Fan + Underdrives = Overheat?

Strype

Cuthbert catcher
Founding Member
May 11, 1999
61
34
104
Huntsvegas, AL
So I put an electric fan on & I put underdrive pullies on... nothing but problems since :notnice: I also had the crappy red antifreeze flushed out and green put in.

It took about 30 minutes of driving for it to get there, but it got up to about 225-230 and will not go back down.

I have a 16" fan and Mac pullies. I figure maybe the water pump isn't being turned as much and I need two 12" fans instead of one 16" :shrug: Maybe a 180 thermostat

Anyone had this problem :nonono:
 
I run BBK steel (black paint) underdrive pullies + a FFI overdriven alternator pulley with my Mark Viii fan and never had over heating problems.

Location (local temperature differences) might play a role in my experience though. But with my DCC my fan was never required to run at a high CFM rate. And my temperatures never passed the 210 mark.

How does the radiator look?
Thermostat in OK shape?
Radiator Cap (pressure test OK?)
 
srothfuss said:
I run BBK steel (black paint) underdrive pullies + a FFI overdriven alternator pulley with my Mark Viii fan and never had over heating problems.

Location (local temperature differences) might play a role in my experience though. But with my DCC my fan was never required to run at a high CFM rate. And my temperatures never passed the 210 mark.

How does the radiator look?
Thermostat in OK shape?
Radiator Cap (pressure test OK?)

I'm thinking Radiator Cap and Thermostat tonight. :nice: It usually stays about 210, but I revved it a couple of times going through a parking lot after 30 min of driving and it shot up :shrug:

I wonder if my thermostat is stuck
 
I agree. If it gets hot at speed, it's not an UD issue as much as a heat rejection or flow issue.

I dont know how spirited you were driving but higher RPM's can delay an unbalanced t-stat from opening by a little bit.

If it takes slowing down to cool down, is the little air deflector present (I think I recall you're having it but it doesnt hurt to ask).

I'd try a Mr Gasket (or other quality perf stat - Robert Shaw, Moroso, et al are all good) 180* stat, like you mentioned. It'll give you a little extra buffer.


Good luck.


EDIT: Did it run hot while at speed, or only when you revved it up in the parking lot after the romp?
 
HISSIN50 said:
I agree. If it gets hot at speed, it's not an UD issue as much as a heat rejection or flow issue.

I dont know how spirited you were driving but higher RPM's can delay an unbalanced t-stat from opening by a little bit.

If it takes slowing down to cool down, is the little air deflector present (I think I recall you're having it but it doesnt hurt to ask).

I'd try a Mr Gasket (or other quality perf stat - Robert Shaw, Moroso, et al are all good) 180* stat, like you mentioned. It'll give you a little extra buffer.


Good luck.


EDIT: Did it run hot while at speed, or only when you revved it up in the parking lot after the romp?

It jumped when I romped on it in a parking lot, it stayed roughly 210 until I did that which is still a little warm for me, I like Stangs that run a constant 180-200. It wouldn't cool back down either, it just hanged there. I've never seen a car that doesn't fluctuate- it just hangs at the highest temperature. I think it has a 180 in it, but I've seen the red coolant (dexcrap) corode the thermostat and heater core before, so this car is probably no different.
 
Your right on about the DexCool stuff being really bad. You should really make sure the radiator is free and clear of any buildup that stuff might have caused prior to your saving it.

I know you know, but I'll ask for the sake of asking: Your readings are taken from an aftermarket gauge correct?
 
Pulled the thermostat out, it was a 180 already, and to make matters worse, it looked great. Didn't get to test drive the car though so I'll do that tonight :(

I did notice that there's a hard whitish-green shell type substance growing on the "racks" or "runner ends" of my radiator. Basically all down the length of what you can see from pulling the radiator cap off
 
You did a good flush I assume? Try some water wetter also. Have you done a 3G swap, how's the voltage on the system? Maybe you have some air in the system left?

Just throwing ideas at ya.
 
Just because the thermostat looked good doesn't mean it was ok. You can test it by putting it into water on the stove and use something like a candy thermometer to check the temp it opens at. Bring it up to temp slowly and see if it opens completely before it gets to 190. If it doesn't throw in a quality new one (robertshaw, factory etc.)
 
Boss 351 said:
You did a good flush I assume? Try some water wetter also. Have you done a 3G swap, how's the voltage on the system? Maybe you have some air in the system left?

Just throwing ideas at ya.

I went to Express to get the flush done by machine, as they work better and I wanted no trace of the dexcool left.

No 3G swap, I need to though.

