Overheating issue. Pump maybe?

[93GtMustang50]

I searched the forums for an answer and I couldnt find this problem so here it goes:

How can you tell if a water pump is bad?

I've replaced every hose, added a fluidyne radiator, new 195 deg. thermostat/gasket, and replaced the worn out crank fan with a new crank fan and sometimes (not all of the time) at idle the temperature will slowly rise above normal on the stocker gauge to 3/4 of the way or more. At a normal operating speed it drops back to normal, at WOT is drops even more(a significant amount more). What are your thoughts as to what is causing this?

 

[Coast2CoaStang]

When my water pump went bad, there was coolant coming from the weep hole on the top of the pump.

Are you using a fan shroud?

 

[stang&2Birds]

Water pump's bearings and seals go. So, a bad water pump is one that leaks. A water pump impeller's blades get very little wear. So, a "bad" water pump isn't your problem.

Do you have under-drive pulleys on the car? What engine mods do you have? Are those temps with the AC running?

The Fox cooling is barely adequate for a stock engine. That's why Ford used a smaller water pump pulley for the '93 Cobra.

A higher flow water pump may help.
A smaller '93 Cobra water pump pulley should help. But, you may also likely need a shorter belt! That's why mine is still in the box. It's on my long list of "stuff to do when I get a chance".


PPI still sells the pulleys: $75 plus S&H. Yea, I also paid a lot for mine.
PPI | Engine | 1979-1993


1993 Cobra water pump pulley, genuine F3ZZ-8509-A over-drive pulley that accelerates water pump delivering greater coolant volume to 1979-1993 5.0L engines without cavitation issues, very limited quantities, new...view $ 74.99/each

 

[stang&2Birds]

BTW: As I remember, those pulleys have been sold out for a while. So, I was surprised to see them listed again. Then, after a Google search, I just found the posts by PPI below on another site:


'93 COBRA WATER PUMP PULLEY... THE LAST OF 'EM!!! We have a very limited quantity of brand new (NOS) 1993 Cobra water pump pulleys!!! These are genuine F3ZZ-8509-A pulleys that are impossible to find new or used!!! Order on-line or call ASAP as a sell-out is assured!!!

A sell-out is near... These have gone for over $100.00+ on eBay...

 

[93GtMustang50]

The car is very mildly modded. Full intake/Full exhaust/Fluidyne. I do not have underdrive pulleys, I do have a fan shroud/air dam and those temps are with the A/C off. Maybe the temperature sensor?

 

[mustangmutt]

If the car over heats or runs hot at idle, it is most likely an airflow problem. If you doubt the accuracy of the factory gauge, hook up an aftermarket one. If it is really overheating it will set a DTC 21 (I think). If the fan clutch is in good shape, you might consider running the Cobra pulley or installing the stock crank pulley.

 

[mustangmutt]

Or you could throw that rotating mass away and install a good electric fan. Free up a few more ponies.

 

[CDQICKGT]

You said you replaced the fan... How bout the clutch? Definetly a air delivery problem.

 

[HISSIN50]

I agree with getting a real gauge - the stock gauge was not intended for diagnostics.

Also agree with CD's sentiments - what kind of shape was the fan clutch in? Did you see silicone leaking out around the hub? Is the fan properly centered (longitudinally) in the shroud?

 

[93GtMustang50]

The clutch fan seems to be in good shape. There is still a decent amount of resistance when you spin the fan when the vehicle is off. There doesnt appear to be any silicone leaking from the hub. The fan is centered in the shroud. I also agree with getting the real gauge.

 

[stang&2Birds]

If the temp sensor was bad/off_a_lot, then he wouldn't see the temps going down at highway speeds.

A 93 Cobra pulley will not only increase the water pump flow, but also (as important, if not more) increase the fan rate.

Which Fluidyne radiator did you get? What's the width? IMHO, some aluminum radiators don't cool any better than the older 3-core. The FRPP aluminum radiator, or Summit general purpose aluminum radiator (for manual cars only) are the best/biggest you can stuff into a Fox.

Also, they make an "FRPP police package" thermal clutch. It has less slip at idle. A good thermal clutch has very little power loss on the highway. The thermal spring "opens", and there is very little HP loss (~3-4 HP) on the highway.


About electric fans, an electric fan requires an alternator and wiring upgrade. IMHO, one of the biggest benefits of an electric fan is that even at idle, the max air flow is available!

 

[BYRDPE]

If the temp sensor was bad/off_a_lot, then he wouldn't see the temps going down at highway speeds.

A 93 Cobra pulley will not only increase the water pump flow, but also (as important, if not more) increase the fan rate.

Which Fluidyne radiator did you get? What's the width? IMHO, some aluminum radiators don't cool any better than the older 3-core. The FRPP aluminum radiator, or Summit general purpose aluminum radiator (for manual cars only) are the best/biggest you can stuff into a Fox.

Also, they make an "FRPP police package" thermal clutch. It has less slip at idle. A good thermal clutch has very little power loss on the highway. The thermal spring "opens", and there is very little HP loss (~3-4 HP) on the highway.


About electric fans, an electric fan requires an alternator and wiring upgrade. IMHO, one of the biggest benefits of an electric fan is that even at idle, the max air flow is available!

i have a spare one of these. i've run one of these for ~6-8 years with great results. pm me if interested.

 

[93GtMustang50]

Which Fluidyne radiator did you get? What's the width?

About electric fans, an electric fan requires an alternator and wiring upgrade. IMHO, one of the biggest benefits of an electric fan is that even at idle, the max air flow is available!

The dimensions for the radiator is as follows: 29.94W x 17.243H x 2.4D. I'd like to get an electric fan, however I need to upgrade my alternator first. Eventually I will get around to that.


BYRDPE PM Sent.