My car wont heat up on highway

JustA5.0 · Jun 9, 2011

Is the FC switching the fans on/off properly?

HISSIN50 · Jun 9, 2011

This is kinda weird. Just to recap, the vehicle was thought to run cool and now turns out to run hot. The only change between the two was moving the temp gauge sender and possibly removing the t-stat? Is the gauge known to be good?

Are you sure the stat is opening all the way? I know it's a pain to check or swap out, but it's a relatively cheap variable to try and remove, as other options are more expensive.

bdazzgt · Jun 9, 2011

fans come on at 194* and pull air in they are both wired correctly. When I installed the radiator kit i took the gauge out of the stock position on driver side front and placed it in the back of the intake by the firewall, then i put the fan switch where the stock gauge was. After reading your post about lack of water flow to the back water port i bought the thermostat neck with a threaded hole in it. i then switched the fans to the waterneck and the gauge back to the stock place in the front of the intake. when i switched the waterneck i checked the mr gasket 180* thermostat to make sure it opens properly and at correct temp and it does, now it might not open all the way i dont know how to really measure that. i never changed the thermostat out, now with that being said the gauge is a brand new mechanical gauge? i know new parts are known to be bad but at the same time i do realize that there isnt a whole lot of moving parts known to break in a gauge. i hope this clarifies everything up. now does anyone think i would benefit to switch to a 192* ford thermostat and maybe keep the water in the radiator longer?

2000xp8 · Jun 9, 2011

With a radiator that size, the coolant does not need to be in there longer.
Forget the ford thermostat, they open late and very slow, probably is not completely open until past 200 degrees.

bdazzgt · Jun 10, 2011

what would anyone recommend?? im lost on what to do

FastDriver · Jun 10, 2011

You will not benefit from the higher temp thermo unless yours isn't working.

Your problem sounds like a bad water pump.

TRICKYGT · Jun 10, 2011

My 2c would be to change out the stat. Mine went bad in my truck when I changed out the coolant. Not the same car but similar issue until it went completely slap bang in the middle of winter. Heaters make NY winters bearable at best.

bdazzgt · Jun 10, 2011

FastDriver said:
You will not benefit from the higher temp thermo unless yours isn't working.

Your problem sounds like a bad water pump.

How would i check this? the weep hole is dry even during idling, i will buy a new thermostat tonight and try that option and i will go from there

FastDriver · Jun 10, 2011

Maybe someone else that's smart can tell you how to check without replacement, but honestly waterpumps aren't expensive and come with a lifetime warranty. So, I'd just change it out and see what happens.

bdazzgt · Jun 10, 2011

true i guess i will replace it, ive changed everything else so why not? i do have a few extra pumps laying around from my last rebuild

ratio411 · Jun 10, 2011

Could your probe in the stat housing be affecting the movement of the stat itself?

What is it doing now, I am a bit lost.

It is running hot on the road now? Simply from moving the temp sensor?

I am going to use the shotgun method to point out the high points of cooling in my mind:

Fan shrouding is important around town.
Lower radiator hose must not be soft, and should have a spring to keep from sucking shut and cutting off water flow on the highway.
Fan is not required when traveling faster than approx 40 mph.
Any air deflector placed stock under the radiator must be in place.
Water pumps are only bad when the bearing goes out or something physically BREAKS.
The bearings will either make a heck of a noise, or (more often) cause the weep hole to leak.
The impeller has to break off otherwise for the water pump to stop pumping, and it will stop totally.
Radiator cap must be on tight and hold pressure. The more pressure, the better cooling, but the harder on possible leak points in your system.
Air in the system is no good.

I would look at simple things first.
I also wouldn't sweat where the thermoprobes are. The rear of the engine would be hotter than the front if the flow wasn't the same.

Also, water flow that is too fast will not remain in the radiator long enough to dissipate heat.
This is why you should never run without a stat.

FastDriver · Jun 10, 2011

ratio, I'm with ya on most things. Maybe you're right about the waterpump, but I'm sure and it sounds like he's done everything else.

That, "too fast to dissipate heat" is a myth, though. The faster the water flows through the radiator, the hotter the water in the radiator is on average. This means that the difference between ambient temps and radiator temps are greater, which increases heat transfer, not the other way around. The reason you need a t-stat is to keep the motor from running too cold, and to allow the motor (and the heater) to warm up more quickly after initial start.

90stang5speed · Jun 11, 2011

I would agree with ratio411 about the T stat because I had it happen to me. In my old bronco the T stat failed. it was early spring so I thougt I would just take the T stat out & replace it in the fall before I needed a heater. On short trips it would never reach operating temp but, after a few hour drive & then getting stuck in trafic caused by a wreck up the road, the truck actually started to over heat. I also had a buddy who had water pump blades brake off & cause over heating without leaking out the weap hole. He did a radiator flush just as a preventive maintenance and then had the pump failure. Not sure if one caused the other or just coincidence. If you have an old pump laying around from another build, you could swap it out as an almost free test. just fill it with water & if that was the problem, then go buy a new pump & antifreeze. good luck and please post what finally fixes it for you.

bdazzgt · Jun 11, 2011

ratio411 said:
Could your probe in the stat housing be affecting the movement of the stat itself?

