Overheating!! - Page 2

Tom Wells · #16 (**permalink**) 09-06-2010, 05:18 PM

Mike,

The back of the gauge is likely not easily accessible being behind the dash panel so the sending unit is where I'd begin.

The temp sender is toward the front of the intake manifold, if it's similar to mine - I have an Edelbrock Torker II - yours may be different.

Anyway, mine is just behind the thermostat housing, a little bit to the passenger side rear of the distributor.

Put a lead from the voltmeter there, ground the other one and watch it and the gauge while you increase the engine speed if the cables are long enough. Get a volunteer to watch one or the other if need be. I don't think the car needs to move, just the engine speed would need to be increased to say 2500 rpm.

If the voltmeter and the gauge are both steady from idle to 2500, then that would seem to rule out the sender and the gauge.

Caution: I haven't actually tried this - it does seem logical...

Tom

PS: The infrared temp measurement does sound like the way to go.

HighPlainsDrifter · #17 (**permalink**) 09-06-2010, 05:57 PM

Hi,
I had a 460 for 12 years so I know how hot they get.

1- take a small 4" x 4" piece of paper and put it infront of rad while fans are ON. if it sticks to the rad you have them correct, if it doesn't then the fans are blowing the wrong way ! rewire them.

2- You can NEVER burp the rad properly. The only way to do it is to put a T fitting (from a prestone rad backflush kit) in the TOP line of the heater line from the intake manifold.Open it and fill the water until it runs out, now all the air is out.

Good luck,
Perry.

kitcarbp · #18 (**permalink**) 09-08-2010, 07:19 PM

OK the info you provide here if accurate is important. you stated:

Regarding overheating, it will go up to 225+ shortly after I get on the road and will vary between 200 and 240. If I come to a stop with it idling (after running hard) the temp will drop very quickly to 190-200. As I said before, the fans come on at 195. If I cruise about 35 down the street, it will go down to 200 and mostly stay there. If I hit it hard off the line, it will jump to 200-230 and then come down when I stop again.

I would first install another gauge and sender (mechanical one is cheap and quick) to verify it behaves the same way and that you dont have a fault with gauge, sender or the wiring. The fact that your temp drops when your engine speed and road speed (less air flow) drops is opposite as to what should happen (until the fans kick-on).
If the new gauge confirms temps are still erratic, air in the system is likely for this fluctuation. I sent you the changes I made to my WCC 460 system to make it easier for air to exit during system fill. The changes I made eliminates the "ritualistic and repeated burping" you will need to do over and over as others have experienced.

BTW assuming the fans are wired correctly to pull, is your alternator and wiring for your new twin fans up to the task ? you did not share any info on this. Twin fans will use alot of current. Make sure they are operating with the required current to get the proper cfms. You will need dedicated heavy duty relays to run the fans when the FAST system triggers these relays.

Mohuska · #19 (**permalink**) 09-08-2010, 07:50 PM

Bill,

Checked out the plumbing today after talking to you. The hose that comes out of the bottom of the surge tank actually goes to a fitting in the top of the radiator on the low pressure side.

I am going to remove the hose that now goes from the T-stat to the surge tank and plug the fitting in the surge tank. I should then have only ONE hose from the bottom of the surge tank to the top of the radiator and the radiator cap overflow hose to the bottom of the overflow tank.

We ordered the GM bleeder valve and it will be here next Monday. We'll then bleed the air and hopefully all will be much better. I will check temps with my infrared and see then what the gauge reads. If in doubt, I will replace the gauge and we'll go from there.

I will keep you posted. Thanks for all your help.

Mike

mdross1 · #20 (**permalink**) 09-09-2010, 10:54 AM

Assuming you have enough cooling capacity,you have some great advice to work with.My 460 high effeciency radiator made of copper was sized by a 30 yr veteran in the radiator business.At first made me nervous until system was completely burped of air.It goes to 190 degrees quite fast then stays there.On hot days and in traffic the fan runs contantly,only shuts off when cruising for a while no load.

kitcarbp · #21 (**permalink**) 09-10-2010, 12:39 PM

Food for thought.
If your surge tank has the 5/8 or 3/4 "fill line" entering into the top of the low pressure side rad tank, its still not as good as it being connected to the bottom of the low pres. side tank or "Tee'd" into the suction (low pressure) hose leading to the water pump.