I will try some water wetter, and I'll check for air in the system. My friend bleeds air out from the heater hoses or somewhere in that area, so I'll call him and find out how he does that :nice:


RaceDvr50 said:
Just because the thermostat looked good doesn't mean it was ok. You can test it by putting it into water on the stove and use something like a candy thermometer to check the temp it opens at. Bring it up to temp slowly and see if it opens completely before it gets to 190. If it doesn't throw in a quality new one (robertshaw, factory etc.)

True, and I swear, I thought I heard it "pop" open 2 days ago about 200 deg, so I did change it out. Just couldn't drive it last night to test it. It's been in there some 5-6 years but looks immaculate
 
I like to see mine run around 180* too. Sounds like it might be air in the system, you could try parking on a big hill, open the radiator, and start it, and see if it sucks the radiator dry, and then refill it to see if that works. Just throwing it out there. I'm fighting to keep mine around 180. Mine creeps up to 200 when I'm in stop and go traffic and at idle. I'm going to go to an electric fan soon, just trying to pick which one. I swapped to a Mr. Gasket 180 high flow, and it did make a difference for the better. Good luck, keep us informed....
 
Strype to bleed the air from your system correctly:

With the car cooled all the way down:

pop the radiator cap off and set it aside
start the car (with the cap still off) and turn on your heater
look at the level after you just started the car, refill if the level of coolant drops
let the car idle in the driveway for at least 10 minutes (possibly longer) until you reach operating temp.
At this point the thermostat should open
if the level of coolant drops again, add more
let the car run for a few more minutes (5 minutes possibly) to verify that there is no more fluid drop
add some to the overflow bottle and there should be no more air in your system

*note* some people prefer that the radiator cap is the highest point in the entire system to help get the trapped air out. I have never had to use a ramp or jacks, but it is worth noting because some people swear by this step.
 
daddystang said:
I like to see mine run around 180* too. Sounds like it might be air in the system, you could try parking on a big hill, open the radiator, and start it, and see if it sucks the radiator dry, and then refill it to see if that works. Just throwing it out there. I'm fighting to keep mine around 180. Mine creeps up to 200 when I'm in stop and go traffic and at idle. I'm going to go to an electric fan soon, just trying to pick which one. I swapped to a Mr. Gasket 180 high flow, and it did make a difference for the better. Good luck, keep us informed....

Yea- I'm the same way. I'd be happy a 200 though... I'm hoping it's just air


srothfuss said:
Strype to bleed the air from your system correctly:

With the car cooled all the way down:

pop the radiator cap off and set it aside
start the car (with the cap still off) and turn on your heater
look at the level after you just started the car, refill if the level of coolant drops
let the car idle in the driveway for at least 10 minutes (possibly longer) until you reach operating temp.
At this point the thermostat should open
if the level of coolant drops again, add more
let the car run for a few more minutes (5 minutes possibly) to verify that there is no more fluid drop
add some to the overflow bottle and there should be no more air in your system

*note* some people prefer that the radiator cap is the highest point in the entire system to help get the trapped air out. I have never had to use a ramp or jacks, but it is worth noting because some people swear by this step.


That sounds easy enough :shrug:

I'll do that when I get home from this horrible place :nice:
 
Also umm... I don't know if it was mentionned but does your radiator cap hold pressure? If the cap is old and crappy it won't hold pressure and will allow the water to boil early and warm up the engine faster?
 
Boss 351 said:
Also umm... I don't know if it was mentionned but does your radiator cap hold pressure? If the cap is old and crappy it won't hold pressure and will allow the water to boil early and warm up the engine faster?


Good point, I've had a run with pressure caps in the last three years I swear I've replaced half a dozen of them so I test every car I look at lately.
 
Boss 351 said:
Also umm... I don't know if it was mentionned but does your radiator cap hold pressure? If the cap is old and crappy it won't hold pressure and will allow the water to boil early and warm up the engine faster?

I replaced it too :nice:

Still haven't tested the car- been too busy. Knocked the dang thang outta timing yesterday putting the drivers side bolt into the thermostat housing :rlaugh:
 
Tested car... still rises a little above 210 after 20-30 minutes of driving :(

Radiator? Water Pump? MyBad70 said it didn't look like it was turning enough water... I think he's right my 86 turned a lot more than this one does.

Who makes a good cheap water pump :shrug:
 
Um i think it's your under drive's. Did you get the race or street one? They have been known to make a car run hotter then normal, because the water pump dont turn as fast. You could always get an electric water pump. i think the brand is CER? or something like that? It runs around $400 but is worth every penny! I dont have one but when i do the 408 i will! Kinda a dumb question but are you sure the thermostat is working on the fan properly or that the fan is even comming on? What kind of fan are you using? peace




john:p