What is it doing now, I am a bit lost.

It is running hot on the road now? Simply from moving the temp sensor?

I am going to use the shotgun method to point out the high points of cooling in my mind:

Fan shrouding is important around town.
Lower radiator hose must not be soft, and should have a spring to keep from sucking shut and cutting off water flow on the highway.
Fan is not required when traveling faster than approx 40 mph.
Any air deflector placed stock under the radiator must be in place.
Water pumps are only bad when the bearing goes out or something physically BREAKS.
The bearings will either make a heck of a noise, or (more often) cause the weep hole to leak.
The impeller has to break off otherwise for the water pump to stop pumping, and it will stop totally.
Radiator cap must be on tight and hold pressure. The more pressure, the better cooling, but the harder on possible leak points in your system.
Air in the system is no good.

I would look at simple things first.
I also wouldn't sweat where the thermoprobes are. The rear of the engine would be hotter than the front if the flow wasn't the same.

Also, water flow that is too fast will not remain in the radiator long enough to dissipate heat.
This is why you should never run without a stat.

ok the car is running around 210* without the a/c on with a new 180*thermostat, and the complete radiator kit posted previously. I put a new motor in the car and the stock radiator was not sufficient enough to cool properly so instead of piecing a kit together i bought the entire kit (radiator, fans, hoses, clamps, relay, tstat, shroud) from 50 resto. All air dams are in place and everything is tight. For the electric fans i only had two options for the temperature switch placement, the front of the intake and the rear of the intake on the drivers side. I took the sending unit/cable for my mechanical gauge and placed it in the rear intake hole that was previously plugged then put the fan controller in the stock location in the front. Initially i did not think the car was heating up all the way, which is why i made this post. Hissin50 posted that the gauge was not reading properly due to the lack of coolant flow at the back on the intake and suggested that i purchase the coolant neck with the 3/8'' hole already in it for the fan switch and put the mechanical gauge back to the stock position in the front of the intake. I did just that, now the gauge reads correctly only to find out that the car is running hot without the a/c even on. I took out the thermostat and boiled it to make sure it opens, which it does, now question is does it open all the way. I am flushing the system as we speak, and will post what i find out about the thermostat/waterpump situation. I am running out of ideas here

FastDriver · Jun 11, 2011

Have you visually ensured that fans are coming on when you want them to (maybe 200 with a 190 shut off)?

bdazzgt · Jun 11, 2011

well changed the thermostat/waterpump/ and changed all the hose clamps with no luck, the fans turn on at 194* and off at 178*. it seemed to cool better at idle but still the same temps on the highway. has anyone used the water wetter with good results?

FastDriver · Jun 11, 2011

Damn, man. What kind of radiator is this thing? You aren't losing water are you?

bdazzgt · Jun 12, 2011

1979-93 Mustang Aluminum Radiator for Manual Transmission by Mishimoto at LRS - Same Day Shipping!
1979-93 Mustang Aluminum Fan And Shroud Kit by Mishimoto at LRS - Same Day Shipping!
I replaced all the hoses last night with new hose clamps, I'm stumped i dont know what to do with it. it builds plenty of pressure, and no water loss that i see i even checked the oil....

P51MustangFreak · Jun 12, 2011

warm up the car with the rad cap off and watch the coolant for flow as the thermostat opens.what is the overbore on the engine.

2000xp8 · Jun 12, 2011

Try putting the stock shroud and fan clutch on, maybe that shroud on your fan setup restricts the airflow. I know we discussed the fans before, just doesn't appear to be an efficient setup.
I just can't see how a shroud that flat could funnel all that air out properly through those 2 fan holes at speed when you are cruising, the stock shroud pretty much lets air through at will on the highway, that thing surely doesn't.

My car wont heat up on highway

JustA5.0

Member

HISSIN50

"How long does it take to get help in here?

bdazzgt

I had to jerk off the cable to get it to stop.

2000xp8

bdazzgt

I had to jerk off the cable to get it to stop.

FastDriver

I was uncomfortably high & wearing a helmet

TRICKYGT

New Member

bdazzgt

I had to jerk off the cable to get it to stop.

FastDriver

I was uncomfortably high & wearing a helmet

bdazzgt

I had to jerk off the cable to get it to stop.

ratio411

FastDriver

I was uncomfortably high & wearing a helmet

90stang5speed

Member

bdazzgt

I had to jerk off the cable to get it to stop.

FastDriver

I was uncomfortably high & wearing a helmet

bdazzgt

I had to jerk off the cable to get it to stop.

FastDriver

I was uncomfortably high & wearing a helmet

bdazzgt

I had to jerk off the cable to get it to stop.

P51MustangFreak

New Member

2000xp8

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My car wont heat up on highway

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