My car wont heat up on highway

[bdazzgt]

I installed a new radiator and electric fans because my old one was causing overheating problems, now on the highway the temp wont go over 150-160* until i get back in town then it will heat up to 190 at idle, but as soon as i hit the highway back down it goes. I have a 180* thermostat is this too low should i go back to 190? Doesn't this keep me from going to open loop and cause the car to run pig rich?

 

[RangerJoe]

Your thermostat should keep coolant in the engine until it hits the 180 degree mark, then open. Sounds like maybe you have a bad thermostat.

 

[Mustang5L5]

Sounds like bad stat to me....or installed backwards.

 

[bdazzgt]

its a 180* mr gasket it worked fine before in town but once i got on the highway the old radiator just couldn't keep up ran 210-215 in town it ran 190's. now with the new radiator it doesn't make sense because the car runs a steady 190* in town, but once i hit the highway it just goes down to 150-160*

 

[HISSIN50]

It's a bit low for a balanced stat. They begin to open before the rated temperature. Freeway cruising in mild temps at 170* on a 180* balanced stat is about normal.

The car will be in closed loop at the temps you're seeing - that's a function of the O2's lighting off, not coolant temps. If the coolant temps get too low, it affects the trim but it's still CL.

 

[bdazzgt]

so what would u recommend me do hissin?

 

[HISSIN50]

Where is the gauge sender located for the gauge you're using?

 

[bdazzgt]

in the waterjacket closest to the firewall on the drivers side

 

[HISSIN50]

I had a feeling it was, hence asking. That's an inaccurate location. The lack of coolant flow back there means the gauge can read low. The stock location is the most accurate.

 

[bdazzgt]

so should i switch the two, the fan relay is in the front and the gauge is in the back, if i switch the two then the electric fan will be off correct?

 

[HISSIN50]

You're correct. The thermostatic switch on the fan controller would need to be goosed to accommodate the new location. This is not real great. That rear port you're using for your gauge is only really useful for keeping a stock gauge functional (the stocker is fairly inaccurate so the lack of water flow really doesn't matter).

I think it's better to have the fan switch in the t-stat housing or install a metal union in a cut coolant hose (Autometer, for one, makes these for radiator and heater hoses), and put the fan switch in the new location.

 

[bdazzgt]

Can i drill and tap the thermostat housing for this?

 

[HISSIN50]

You can but it might be easier to buy a new housing that already has a 3/8" NPT hole already tapped. They're around 10 bucks at the parts stores.

 

[bdazzgt]

Update:
Well i bought the new water-neck, switched the gauge back to the front of the intake, fan controller back in water-neck, now running down the highway the car runs around 210* cruising then around 215 and keeps rising with the ac on. i was like WTF that was the whole reason i bought the new radiator electric fan setup so i could run the a/c while running down the highway. I took the thermostat out and put it in water and it opens correctly, starts at 175ish with a candy thermometer its a Mr gasket 180* thermostat. I flushed the system put in nothing but distilled water/antifreeze. I'm running out of options besides shooting the car several times, speed holes make it more aerodynamic right?....

 

[ID89GT]

Are you bleeding all the air out of the system?

 

[bdazzgt]

I burped it again today, but the temp rises steadily not rapidly and goes down with the thermostat opening, its mainly at highway speeds for distances which doesn't make sense, normally thats the radiator not being able to disperse the heat, the only problem is that the radiator is brand new. thats why i cant figure it out

 

[tb9050lx]

what are you using for a gauge ?

 

[bdazzgt]

aftermarket mechanical gauge, just took it around town, it runs great at idle, but just slowly creeps up and up, im going to go postal here

 

[HISSIN50]

If you have a GT, is the air dam in place?

What fan are you using?

 

[bdazzgt]

air dam is in place
Hissin* this is the kit i bought and installed, everything you see there is in my car, except i have a mr gasket 180* thermostat
1986-93 Mustang 5.0L Complete Aluminum Radiator Upgrade Kit for Manual Transmission at LRS - Same Day Shipping!