Running HOT HOT HOT, help me out

[Andres2882]

Hey guys, just got done with my marathon of car labor today. Problem is, car is running hotter than ever before. Someone help me out.

Install aluminum Ron Davis Radiator and Twin Flex-lite fans. Put in new 180* thermostat and bypass the heater core cuz mine blew.

Car now runs at the N of Normal on the stock temp gauge and I know its hot cuz hot mist comes out of the radiator cap, obviously not ideal. So can someone tell me, what's the deal? Would bypassing the heater core do it? I put a U-shaped hose in on the two pipes that normally lead to the pipes in the firewall. Also put in a new high flow water pump. Someone help!

 

[5spd GT]

Burp the system (squeeze the upper radiator hose for a few minutes) with radiator cap off...while car is running and do it when it is cold...then turn off car put on cap and see what happens...

Make sure you installed the t-stat correctly...spring facing towards the lower intake...

You may have to much coolant/water in the system...

Make sure your radiator cap is good still...

 

[2muchtime]

whats the pressure rating on the cap
and i have never trusted those NORMAL guages install one that gives you numbers. especially after spending all that money on a cooling system.

 

[Andres2882]

Hey guys, thanks for the quick replies, I'm using the stock radiator cap on the new radiator cuz it didn't come with one of its own.

Can anyone tell me if bypassing the heater core might be to blame? I used a smaller hose to bypass and was wondering if that would have anything to do with it?

 

[2muchtime]

Hey guys, thanks for the quick replies, I'm using the stock radiator cap on the new radiator cuz it didn't come with one of its own.

Can anyone tell me if bypassing the heater core might be to blame? I used a smaller hose to bypass and was wondering if that would have anything to do with it?

call the manufacturer you got the radiator from and find out the cap pressure
recomended

 

[Andres2882]

Would a radiator cap cause me to run so hot?

 

[HISSIN50]

Would a radiator cap cause me to run so hot?

the pressure in the system is crucial for proper operation. water boils at 212*F (IIRC). pressurize the water to 15 psi, and it wont boil for another 40-50* or so. it is very important, IMHO. those temp ranges are right in the sweet spot of normal operation and make a difference (pressure is much more important, IMHO, than coolant).

good luck.

 

[UMDSmith]

bypassing the heater core really won't cause a huge deal. It acts like a 2nd mini radiator in a sense, allowing only a TINY amount of heat dissapation. It may change the pressure a little bit as the system now has a bit less volume overall, but once again, I don't think the heater core has squat to do with your problem.

 

[Andres2882]

Alrighty, here's the scoop. I started the car up with the radiator cap off and squeezed the upper radiator hose on and off till it got hot.

In addition, the coolant level in the radiator was about 2-3 inches from the top of cap when I opened it up. It dropped when the hose got warm, which would lead me to believe that the therm is acting correctly.

From that point I just let the car idle with both my fans on. The temperature was still climbing, but very slowly. I'm going to pick up another radiator cap to be safe, and then I'll take it on a little road test.

Should I fill the radiator to the top of where the cap goes in the meantime? What's the next step.

BTW, hate to revisit the heater core scenario, but the u-hose I used to bypass has a slight crimp in it caused by the shape I bent it in. For any reason could that make me run hot? Last time I ask, I promise.

 

[5spd GT]

Andres2882 - There is no problem with asking about the heater core bypass question...I don't know nothing about it though...maybe somebody else will chime in...

I use a 16psi radiator cap...just get one that is around 14-16 and you should be fine...

Does the car run hot when you driving it (highway speeds)...if it does there to...or I guess just at idle?

Try a new radiator cap...it shouldn't be spewing fluid out if you have it tightened down correctly...you know the radiator cap makes "two turns"...to lock don't you...

Even though the guages aren't the most accurate they are usally fairly close if they haven't been messed with...

 

[bmorrisj]

keep filling with water/coolant until the system is full and stops burping, you could just have an air pocket.....just happened to me, my temps would coast to 220* then drop right back down to 185*

 

[TheUser]

keep filling with water/coolant until the system is full and stops burping, you could just have an air pocket.....just happened to me, my temps would coast to 220* then drop right back down to 185*

yep...if it's overheating at idle then it's probably low coolant. When it fills the block and drops in the radiator, you want to fill the radiator back up like bmorris said. Also, go drive it, bring it home, let it cool down and check coolant level...you may have to do this a few times until it stays full.

As far as the heater hose...if it's a normal straight piece of hose that you bent and it's keeping coolant from circulating, then that might be a problem. Try to find a piece of hose that's already in a half-circle shape if possible - that's what I would do anyway.

 

[Andres2882]

Good news all, after burping the system for a bit and going to town on my radiator cap, my temperature seems to have leveled off. I drove to work today in the car and my stock temp gauge never rose above the middle line (thinking 200ish degrees?)

Even when I was hitting WOT no real rises. Still, does seem to be running a little hotter than I'd like, going to work on that heater hose on Monday with a better suited one. Thinking about dropping a 160* therm back in as well to keep it a little cooler. Any ideas about that?

Anyway, thanks for all the advice you save me a hell of alot of time and probably some cash too

 

[HISSIN50]

before swapping stats, i would really recommend a real gauge. otherwise you are guessing. a properly functioning cooling system can run a stock stat and not overheat.
now in the real world, we often dont get to renew everything to new condition. but with a real gauge you will know where you are running exactly, to better determine what stat to try. BTW, what part of the country are you in (temp wise)?
good luck.

 

[Andres2882]

Yeah, I plan to order my gauges today. I live in Florida btw.

 

[HISSIN50]

Yeah, I plan to order my gauges today. I live in Florida btw.

sounds good. in those temps, it would be real nice to know what is going on while idling in traffic.
my stock gauge does not move between 180 and 210 (per my other gauge). that is a pretty large difference, to me. nice to know exactly where i am at.

good luck.

 

[malik641]

Bypassing the heater core doesnt do anything wrong with your car. The only problem youll run into is having too much air in your system, which is typical when hoses are changed/busts etc. The major indicator to tell if you have air in your system is if the temp rises dramatically and then quickly drops after a few minutes...ive run into this problem before. If your motor stays consistantly hot...check for a pinched hose...you never know where you might find one.

 

[gt90stang]

Don't worry about bypassing the heater core. I tried running the output of the heater directly into the upper radiator hose and all it did was make it take longer for the motor to warm up, but eventually it would still get as hot as it would before the change. I also put a restrictor in the bypass and it did the same thing but didn't affect the overall final temps.

What CFM are those twin fans? My Lincoln Mark VIII fan is barely adequate for my 306 with AC running in 110*F ambient because the coolant out of the motor gets to 225*F. The AC adds about 45-50*F on top of ambient before it gets to the radiator, so it doesn't have much to work with. My FMS 2 core aluminum radiator only drops the coolant 10-12*F under the 110*F ambient conditions. I'm running a 195*F stat and with AC it can only hold the temps below 202*F up to 86*F ambient and then it increases about 0.9*F per degree ambient. I need more CFM (doesn't exist), better radiator (FMS is pretty huge) or turn of the AC (no way).

Good Luck, Don

 

[Andres2882]

I was told by the person who had run it before me that the fans pushed 3700 CFM and the setup had worked like a charm on his car up to 650rwhp.

 

[gt90stang]

Andres2882,

That should be plenty of airflow, especially with cast iron heads. If it still wants to run warm after you get the system burped make sure you have the air diverter that goes under the radiator support. Then look into sealing air paths back around the radiator from the engine compartment, this was costing me 15-20*F in cooling capability.

Good luck, Don