back up

 

[StillKicken]

Does it take a long time to warm up when you first turn it on? That would be a good indication its stuck open.
How long have you had this truck? A while? Might not be a bad idea to flush system and replace t-stat. Cheap PM.

 

[Masterd]

Doesn't seem to take too long to warm up the little bit that the guage shows

 

[LXNavajo_94]

I recently went through the same thing my self. I replaced the thermostat and the sender. I wasn't sure which one was bad. the sender only cost like 4 bucks and the thermostat was like 6. Either way its fixed now but it did take a bit of burping to get all the air out of it.

 

[93TwotoneXLT]

Make sure that you install the thermostat with the vent valve in the 12 o'clock position. If installed incorrectly it will lead to the guage reading erratically(not crazy eratic, but rather a slow up and down motion) Hope this helps

 

[Masterd]

thanks for all the feedback

 

[StillKicken]

Where exactly is the sender? I have never replaced this before.

 

[old mechanic]

If it throws heat I wouldn't worry too much about it. My 92 EX doesn't read much from the cold line and I get great heat out of it. But a new "no fail thermostat" would be a good up grade.

 

[Masterd]

A no fail thermostat? Ive never heard of it.

 

[BrooklynBay]

I think he's referring to the one with the weep hole.