Getting Warm While Driving

[MafiaMustang]

I must look to the Mustang gods once again for advise. I just had my lower end re done on my 1990 GT and While i'm Driving after about 30 minutes or less my car is showing a temperature reading about the N on the stock gauge. When I'm at home just running the car in the garage it doesn't seem to get hot at all. Here is what I have done to the cooling system. I have a Cobra/GT40 upper and lower intake. Accufab 75mm throttle body with no coolant spacer. I have a 3 core radiator, 2 Electric fans that run when the car is on. I have replaced the thermostat multiple times and 2 different water pumps. 1 high flow and the other was a stock replacement. Anything else just ask. My question is what would cause a car only to get hot while driving and not in the garage?

 

[General karthief]

Higher rpms = more combustion events = more heat
But then you knew that
Could be your lower radiator hose collapsing at higher rpms
Restricted air flow through radiator
Too much antifreeze (highly doubtful)
A prius stuck in your grille
But seriously, stock gauges are finicky and thermostats don't always work like they should. I test all my thermostats on the stove (only when SHE's not around) some open later than others. Get a mechanical temp gauge and zip tie it to a wiper arm and match it to you stock gauge
195 = M
200 = A then you know about what your stock gauge is telling you

 

[jrichker]

Is the air deflector on the bottom of the radiator support present and in good condition?

 

[mikestang63]

thicker radiator= less air flow
what fans are you running
is the belt running the water pump clockwise or counter clock wise. the backside of the belt should be ridingon the water pump pulley
did you burp all the air out of the system

 

[Mustang5L5]

I wouldn't hold any faith to what the stock gauge is telling you. Got to put a real temp gauge and see what you are actually running in degrees.

With a stock tstat on an EFI engine, you want to target 195-200 degrees or so.

 

[MafiaMustang]

No to the Air Deflector. I have however removed the A/C condenser so the radiator should be getting all the air. I did burp the system using methods I found online. My Theory is the Thermostat is not releasing a is stuck shut. The upper radiator hose feels like it has a ton of pressure on it after warming up.

 

[jrichker]

You can chase rabbits and throw money at a problem, or listen to reason. The air defector directs the air up into the radiator at highway speeds and is critical to managing airflow into the radiator. If you think that you are smarter than the engineers who studied the aerodynamics and airflow in wind tunnels, you have rude awaking coming to you.

I looked at the picture of the engine in your car, and I already saw one nono - the air filter next to the radiator and fan -a hot air intake.
A cone type filter located inside the engine compartment is almost sure to have surge problems due to the hot, turbulent airflow around it.

Don't do this: it is a big NO NO.

 

[General karthief]

Jrichker is right about the air damn under the radiator but it actually has two jobs, think of it like an inverted spoiler, it allows the air coming through the radiator into the engine compartment to escape under the car also.
The thermostat can be tested in a pan of water heated on the stove using a meat thermometer, just don't tell the cook!

 

[a91what]

The airdam is very important, in fact it has such a large impact that road course racers install oversized airdam on there cars. This creates a negative pressure under the car, this pulls the car down onto the road no giant wing needed.

Case in point.

the air deflector used here is from an early ranger/bronco