Why ? As you fill the system via the chrome surge tank where pressure cap is, in your configuration, the coolant will enter into the top of the low side tank and as it fills the rad core tubes will trap some air making it more timing consuming to burp the system after a few heat cycles. Not impossible, just more troublesome.

If the "fill line" is connected to the bottom of the low pres side tank or lower rad hose, during filling, the liquid will travel into engine block (via lower rad hose) and into rad and then force the air up and out from the bottom of rad core upward (via the small air bleed line at top of low side tank on my set-up). likewise as coolant travels into the engine block from the bottom, it forces the air up and out of the therm housing bleed valve.

Ahh the fun of custom cooling systems !

Mohuska · #22 (**permalink**) 09-10-2010, 01:58 PM

Bill,

That makes complete sense. I will look into that. Do you know of anyone who sells the bottom hose "T" fittings that aren't plastic??

Thanks.

mdross1 · #23 (**permalink**) 09-14-2010, 03:13 AM

One thing forgot to mention is sealing around radiator so with hood closed all air has to go through radiator not around it.Very important! also fan shrouding is second most important issue.Again, assuming you have the cooling capacity the motor requires.

kitcarbp · #24 (**permalink**) 09-14-2010, 07:40 PM

Eldon James is one company that supplies automotive grade glass filled nylon fittings but dont seem to make them in 1.75" sizes. I dont know of a supplier but there must be some out there for metal "T"s as well. I purchased my lower GF Nylon lower rad hose "T" from Advance Auto by looking at their inventory of lower hoses on the wall, but I dont remember the application. It has a 1" nipple for the FILL LINE from my chrome surge tank.

Mohuska · #25 (**permalink**) 09-29-2010, 09:06 PM

Well after many hours of thought and an equal number of hours of pulling things apart, I no longer have an overheating problem.

The source of my angst was a combination of a faulty temp sender (not the primary issue) and some significant air bubbles in the system.

I made some minor plumbing corrections (thanks Bill) and put a GM coolant bleeder valve in the top of the thermostat housing. After 4 sessions of burping, bleeding and filling, no more air!! What a PITA!

I ran my car hard this week when the outside temp was 104-106 and the car stayed at a comfortable 190-200 all the time. I tested several areas with the laser thermometer and everything was cool.

Thanks to everyone with their great ideas. I really appreciate it

Mike

Tom Wells · #26 (**permalink**) 09-30-2010, 04:09 AM

Mike,

YEEEEEEHAAAAAA!

Tom

kitcarbp · #27 (**permalink**) 10-02-2010, 02:54 PM

Glad to hear you fixed it, I also fixed my annoying therm. housing leak today by finding an OEM FORD therm housing off of a 429 which is properly designed and wont warp like all the after market ones I have tried.

Tom Wells · #28 (**permalink**) 10-02-2010, 05:14 PM

kitcarbp,

Glad to hear it! Sounds like everyone is being successful at solving problems. Now for some cruising!

Tom

Mohuska · #29 (**permalink**) 10-02-2010, 07:12 PM

Bill,

Found a stock one..good..Yeah the aftermarket foreign cr@p causes lots of folks much angst..... Glad to hear you got it straightened out. When are you going to be on the road?

Mike

Xack · #30 (**permalink**) 11-26-2010, 08:16 PM

The filler tank on this car is below the top of the water neck when the car is level. The elaborate hoses are supposed to push out the air, but the fill tank must be higher than the water neck. You need to jack up the front of the car in order to fill the radiator and remove the air.

I'm looking to get a Meziere water fill neck to fill at the engines highest point. I'll use a slightly higher pressure cap at the neck filler. I may redesign the resevoir system and incorporate an air bleed valve.

I found that the radiator I recieved from WCC had a fan that was mounted backwards. it was a push type mounted as a pull. While it did pull running backwards, flow was only around the outside of the fan and roughly 1/3. I had to reverse the blades in order for it to work as the fan was designed. I just replaced the fan with an "S" blade design. This is much better.

Xack